Conditioned reflex activity.
Physiological basis of human bechaviour.
Physiology of work
Conditioned reflex activity
Common characteristic of reflector theory
Conception about higher and lower nervous activity.
§ The lower nervous activity is directed to regulation of body functions and organ systems, unification them to entire organism. The lower nervous activity is performed due to congenital forms of behavior. The congenital forms are unconditioned reflexes, instincts; biological motivations and emotions.
§ At the adult person the lower nervous activity usually is not arises separately from other forms of behavior. Life training and purchase of acquiring experience results in specification and modification of congenital forms of behavior due to the conditioned-reflex mechanism.
Determination of notion “conditioned reflexes”.
§ Conditioned reflexes are individually acquired system of adaptive reactions of the person and animals. It arises on the basis of formation in the central nervous system of temporary communication between centers, some of which percept new irritant and other control some unconditioned reflex. Thus, new irritant form an environment becomes conditional irritant. It warns person about approach of the subsequent kinds of activity and prepares him for future kinds of activity (eating, avoidance of danger and another).
§ With the help of the conditioned-reflex mechanism such function of nervous system as purposeful behavior of the person in an environment and society, the adaptation to varied conditions of an environment are carried out. Such activity of nervous system concerns to the higher nervous activity.
Differences of conditioned and unconditioned reflexes
|
Property |
Unconditioned reflexes |
Conditioned reflexes |
|
Irritant |
Direct adequate irritant |
Direct irritants and their traces |
|
Receptive field |
Is precisely determined |
Is not present a certain receptive field |
|
Formation and reaction |
Under the genetic program |
On action of special conditions of the external and internal environment |
|
Terms of occurrence of a reflex |
After birth, in process of maturing nervous and endocrine system |
Precisely are not determined |
|
The central part of a reflex arch |
The spinal cord, a brain stem, cortical representation of an unconditioned reflex |
The brain cortex and subcortical nucleus |
|
Specific specificity |
Is expressed |
Not expressed |
|
Physiological importance |
Provide a survival of a species |
Provide behavior and the higher nervous activity |
Classification of conditioned reflexes
1. Classical conditioned reflexes – are formed in natural conditions.
2. Tool conditioned reflexes – are developed artificially. More often they represent purposeful motor reactions. As supporting stimulus for their development the unconditioned reflex causing in a laboratory animal feeling of pleasure (effect of “award”) or painful irritant, causing avoidance reaction usually serves.
II. Under the relation of conditional irritant to unconditional:
1. Natural conditioned reflexes – conditional irritant it is related to an unconditioned reflex. For example, a smell and how a food looks have the direct relation to irritation by food of tongue receptors, which starts unconditional salivatory discharge reaction.
2. Artificial conditioned reflexes – conditional irritant has no the direct relation to an unconditioned reflex which serves as a reinforcement. For example, the bell or a light signal iatural conditions have no the relation to unconditional salivatory discharge reflex.
III. On biological importance:
1. Food conditioned reflexes – provide getting food and digestion.
2. Sexual conditioned reflexes – provide sexual behavior.
3. Protective conditioned reflexes – provide defensive reactions.
4. Statokinetic conditioned reflexes – provide motor behavioral reactions and impellent skills.
5. Homeostatic conditioned reflexes – are directed on maintenance of a constancy of the inner environment of an organism.
III. On a degree of complexity:
1. Conditioned reflexes of the first order – the conditioned reflex is developed on the basis of a unconditioned reflex.
2. Conditioned reflexes of the second order – the conditioned reflex is developed on the basis of other conditioned reflex of the first order.
3. Conditioned reflexes of the third order – the conditioned reflex is developed on the basis of a conditioned reflex of the second order.
4. Conditioned reflexes of the higher order – are formed only at the high organization of nervous system. In human formation of conditioned reflexes of the second – twentieth order is probably.
Regularity of forming and manifestation of conditioned reflexes
Signals of conditioned reflexes.
For development of a conditioned reflex it is necessary, that any factor of an environment, which may be perceived by one of analyzer systems of an organism, occur repeatedly and acted on an organism of the person or an animal. If at each occurrence this irritant outstrips a little or takes place simultaneously with performance of any unconditioned reflex in an organism, probability of development of a conditioned reflex very high. But for formation of a conditioned reflex still it is necessary, that the brain cortex be in an active, awake condition.
For development of a conditioned reflex the important value has optimum force of irritant, which may become conditional irritant. Small force irritant does not cause a sufficient level of activity in neurons of appropriate analyzer system. In this case the conditioned reflex is formed slowly. Such conditioned reflex exists the short period of time and then is fast inhibited.
In real conditions irritants from the environment do not occur as isolated factor. There are a set of similar irritants and such irritants, which operate simultaneously
Condition of forming of conditioned reflexes.
Dominanta (from Latin dominare – to dominate) – is the centers of excitation prevailing in the central nervous system, which change and subordinate to themselves activity of other nervous centers at present. The principle of a dominant is one of main principles of activity of the central nervous system. The Russian scientist O.O. Ukhtomsky was formulated these principles.
The prepotent centre of excitation is characterized by such properties:
1) Increase of excitability;
2) Stability of excitation;
3) Ability to summarize excitation – to accumulation of excitation from stranger irritants;
4) Ability to inhibit function of other nervous centers and reflex reactions;
5) Ability long time to keep excitation after the termination (ending) of irritation, which has caused it (inertia of a dominant).
Mechanisms of forming of conditioned reflexes
The structural basis of the higher nervous activity is brain cortex and the nearest subcortical centers. At formation of behavior in the central nervous system on some time are formed neuronal circuits of a different degree of complexity. In the environment all the time new irritants occur. Therefore in a brain cortex at each moment of time new combinations of neurons are activated.
Thus, in the brain cortex and the subcortical centers there is a mosaic and dynamics of excitation and braking, due to performance of the higher nervous activity. Such interactions betweeeurons give basis of thinking, emotions and behavior of the person.
The opportunity spreading excitation in the central nervous system is caused by presence in it of numerous branches of shoots of nervous cells – axons and dendrites. Shoots connect neurons and the nervous centers in a uniform network. Strengthening of irritatioeurons stimulates distribution of excitation oervous circuits. Due to existence of such communications excitation long time may circulate on closed neuronal to circuits, till opportunities of synapses to transfer impulses will be exhausted or there will be a braking process in any of neurons, so the circuit will be opened.
The centre of excitation, which arises in a brain cortex under action of conditional stimulus may be spread oeuronal circuits in all directions. But if simultaneously in an organism the unconditioned reflex is carried out, in a zone of cortical representations of this reflex the prepotent centre varying a direction spreading of excitation develops. In such a case distribution of the excitation caused by a conditional irritant, will be directed aside dominants.
It agrees when giving experimental researches, two neuron classes take part in formation of conditioned reflexes: command neurons which realize specific behavioral acts and modulating neurons, which adjust a condition of command neurons. Before the first appearance of stimulus and supporting reflex neurons were mainly monotouch. In process of the further development of a conditioned reflex neurons get ability to answer different stimulus, that is become polytouch. After the conditioned reflex is produced, again it is observed selective reaction of neurons – they answer only stimulus, which became conditional irritant.
The synaptic hypothesis considers that the mechanism of formation of a conditioned reflex is caused by change of an overall performance of synapses.
The membrane hypothesis asserts that in a basis of the mechanism of formation of a conditioned reflex change of excitability of postsyneptic membrane lays.
Characteristic of unconditional inhibition
Conception of inhibition
Formation of conditioned reflexes is not possible without process of inhibition in the central nervous system.
Braking of spreading impulses is provided with various mechanisms and results thus in various effects. I.P.Pavlov classified braking processes in the brain cortex as two groups: external (unconditional) and internal (conditional).
External inhibition.
The rough reflex causes unconditional braking because it protects an organism from new unknown influences of an environment, which possibly may cause damaging or to warn of danger. At repeated occurrence of new irritant, which was no dangerous, its braking effect decreases. Such brake irritants refer to as time or dying away. There are also constant brake irritants, which keep brake effect long time. Pathological processes (for example inflammatory processes) or strong irritation of proprioreceptors (for example, overflow of a urine bladder, a rectum) often have such a value.
One more kind of external braking is security braking. It arises at action of very strong irritants or very long influence of usual force irritants.
Physiological meaning of unconditional inhibition is protective
Physiological importance of external braking, according to I.P.Pavlov, is protection of cells of a brain cortex against a functional exhaustion that may be caused by superfluous irritation. External braking promotes restoration of metabolic reserves and function of nervous cells if they were exhausted by superfluous activity before.
Characteristic of conditional inhibition
This is specific process, which is characteristic for cerebral cortex. It demands special conditions and training. The basic condition of development of internal braking is absence of unconditional reinforcement after action of conditional irritant when the reflex is already produced and functions.
Regular repeated action of conditional irritant without a reinforcement of it by unconditioned reflex results in gradual easing a conditioned reflex, and so to its disappearance, fading away. Such kind of braking refers as fading away.
Thanking to fading away braiking the brain is released from the information which under the present conditions has lost the value.
Differential braking develops, if one of two conditional irritants is always supported with an unconditioned reflex, and another – is not. In this case the conditioned reflex on supported irritant is kept. Another conditional irritant, which is not supported, every time causes a conditioned reflex worse while it will not disappear absolutely.
Differential braking allows specialization of conditioned reflex and is a basis of the adequate analysis of subjects and the phenomena of an environment, and also changes in the inner environment of an organism.
One of versions of differential braking – a conditional brake. If to add new irritant to conditional irritant and to repeat this combination many times without any reinforcement, new irritant brake conditioned reflex produced earlier. In this case conditional irritant loses the alarm action, and inhibition of conditioned reflex occurs.
Conditional brake permits constantly specify character of conditional reflex reactions for concrete irritants from an environment.
When the time interval between action of conditional and unconditional irritant is increased, the conditioned reflex appears with delay. In performance of a late reflex distinguish two phases – inactive, when reactions on conditional irritant is not present, and active, when there is a reflex reaction. Late braking helps to regulate work of internal visceral organs (for example, regulation secretion of the stomach after meal), develop skill to wait and to keep energy in case of strong irritation.
Braking in brain cortex is carried out by braking neurons. Most likely, this function is performed by star cells. It is established, that on the mechanism of braking in a brain cortex is caused by postsynaptic hyperpolarizing. It is caused basically by change of permeability of Cl- channels of postsynaptic membrane. The basic neurotransmitter in braking neurons is gamma-aminobatteric acid.
Stages of coditioned reflex activity
|
Mechanisms |
Conditions |
Stages |
|
Formation of temporary communications in a brain cortex and the subcortical centres (dominant) |
Indifferent irritant outstrips unconditioned reflex or synchronize it. An awaking condition of a brain cortex, free from other kinds of activity. Sufficient force of indifferent irritant. Proper repetition of all these conditions.
|
Stage of generalization of a conditioned reflex |
|
Differential braking |
Recurrence of conditions, recurrence of concrete irritant action. |
Stage of specialization of a conditioned reflex |
|
Security braking. A conditional brake. Late braking.
|
Recurrence of action of conditioned irritant without unconditional reinforcement. Backlog in time of an unconditional reinforcement from conditional irritant.
|
Inhibition of the conditioned reflex
|
Age peculiarities of inhibition. Braking of conditioned reflexes is possible since the first days of life of the child, basically with the help of external braking. At children of the first year of life both external and internal braking easily arises. Long action of irritant can brakes even rough reaction. Immaturity of the brain cortex neurons iewborn children causes fast development of braking process.
Conditional braking in the first years of life of the child is advanced very poorly. The force of all kinds of internal braking and speed of braking of conditioned reflexes increased with age. Children till 4 years of life distinguish irritants according to one attribute – color or shape usually. Integrative functions of the brain develop quickly. 5-6 year children already differentiate irritants according to 2-4 attributes. Ability to allocate the basic essential component among set of irritants develops later – by 10-17 years. In old age internal braking is disturbed, that decreases workability of a person. Ability to security braking raises with aging, the excitation and braking ratio in the central nervous system is broken.
Coordination of functions in a brain cortex. All kinds of activity of the person are based on coordination of functions in a brain cortex due to processes of excitation and braking. In a healthy organism processes of excitation and braking in the central nervous system are in dynamic balance.
Processes of excitation and braking in the central nervous system are in complex cooperation and influence to each other. I.P.Pavlov has established such laws of excitation and braking interaction. Excitation arising in any centre inhibits other centres. Concentration promotes processes of differentiation and an induction. Around of the centre of excitation there are centres of braking, and around of the centres of braking – the centres of excitation. I.P.Pavlov has named it as cortical mosaic. But cells of the brain all time pass from exciting condition in braking and on the contrary. This phenomenon is named dynamics of excitation and braking in a brain cortex.
Studying of excitation and braking processes in cerebral cortex has grate importance for understanding of medical psychology. By the subsequent researches in laboratory and clinic both it was shown, that overstrain of excitation and braking processes results in infringements of the higher nervous activity. This underlies neurosis and other disorders.
Creation of conditioned-unconditioned pupillary reflex to sound stimulation
All the students take part in creation of conditioned reflex. Experimentator gives stimulation by sound. Just after this examinees close right eyes by palm, which removes light stimulation, and so causes dilation of pupil. After removing of sound stimulation, examinees open right eyes. Repeat all these conditions 13-15 times. After this observe one to each other dilation of pupil after the sound.
Draw schematically mechanism of creation of conditioned reflex. Note in conclusion, what conditions are necessary for creation of conditioned reflex.
Inhibition of conditioned-unconditioned pupillary reflex to sound stimulation
All the students take part in inhibition of conditioned reflex. Experimentator gives stimulation by sound. Just after this nobody close right eyes by palm, which gives light stimulation, and so removes unconditional support for the reflex. Repeat all these conditions 13-15 times. After this observe one to each other absence of dilation of pupil after the sound.
Draw schematically mechanism of inhibition of conditioned reflex. Note in conclusion, what kind of inhibition have you observe.
The Pavlov’s Dog game and related reading are based on some of the scientific achievements of Ivan Pavlov, who was awarded the 1904 Nobel Prize in Physiology or Medicine. Even though the first image that comes to mind with Ivan Pavlov is his drooling dogs, he was awarded the Nobel Prize for his pioneering studies of how the digestive system works.
In this game, you will find out if you can train a dog to drool on command – an example of a conditioned reflex. Ivan Pavlov’s description of how animals (and humans) can be trained to respond in a certain way to a particular stimulus, paved the way for a new and objective method of studying animal and human behaviour.
The object of the game is to train Pavlov’s dog to respond to a signal that it will associate with being fed. Choose the right signals with his food and you will successful; choose the wrong options and the dog will refuse to respond to your signals.
For instructions on how to play the game, click on the HELP button found at the bottom of the game window.
Read “Ivan Petrovich Pavlov (1849-1936)” »
Physiological bases of sleep
From 1916 to the mid-1920s, an epidemic spread throughout Europe and
Activation of sleep-promoting pathways eventually yields sleep. However, sleep is not homogenous. Rather, the brain cycles through a number of physiological states over the typical sleep period. Adult humans cycle through these states at a rate of 90 mins per cycle [20]. Cycles are shorter in human infants (approximately 45 mins) and small animals (e.g., 10 mins in rats) but are longer in larger animals (e.g., >100 mins in elephants).
In humans, healthy adult sleep typically begins in nonrapid eye movement (NREM) sleep. The earliest stage of NREM sleep, stage 1 (NREM-1), is evident by a transition from the wake-like alpha waves (8–13 Hz) to the theta waves (4–7 Hz), characteristic of early sleep. This transition is often referred to as the hypnogogic state.
Stage 2 of NREM (NREM-2) sleep follows and is characterized by the appearance of K-complexes and sleep spindles on a background of theta activity. K-complexes are composed of a brief negative sharp wave followed immediately by a positive inflection, taking place within .5 secs. They are generated broadly throughout the cortex and reflect a cortical downstate (i.e., neural inactivity). K-complexes can be induced by an auditory stimulus and thus are associated with sleep maintenance.
Along with K-complexes, NREM-2 is marked by sleep spindles. Sleep spindles are brief bursts (approximately .5 secs) of very high frequency waves (11–16 Hz). Like K-complexes, spindles have also been associated with sleep maintenance yet physiologically spindles and K-complexes are quite distinct. GABAergic activity in the reticular nucleus of the thalamus underlies the generation of sleep spindles which then spread to the thalamocortical system. Spindles may be uniform but emerging evidence suggests a distinction between “fast” and “slow” sleep spindles. Fast sleep spindles are 13–16 Hz in frequency and are associated with activation in the mesial frontal cortex, hippocampus, and sensorimotor processing areas (pre- and postcentral gyrus and supplementary motor area). Slow spindles have a frequency of 11–13 Hz and are associated with superior frontal gyrus activity.
While the majority of spindles are fast spindles and found in NREM-2, slow spindles are also found in stage 3 of NREM sleep, known more commonly as slow wave sleep (SWS). SWS is unique because, as the name implies, background EEG slows to .5–2 Hz, or delta waves. SWS spindles occur within slow oscillations. Slow oscillations, which are likely distinct from the visible delta waves, represent widespread alternation between depolarized “up-states” and hyperpolarized “down-states”.
Early in the night, for humans, SWS is followed by brief bouts of rapid eye movement (REM) sleep. REM bouts lengthen over the night as SWS is replaced by NREM-2. REM’s discovery is another noteworthy tale in the history of sleep research. Eugene Aserinsky, a graduate student under Nathanial Kleitman, devised a way to record eye movements during sleep with the intent to study blink rate at sleep onset. He attached the electrodes to the scalp and face of his 8-year-old son, Armond, an opportunistic research subject. Late in the night, Aserinsky observed wake-like EEG and eye movements on the record. Thinking his son had awoken, the father checked on his son only to find him fast asleep. This observation marked the discovery of REM sleep and what is claimed to be the birth of modern sleep science.
REM sleep is characterized by rapid ocular saccades and muscle atonia. EEG, with a frequency of 30–80 Hz, is almost indistinguishable from wake EEG [22]. This high level of brain activity is particularly evident in the thalamus, anterior cingulate cortex, parietal operculum, and amygdala and has been associated with the vivid and imaginative dreams that are typical in this sleep stage [33]. In contrast to this, dreams are unremarkable when awoken from NREM sleep, with dream reports often resembling explicit recent memories [34]. This is consistent with NREM brain activity in parahippocampal gyrus [3], an area of the brain associated with memory encoding.
The neurochemical amalgam also differs greatly between NREM and REM sleep. On the one hand, noradrenergic activity, although lower during sleep than wake, is greater during SWS than REM sleep. On the other hand, acetylcholine levels are low during SWS and high during REM, close to waking levels [36]. Acetylcholine has a known role in memory formation during waking and it has been proposed that high levels of acetylcholine suggest a memory function of REM sleep.
While this section provides only a brief review of the neuroanatomical and neurochemical states (for more detail see), the physiological potential for one or more cognitive processing steps to take place during sleep is nonetheless evident. Activity in the medial temporal lobe during SWS and in the amygdala and anterior cingulate cortex during REM sleep hints at this cognitive function. Moreover, these dramatic differences in brain activity across sleep stages along with neurochemical distinctions emphasize that sleep cannot be considered singly. Rather, specific neurophysiological events are likely to underlie specific changes in cognitive functions associated with sleep.
Sleep-Dependent Memory Consolidation
A pioneer of cognitive psychology, Hermann Ebbinghaus, is regarded for his experimental studies of memory. In
Interest in Ebbinghaus’s observation emerged very briefly in 1924 when John Jenkins and Karl Dallenbach at Cornell University deliberately compared “obliviscence” (i.e., forgetting) over sleep and wake intervals. In doing so, Jenkins and Dallenbach replicated Ebbinghaus, reporting reduced forgetting over sleep relative to wake. Specifically, participants recalled twice as many of the learned syllables following sleep as they did following wake.
In the past decade, a number of studies have replicated Ebbinghaus’s observation with more participants than Jenkins and Dallenbach (who had only two) and more scrupulous control conditions. Collectively, these studies support a role of sleep in memory consolidation. In its simplest form, sleep-dependent memory consolidation can be seen by studies examining the change in recall following an interval with sleep relative to an interval with wake. For instance, one may learn a list of semantically unrelated word pairs in the morning and recall them 12 hrs later (e.g., 8 am to 8 pm) following a daytime interval spent awake, or one might learn the list in the evening and recall the word pairs 12 hrs later following an interval primarily spent in overnight sleep (e.g., 8 pm to 8 am). Recall is superior in the latter condition, following an interval with sleep (e.g.,).
Of course, attention or other cognitive processes necessary to perform well on the task may be at their best in the morning and, as such, superior recall following sleep relative to wake may be a circadian, or time of day, effect. Ours and other studies have ruled out this alternative explanation. For instance, immediate recall (which takes place in the morning for the “wake group” and in the evening for the “sleep group”) does not differ for the two groups, suggesting that time-of-day does not alter performance on this task. Moreover, other studies have used a nap paradigm. By comparing recall on a similar task after a mid-day nap with recall following an equivalent mid-day interval spent awake, there is no circadian difference in the time of encoding or recall and yet the sleep benefit remains.
Similar benefits have been observed on a wide range of learning tasks. Consider a visuospatial learning task that requires learning the locations of specific items in a matrix, similar to the children’s game of “Memory” (also known as “Concentration”). Like word-pair learning, this task is considered to be largely hippocampus dependent, relying on the same spatial learning capabilities that make this structure enlarged in spatial experts like
Sleep’s role in memory consolidation is observed throughout development. Children with sleep disorders, such as sleep apnea, narcolepsy, and excessive daytime sleepiness, have impairments in memory and daytime function. Moreover, memory consolidation is greater over intervals with sleep compared to intervals with wake even at a young age. This has been seen in studies of adolescents and young children. For example, Wilhelm and colleagues found that children, 6–8 yrs of age, were able to recall more word pairs following an interval with sleep than after an equivalent interval of wake. This benefit of sleep was nearly equivalent for the 6–8 yr old children and young adults (average of 26 yrs). We have demonstrated that mid-day naps in preschool children (3–5 yrs) also serve a memory function. When children learn a matrix of locations in a visuospatial task in the morning, memory is superior in the afternoon following a mid-day nap compared to memory following an equivalent interval awake. This result suggests that mid-day sleep is equally important as overnight sleep at least at this young age.
Sleep-dependent memory consolidation is not unique to humans and, in fact, has been observed in a range of nonhuman models from the miniscule fruit fly (Drosophila) to our nearest neighbors, the great apes. Drosophila, which is an ideal model system due to their known genetic make-up and relatively simple nervous system, consolidate its memories over sleep. To demonstrate this, Donlea and colleagues modified Drosophila to express temperature-gated channels downstream from the dorsal fan-shaped body, an area associated with sleepiness in Drosophila. These flies received massed training on a courtship protocol, a probe of long-term learning that takes advantage of the fact that male flies who unsuccessfully court female flies will subsequently reduce courtship attempts with receptive virgin female flies. Following training, the temperature-gated channels were activated through a temperature change, thereby inducing sleep. After sleep, long-term memory for the training experience (i.e., reduced courtship) was present whereas no such memory for the courtship training was evident when sleep was not induced.
Sleep also benefits bird song learning and discrimination. Following exposure to a tutor’s song, juvenile zebra finches reproduce the tutor song, an important step in sensorimotor development. Shank and Margoliash found that incorporation of the tutor song was the greatest following intervals containing sleep. Likewise, sleep is beneficial to discrimination learning in adult starlings. Brawn et al. demonstrated this using a go/no-go task where one song segment served as a “go” cue and responses were rewarded with food access while another song segment served as a “no-go” cue and responses to it were punished with an interval of lights out. Discrimination of the two song segments improved significantly over sleep but no change in discrimination ability was found following an equivalent interval spent awake.
The largest nonhuman animals in which sleep-dependent memory consolidation has been studied are the great apes. Chimpanzees, bonobos, and orangutans were tested on their ability to remember the location of a food reward that was placed under one of three cups. Although correct responses steadily decreased over waking intervals of 1, 2, 4, or 8 hrs, recall was largely unchanged over 12 and 24 hr intervals, intervals that contained sleep. This suggests that sleep provides, at minimum, a protective service to memories in the great ape family. Moreover, when animals were given an interference trial before recall of the food reward location, performance remained accurate if sleep occurred following learning. Performance was impaired by the interference trial for those animals that stayed awake following learning. This latter result suggests that sleep’s role was not merely through passive protection of the memory but played an active role, resulting in a more stable memory that was resistant to interference.
In summary, sleep-dependent consolidation is a function of sleep observed across species and from early development into adulthood. With the wealth of evidence in support of this function of sleep, it is useful to turn to understanding how memories are consolidated in the brain and why this takes place during sleep.
Processes of excitation and braking in the central nervous system, as well as other functions of an organism have daily cycle. The cycle of dream and wakefulness is one of vital needs of the organism. The basic function of dream is restoration of physical and mental forces, which allows maximal adaptation to change of conditions of the external and internal environment.
Dream is alternation of different functional conditions of the brain. During dream brain activity is reconstructed. There is a consolidation and processing of the information, which has arrived during wakefulness. In dreaming information moves from the short-term memory in the long-term. Activity of neurons in different departments of the brain cortex and subcortical nerve centers during dream remains practically same as well as during wakefulness.
According to modern representations, dream consists of two qualitatively various conditions – slow and fast dream. Slow dream is divided on some stages, according to changes on electroencephalogram.
The first stage is characterized by oppression of the basic alpha-rhythm, which is gradually replaced with low amplitude waves of different frequency.
The second stage is characterized by periodic occurrence of dream spindles.
The third and fourth stage is characterized by gradual increase on electroencephalogram of high amplitude slow deltas-waves. These stages correspond to deep dream.
Numerous brain structures, which take part in the organization of dream, are located in the brain stem and were joined in somnolence system. Nucleus in the brain partition, in hypothalamus, serotoninaergic neurons iucleus of a seam and thalamic synchronizing system concern to these structures.
Formation of fast dream connects with reticular nucleus of the midbrain and limbic structures of the brain.
Reticular inhibitory area is located medially and ventrally in the medulla. This area can inhibit the reticular facilitory area of the upper brain stem and thereby decrease activity in the superior portions in the b5rain as well. One of the mechanisms for this is to excite serotoninergic neurons ar crucial points in the brain.
Functions of speech
Speech Functions for Sociolinguistics
Conveying Information and Expressing Social Relationships
1. Expressive (express speaker’s feelings–I feel great today.)
2. Directive (get others to do things–Clean up your room.)
3. Referential (provide information–The apples are on the table.)
4. Metalinguistic (comments on language–Nouns can be mass or count.)
5. Poetic (aesthetic language–poems, mottos, rhymes–A stitch in time saves nine.)
6. Phatic (language for solidarity and empathy–Yo, bro. Put ‘er there.)
Language, when seen as a system of rules (including phonology, morphology, syntax, grammar, semantics,pragmatics), and focusing on rules describing competence rather than performance, limits our ability to look at communication systems more generally and to see important characteristics of speech forms that are used within speech communities and between them.
Basic limitations of theoretical linguistics of the past to the sentence as the largest unit of analysis and to referential meaning as the only relevant sort of meaning, and of analytical interest primarily in terms of “same or different,” can be overcome in part by taking a more inclusive view of speech as a form of communication; by starting with an analysis of the “communicative act” (or simply the “speech act”) in terms of the components that comprise it and the functions that can be served through it.
Speech Act (or Communicative Act) Components (Hymes and Jakobson)
The components and functions above are all within (or “enclosed by”) another component, the
SETTING, and an associated function of the communicative act as a whole could be called
contextual
Different societies will make differential use of and definitions of these speech act components.
The ethnographer (one who wants to describe a culture) would like to list all the possible
named speech acts, all the possible senders, all the possible receivers, all the kinds of codes,
all the named kinds of message form, all the message channels possible, all the named topics, etc.
Speech Act (or Communicative Act) Functions
Identificational function of the communicative act is most closely associated
with the sender — such things as voice set, accent, intonation, etc. tell receiver
about sender’s age, sex, etc.; ie. they identify him or her, and they are generally
involuntary.
Expressive — choice of words, intonation, etc. express emotions and attitudes
toward receiver or other component of speech act.; generally under voluntary control.
b. message channel (could be gestures, whistling, drumming, speech)
Contact — physical – sound hits ears. psychological – phatic communion (i.e. social contact)
c. message form
Poetic function. Not limited to poetry, this function is expressed as manipulations
of and restrictions on message form, and these can be of many different sorts. Different amounts and varieties of aesthetic appreciation are derivable from various ways of formulating a message with any given referential content.
d. topic (what the message is about)
Referential function :most directly associated with the topic;
closely tied to the dictionary meanings of messages.
e. code (Signaling units of which a message is composed – based on a set of
conventions for communicating meaning).
Metalinguistic function, i.e. information about the code that is conveyed in a
speech act.
f. receiver – (hearer, audience)
Directive function – concerns subsequent activity of the receiver as
directed by what the speaker says.
(e.g. “Would you close the door, please?”)
Rhetorical function – concerns the receiver’s outlook as it is affected by
what is said. (e.g. “What a nice dress.”)
g. setting (context)— (relevant features constituting a specific setting most often
involve place and time, but may also include physical circumstances germane
to the place and time of the speech act)
Setting function of the speech act associated with the setting component is
reflected in messages saying something about the time, place, or persons in
the interaction. Many linguistic forms referring to these things cannot be interpreted without reference to the speech act itself, for their meanings are
not fixed but relative (e.g. ‘me’, ‘you’, ‘here’, ‘there’, ‘now’, ‘then’)
(e.g. “It happened yesterday”; “Oh, there you are”). In some cases, the
primary function of the whole speech act is contextual.
Once we are familiar with the functions of the speech act we can think of them in a
slightly different way by referring to them as meanings that can be associated with
the speech act. So in this sense there are at least 9 general kinds of meanings that can
be associated with the speech act.
Later, Dell Hymes developed another, model based in part on a mnemonic (SPEAKING)
Making the components easier to remember. This model, based on the notion of discourse
seen as a series of speech acts (themselves components of speech events) with in a situational
and cultural context. This model can be used to examine and analyze all kinds of discourse.
Setting and scene
“Setting refers to the time and place of a speech act and, in general, to the physical
circumstances” (Hymes, p. 55).The living room in the grandparents’ home might be a setting
for a family story. Scene is the “psychological setting” or “cultural definition” of a scene,
including characteristics such as range of formality and sense of play or seriousness
(Hymes 55-56). The family story may be told at a reunion celebrating the grandparents’
anniversary. At times, the family would be festive and playful; at other times, serious and
commemorative.
Participants
Speaker and audience. Linguists will make distinctions within these categories; for example,
the audience can be distinguished as addressees and other hearers (Hymes 54 & 56). At
the family reunion, an aunt might tell a story to the young female relatives, but males,
although not addressed, might also hear the narrative.
Ends
Purposes, goals, and outcomes (Hymes 56-57). The aunt may tell a story about the
grandmother to entertain the audience, teach the young women, and honor the grandmother.
Act sequence
Form and order of the event. The aunt’s story might begin as a response to a toast to the
grandmother. The story’s plot and development would have a sequence structured by the
aunt. Possibly there would be a collaborative interruption during the telling. Finally, the
group might applaud the tale and move onto another subject or activity.
Key
Cues that establish the “tone, manner, or spirit” of the speech act (Hymes 57). The aunt
might imitate the grandmother’s voice and gestures in a playful way, or she might address
the group in a serious voice emphasizing the sincerity and respect of the praise the story
expresses.
Instrumentalitis
Forms and styles of speech (Hymes 58-60). The aunt might speak in a casual register with
many dialect features or might use a more formal register and careful grammatical
“standard” forms.
Norms
Social rules governing the event and the participants’ actions and reaction. In a playful story
by the aunt, the norms might allow many audience interruptions and collaboration, or
possibly those interruptions might be limited to participation by older females. A serious,
formal story by the aunt might call for attention to her and no interruptions as norms.
Centre
The kind of speech act or event; the kind of narrative, comment, exclamation, etc. The aunt might tell a character anecdote about the grandmother for entertainment, but an exemplum as moral instruction. Different disciplines develop terms for kinds of speech acts, nd speech communities have their own terms for types.
These terms provide a structure facilitating your perception of the elements / components of the speech act. In some cases you might emphasize only one or two of the letters in the mnemonic (SPEAKING).
(Hymes, Dell. Foundations of Sociolinguistics: An Ethnographic Approach.
Philadelphia: U of Pennsylvania P, 1974.)
Main functions of speech are communicative, regulatory, programming and gives general notion about surroundings. Communicative function permits exchange of information between people. Such a function is also present in animals, which use for this aim vocalization of different intensity to warn about danger or express positive and negative emotions. People use verbal signals for everything he perceives through the receptors. Words are abstraction of reality and allow generalization, processing of surrounding primary information.
Verbal instructions may direct human activity, give suggestion about proper mode of behavior. This is programming function of speech. Programming function of speech involves emotional component also, which may influence to emotional status of a person. As limbic system, which controls emotions, has direct connection with autonomic nervous system.
So speech through emotions may influence to functions of visceral organs. Physician may use this effect for psychotherapy. It is necessary remember about jatrogenic disorders also.
Physiological basis of human bechaviour
Central securing of language’s formation
There are two aspects of communication: sensory, involving reading, hearing of speech, and second, the motor aspect, involving vocalization and its control. It is known, that lesion of posterior portion of the superior temporal gyrus, which is called
The formation of thoughts is the function of associative areas in the brain. Wernicke’s area in the posterior part of the superior temporal gyrus is most important for this ability. Broca’s speech area lies in prefrontal and premotor facial region in the left hemisphere.
The skilled motor patterns for control of the larynx, lips, mouth, respiratory system and other accessory muscles of speech are all initiated from this area.
The skilled motor patterns for control of the larynx, lips, mouth, respiratory system and other accessory muscles of speech are all initiated from this area. Articulation means movements of mouth, tongue, larynx, vocal cords, and so forth that are responsible for the intonations, timing, and rapid changes in intensities of the sequential sounds. The facial and laryngeal regions of the motor cortex activate these muscles, and the cerebellum, basal ganglia, and sensory cortex all help control the sequences and intensities of muscle contractions.
Transmitters such as dopamine, noradrenaline, serotonin and certaieuropeptides transmit their signals by what is referred to as slow synaptic transmission. The resulting change in the function of the nerve cell may last from seconds to hours. This type of signal transmission is responsible for a number of basal functions in the nervous system and is of importance for e.g. alertness and mood. Slow synaptic transmission can also control fast synaptic transmission, which in turn enables e.g. speech, movements and sensory perception.
Development of signaling systems in children. The ability of a full-term baby to develop temporary connections of the first signaling system arises in a few days after the birth.. In the first six months of life speech sounds mean little to a child. They are simply stimuli to the auditory analyzer like any other sounds. The first signs of development of the second signaling system appear during the second half of the first year of life. If a person or an object is named and shown to a child many times, reaction to this name develops. Later after leaning a few words, a child begins to name objects itself. Finally, at a later time he uses a stock of words to communicate with other people.
Individual (typological) peculiarities of people
Type of nervous system determines rate of creation of new conditioned reflexes, strength and stability of these reflexes, intensity of external and internal inhibition, rate of irradiation and concentration of nervous processes, the capacity for induction and less or grater possibility for development of abnormalities of higher nervous activity.
I.P. Pavlov classifies types of higher nervous activity according to several attributes that considered as most reliable indices of higher nervous activity. These were intensity of the excitation and inhibition, the ratio of these processes in central nervous system and their mobility, that is rate at which excitation was replaced by inhibition and wise versa. In experimental practice the following four principle types of higher nervous activity are met:
1) strong unbalanced type, characterized by predominance of excitation over inhibition;
2) strong well-balanced active type, characterized by high mobility of nerve processes;
3) strong well-balanced passive type, characterized by low mobility of nerve processes;
4) weak type, characterized by extremely weak development of both excitation and inhibition, which cause fatigue and low workability.
Look to reactions of people with different type of temperament to the crumpled hat (after H. Bitstrup). Estimate the type of temperament in eacn case.
Characteristic of types of higher nervous system depending on cooperation between I and II signal systems.
The analysis and synthesis of the direct stimuli from surroundings first signal system performs. This includes impressions, sensations.
This functional mechanism is common in human and animals. In the course of his social development and labor activity second signal system, which based on using verbal signals, develop. This system includes perception of words, reading and speech.
The development of the second signaling system was incredibly broadened and changed by quality of higher nervous activity of cerebral hemispheres. Words are signals of other signals. Man uses verbal signals for everything he perceives through the receptors. Words are abstraction of reality and allow generalization, processing of surrounding primary information. This gives the first general human empiricism and finally science, the instrument of man’s higher orientation in the environment and its own self.
So, second signaling system is socially determined. Outside the society, without association with other people second signaling system is not developed.
Types of higher nervous activity according to Eizenck’s classification. The set of external manifestations of human temperament is various. H. Eizenck on the base of customs of different types of temperament was revealed three personal parameters: 1) extraversion or introversion; 2) neurotizm; 3) psychotism. Extroversive person is openhearted, has high social activity, interesting in public relations. On other hand, introversive person is passive emotionally unstable and interested mainly in his inner world. It concerned peculiarities of reticular-cortical interconnections lay in the basis of this personal fiche. Introversive temperament correlates with grater activity of septal and hippocampal inhibitory system in the brain. Neurotic person is high irritable, has unbalanced emotional status even in usual conditions. Level of neutotizm correlates rate of activity of limbic and cortical interconnections in the brain. Psychotic person is highly egocentric, cool people relations and aggressive. Importance of social medium in formation of personal temperament is high. Personal fiches of temperament get brighter with age.
Attention
Determination of “attention” notion
Attention is selectiveness of psychical processes or any kind of mental activity, which helps in getting and processing the information. There are sensory, motor, intellectual and emotional forms of attention, depending to kind of activity of a person.
There are voluntary and involuntary levels of attention. Involuntary attention is present from the birth of man. Voluntary attention develops in life course, due to mental activity, formation of speech function and studying languages.
Forms and levels of attention.
Involuntary attention is controlled by lower portion of brain stem and midbrain, where centers of roof reflexes are locates. Voluntary attention appears as a result of higher cortical activity in visual, auditory, motor areas and so on.
Lesion of these cortical areas leads to such disturbances in processing special sensory information as ignore of stimuli of different modality. Intellectual attention appears because of function of prefrontal associative cortical area. The limbic system of the brain is responsible for emotional attention.
Physiological mechanisms of attention.
Involuntary attention is controlled by lower portion of brain stem and midbrain, where centers of roof reflexes are locates. Voluntary attention appears as a result of higher cortical activity in visual, auditory, motor areas and so on. Lesion of these cortical areas leads to such disturbances in processing special sensory information as ignore of stimuli of different modality. Intellectual attention appears because of function of prefrontal associative cortical area. The limbic system of the brain is responsible for emotional attention.
Memory function
The “memory” notion.
Memory function helps fixing of perceived information, keeping it in verbal form or as traces of percept stimuli and recognizing of this information in proper time. Genetic memory keeps information about body structure and forms of its behavior. Biological memory is presented in both philogenetic and ontogenetic forms. The immune memory and psychical memory for instance, belong to ontogenetic memory.
General characteristics of memory are duration, strength of keeping the information and exactness of its recognizing. In man mechanisms of perception and keeping the information are developed better, comparing to other mammalians.
According to duration is concerned short-time and long-time memory; in relation to kind of information – sensory and logic.
Physiologic mechanism of memory.
At the molecular level, the habitation effect in the sensory terminal results from progressive closure of calcium channels through the presynaptic terminal membrane.
In case of facilitation, the molecular mechanism is believed to be following. Facilitated synapse releases serotonin that activates adenylyl cyclase in postsynaptic cell. Then cyclic AMP activates proteinkinase that then causes phosphorylation of proteins. This blocks potassium channels for minutes or even weeks. Lack of potassium causes prolonged action potential in the presynaptic terminal that leads to activation of calcium pores, allowing tremendous quantities of calcium ions to enter the sensory terminal. This causes greatly increased transmitter release, thereby markedly facilitating synaptic transmission.
Thus in a very indirect way, the associative effect of stimulation the facilitator neuron at the same time that the sensory neuron is stimulated causes prolonged increase in excitatory sensitivity of the sensory terminal, and this establishes the memory trace.
Eric Kandel showed initially that weaker stimuli give rise to a form of short term memory, which lasts from minutes to hours. The mechanism for this “short term memory” is that particular ion channels are affected in such a manner that more calcium ions will enter the nerve terminal.
This leads to an increased amount of transmitter release at the synapse, and thereby to an amplification of the reflex. This change is due to a phosphorylation of certain ion channel proteins, that is utilizing the molecular mechanism described by Paul Greengard.
A more powerful and long lasting stimulus will result in a form of long term memory that can remain for weeks. The stronger stimulus will give rise to increased levels of the messenger molecule cAMP and thereby protein kinase A. These signals will reach the cell nucleus and cause a change in a number of proteins in the synapse. The formation of certain proteins will increase, while others will decrease. The final result is that the shape of the synapse can increase and thereby create a long lasting increase of synaptic function.
In contrast to short term memory, long term memory requires that new proteins are formed. If this synthesis of new proteins is prevented, the long term memory will be blocked but not the short term memory.
Brain mechanism of memory.
It’s discovered the nervous substrate of long-term memory is mostly cerebral cortex. The most important regions are temporal lobes, prefrontal area and hippocampus. Experimental researches revealed that some thalamic nuclei and reticular formation take part in memory function.
Reticular formation gives ascending stimulatory influences to cerebral cortex, which help in keeping awake condition of cortex and provides voluntary attention.
In the human brain there are more than hundred billioerve cells. They are connected to each other through an infinitely complex network of nerve processes. The message from one nerve cell to another is transmitted through different chemical transmitters. The signal transduction takes place in special points of contact, called synapses. A nerve cell can have thousands of such contacts with other nerve cells. The protein phosphorylation affects a series of proteins with different functions in the nerve cell. One important group of such proteins forms ion channels in the membrane of the cell. They control the excitability of the nerve cell and make it possible for the nerve cell to send electrical impulses along its axons and terminals. Each nerve cell has different ion channels, which determine the reaction of the cell. When a particular type of ion channel is phosphorylated the function of the nerve cell may be altered by, for example, a change in its excitability. Paul Greengard has subsequently shown that even more complicated reactions occur in particular nerve cells. The effects of the transmitters are elicited by a cascade of phosphorylations and dephosphorylations (that is, phosphate molecules are added or removed from the proteins). Dopamine and several other transmitters can influence a regulatory protein, DARPP-32, which indirectly changes the function of a large number of other proteins. The DARPP-32 protein is like a conductor directing a series of other molecules. When DARPP-32 is activated it affects several ion channels altering the function of particular fast synapses.
A phosphorylation of proteins has great importance also for the discoveries for which Eric Kandel is rewarded that is for revealing molecular mechanisms, important for the formation of memories. Eric Kandel started to study learning and memory in mammals, but realized that the conditions were too complex to provide an understanding of basic memory processes. He therefore decided to investigate a simpler experimental model, the nervous system of a sea slug, Aplysia. It has comparatively few nerve cells (around 20.000), many of which are rather large. It has a simple protective reflex that protects the gills, which can be utilized to study basic learning mechanisms. Eric Kandel found that certain types of stimuli resulted in an amplification of the protective reflex of the sea slug. This strengthening of the reflex could remain for days and weeks and was thus a form of learning. He could then show that learning was due to an amplification of the synapse that connects the sensory nerve cells to the nerve cells that activate the muscle groups that give rise to the protective reflex. Paul Greengard’s discoveries concerning protein phosphorylation have increased our understanding of the mechanism of action of several drugs, which specifically affects the phosphorylation of proteins in different nerve cells.
Short and long term memory.
The weaker stimuli give rise to a form of short term memory, which lasts from minutes to hours. The mechanism for this “short term memory” is that particular ion channels are affected in such a manner that more calcium ions will enter the nerve terminal. This leads to an increased amount of transmitter release at the synapse, and thereby to an amplification of the reflex. This change is due to a phosphorylation of certain ion channel proteins, that is utilizing the molecular mechanism described by Paul Greengard. A more powerful and long lasting stimulus will result in a form of long term memory that can remain for weeks. The stronger stimulus will give rise to increased levels of the messenger molecule cAMP and thereby protein kinase A. These signals will reach the cell nucleus and cause a change in a number of proteins in the synapse. The formation of certain proteins will increase, while others will decrease. The final result is that the shape of the synapse can increase and thereby create a long lasting increase of synaptic function. In contrast to short term memory, long term memory requires that new proteins are formed. If this synthesis of new proteins is prevented, the long term memory will be blocked but not the short term memory.
Synaptic plasticity, a precondition for memory.
Eric Kandel thus demonstrated that short term memory, as well as long term memory in the sea slug is located at the synapse. During the 1990’s he has also carried out studies in mice. He has been able to show that the same type of long term changes of synaptic function that can be seen during learning in the sea slug also applies to mammals.
The fundamental mechanisms that Eric Kandel has revealed are also applicable to humans. Our memory can be said to be “located in the synapses” and changes in synaptic function are central, when different types of memories are formed. Even if the road towards an understanding of complex memory functions still is long, the results of Eric Kandel was provided a critical building stone. It is now possible to continue and for instance study how complex memory images are stored in our nervous system, and how it is possible to recreate the memory of earlier events. Since we now understand important aspects of the cellular and molecular mechanisms which make us remember, the possibilities to develop new types of medication to improve memory function in patients with different types of dementia may be increased. This presumably results from some of the same capabilities of the prefrontal cortex that allow it to plan motor activities. The prefrontal association area is frequently described as important for elaboration of thoughts to store on a short-term basis “working memories” that are used to analyze each new thought while it is entering the brain. The somatic, visual, and auditory association areas all meet one another in the posterior part of the superior temporal lobe. This area is especially highly developed in the dominant side of the brain – the left side in almost all right-handed people. It plays the greatest single role of any part of cerebral cortex in the higher comprehensive levels of brain function that we call intelligence. This zone is also called general interpretative area, the gnostic area, the knowing area, tertiary association area. It is best known as Wernike’s area in honor of the neurologist who first describes it.
Thought
Determination of “thought” notion.
The prefrontal association area is essential to carrying out thought processes in the mind. This presumably results from some of the same capabilities of the prefrontal cortex that allow it to plan motor activities.
The prefrontal association area is frequently described as important for elaboration of thoughts to store on a short-term basis “working memories” that are used to analyze each new thought while it is entering the braine. The somatic, visual, and auditory association areas all meet one another in the posterior part of the superior temporal lobe. This area is especially highly developed in the dominant side of the brain – the left side in almost all right-handed people.
It plays the greatest single role of any part of cerebral cortex in the higher comprehensive levels of brain function that we call intelligence. This zone is also called general interpretative area, the gnostic area, the knowing area, tertiary association area. It is best known as Wernike’s area in honor of the neurologist who first describes it.
Consciousness and its mechanisms.
Consciousness is special form of perceiving surroundings and goal-orientated activity of person with interrelation to surroundings. Only social life forms consciousness. It involves life experience of entire society. This ability of prefrontal areas to keep track of many bits of information could well explain abilities to prognosticate, do plan for the future, delay action in response to incoming sensory signals, consider the consequences of motor actions even before they are performed, solve complicated mathematical, legal, or philosophical problems, correlate all avenues of information in diagnosing rare diseases and control our activities in accord with moral laws.
Estimation of type of higher nervous activity using Azenk’s questionnaire
Answer the questionnaire using “yes” or “no” answers. Express your first thought. Note your answers opposite the number of questions. Use key to estimate your mark according to every scale in Azenk’s test.
In the conclusioote, what is your type of higher nervous activity.
Estimation of prevalation of I or II signaling system
Get test card with 9 words. Rank these words by 3 according to some principle. As you deside. Use key to estimate prevailation of I or II signal system.
In the conclusioote, what is your type of higher nervous activity.
Notion “emotions”
Emotions are aspect of higher nervous activity that characterize subjective attitude of person to various stimuli arousal in surroundings. Emotional status reflects actual needs of man and helps in its realization.
Classification of emotions
According to subjective status there are positive and negative emotions. Negative emotions are sthenic (aggression, affect) that stimulate human activity and asthenia (horror, sadness, depression) that inhibit behaviour. Lower or elementary emotions are caused by organic needs of man or animal as hanger, thirst and survival, so on). In humans even lover emotions undergo to cortical control and are brining up. Social, historical and cultural customs cause also formation of higher emotions that regulates public and private relations in society. Higher emotions appear due to consciousness and may inhibit lower emotions.
Appearance of emotions in ontogenesis.
Iewborns emotions of horror, anger, pleasure, are revealed just after birth. Hunger, pain, getting cool, wet bedclothes cause iewborn child negative emotions with grimace of suffering and crying. Sudden new sound or loss equilibrium causes horror and loss of free movement causes anger. Final formation of human emotions develops gradually with maturation of nervous and endocrine regulatory systems and needs up brining.
Biological importance of emotions
Emotions are important element of human behaviour, creation of conditioned reflexes and mentation. Negative emotions give fusty evaluation of current situation does it useful or not. Mobilizing of efforts helps then to satisfy current needs of person. Positive emotions help to put in memory scheme of behaviour, which was useful and have lead to success.
Animal experiments have shown that a sensory experience causing neither reward nor punishment is remembered hardly at all. Electrical recordings from the brain show that newly experienced types of sensory stimuli almost always excite wide areas in the cerebral cortex. But repetition of the stimulus over and over leads to almost complete excitation of the cortical response, if the sensory experience does not elicit a sense or either reward or punishment. That is, the animal becomes habituated to the sensory stimulus and thereafter ignores it. If the stimulus causes either reward or punishment rather then indifference, the cortical response becomes progressively more and more intense during repeated stimulation, and the response is said to be reinforced. An animal builds up strong memory traces for sensation that are either rewarding or punishing but, conversely, develops complete habituation to indifferent sensory stimuli.
External manifestations of emotions are revealed in motor acts, effects of autonomic and endocrine regulation. Motor manifestations of emotions are mimic, gesticulation, body posture and walk. Emotional excitation usually is followed by autonomic reactions as blush, dilation of pupils; increase of arterial pressure, rate of heartbeat and breathing. Level of catecholamines in blood and 17-oxycetosteroides in urine rises also. Positive emotion may activate parasympathetic division of autonomic nervous system. Severe emotional excitation may result in visceral disorders because of circulatory disturbances and excess hormones in blood.
Nerve substrate of emotions
Several limbic structures are particularly concerned with the affective nature of sensory sensations – that is whether the sensations are pleasant or unpleasant. The major rew3ard centres have been found to be located along the course of the medial forebrain bundle, especially in the lateral and ventromedial nuclei of the hypothalamus. Less potent reward centres are found in the septum, amygdala, certain areas of the thalamus, basal ganglia, and extending downward into the basal tegmentum of the mesencephalon. The most potent areas for punishment and escape tendencies have been found in the central grey area surrounding the aqueduct of Sylvius in the mesencephalon and extending upward into the periventricular zones of the hypothalamus and thalamus. Less potent punishment areas are found in some locations in the amygdala and the hippocampus. Electrical recording from the brain show that newly experienced types of sensory stimuli almost excite areas in the cerebral cortex.
Theories of emotions
Biological theory of emotions (P.K. Anochkin) considers that life course includes two main stages of behavioural act: 1) formation of needs and motivations that results from negative emotions and 2) satisfaction of needs that leads to positive emotions it case of complete accordance of image and result of action. Incomplete compliance of suspected and real result of action cause negative emotions and continues behavioural act.
Information theory of emotions (P.V. Simonov)considers that emotions reflect strength human of need and possibility of its satisfaction in current moment. In absence of needs emotions can’t arise. There is also not emotional excitation, if getting excess information about mode of satisfaction this need. Lac of information already causes negative emotions that help to recall to mind life experience and to gather information about current situation.
Neurotransmission of emotional excitation
Emotional excitation is spread in the brain due to variety of neurotransmitters (noradrenalin, acetylcholine, serotonin, dopamine and neuropeptides including opioides. Positive emotions may be explained by revealing catecholamines and negative emotions, aggression result from production acetylcholine in the brain. Serotonin inhibits both kinds of emotions. Decrease of serotonin in blood is followed by groundless anxiety and inhibition of noradrenergic transmission results in sadness.
Structure of behavioural act
According to theory of functional systems (Anochking) there are such stages of behavioural act: 1) afferent synthesis; 2) taking of decision; 3) acceptor of result of action; 4) efferent synthesis (or programming of action); 5) performing of action; 6) evaluation of final result of action. Due to converging and processing of both sensory information and memory traces afferent synthesis in the brain is performed. Taking of decision is based on afferent synthesis by choosing optimal variant of action.
Neuronal mechanisms of behaviour.
In the very lowest animals olfactory cortex plays essential roles in determining whether the animal eats a particular food, whether the smell of a particular object suggest danger, and whether the odour is sexually inviting, thus making decisions that are of life-or-death importance. The hippocampus originated as part of olfactory cortex. Very early in the evolutionary development of the brain, the hippocampus presumably becomes a critical decision-making neuronal mechanism, determining the importance of the incoming sensory signals. Once this critical decision-making capability had been established, presumably the remainder of the brain began to call on it for the same decision making. Therefore, if the hippocampus says that a neuronal signal is important, the information is likely to be committed to memory. Thus, a person rapidly become habituated to indifferent stimuli but learns assiduously any sensory experience that causes either pleasure or pain. It has been suggested that hippocampus provides the drive that causes translation of short-term memory into long-term memory.
Adaptation as a process
Adaptation is process of adjustment of body functions to surrounding conditions or some new level of activity, which is carried out through human’s life. For instance there is adaptation to outer temperature, oxygen supply, physical load, emotional pressure, rate of activity, light conditions, so on. People, who live in different Earth regions differ one to each other to functional peculiarities of their organisms, bat have similar body structure. This is adaptation to climate as complex of various outer conditions. Stress syndrome explains main regularities of adaptation as physiological process. Low intensity of stress factors cause improvement of workability iew conditions. Extreme strength of stress factors causes distress that may result in pathological disorders in body functions.
Stages of adaptive process
Changing in outer conditions may causer adjustment of function of one organ, for instance rising of mass of the heard in chronic increase of blood return to the heart. Adaptation to high altitude or new climate causes functional and morphological changes in entire body. New outer conditions mobilize homeostatic mechanisms.
Energetic resources of cells are activated at first and plastic changing are of second order. So, first stage is urgent adaptation or alarm stage. It’s performed due to mobilizing of functional reserves of organs and their systems like increase of stroke volume in heart, tidal volume in lungs, so on. Usual level of organs activity at rest consist 1/6 – 1/10 part of potential activity. Increase of functional activity of organ or their systems requires rising of metabolic rate and oxygen consumption. Sympatho-adrenal regulatory system controls these ergotropic reactions of the human organism. Such kind of regulatory effects last not long.
Second stage of adaptation is morphological that is named stage of resistance also. In case of repeated action of all new conditions as physical load or high altitude, so on, structural reorganization of functioning cells occur. For example in regular hard physical exercises rises quantity of contractile elements in muscle cell and number of cells in motor units.
Cross–adaptation
When adaptive processes are not considerable, besides adjustment to some special factors, general body adaptation occurs. For instance, adaptation to physical exercises is followed by high resistance to cold, hypoxia and bad weather. Such a condition is named as cross-adaptation. Factually this is side effect of stimulation of sympathetic system and metabolic supply as a result. Cross-adaptation is possible mainly for factors, which require increased activity of similar organ system and regulatory mechanisms.
Individual peculiarities of adaptation
Adaptive processes in different people use similar regulatory systems, bat everybody has some peculiarities of physiological functions. It depends on hereditary and acquired fitches. For example people, who have grater activity of parasympathetic regulation, comparing to sympathetic, are more resistible to extreme factors of surroundings. There is correspondence: grater volume of functional reserves in the human body, the easier adaptation to outer conditions. Physical exercises, tempering of the body, using special plant extracts are used to increase adaptability of a person.
Loss of adaptation and readaptation
After development of morphological adaptation to certain kind of outer conditions human organism keeps this ability for a long time. There are various duration of adaptive changing in different organs. In case of repeated action of the same set of conditions adaptive abilities may be renewed and are developed rapidly. This is readaptation. Very often effort for adaptation may course functional and morphologic disorders in the body. This is loss of adaptation.
Age peculiarities of adaptation
In early age adaptive processes are performed more rapid then in aged persons. In children regulatory systems of the body are not maturated yet. So, both high reactivity and low resistance to stress occur. For instance, newborn children are very sensitive to change of outer temperature that may lead to deep functional disorders. In old age functional reserves of most important organ systems like circulatory or respiratory get decreased. Low activity of hormonal regulation in aged persons also occurs. So, both urgent and morphologic adaptation gets worse in old age.
Physiology of work
General characteristic of mental work
Mental work is kind of activity, which provides receiving and processing of information by a person. It needs activation of attention, memory, thinking and emotional control also. Mental work produces great activation of central nervous system, mostly cortical areas and subcortical centers, which provide functioning of second signal system.
Work of operator includes professions, which require machining control of some technologic processes. This work gives great load to attention, thin motions of arms and static contraction of large muscles for keeping the certain body posture. Work of official includes leadership of factories, companies and hospitals so on. This work requires processing of great volume of information, taking complex decision in lack of time and high responsibility for result of work. Modern official have to keep in memory large volume of professional information be good in social relations and muster a lot of professional skills. Creative work is one of most complex forms of human activity, as work of artist, scientist so on. Work of physician includes communication with patients, taking decision of high responsibility in lack of information and performing of complex medical manipulations. So, physician have to master a lot of professional information, practical skills, know people psychology and be high responsible for his action. Work of students includes processing and storage in long-term memory great volume of information. It requires high activity of cortical areas, which provide attention, perception, memory and thinking. Passing exams, without proper learning before, may produce a stress for the student with all following functional disorders.
Workability and tiredness in course of mental work
Main functional mechanism, which explains mental work is producing dominant center in the brain. Different areas in the brain when performing mental work act independently bat are interconnected functionally for performing common task. Analyzer systems provide income of information, and associative areas help in its processing. During mental activity the more complex task is solved, the greater quantities of brain centers get synchronization of their activity. For performing mental work autonomic and emotional reactions, which provide activation of attention and memory, occur. Activity of sympathetic system and adrenalin production helps in proper metabolic supply of central neurons. Long lasting mental work may result in tiredness, inhibition of thinking and memory process, decrease of attention, incomplete coordination of movements and some functional circulatory disorders in viscera.
Age specialties of central regulatory mechanisms cause different workability in young and old persons, comparing to adults. In children tiredness because of slight inhibitory process develops rather quickly. They can’t keep attention in the same subject for along time. It’s caused by not perfect maturation of central neurons and incomplete myelinisation of all conductive pathways in the brain. In old age both metabolic rate of neurons and synthesis of neurotransmitters decreases. Some quantity of neurons dies in life course. So, close nerve cells take their function. In old age mental work may lead to severe autonomic and emotional reactions. For example, stimulation of heart activity in mental work may result in disorders of heart function.
Daily, week and year cycle of mental workability
Mental work is most effective in regular regimen of work and rest. The phenomena of dynamic stereotype underlie many behavioral reactions of the person, and also speech, labor, professional, musical, sports and other skills of the person. In conditions of a dynamic stereotype activity of the person occurs much more effectively, saving regulatory systems of an organism. Therefore principle of dynamical stereotype may be used for organization of a mode of day in medical, educational, children’s establishments. The same principle is useful the individual organization of labor activity. It is more usable to build this dynamic stereotype according to biologic rhythms of a person – day, week and year cycles of activity.
Functional peculiarities of central nervous system when performing mental work
Keeping of high mental workability requires autonomic control of metabolic supply in the brain, which is necessary for proper excitability of nerve cells. Intensive blood circulation ierve centers is possible due to redistribution of blood. Activity of sympathetic-adrenal and hypothalamo-hypophisial systems rises considerably. Positive effect causes only not long duration of emotional excitation. Stimulation of adrenal glands provides high level of glucose and free fatty acids in blood. Arterial pressure rises. Long lasting mentation and emotional pressure leads to unwanted result. For instance ECG failure is reveled.
Notion about Physical exercises
Exercise is associated with very extensive alterations in the circulatory and respiratory system. If some of the extremes of exercise were continued for even moderately prolonged periods, it may act as stressor. Main systems, which help to keep high level of physical activity, are phosphocreatine-creatine system, the glycogen-lactic acid system and aerobic system. In addition to large usage of carbohydrates by the muscles during exercise, especially during early stage of exercise, muscles use large amount of fat for energy in the form of fatty acids and acetoacetic acid. They use also to a much less extent proteins in the form of amino acids. Ability to training depends on genetic peculiarities of the organism.
Main kinds of work activity
1) hard physical load – not mechanizing work that is low effective and causes hard efforts, produce severe load to circulatory and respiratory system; 2) mechanizing work – decrease role of large body muscles, but give load to small muscles (arms and fingers), requires exact and rapid movements, complex program of action requires special skills and knowledge; 3) conveyer – requires also synchronizing of work in people group, produce monotone load and so increases pressure to central nervous system; 4) partial mechanizing of work, driving and control of machine requires rapid reaction and taking decision; 5) control of machine using electronic monitoring – produce load mostly to central nervous system, because requires high sensory attention, using special knowledge and taking correct and rapid decision.
Condition before starting exercises
Before starting well known exercises stimulation of appropriate regulatory systems occur. This causes preparing the organism for future physical activity. For instance increase of heart beat rate, breathing and gas transport are revealed. Activation of sympathetic nervous system and adrenal glands provide it. Repeated occurrence of all these conditions helps to produce conditioned reflex to time of the day, kind of work or surrounding situation.
Rising workability
After starting the exercises activity of muscles rises rather quickly – after 4-5 sec. Excitation of central nervous system and neurotransmission take this time. After 20-30 sec due to somato-visceral reflexes stimulation of breathing occurs, but perfect correspondence of lung ventilation to metabolic needs appears only after some minute. Rising of heart beat rate and stroke volume provide proper intensity of blood supply after 3-5 min. Time of development of high workability during exercises depends on previous training and hereditary fitches of the organism.
High workability
There is correspondence: the harder physical load, the shorter time of high workability. It depends on previous training and hereditary fitches of the organism also. Functional processes, which provide high intensity of exercises, are muscle blood flow and metabolic supply, systemic circulatory changes, temperature regulation.
Tiredness after exercises
Tiredness in physical exercises has some reasons – decrease of metabolic reserves in muscle cells, exhaustion of neurotransmitters ierve cells, excess of metabolic products in blood and tissues, defensive inhibition in central nervous system, so on.
Recovery after exercises
There are two effects of tiredness – training that helps to increase workability and severe chronic tiredness that lead to functional disorders and disease. The result depends on correspondence between exhaustion of functional reserves of the organism and activity of recovery processes. For recovery status of central nervous system is important. Active rest means change of kind of activity. This helps to create the new dominant focus in the brain that causes centers, which are tired from previous activity, to inhibit impulsation and get rest. Aging process decreases both physical and mental workability.
ATP as a direct energy source
Regeneration of ATP
An anaerobic glycolysis for physical workability
Investigation of circulatory system in experimental emotional load
Evaluate at rest condition arterial pressure and pulse rate in examinee. Then he should perform test load. Examinee counts summary of two figures in voluntary order. Then put this result in upper line and previous upper figure goes in lower line and so on. If summary is grater 10, first numeral should be removed. Such a calculation looks like following:
5 7 2 9 1 0 1 1 2 3
2 5 7 2 9 1 0 1 1 2…….
After performing 40 summarizing in free rate, evaluate arterial pressure and pulse rate in examinee. Repeat this task in lack of time – through 1 min. Experimentator should control quality of examinee’s calculation and often tell: “You have done a mistake. You are not attentive. You are working badly!” Evaluate once more arterial pressure ant pulse rate lust after this test load. Put results in the table:
|
N |
Current situation |
Arterial pressure |
Pulse |
|
1. |
At rest |
|
|
|
2. |
Mental work in free regimen |
|
|
|
3. |
Mental work in emotional load |
|
|
Compare results.
In the conclusioote, what mechanism changes activity of circulatory system?
Adaptation of respiratory system to hypoxia
Record spirogram of examinee at rest. Join to mask elastic gofer tube to increase anatomical dead space. Record spirogram after 20 sec. Compare indexes of respiratory function before and after the test.
In the conclusioote, what regulatory mechanisms support adaptation of respiratory system?
Evaluation of mental workability using Krepelin’s test
Check the time before starting the test. Give order to examinee start his work. Examinee should summarize numerals in upper and lover line and put summary under each couple of numerals. Calculation of each line should be stopped after 20 sec, and examinee takes next line.
Evaluate result using formula:
Kw=C2/C1, where
Kw – coefficient of mental workability;
C2 – quantity of summarizing without mistakes in 5-8th lines;
C1 – quantity of summarizing without mistakes in 1-4th lines.
High level of mental workability correlates to Kw=1.
In the conclusioote, what nerve processes help to keep high level of mental workability.
Compare results.
In the conclusioote, what mechanism changes activity of circulatory system?
Adaptation of respiratory system to hypoxia
Record spirogram of examinee at rest. Join to mask elastic gofer tube to increase anatomical dead space. Record spirogram after 20 sec. Compare indexes of respiratory function before and after the test.
In the conclusioote, what regulatory mechanisms support adaptation of respiratory system?
Evaluation of mental workability using Krepelin’s test
Check the time before starting the test. Give order to examinee start his work. Examinee should summarize numerals in upper and lover line and put summary under each couple of numerals. Calculation of each line should be stopped after 20 sec, and examinee takes next line.
Evaluate result using formula:
Kw=C2/C1, where
Kw – coefficient of mental workability;
C2 – quantity of summarizing without mistakes in 5-8th lines;
C1 – quantity of summarizing without mistakes in 1-4th lines.
High level of mental workability correlates to Kw=1.
In the conclusioote, what nerve processes help to keep high level of mental workability.
PWC170 (veloergometry)
Evaluate body weight in examinee and let he sit on the veloergometer. Correct position of sit to permit reaching the pedal by straightened leg. Evaluate initial heartbeat rate. Then examinee performs first load, which equal to 1 Vat/kg for male and 0,5 Vat/kg for female. Rate of rotation pedals is 60/min. Duration of the first load is 5 min. Evaluate heartbeat rate at last 30 sec. of this load. Then examinee gets 3 min rest. If after the first load heartbeat rate was not greater 100 /min, next load would be 2 Vat/kg for male and 1,5 Vat/kg for female. If heartbeat rate after the first load was greater the 100 /min, next load would be 1,5 Vat/kg for male and 1,0 Vat/kg for female. Evaluate heartbeat rate at last 30 sec. of this load also.
Estimate PWC170 using formula:
PWC170=N1+[(N2-N1)·(170-f1/f2-f1)], where:
PWC170 – personal work capacity at heartbeat rate 170/min, which is standard;
N1 – capacity of the first load;
N2 – capacity of the second load;
f1 – heartbeat rate at the end of first load;
f2 – heartbeat rate at the end of second load.
Compare your results with normal work capacity:
|
Low |
Low-to-moderate |
Moderate |
High-to-moderate |
High |
|
Female |
||||
|
74 |
75-89 |
90-124 |
125-139 |
140 |
|
Male |
||||
|
115 |
116-139 |
140-189 |
190-217 |
218 |
Note in conclusion is result normal or not.
References:
1. Review of Medical Physiology // W.F.Ganong. – Twentieth edition, 2001. – P. 530-535.
2. Textbook of Medical Physiology // A.C.Guyton, J.E.Hall. – Tenth edition, 2002. – P. 114-119.
3. Buck, L. and Axel, R. (1991) Cell, vol. 65, 175-187.
4. Review Article Neurophysiological Basis of Sleep’s Function on Memory and Cognition // Rebecca M. C. Spencer ISRN Physiology.Volume 2013 (2013), Article ID 619319, 17 pages/
http://dx.doi.org/10.1155/2013/619319
