Physiological bases of behavior

1
Physiological bases of behavior
2
Type of nervous system

• 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.

3
Type of nervous system after I.P. Pavlov

• 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.

4
The first and second signaling system

• 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 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.

5
Nerve substrate of speech

• 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 Wernicke's area, and is part of auditory
  associative cortex, make impossible to the person
  to interpret the meanings of words. This
  Wernicke's area is located in dominant
  hemisphere, which is usually the left. The
  process of speech includes two principle stages
  of mentation formation of thoughts to be
  expressed and motor control of vocalization. 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. 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 certain
  neuropeptides 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.

6
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.

7
Functions of speech

• 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.

8
Attention as psychical function

• 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.

9
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.

10
Memory as psychical function

• 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.

11
Thinking process as psychical function

• 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 Wernikes area in honor of the
  neurologist who first describes it.

12
Nerve substrate of memory

• Its 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.

13
Physiological mechanisms 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.

14
Short and long term memory

• 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.

15
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.

16
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.

17
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.

18
Appearance of emotions in ontogenesis

• In newborns emotions of horror, anger, pleasure,
  are revealed just after birth. Hunger, pain,
  getting cool, wet bedclothes cause in newborn
  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.

19
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.

20
External manifestations of emotions

• 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.

21
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.

22
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
  cant 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.

23
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.

24
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.

25
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.