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Higher Functions of the Brain
Higher Functions of the Brain
• Behavior
• Sleep and arousal
• Emotions
• Memory and Learning
• Language
• Personality
• Movement - Integration
Higher Functions of the Brain
• Behavior
• Sleep and arousal
• Emotions
• Memory and Learning
• Language
• Personality
Consciousness and its mechanisms
• Consciousness is special form of perceiving surroundings and goalorientated 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.
Structure of behavioural act
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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.
Behavioral State
• Four different systems which appear to modulate sensory and cognitive
processes and motor output
• Neurons composing them form diffuse modulatory systems
• These clumps of neurons form nuclei sending axons which travel toward various
areas of the brain
• The nuclei are located in reticular formation in brain stem
• The 4 processes are:
- the noradrenergic modulatory system
- the serotonergic modulatory system
- the dopaminergic modulatory system
- the cholinergic modulatory system
Noradrenergic modulatory system
• Role:
• sleep-wake cycle,
• attention,
• arousal,
• anxiety,
• pain and
• mood
- Promotes brain responsiveness
- Part of the Reticular Activating
System (RAS)
How to mess up the system?
• Drugs that interfere with
epinephrine /
norepinephrine metabolism
will affect this system.
• Amphetamine and cocaine
block NE reuptake  remain
in the synapse longer
Serotonergic modulatory system
• Role:
- Pain, locomotion
- mood and emotional
behavior (aggression and
depression)
- Part of the RAS
- modulates sleep
How to mess up this system?
• Amphetamines: block reuptake
• LSD: serotonin agonist – hallucinogen
Dopaminergic modulatory system
• Roles:
- motor control
- reward center (linked to
additive behavior)
Dopamine/substantia nigra
• Involved in motor control  helps with
smoothness of movement, muscle tone
• Disease: Parkinson’s disease due to a deficit of
dopamine secretion
Dopamine/ Ventral tegmental area
• Reward pathway
• Rates offered choices,
will take the drug even if
it has deleterious effects
on its health
How to mess it up?
• Many drugs affect this
pathway:
- nicotine, cocaine,
morphine, heroin
- This pathway is downregulated  withdrawal
symptoms develop if the
person stops taking the
drug.
Physiological dependence:
The drug overwhelms the
receptors in the synapse 
they are pulled out  more
drug is needed for the same
effect  if the drug is stop
the person suffers withdrawal
symptoms
Cholinergic modulatory system
• Role:
- Sleep-wake cycle,
arousal
- learning and memory
- control sensory info.
passing by the thalamus
States of Arousal – Sleep cycle
Reticular activating system
keeps “conscious brain”
awake
Some of the previous
modulatory systems are
part of the RAS
Higher Functions of the Brain
• Behavior
• Sleep and arousal
• Emotions
• Memory and Learning
• Language
• Personality
SLEEP
• Unconciousness state from
which a person can be aroused
by sensory or other stimuli;
• It’s divided into two entirely
different types of sleep that have
different quantities & alternate:
• slow- wave sleep (NREM) &
• rapid eye movement sleep
(REM)
ECG stages of sleep
Has multiple stages: from very deep to very light sleep
SLEEP & BRAIN WAVES
Measured by
“Electroencephalograp
hy (EEG) is the
measurement of
electrical activity
produced by the brain
(cortex) as recorded
from electrodes placed
on the scalp.“
Determined by the level of excitation
of sleep, wakefulness or brain diseases
(epilepsy and psychosis).
SLEEP : SLOW- WAVE SLEEP
• In this type of sleep the brain waves are very strong & show a
low frequency;
• Occurs during the first hour after going to sleep & it’s exceedingly
restful;
• ↓ of peripheral vascular tone & other vegetative functions of the
body, such as: a 10 to 30 % ↓ in BP, in respiratory rate & in basal
metabolic rate;
SLEEP : SLOW- WAVE SLEEP
• More restful type of sleep;
• Associated with
(viscero-)motor activities;
• 4 Phases:
- I (Drowsiness): low voltage fluctuations,
alpha waves reduced;
- II (Light sleep): low voltage of delta waves;
- III (Medium sleep): frequency of delta waves
reduced, amplitude increases;
- IV (Deep sleep): delta waves more
prominent, low frequency and high altitude.
SLEEP : REM ( RAPID EYE MOVEMENT) SLEEP, PARADOXICAL SLEEP,
DESYNCHRONIZED SLEEP
Bouts of REM sleep last for 5 to 30 min & usually appear on average every 90
minutes;
As the person becomes more rested during the night, the durations of the
REM bouts ↑;
REM characteristics:
1. Active dreaming & active bodily muscle movements;
2. The person is more difficult to arouse by sensory stimuli than during the deep slow- wave
sleep & people usually awaken spontaneously during a REM episode;
3. Muscle tone is exceedingly depressed – strong inhibition of the spinal muscle control
areas;
4. Heart rate & respiratory rate become irregular;
5. Irregular muscle movements occur;
6. Brain is ↑ active & brain waves are similar to those of wakefulness.
SLEEP : REM ( RAPID EYE MOVEMENT)
SLEEP, PARADOXICAL SLEEP,
DESYNCHRONIZED SLEEP
• 5-30 minutes long, every 90
minutes;
• ↓ muscle tone;
• ↑ brain metabolism ( as much as
20 % );
• Irregular heart and respiratory rate;
• Rapid eye movements;
• Less restful, desynchronised;
• Associated with psychical activities,
such as dreaming.
BASIC THEORIES OF SLEEP
• PASSIVE THEORY OF SLEEP: this earlier theory of sleep said that the RAS became
simply fatigued during the day & as a result inactivated during the night;
• It was later proved that sleep is caused by an active inhibitory process, once
that there seems to be a center located below the midpontile level of the brain
stem that is required to cause sleep by inhibiting other parts of the brain;
• ONTOGENIC HYPOTHESIS OF REM SLEEP says that the activity occurring during
neonatal REM sleep (or active sleep) seems to be particularly important to the
developing organism. Deprivation of active sleep early in life was shown to
result in behavioral problems, permanent sleep disruption, decreased brain
mass.
PHYSIOLOGICAL EFFECTS OF SLEEP
• Sleep has two major effects: at the level of the nervous system & at the level of
other functional systems of the body;
• The effects on the CNS are far more important; prolonged wakefulness is
associated with progressive malfunction of the thought processes & can cause
abnormal behavioural activities;
• Sleep, in multiple ways, restores both NORMAL LEVELS OF BRAIN ACTIVITY &
NORMAL BALANCE AMONG THE DIFFERENT FUNCTIONS OF THE CNS;
“ The principal value of sleep is to restore the natural
balances among the neuronal centers.”
Higher Functions of the Brain
• Behavior
• Sleep and arousal
• Emotions - Moods
• Memory and Learning
• Language
• Personality
Emotion and Motivation
The link between emotions and
physiological functions.
- The limbic system controls many
emotions.
- The amygdala is an important
center of fear, anxiety.
- Emotions can influence
- somatic,
- autonomic,
- endocrine and
- immune responses.
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.
• Areas of the brain
that play an
important role in
the production of
emotions include
the reticular
formation, the
limbic system, and
the cerebral
cortex.
Nervous structures
and emotional reactions
Classification of emotions
• According to subjective status there are positive and negative
emotions.
• Negative emotions are asthenic (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
• 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.
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.
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.
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.
• Low 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 opioids.
• 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.
Higher Functions of the Brain
• Behavior
• Sleep and arousal
• Emotions
• Memory and Learning
• Language
• Personality
• Memory and learning
• Memory is the ability to hold on to or recall a piece of information
• Learning is the ability to retain and apply past memories
• Types of memory
• Short-term memory
• Retained for short period like a phone number you look up
• Long-term memory
• Retained for long period, perhaps for life
• Combination of semantic memory (words, numbers) and episodic memory (people,
events, etc.)
• Skill memory
• Combinations of motor activities like swimming, using scissors, etc.
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.
Long-term memory circuits
• Long-term memory storage and retrieval
• Memories are stored in bits and pieces in association areas
• Hippocampus pulls these all together to allow us to recall them all as a single event
• Amygdala is responsible for emotions associated with some memories
Short term – Long term and working 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.
Short term – Long term and working memory
• 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.
Short term – Long term and working memory
• 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.
• Is associated with structural changes in
synapes
• increase in # of both transmitter
vesicles & release sites for
neurotransmitter
• increase in # of presynaptic terminals
• changes in structures of dendritic
spines
• increased number of synaptic
connections
are caused by groups of neurons that
Long term potentiation • Memories
fire together in the same pattern each time they
Presynaptic
axon
Glutamate
6
are activated.
• The links between individual neurons, which
bind them into a single memory, are formed
through a process called long-term
potentiation. (LTP)
1
Glutamate is released.
2
Net Na+ entry depolarizes
the postsynaptic cell.
3
Depolarization ejects Mg2+
and opens channel.
4
Ca2+ enters cytoplasm.
5
Cell becomes more sensitive
to glutamate.
6
Paracrine from postsynaptic
cell enhances glutamate
release.
1
Ca2+
Na+
Mg2+
3
AMPA
receptor
2
Na+
Paracrine
release
4
Ca2+
5
Postsynaptic
cell
Ca2+ entry activates second
messenger pathways.
NMDA
receptor
• Long-term potentiation (LTP)
• An enhanced synaptic response in hippocampus
• Important to memory storage
• Excitotoxicity-death of postsynaptic neuron most
likely from mutation
• Glutamate may mediate this
• Explains small memory difficulties as we age
Learning
• Learning has two broad types
• Associative (2 stimuli are
associated  Pavlov’s dog)
• Nonassociative
• Habituation (decreased
response to irrelevant signals
but response to significant
stimuli)
• Sensitization (opposite of
habituation: strong response to
a repeating stimuli –first
exposure was distasteful or
scary)
Habituation
• The sensory neuron, receiving
constant stimulation, slows down its
response  less neurotransmitter
released at the synapse.
• Ex: blanking out excess sounds
• At the molecular level, the
habitation effect in the sensory
terminal results from progressive
closure of calcium channels through
the presynaptic terminal membrane.
Sensitization
•
•
•
•
•
•
•
Stimulating the sensory neuron results in an increased response (release of neurotransmitter)
Ex: Strong fear response to an insect if we have been stung once
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.
Associative learning
• Ex: Pavlov’s dog
• Learning through long term memory of events
• At neuron level: Long Term Potentiation  synapses are reinforced
• And memory consolidation through protein synthesis
Classification of Memory
Memory can also be classified as:
• Declarative-memory of details of an integrated
thought
• memory of: surroundings, time relationships
cause & meaning of the experience
• Reflexive (Skill)- associated with motor activities
• e.g. hitting a tennis ball which include
complicated motor performance
Higher Functions of the Brain
• Behavior
• Sleep and arousal
• Emotions
• Memory and Learning
• Language
• Personality
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.
Language and speech
• Language is dependent upon memory
• Seeing and hearing words- dependent upon primary visual and
auditory center functions
• Speaking words-depends upon primary motor cortex function
• Left and right cerebral hemispheres have different functions related
to language and speech
• Broca’s and Wernicke’s areas are only in the left hemisphere
• Broca’s- ability to speak
• Wernicke’s- ability to comprehend speech
• Both hemispheres process information, but differently
• Left is very specific
• Right is very global
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.
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.
Higher Functions of the Brain
• Behavior
• Sleep and arousal
• Emotions
• Memory and Learning
• Language
• Personality
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 greater possibility for development of
abnormalities of higher nervous activity.
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;
Choleric temperament
2) strong well-balanced active type, characterized by
high mobility of nerve processes;
Sanguinen temperament
3) strong well-balanced passive type, characterized
by low mobility of nerve processes;
Phlegmatic temperament
4) weak type, characterized by extremely weak development
of both excitation and inhibition, which cause fatigue and
low workability.
Melancholic temperament