PHYSIOLOGY OF PHYSIOLOGY OF HIGHER NERVOUS HIGHER NERVOUS

ACTIVITYACTIVITY

behaviourbehaviour It’s a complex of movements It’s a complex of movements

enabling interaction with the external enabling interaction with the external environmentenvironment;;

Accompanied by vegetative reactionsAccompanied by vegetative reactions

Lower nervous activityLower nervous activity Regulation of organs &

systems functioning; organs & systems connections

in the body Structure – spinal cord,

medullar & midbrain Reflexes- simple & complex

Higher nervous activityHigher nervous activity Human behavior in the external Human behavior in the external

environmentenvironment Human adjustment to the changed Human adjustment to the changed

conditions of the external conditions of the external environmentenvironment

StructuresStructures – – cortex & sub-cortical cortex & sub-cortical structures, sub-cortical gangliastructures, sub-cortical ganglia

ReflexesReflexes – – the most complexthe most complex

History of the subjectHistory of the subject R.R. DecartDecart (1596-1650) – (1596-1650) – reflex archreflex arch SechenovSechenov (1829-1905) – (1829-1905) – the monographthe monograph

««Reflexes of the BrainReflexes of the Brain» - 1863г» - 1863г

Forms of behaviorForms of behavior InbornInborn – – unconditioned reflexes unconditioned reflexes UCRUCR AcquiredAcquired – –conditioned reflexes conditioned reflexes CRCR

Unconditioned reflexesUnconditioned reflexes Have species specificityHave species specificity Displayed as the body grows (in Displayed as the body grows (in

ontogenesis)ontogenesis) ConstantConstant StereotypicalStereotypical Basis for CR formationBasis for CR formation Adequate stimuli cause themAdequate stimuli cause them Cortex isn’t involvedCortex isn’t involved Enable species representatives and whole Enable species representatives and whole

species survivalspecies survival ( (maintain homeostasismaintain homeostasis))

Unconditioned reflexUnconditioned reflex Is Is species specified reaction of the species specified reaction of the

bodybody, , performed on the basis of performed on the basis of inborn nervous connectionsinborn nervous connections, , ii.е. .е. reflecting phylogeneticreflecting phylogenetic adjustment of adjustment of species to the environment of their species to the environment of their inhabitantinhabitant

Conditioned reflexesConditioned reflexes IndividualIndividual Formed during the individual life timeFormed during the individual life time Can be inhibitedCan be inhibited Can be changed with the changing of Can be changed with the changing of

the external environmentthe external environment Non-adequate stimulusNon-adequate stimulus – – stimulus isn’t stimulus isn’t

specific to the receptorsspecific to the receptors Cortex or higher centers involvment is Cortex or higher centers involvment is

obligatoryobligatory Adjustment to the changing conditionsAdjustment to the changing conditions

Conditioned reflexConditioned reflex Is an Is an individually acquired individually acquired

compensatory reactionscompensatory reactions, , which occur which occur on the basis of temporal connection on the basis of temporal connection in CNS between the centers of in CNS between the centers of conditionedconditioned && unconditionedunconditioned reflexesreflexes

INSTINCTSINSTINCTS It’s integrativeIt’s integrative UCR, a synthesisUCR, a synthesis of of

coordinated movements with coordinated movements with vegetative supplyvegetative supply

Chain characterChain character StereotypicalStereotypical, , stiffly fixed forms of stiffly fixed forms of

behaviorbehavior Maintain homeostasis and enable Maintain homeostasis and enable

species survival regardless of anyspecies survival regardless of any incidental changes in the external incidental changes in the external environmentenvironment

INSTINCTS INSTINCTS CLASSIFICATIONCLASSIFICATION

Reflexes enabling species Reflexes enabling species survivalsurvival

SexualSexual ParentalParental TerritorialTerritorial HierarchicHierarchic ( (leaderleader, , herdherd))

Reflexes enabling individual Reflexes enabling individual survivalsurvival

NutritionalNutritional OrientationOrientation ThermoregulatoryThermoregulatory DefensiveDefensive othersothers

Reflexes enabling trans-Reflexes enabling trans-species interaction species interaction

HostilityHostility FriendshipFriendship OthersOthers

Reflexes of developmentReflexes of development Imitative behaviorImitative behavior Exploratory behaviorExploratory behavior Game instinctGame instinct Instinct of learningInstinct of learning othersothers

Rules for building Rules for building conditioned reflexesconditioned reflexes

1.1. ConditionedConditioned ( (neutralneutral) ) stimulusstimulus && unconditioned stimulationunconditioned stimulation should be should be applied simultaneouslyapplied simultaneously

2.2. Multiply repetitionMultiply repetition3.3. Absence of external irritating factorsAbsence of external irritating factors4.4. Alert cortexAlert cortex5.5. Absence of pathological processesAbsence of pathological processes6.6. The force of conditioned stimulus should The force of conditioned stimulus should

be lower than that of unconditioned one, be lower than that of unconditioned one, but not lower than thresholdbut not lower than threshold

MECHANISM OF MECHANISM OF CONDITIONED REFLEX CONDITIONED REFLEX

FORMATIONFORMATION – – By AsratyanBy Asratyan

Mechanism of temporal connection Mechanism of temporal connection formationformation

STIMULUSSTIMULUS

Unconditioned nutritional reflexUnconditioned nutritional reflexUnconditioned light reflexUnconditioned light reflex

STIMULUSSTIMULUS

Possible mechanisms of Possible mechanisms of temporal connectionstemporal connections

Increase in the number of active Increase in the number of active synapsessynapses

Myelinization of non-myelinized fibersMyelinization of non-myelinized fibers Synaptic facilitationSynaptic facilitation Activation of protein biosynthesisActivation of protein biosynthesis

Conditioned reflex of the first order

Conditioned reflex of the second order

Conditioned reflex of the third order

Inhibition of Inhibition of conditioned reflexesconditioned reflexes

UnconditionedUnconditioned - - externalexternalConditionedConditioned - - internalinternalTransmarginalTransmarginal

Inhibition protects the body from Inhibition protects the body from excessiveexcessive biologically non-biologically non-

grounded reactionsgrounded reactions It’s a complex process of interaction It’s a complex process of interaction

of elementary reactions of of elementary reactions of excitationexcitation ((EPSPEPSP) ) & inhibition& inhibition ( (IPSPIPSP) ) on the on the membranes of the neuronsmembranes of the neurons

UnconditionedUnconditioned ( (externalexternal)) – – occurs due to the stimuli occurs due to the stimuli

arousing new reflex reactionarousing new reflex reaction

Extinguishing inhibitionExtinguishing inhibition – – based on based on orientation reflexorientation reflex ( (any inhibitory any inhibitory factorfactor))

Constant inhibitionConstant inhibition – – any factor of any factor of biological importancebiological importance, , which doesn’t which doesn’t cause adaptationcause adaptation ( (painpain))

Conditioned reflexConditioned reflex External inhibition of CRExternal inhibition of CR

INDIFFERENT irritating factor Of no biological importanceOf no biological importance First causes excitationFirst causes excitation – – orientation orientation

reflexreflex ««What is it?What is it?»» reflex reflex

ConditionedConditioned ((internalinternal)) ExtinctionExtinction Differentiation of conditioned stimuliDifferentiation of conditioned stimuli Conditioned inhibitionConditioned inhibition Delayed conditioned reflexesDelayed conditioned reflexes

ExtinctionExtinction

Develops when conditioned signal Develops when conditioned signal isn’t isn’t reinforced by an unconditioned reinforced by an unconditioned stimulusstimulus

Multiply repetition is requiredMultiply repetition is required On the reestablishment of the On the reestablishment of the

reinforcement the reflex can be reinforcement the reflex can be restoredrestored

Differentiation of conditioned Differentiation of conditioned stimulistimuli

One conditioned signalOne conditioned signal ( (that is that is reinforcedreinforced) ) is chosen out of many is chosen out of many similarsimilar

900900HzHz 10001000HzHz 11001100HZHZ

foodfood

SalivaSaliva secretionsecretion

SalivaSaliva secretionsecretion

SalivaSaliva secretionsecretion

Conditioned inhibitorConditioned inhibitor A type of differentiationA type of differentiationflashflash

foodfood

SalivaSaliva secretionsecretion

SalivaSaliva secretionsecretion

flashflashsoundsound ++

ConditionedConditioned inhibitorinhibitor

Delayed inhibitionDelayed inhibitionCS ---------- CS -------------- CS-------------UCS --------- UCS-------- UCS

-------- ---------- ------------- ----------- c.r. c. r. c.r. CS – conditioned stimulus, UCS – unconditioned

stimulusc.r. – conditioned reaction

Transmarginal inhibitionTransmarginal inhibition Caused byCaused by:: Suprathreshold stimuliSuprathreshold stimuli Weak long-lasting stimuliWeak long-lasting stimuli Overexcitation of CNSOverexcitation of CNS Defense mechanismDefense mechanism

Analysis & synthesis Analysis & synthesis in the cortexin the cortex

AnalysisAnalysis – – differentiation of different differentiation of different signalssignals, , formation of conditioned formation of conditioned inhibitioninhibitionSynthesisSynthesis – – connection, summarizing connection, summarizing excitations,excitations, formation of conditioned formation of conditioned reflexreflex

Dynamic stereotypeDynamic stereotype A system of conditioned reflexes A system of conditioned reflexes

which were formed as conditioned which were formed as conditioned signal place related signal place related , , not signal not signal quality relatedquality related

The basis of habits & professional The basis of habits & professional skills formationskills formation

lightlight soundsound metronomemetronome

15 15 dropsdrops10 10 dropsdrops 25 25 dropsdrops

15 15 dropsdrops 10 10 dropsdrops25 25 dropsdrops

lightlightmetronomemetronome soundsound

Main nervous processes Main nervous processes in the cortex & their in the cortex & their

quantitative evaluationquantitative evaluationExcitation & inhibition are Excitation & inhibition are

complex combinations of post-complex combinations of post-synaptic potentials on the neurons synaptic potentials on the neurons

membranesmembranes

Characteristics of nervous Characteristics of nervous processesprocesses

1. Force – working capacity of cortex neurons, their ability to withstand long-lasting & high intensity stimuli .

2. Balance – interrelation between excitation & inhibition.

3. Flexibility – ability of neurons to go from excitation to inhibition & back .

Evaluation of excitation Evaluation of excitation strengthstrength

1) By the velocity of conditioned reflex formation.

2) By the ability to form conditioned reflexes in response to very strong stimuli.

Evaluation of inhibition Evaluation of inhibition strengthstrength

1) By the velocity of differentiational inhibition formation, by its preciseness ( i.e. ability to define between 100 & 90 Hz).

2) By the increased duration of differentiative stimulus.

BALANCE BETWEEN BALANCE BETWEEN EXCITATION & INHIBITIONEXCITATION & INHIBITION

Can’t be defined in special terms yetCan’t be defined in special terms yet

MOBILITY OF NERVOUS MOBILITY OF NERVOUS PROCESSESPROCESSES:

1) CHANGING OF THE SIGNALING MEANING OF THE STIMULUS.

2) NEW STEREOTYPE FORMATION. 3) DECREASED TIME INTERVAL BETWEEN

POSITIVE & DIFFERENTIATIVE STIMULI.

Type of Higher NERVOUS Type of Higher NERVOUS ACTIVITYACTIVITY

• It’s a combination of inborn & acquired properties of nervous system – genotype + phenotype.

According toAccording toHypocrateHypocrate SanguinicSanguinic PhlegmaticPhlegmatic CholericCholeric MelancholicMelancholic

According to According to PavlovPavlov

LivelyLively ССalmalm БезудержныйБезудержный WeakWeak

4 Main types:

CholericCholericMelancholicMelancholic

PhlegmaticPhlegmaticSanguinicSanguinic

Nervous processesNervous processes

strongstrong weakweak

balancedbalancedNon-balancedNon-balanced

mobilemobilestillstill

Weak Weak melancholicmelancholic

Lively Lively sanguinicsanguinic

Calm Calm phlegmaticphlegmatic

Unrestrained Unrestrained cholericcholeric

1- Strong, Balanced, Flexible – lively - sanguinic

2- Strong, Balanced, inert - сalm - flegmatic3- Strong,unbalanced - unrestrained- choleric

4- weak - melancholic

Signaling systemsSignaling systemsI s.s. – system of conditioned reflexes to certain stimuli ( light, sound , others), is common for animals & people

II s.s. - system of conditioned reflexes to abstract stimulus – a word & its meaning,is characteristic only for people

Characteristics of Characteristics of conditioned reflexes in conditioned reflexes in the I and II signaling the I and II signaling

systemssystems

I and II s.s. are connected, they interact continuously

I s.s.:1. Conditioned reflexes are slowly

formed & changed.2. Reaction delay is little (minutes)3. Motivation to action is mainly

biological.4. Maintain body homeostasis.

II s.s.:1. Conditioned reflexes are quickly

formed & changed.2. Reaction delay is quite long (may be

years)3. Motivation to action is both biological

& social.4. Forms consciousness, abstract

thinking, allows social behaviour of man.

Interaction between I and II s.s. in human’s psychics defines special type of higher nervous activity in humans.

1. Artistic typeArtistic type – prevailing role of I s.s. , i.е. figurative perception ( it’s better once to see than 7 times to hear). Right hemisphere is a dominating one.

2. Intellectual typeIntellectual type – prevailing role of II s.s. – analysis activity. Left hemisphere is a dominating one.

3. Medium typeMedium type – no one signaling system is prevailing