INTEGRATIVE FUNCTIONS INTEGRATIVE FUNCTIONS OF DIENCEPHALON & OF DIENCEPHALON &

SUBCORTICAL GANGLIASUBCORTICAL GANGLIA

MD, Ph.D. Ivasenko A.MD, Ph.D. Ivasenko A.

THALAMUSTHALAMUS

Consists of about 40 nuclei which are Consists of about 40 nuclei which are divided functionally into groupsdivided functionally into groups

I. I. SPECIFIC OR RELAY SPECIFIC OR RELAY NUCLEINUCLEI

Lateral geniculate bodyLateral geniculate body ( (LGBLGB) – ) – visual modalityvisual modality Medial geniculate bodyMedial geniculate body ( (MGBMGB))– – auditory modalityauditory modalityVentro-basilar complexVentro-basilar complex ( (VPVP) – ) – somato-sensory modalitysomato-sensory modality

Ventro-posterio-lateral nucleusVentro-posterio-lateral nucleus (( VPLVPL ))

Lemniscus medialis & Spino-thalamic tracts

Skin & proprio-receptors,Including pain receptors

n.vagus

interoreceptors

Ventro-posterio-medial nucleusVentro-posterio-medial nucleus (( VPMVPM ))

Vestibulo-receptors

Face receptors

Lemniscus medialis

Gustatory receptors

Vestibular pathways

n. trigeminus

Specific nucleiSpecific nuclei

FunctionFunction – – get sensory information from get sensory information from specific pathways & send it to specific specific pathways & send it to specific sensory zones of cortexsensory zones of cortex. . Topical organizationTopical organization – – each neuron is each neuron is connected with specific receptive fieldconnected with specific receptive field

Lateral inhibition in thalamus helps Lateral inhibition in thalamus helps to cut off aberration & define to cut off aberration & define important sensory signalimportant sensory signal – –

information

Goldgi neurons

Afferent neurons

II II MOTOR NUCLEUSMOTOR NUCLEUS ventrolateralventrolateral ( (VLVL))

Is included in the system of movemnt Is included in the system of movemnt regulationregulation. . Gets impulses from cerebellum & basal Gets impulses from cerebellum & basal gangliaganglia. . Sends information to motor cortexSends information to motor cortex ( (pre-pre-central gyruscentral gyrus).).

Th

Cortex

Hypothalamus

Cerebellum &Basal ganglia

Information analysis

Regulation of visceral functions

Regulation of movements

III III ASSOCIATIVE NUCLEIASSOCIATIVE NUCLEIPulvinarPulvinar - - is connected with temporal & is connected with temporal & parietal associative cortexparietal associative cortexPosterio-lateral nucleusPosterio-lateral nucleus ( (LPLP) – ) – is connected is connected with temporal cortexwith temporal cortexMedio-dorsal nucleusMedio-dorsal nucleus ( (MPMP) – ) – is connected is connected with frontal cortexwith frontal cortexAnterior nucleusAnterior nucleus – – is connected with limbic is connected with limbic cortexcortex

All associative nuclei are getting All associative nuclei are getting poly-modal signals frompoly-modal signals from::

Specific relay nucleiSpecific relay nucleiSpecific afferent pathwaysSpecific afferent pathwaysThey are included into the associative They are included into the associative systems of the brain & take part in the systems of the brain & take part in the integrative processesintegrative processes forming behaviour forming behaviour and memoryand memory..

IV IV NON-SPRCIFIC NUCLEINON-SPRCIFIC NUCLEI

INTRALAMINAR & MEDIUM GROUP OF INTRALAMINAR & MEDIUM GROUP OF NUCLEINUCLEI , they are continuation of reticular , they are continuation of reticular formation of the brain stem and are poly-formation of the brain stem and are poly-modal because they get information frommodal because they get information from : :RF of brain stemRF of brain stem Specific afferent pathwaysSpecific afferent pathways SpecificSpecific thalamus nucleithalamus nucleiSend impulses diffusively to all the cortex Send impulses diffusively to all the cortex zoneszones

THALAMUS IS THE HIGHEST THALAMUS IS THE HIGHEST CENTER OF PAINCENTER OF PAIN

FUNCTIONAL FUNCTIONAL CLASSIFICATION OF CLASSIFICATION OF THALAMUS NUCLEITHALAMUS NUCLEI

Sensor zones of cortex

Associative zonesof cortex

Motor zonesof cortex

Sensor information from receptors

Sensor specificnuclei

Non-specific nuclei

Associative nuclei

Cerebellum & basal ganglia

Motor nuclei

HYPOTHALAMUSHYPOTHALAMUS

ANATOMICAL STRUCTURESANATOMICAL STRUCTURES::

TUBER CINEREUMTUBER CINEREUMHYPOPHYSISHYPOPHYSISCORPORA MAMMILLARIA CORPORA MAMMILLARIA

ANATOMICAL PECULIARITIESANATOMICAL PECULIARITIES

GROUS OF NUCLEA ARE NOT GROUS OF NUCLEA ARE NOT STRICTLY LOCALISEDSTRICTLY LOCALISEDNO BLOOD-BRAIN BARRIERNO BLOOD-BRAIN BARRIERMULTIPLY CONNECTIONS WITH MULTIPLY CONNECTIONS WITH OTHER OTHER ССNS STRUCTURESNS STRUCTURES

Medial hypothalamus

Lateralhypothalamus

Thalamus – anterior nuclei

Cortex

adenohypophysis neurohypophysis

liquor blood

RF of hindbrain

RF of midbrain

Globuspallidus

Limbic system

Modern views on Modern views on hypothalamic functionshypothalamic functions

GETTING INFORMATIONGETTING INFORMATION

ABOUT EXTERNAL ENVIRONMENTABOUT EXTERNAL ENVIRONMENT – – via via nervous connections from thalamus, RF, cortexnervous connections from thalamus, RF, cortexABOUT INTERNAL ENVIRONMENTABOUT INTERNAL ENVIRONMENT - - from from blood & liquorblood & liquor ( (HEB is very lowHEB is very low))Information is received by sensory neuronsInformation is received by sensory neurons ((osmoreceptorsosmoreceptors, , volumoreceptorsvolumoreceptors, , glucoreceptorsglucoreceptors & others& others),), which process this which process this info & form sensationsinfo & form sensations..

CENTERS OF SENSATION IN CENTERS OF SENSATION IN HYPOTHALAMUSHYPOTHALAMUS

hungerhunger – – satietysatietythirstthirst – – thirst satisfactionthirst satisfactionsleepsleep- - awakenessawakenesswarmthwarmth – – coldcoldaggressionaggression – – calmnesscalmness

EFFECTOR FUNCTIONSEFFECTOR FUNCTIONS

Formation of emotions & motivation of Formation of emotions & motivation of behaviorbehavior due to the connections with limbic due to the connections with limbic systemsystemGive rise to behavioral programs Give rise to behavioral programs (instincts)(instincts) with the involvement of somatic & with the involvement of somatic & vegetative NSvegetative NS

Performed by neurons effectorsPerformed by neurons effectors

Neurons effectors

Somatiс NS

Locomotor component

Vegetative NS(brain stem)

Endocrine system

Vegetative component

Hypothalamus FUNCTIONSHypothalamus FUNCTIONS

Sensory neurons

Effectoryneurons

Externalsignals

Internalsignals

Limbic system

feelings

CORTEX Emotions & motivations

Somatic NS Vegetative NS Endocrine system

Behaviour aimed at homeostasis maintanense

Basal gangliaBasal ganglia ( (striopallidum systemstriopallidum system))

Are paired structures, grey matter located in Are paired structures, grey matter located in the white matter of hemispheres between the the white matter of hemispheres between the

frontal lobes & diencephalonfrontal lobes & diencephalon

Striopallidum integrates the functions of Striopallidum integrates the functions of associative &motor cortexassociative &motor cortex

Motor cortexAssociative cortex

Striopallidar system

        

 

Cortex zonesSENSORY ASSOCIATIVE MOTOR

n. caudatus

puta

men Gl.Pal.

Motor nn. of thalam.

Brain stemSubthalamic nucleus

Subst. Nigrum

dopamine

dopamine

As it is clear from the scheme the afferent As it is clear from the scheme the afferent input gets into striatuminput gets into striatum, а, аndnd the efferent the efferent influences are performed by globus influences are performed by globus pallidum alonepallidum alone..Due to the connections with motor cortex Due to the connections with motor cortex via thalamusvia thalamus BG take part in realization of BG take part in realization of movement programmemovement programme..

MediatorsMediators::

Substantia nigrum neurons secreteSubstantia nigrum neurons secrete dopaminedopamineN.caudatum & claustrum neuronsN.caudatum & claustrum neurons – – are are connected with pallidus, they secrete connected with pallidus, they secrete GABAGABA Cortex neurons send impulses to striatum Cortex neurons send impulses to striatum & secrete& secrete acetylcholineacetylcholine

Striopallidum effectsStriopallidum effects::

Activates motor neurons ofActivates motor neurons of flexorsflexors via via pyramidal tractspyramidal tractsMultiply influences on flexors & extensors tone Multiply influences on flexors & extensors tone via motor neurons of brain stemvia motor neurons of brain stemInhibits stretching reflexes Inhibits stretching reflexes влияя на альфа и влияя на альфа и гамма мотонейроны вместе с черной гамма мотонейроны вместе с черной субстанцией через двигательные ядра субстанцией через двигательные ядра ствола мозгаствола мозга

So striopallidum facilitates the performance of So striopallidum facilitates the performance of such complex movement programs as such complex movement programs as writing, writing, musical instruments playing,musical instruments playing,

Striopallidum effectsStriopallidum effects: :

Control of some involuntarily movements Control of some involuntarily movements in emotional statesin emotional statesTogether with cerebellum helps to keep Together with cerebellum helps to keep movement programs & information about movement programs & information about learnt movementslearnt movementsRegulate the glossary musclesRegulate the glossary muscles activity to activity to modulate voice & speechmodulate voice & speech

STRIOPALLIDAR SYSTEM STRIOPALLIDAR SYSTEM FUNCTIONSFUNCTIONS

1.1. Regulation of acurate hand movementsRegulation of acurate hand movements2.2. Keeping movement programsKeeping movement programs3.3. Regulation of vegetative functionsRegulation of vegetative functions4.4. Switches on programs of instinct behaviourSwitches on programs of instinct behaviour

((orientation, defense orientation, defense reflexesreflexes).).

Pathological states at strio-pallidum Pathological states at strio-pallidum affectionaffection

When Substantia Nigrum connections with When Substantia Nigrum connections with subcortical ganglia are affected or at the lack subcortical ganglia are affected or at the lack of dopamineof dopamine tremor at resttremor at rest developsdevelops, , as well as well as other symptoms of Parkinsonismas other symptoms of ParkinsonismWhen striatum is affected tremor develops When striatum is affected tremor develops both at rest & during movement (chorea), plus both at rest & during movement (chorea), plus hyperkinesiahyperkinesia

Pathological signs at strio-Pathological signs at strio-pallidum affectionpallidum affection

When globus pallidum is affected hypokinesia When globus pallidum is affected hypokinesia developsdevelopsIn rheumatic chorea both hypo -& In rheumatic chorea both hypo -& hyperkinesias develop, mimic muscles are hyperkinesias develop, mimic muscles are affected, handwriting is changedaffected, handwriting is changed

PARKINSON DISEASEPARKINSON DISEASE CLINICAL SIGNSCLINICAL SIGNS

Stereotaxis: 1 - electrode, 2 – ear fixators, 3 – upper jaw fixators

Frontal cross-section of cat/s brain with marked subcortical structures мозга