THETHE DIENCEPHALONDIENCEPHALON

Inst.Inst. ofof Anatomy,Anatomy, 1st1st MedicalMedical FacultyFaculty R.R. DrugaDruga

THETHE DIENCEPHALONDIENCEPHALON

 EPITHALAMUSEPITHALAMUS  THALAMUSTHALAMUS  SUBTHALAMUSSUBTHALAMUS  HYPOTHALAMUSHYPOTHALAMUS

AMPHIBIANS MAMMALS

AMFIBIA MAMMALIA

DIENCEPHALON – medial aspect

BRAIN STEM AND DIENCEPHALON

Superior aspect

Pulvinar - cushion

THALAMUS AND BASAL GANGLIA – horizontal section

THETHE THALAMUSTHALAMUS -- NUCLEINUCLEI

 Anterior nuclei  Medial nuclei (mediodorsal nc.)  Lateral nuclei – dorsal tier (lateral dorsal nc., lateral posterior nc.,posterior ncc.,(ncc. of pulvinar)  ventral tier ( ventral anterior – VA, ventral lateral – VL, ventral posterolateral- VPL, ventral posteromedial – VPM, ventral intermediateintermediate -- VIM,VIM,  Medial geniculate nc.,  Lateral geniculate nc.,  Intralaminar nuclei  Midline nuclei  Reticular nucleus

SUBTHALAMUS

Zona incerta Subthalamic nc.

PULVINAR – posterior nuclei

METATHALAMUS= Medial and lateral geniculate bodies

Parcellation of thalamic nuclei according Michigan ´s school

Neuronal connections of thalamic nuclei

ThalamicThalamic nucleinuclei

 RelayRelay nucleinuclei ((relérelé jádrajádra,, přepojovacípřepojovací jádra)jádra) –– MGN,MGN, LGN,LGN, VPL,VPL, VPM,VPM, VL,VL, VAVA  ReceivesReceives inputinput predominantlypredominantly fromfrom aa singlesingle sourcesource  ProcessedProcessed informationinformation isis sentsent toto aa localizedlocalized regionregion ofof cortexcortex  AreAre modalitymodality specificspecific  SpecificSpecific nucleinuclei (after(after stimulationstimulation sharplysharply localizedlocalized corticalcortical response)response)

AssociationAssociation nucleinuclei

 MD,MD, LD,LD, LP,LP, PosteriorPosterior ncc.,ncc.,  ReceivesReceives inputinput fromfrom aa numbernumber ofof structuresstructures oror corticalcortical areasareas  SendsSends fibersfibers toto thethe associationassociation corticalcortical areasareas  SpecificSpecific nucleinuclei (after(after stimulationstimulation sharplysharply localizedlocalized responseresponse inin thethe cortex)cortex)

NonspecificNonspecific nucleinuclei

 IntralaminarIntralaminar nucleinuclei (centromedian,(centromedian, parafascicular)parafascicular)  AfferentsAfferents -- fromfrom RF,RF, spinothalamicspinothalamic fibers,fibers, cerebellum,cerebellum, BGBG  EfferentsEfferents –– extensiveextensive areasareas ofof thethe frontalfrontal andand parietalparietal lobes,lobes, basalbasal gangliaganglia (striatum)(striatum)  FunctionFunction –– influenceinfluence levelslevels ofof consciousnessconsciousness andand degreesdegrees ofof alertnessalertness

Termination of subcortical projections in the thalamus

Somatotopic organization of the VPL and VPM ncc. = termination of the lemniscal systém and trigeminothalamic pathway

Termination of subcortical fibers in the thalamus – horizontal section

VA - GP

VA - SNr

IL VL – VPL + MD VPM cerebellum

Post. Ncc..

Dentato-thalamic projection

EPITHALAMUS

EPITHALAMUSEPITHALAMUS  HabenularHabenular nucleinuclei  Afferent fibers – stria medullaris thalami (septum verum, olfactory cortex, hippocampus, hypothalamus, basal ganglia (globus pallidus)  Efferent fibers – tractus habenulointerpeduncularis (RF, hypothalamus, ANS)  PinealPineal gland-gland- inin amphibianamphibian andand fishesfishes containscontains light-light- sensitive cells. In mammals transformed to the endocrine gland  Afferent fibers – superior cervical ganglion, hypothalamus, colliculus superior, LGB  Pinealocytes produce serotonin – melatonin (night ),  Supresses development of gonads (pinealectomy stumulates growth of of the reproductive organs

SUBTHALAMUSSUBTHALAMUS –– later,later, nextnext weekweek

HYPOTHALAMUS

Posterior lobe Anterior lobe

THETHE HYPOTHALAMUSHYPOTHALAMUS

• Lateral zone  TuberalTuberal regionregion  No discrete nuclei  VM – satiety center (lesion  Regulation of food and water produces hyperphagia + intakeintake obesity) •Medial zone  Arcuate nc. - delivers peptides to the portal vessels •Well defined nuclei •Chiasmatic region  MamillaryMamillary regionregion  • (SO,PV – hormone release) Posterior nc.- elevating of blood pressure, pupillary •Cardiovascular function (Ant.) dilatation, body heat •Circadian rhytms (SCH) conservation  Mammillary ncc. – memory •Body temperature (Preoptic nc.) formation !!!