THE DIENCEPHALON EPITHALAMUS SUBTHALAMUS HYPOTHALAMUS 1 epithalamus 2

THE DIENCEPHALON • • EPITHALAMUS SUBTHALAMUS HYPOTHALAMUS

1 - epithalamus 2 – thalamus 3 - subthalamus 4 - hypothalamus

DIENCEPHALON – medial aspect

Diencephalon. Superior aspect

Diencephalon – cross section I

Diencephalon – cross section II

Thalamus – relation to the internal capsule

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

Thalamus – pulvinar and epithalamic nuclei (medial and lateral geniculate body)

Pul = pulvinar thalami MGB = medial geniculate body LGB = lateral ge niculate body

Topography of the thalamic nuclei

Thalamocortical and Corticothalamic loop input

Thalamic nuclei • Relay nuclei (specific) – MGN, LGN, VPL, VPM, • • VL, VA Receives input predominantly from a single source Processed information is sent to a localized region of cortex Are modality specific Specific nuclei (after stimulation sharply localized cortical response)

Association (nonspecific) nuclei • MD, LP, Posterior ncc. , • Receives input from a number of structures or cortical areas • Sends fibers to the association cortical areas

Auditory pathway + BG visual pathway trigemino-thalamic tr. Afferent connections of the main thalamic nuclei spino-thalamic tr. lemniscal system

Thalamocortical projections

Inputs and outputs from thalamic nuclei

Cerebello (dentato)C thalamic e projections Majority ofr cerebellar e fibers terminate in the VL nucleusb e l l o

HYPOTHALAMUS

Hypothalamic zones and nuclei

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

References: P. Brodal : Central nervous system, Oxford, 2006 J. H. Martin : Neuroanatomy, Mc. Graw-Hill, 2003 V. Chan - Palay : Cerebellar dentate nucleus, Springer 1977. P. Kopf – Meier. Atlas of Human Anatomy Karger, 2000.