Diencephalon

Thalamus

relay to the cortex and its nuclei

Hypothalamus

the infundibulum, the mammillary bodies, functional homeostasis

Epithalamus

pineal gland, and habenula

Thalamus functions

Neural mediation to/from the cortex (sensory, motor, also limbic)

Hypothalamus functions

Regulates homeostasis (functional connections with autonomic, limbic system)

• Direct relay with pituitary= through infundibulum

• Indirect relay with pituitary= through hormones into Hypothalamohypophyseal portal venous system (HHPV)

Pituitary functions

• Hormone secretion for growth, metabolism, reproductive, and other endocrine functions

• Melatonin (sleep and circadian rhythm)

Thalamus Structural features

2 ovoid-shaped structures, joined by a midline bridge = massa intermedia

The spinal sensory tracts terminate in the ____, then ____ order neurons to the cortex via the ___

thalamus, 3 rd or 4th, internal capsule

Descending motor tracts (____) pass ____ through the internal capsule

corticospinal, corticobulbar, corticopontine; lateral to thalamus

Thalamus is located between the_____to the brainstem

hemispheres, adjacent to 3rd ventricle and superior

“diencephalon” Latin =

in the midst/between the brains

Thalamus nuclei is divided by

Subdivided into dorsal or ventral portions, AND anterior or posterior

Anterior nuclei=

relays within the limbic system, (emotions, memory, and learning)

The medial nuclei=

sensory and emotional integration

Lateral thalamus nucleus has many specific nuclei for

sensory, motor, and integrative information.

Thalamic Pain Syndrome

More frequently leads to the sensation of excruciating pain

VPM and VPL (ventral posterior medial and lateral nuclei) thalamus nuclei

hypo esthesisas from the head and body on the contralateral side.

Hypothalamus Nuclei distributed by “quadrants” in this orientation:

Medial-lateral and Rostro-caudal

Rostral nuclei =

by proximity to optic chiasm

Pre-optic=

reproductive function (engage with hormone release from anterior pituitary, sexually dimorphic)

Supra chiasmatic=

regulate circadian rhythms

Anterior hypothalamic =

heat dissipation

Paraventricular and supraoptic (water conservation) =

production of these hormones=oxytocin and anti-diuretic hormone ADH)

Caudal nuclei =

regulate sympathetic function and heat conservation

Tuberal region with 3 nuclei:

dorsomedial, ventromedial, lateral (food intake by satiety/hunger)

Tuberal region Lateral =

regulates hunger

Tuberal region Medial=

regulates satiety

Fornix (white matter tract) connects to

hippocampus (limbic system)

Arcuate=

energy/metabolism, endocrine functions, (input from insulin for glucose uptake or from leptin for fat utilization)