what are the 4 anatomical components of the diencephalon?
- 2 thalamic bodies divided into 12 nuclei- connected by inter thalamic adhesion aka massa intermedia
- epithalamus- posterior to the thalamic bodies
- hypothalamus- anterior and inferior to the thalamic bodies
- subthalamus- posterior and inferior to the thalamic bodies
what are the connections to the diencephalon?
- 75% projection fibers
- serves as a relay station to cortex or an association center for processing
- projection fibers travel in the internal capsule
what supplies blood to the diencephalon?
branches of the posterior and middle cerebral arteries
what are the anterior, lateral, medial, and posterior external boundaries of the diencephalon?
-anterior- optic chiasm, anterior commissure, lamina terminalis
-lateral- optic tracts and internal capsule
-medial- lateral and 3rd ventricles, massa intermedia
posterior- posterior commissure and basis pedunculi
what are the components of the epithalamus?
- pineal gland
- functions: melatonin; possible seasonal and hormonal regulation
- habenular nuclei: multiple connections may influence: circadian rhythms, inhibition of excess movement via the basal ganglia, social and cognitive functions
what are the components of the subthalamus
- subthalamic nuclei- part of the basal ganglia loops
- zona inserta- possibly superior part of the reticular formation, possible role in pain perception
what are the 4 parts of the hypothalamus
midline nuclei, mammillary bodies, infundibular stalk, posterior lobe of pituitary gland
True or false the thalamus is located laterally to the internal capsule
FLASE the thalamus is located medially to the internal capsule
the thalamus has three major groups that are divided by the intramedullary lamina of white matter (“Y”), what are the 3 groups?
anterior, medial, and lateral
what is found in the anterior group of the thalamus?
anterior nuclei
what is found in the medial group of the thalamus?
medial dorsal, midline, and midline nuclear group
what is found in the lateral group of the thalamus?
- Ventral portion: VA, VL, VPL, VPM, LBG, MGB
- Dorsal portion: LD, LP, Pulvinar
what is the blood supply for the thalamic nuclei?
Posterior cerebral artery and posterior communicating artery
what are the intralmainar nuclei?
they are located in the “Y” of the internal medullary lamina
- centromedian nuclei: linked to arousal and attention
- parafascicular nuclei: damage linked to epilepsy
what are the extra laminar nuclei?
nuclei located in a sheath pf cels on the lateral surface
- thalamic reticular nuclei
- midline nuclei
true or false: the thalamus is 75% projection fibers and 25% interneurons
TRUE
what 3 thalamic nuclei function as part of the limbic system; are they relay or association nuclei?
-anterior nucleus
-lateral dorsal
-medial dorsal
all are association
what 2 thalamic nuclei are for motor planning and coordination, are they relay or association nuclei?
- ventral anterior
- ventral lateral they are relay nuclei
what 2 thalamic nuclei are for somatosensory (pain, temp, and taste), are they relay or association nuclei?
-VPL
-VPM
they are relay nuclei
what thalamic nuclei is for sensory integration?
lateral posterior- association nuclei
what thalamic nuclei is for sensory integration and visual attention?
pulvenar- association nuclei
what thalamic nuclei is for coordination of visual signals?
lateral geniculate- relay nuclei
what thalamic nuclei is for sound localization and perception?
medial geniculate- relay nuclei
hemorrhage of the lenticulostriate artery will cause what?
- in posterior limb- contralateral paralysis and hemianesthesia
- retrolenticular or sublenticular areas: visual deficits
