4. Deep Structures of the Cerebral Hemispheres

1. Lateral Ventricles

- separated by septum pellucidum

- connected to 3^rd ventricle by interventricular foramina of Monro

a. anterior horns

b. body

- parietal lobe

c. posterior (occipital) horn

- occipital lobe

d. inferior horn

- temporal lobe

2. Deep nuclei (basal ganglia) = telencephalic extrapyramidal motor system; (substantial nigra = mesencephalic extrapyramidal motor system)

- corpus striatum = caudate, putamen, globus pallidus

- neostriatum = caudate and putamen

- lentiform nucleus = putamen and globus pallidus

a. Caudate

- tail ends in amygdala (temporal)

b. Putamen

c. Globus Pallidus

d. fornix

- connects hippocampus (temporal lobe) with mammillary bodies (hypothalamus)

3. Underlying White Matter

a. commissural

i. corpus callosum

ii. anterior commissure

- larger in homosexual men

iii. posterior commissure

- crossing fibers for pupillary light reflex

b. association

i. long (much redundancy)

1. superior longitudinal fasciculus

a. arcuate fasciculus (connects Broca’s 44,45; angular and supramarginal 39,40; Wernicke’s 22)

- part of the superior longitudinal fasciculus

- conduction aphasia

2. inferior longitudinal fasciculus

- inferior continuation

3. uncinate fasciculus

- common site of seizures

4. cingulum

- fibers travel perpendicular to corpus callosum

- part of limbic system (connects hippocampus, etc.)

ii. short

1. arcuate fibers

c. projection (corona radiata)

i. internal capsule

- supplied by MCA (isolated limbs can be affected by CVA)

1. anterior limb (pre-frontal)

2. genu limb

- cortico-bulbar fibers = UMN’s; cell bodies of origin: Brodmann’s 4,8

- terminate in motor nuclei of cranial nerves

3. posterior limb

- cortico-spinal tract (Area 4)

4. retrolenticular limb

ii. external capsule

iii. extreme external capsule