Cerebral Hemisphere White Matter: Projection Fibers

Question 1

Projection fibers

Answer 1

Fibers passing through internal capsule either:
1. To cortex from thalamus (Afferents sensory) from thalamus
Or
2. From cortex to lower centers (efferents motor)

Question 2

Projection fibers to cerebral cortex from thalamus

Answer 2

All impulses to cerebral cortex must stop first in thalamus so the only fibers which reach cortex come from the thalamus (thalamo-cortical fibers or thalamus radiation)

Question 3

Thalamus radiations

Answer 3

1. Sensory radiation (superior thalamic radiation)
2. Visual (optic) radiation (posterior thalamic radiation)
3. Auditory radiation (inferior thalamic radiation)
4. Anterior thalamic radiation

Question 4

Superior thalamic radiation

Answer 4

FROM PVNT TO sensory area (3,1,2) in parietal lobe Postcentral gyrus

Question 5

Posterior thalamic radiation

Answer 5

FROM lateral geniculate body TO visual area (17) in occipital cortex

Question 6

Inferior thalamic radiation

Answer 6

FROM medial geniculate body TO auditory area (41, and 42) in temporal lobe

Question 7

Projection fibers from cerebral cortex to lower centers

Answer 7

1. Pyramidal tract
2. Cortico-pontine fibers
3. Many extra pyramidal fibers
4. Cortico-thalamic fibers

Question 8

Pyramidal tract

Answer 8

1. Corticospinal
2. Corticobulbar

Question 9

Cortico-pontine fibers

Answer 9

1. Fronto-pontine fibers
2. Temporo-parieto-occipito-pontine fibers

Question 10

Extra pyramidal fibers

Answer 10

To many extra-pyramidal centers

Question 11

Cortico-thalamus fibers

Answer 11

To different nuclei of thalamus