White matter of the cerebrum

Question 1

White matter:
3 types of fibers classified by their origin and termination

Name them:

Answer 1

Association fibres
Commissural fibres
Projection fibres

Question 2

Question 3

Question 4

Association fibers

Interconnect cortical sites lying within one cerebral hemisphere

Some of these association fibers are short and link nearby areas of the cortex. This is done by arching beneath adjacent cerebral sulci

Other association fibers are much longer, they travel through the white matter to link distant areas of the cerebral cortex

The primary sensory areas located in the parietal, occipital and temporal lobe are linked through long association fibers, to the association areas of the cerebral cortex and these areas in turn will be connected to each other

Question 5

Name the association fibers

Answer 5

Superior longitudinal fasciculus
Arcuate fasciculus
Inferior longitudinal fasciculus
Uncinate fasciculus
The cingulum

Question 6

Superior longitudinal fasciculus

Answer 6

Interconnects the frontal and occipital lobes

Question 7

Arcuate fasciculus

Answer 7

A subsidiary of the superior longitudinal fasciculus

Links gyri in the frontal and temporal lobes important for language formation

Question 8

Inferior longitudinal fasciculus

Answer 8

Runs between the occipital and temporal poles

Contributes to the function of visual recognition

Question 9

Uncinate fasciculus

Answer 9

Connect the anterior and inferior parts of the frontal lobe with the temporal gyri, which are important structures in the regulation of behaviour

Question 10

The cingulum

Answer 10

Lies within the cingulate gyrus and course parallel with the corpus callosum

Connects the frontal and parietal lobes with the parahippocampal
and adjacent temporal gyri

Question 11

Question 12

Depending on where you section the brain, you will see a different part to the corpus callosum

Question 13

Answer 13

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Question 15

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Question 16

Answer 16

Question 17

Question 18

COMMISSURAL FIBRES

Question 19

Name the three commissure fibers

Answer 19

Anterior commissure
Posterior commissure
Hippocampal commissure (commissure of the fornix)

Question 20

Anterior commissure

Answer 20

Runs transversely in front of the (anterior) column of the fornix, near the interventricular foramen

Interconnects the inferior and middle temporal gyri and
the olfactory regions of the two sides

Question 21

Posterior commissure

Answer 21

Lies dorsal to the periaqueductal grey at the transition between the midbrain and the diencephalon

Thought to carry some of the decussating fibres that mediate the consensual light reflex

Important neuroradiological landmark

Question 22

Hippocampal commissure (commissure of the fornix)

Answer 22

Consists of fibres passing between the posterior columns (crura of the fornix) of each side

Question 23

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