Cerebrum II Flashcards
(41 cards)
What are the different classes of white matter of the cerebrum?
- Association fibers
- Projection Fibers
- Commisural fibers
What are association fibers?
white matter that connects the different parts of the same cerebral hemisphere. Classified as eithe short or long association fibers
What are projection fibers?
White matter that connects the cerebral cortex with the brainstem, cerebellum, and Spinal cord
What are commissural fibers?
White matter that connects the right and left cerebral hemisphere
List all the Long association fibers
- Cingulum
- Uncinate fasciculus
- Superior Longitudinal fasciculus
- Inferior Longitudinal fasciculus
- Fronto-occipital fasciculus
What is the cingulum?
Bundle of nerve fibers that lie within the cingulated gyrus, and connects the frontal and parietal lobes with the parahippocampal and adjacent temporal cortical region

What is the significance of the cingulum?
forms part of Papez circuit for emotional integration and recent memory formation
What is Uncinate Fasciculus?
long association fibers that hook around the floor of the stem of the lateral sulcus. It connects the anteromedial temporal lobe with the orbitofrontal cortex
A patient presents with damage to the Uncinate fasciculus. What does the patient present with?
- Deficit in object recognitiion
- Reduced verbal fluency
- Anomia
What is anomia?
unability to recall names
What is arcuate fasciculus?
Connects Broca’s motor speech area with Wernicke’s speech area. Part of uncinate fasciculus, but also referred to as a subset of superior longitudinal fasciculus
What does a patient with damage to the arcuate fasciculus present with?
Conduction aphasia
They retain the ability to speak and comprehension is preserved, but they cannot connect the two, thus the patient would be unable to repeat simple phrases
What is the Superior Longitudinal Fasciculus?
Long association fibers that connect the visual cortex [area 17] with the frontal eye field. Looked external to corona radiata
What is the Inferior Longitudinal Fasciculus?
Long association fibers that connects area 18 and 19 of the occipital cortex to the temporal lobe.
It extends longitudinally along the lateral wall of posterior horn and lateral ventricle outside the fibers of the optic radiation and tapetum of corpus callosum
What is the Fronto-occipital fasciculsus?
Long association fiber that extends anteromedially from the frontal pole to the occipito-temporal lobes. [medial to corona radiate]
List all commissural fibers
- corpus callosum
- Anterior commisure
- Posterior commissure
- Habenular commissure
- Optic chiasma
- Hippocampal commissure
What are the parts of the corpus callosum?
- Rostrum
- Genu
- Trunk/Body
- Splenium
Arranagement of Corpus Callosum Fibers
-
Forceps minor:
- fibers arise from genu
- connects medial and lateral surfaces of frontal lobes
-
Tapetum:
- fibers arise from posterior part of body
- forms roof + lateral wall of posteior horn of lateral ventricle
-
Forceps major:
- dibers arise from splenium
- connect occipital lobes
Relations of the Corpus Callosum
-
Upper surface:
- 2 ACA
- Lower margin of falx cerebri with inferior sagittal sinus
-
Below the splenium:
- PCA
- Great cerebral vein
- Pineal gland
-
In relation to the lateral ventricle
- undersurface of body forms roof of lateral ventricle
- Genu forms anterior wall of lateral ventricle
- rostrrum forms part of floor of anterior horn of lateral ventricle
What are the functions of the Corpus callosum?
Coordination of activities of the two cerebral hemispheres, transfer of learning process and speech function
[connects area 22, 39, 40, 44, and 45 from both hemispheres]
What causes split brain syndrome?
complete section of corpus callsoum
Describe the presentation of a patient with Split brain syndrome
When viewing an image in their left visual field, the patient will be unable to name the what they saw as the speech-control center is on the left, will the image seen is on the right side of the brain.
same thing is the patient’s speech-control center is on the right and an image is placed in the right visual field
What is the anterior commissure?
commissural fibers that plays a key role in pain sensation [acute, sharp] and contains decussating fibers from the olfactory tracts, that are vital for the sense of smell and chemoreception
found in front of intraventricular foramen and grooves the antero-inferior surface of the lentiform nucleus
What is the functional importance of the posterior commissure?
- important for bilateral pupillary light reflex
- interconnects pretectal nuclei, mediating consensual pupillary light reflex

