white matter

white matter composition

myelinated nerve fibers

3 types of nerve fibers in white matter

1. Association fibers

2. Commissural fibers

3. Projection fibers

fibers that interconnect cortical sites lying within one hemisphere

association fibers

fibers that connect functionally related gyri on both hemisphere

commissural fibers

fibers that connect cortex with lower centers in thalamus brain stem or spinal cord

projection fibers

short / long association fibers connect

short association fibers connect NEARER gury, long association connect DISTANT gyri (within same hemisphere)

connects the occipital, parietal, temporal lobes with frontal

superior longitudinal fasciculus

subsidiary bundle of superior longitudinal fasciculus that connects frontal & temporal lobes
( connects Broca’s area in frontal with Wernicke’s area in temporal )

arcuate fasciculus (long association fiber)

which type of the long association fibers contributes to language, attention, memory, emotion

superior longitudinal fasciculus

inferior longitudinal fasiculus connects what

connect occipital & temporal poles

which type of the long association fibers contributes to visual recognition

inferior longitudinal fasiculus

It connects the anterior & inferior parts of the frontal gyrus with the temporal gyri and important for behavioral regulation

uncinate fasciculus

cingulum runs in

cingulate gyrus

cingulum curves _________ (anterior/inferior/posterior/superior) to run in the Parahippocampal gyrus

inferiorly

what begins in the anterior perforated substance in frontal lobe

cingulum

cingulum terminates in

Uncus

These white matter tracts interconnect frontal, parietal and medial temporal regions and are thought to carry signals that contribute to executive control and memory processes.

Cingulum

сори за качество

these are major commisural fibers. name them (all 3)

red - corpus callosum
orange - anterior commissure
green - hippocampal commisure

largest commisure of brain, connects homologous areas of 2 hemisphere

corpus callosum

4 parts of corpus callosum

rostum, genu, body, splenium

corpus callosum где находится относительно median longitudinal fissure

lies in the floor of median longitudinal fissure

inferior surface of corpus callosum attached to what

fornix by the septum pellucidum

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которое из них fornix и corpus callosum?

fornix - green
corpus callosum - gray

(purple - rostrum
orange - genu
purple - trunk
brown - splenium)

rostrum & genu interconnect what part of brain

anterior part of frontal lobe

what parts of brain trunk interconnects

posterior part of frontal / perietal / temporal lobes

what part of brain splenium interconnects

occipital

[important] fibers of the ROSTRUM & GENU arch FORWARD to form

forceps MINOR

[important] fibers of the SPLENIUM arch BACKWARD to form

forceps MAJOR

anterior commisure lies and runs where

behind lamina terminalis
runs transversely in front of anterior column of fornix

interconnects middle & inferior temporal gyri and connects the olfactory regions of the 2 hemisphere

anterior commissure

composed of transverse fibers, interconnects the posterior of the fornix

hippocamal commisure

projection fibers

what lies between head of caudate nucleus and thalamus medially, lantiform laterally, continous above with corona radiata

internal capsule

what contains frontopontine fibers

anterior limb

corticonuclear fibers related to

genu

pure motor hemiparesis without sensory loss, visual defects (lacunar infarct) means affected what structure

posterior limb of internal capsule (carries corticospinal and corticobulbar pathways for the body and limbs)

A neurosurgeon performs a surgical resection near the anterior wall of the third ventricle. During the dissection, a small transverse white matter bundle lying immediately in front of the anterior columns of the fornix and behind the lamina terminalis is identified. Which cortical or subcortical structures are primarily interconnected by this fiber tract?

middle/inferior temporal gyri and olfactory regions

what part of internal capsule contains optic radiation, posterior thalamic radiation

retrolentiform part

what part of internal capsule contains auditory radiation, inferior thalamic radiation

sublentiform

A patient presents following an ischemic stroke affecting the posterior limb of the internal capsule.

why facial weakness is absent in a pure posterior limb stroke?

Isolated lesions of the posterior limb spare the face/head because corticonuclear fibers travel through the genu, anterior to the corticospinal fibers

a patient with stroke symptoms who develops a contralateral homonymous hemianopia due to fiber disruption within the internal capsule. Which specific fibers are affected?

Optic radiation (posterior thalamic radiation).

Which internal capsule region is affected upon hemorrhagic insult with motor deficits of face/arm, executive dysfunction, cognitive/behavioral changes

anterior limb