White matter tracts

corpus callosum

connect cortical areas across hemispheres

genu of corpus callosum

connects prefrontal cortices. Signals about executive function and motor speech planning

Body of corpus callosum

connects premotor, primary motor, primary somatosensory, and somatosensory association areas

splenium of corpus callosum

connects occipital lobes; connects temporal lobes. Connects “what” pathways

anterior commissure

responsible for acute, sharp pain, connects L and R amygdala and temporal cortices

posterior commissure

important in bilateral pupillary light reflex

superior longitudinal fasciculus

Spatial awareness, integrates sensory info from all lobes, connects frontal, parietal, cingulate, temporal, and occipital cortices

superior occipitofrontal fasciculus

“where” visual pathway, connects orbital and lateral frontal cortices to occipital cortex

arcuate fasciculus

ability to repeat language, connects Wernicke’s and Broca’s areas

inferior occipitofrontal fasciculus

plays a critical role in semantic language, goal oriented behavior, and visual switching tasks, connects orbital and lateral frontal cortices to occipital and parietal cortices

middle longitudinal fasciculus

connects paralimbic, associative, and prefrontal cortices, superior temporal gyrus to temporal pole, verbal auditory integration

inferior longitudinal fasciculus

object recognition “what” pathway, connects occipital and temporal lobes

uncinate fasciculus

memory, language, and social emotional processing, connects orbitofrontal to temporal lobes

extreme capsule

Links Broca’s, Wernicke’s, and angular gyrus, prominent in language function

external capsule

Connect cerebral cortex to another cortical area. Route for cholinergic fibers from the forebrain to the cerebral cortex

cingulum

Deep to cingulate gyrus. Connects frontal, cingulate, parietal, and temporal cortices, part of Papez circuit

sagittal striatum

visual pathway, run from LGN in thalamus to primary visual cortex

corona radiata

descending fibers from motor cortex to basal ganglia, midbrain motor nuclei (corticobulbar) and the spinal cord (corticospinal), also ascending from thalamus to cerebral cortex

internal capsule

motor and sensory fibers travel to and from the cortex

anterior limb of internal capsule

contains frontopontine tracts

genu of internal capsule

contains corticobulbar tracts

posterior limb of internal capsule

corticospinal motor tract to UE, trunk, LE; somatosensory pathways from UE, trunk, LE

corticospinal tract

major efferent projection fibers that connect motor cortex to the brainstem and spinal cord. Represent axons of UMNs