cortex
thin layer of gray matter on the surface of the cerebral hemisphere; also known as pallium
iscocortex
contains 90% of the layers; also called Neopallium and Hemogenetic cortex
allocortex
heterogenetic cortex; Three-layered cerebral cortex, which was the first type of cerebral cortex to evolve; humans have mostly neocortex (allocortex means other cortex)
plexiform layer
contains a few neurons & tangential myelinated fibers; also called molecular layer
external granular layer
contains short association fibers
external pyramidal layer
contains long association fibers
internal granular layer
chief receptive layer; has outer band of Baillarger; contains afferent projection fibers
large pyramidal cells
contains inner band of Baillarger; also called Betz cells
Polymorphic cell layer
gives chielfy efferect cortivifugal & commisural fibers
agranular
contains large pyramidal cells & large Betz cells; can be found in the precentral gyrus & pre-motor area
granular
rich in granule cells & poor in pyramid cells; found in the postcentral gyrus & sensory projection area
polar type
has well marked granular layers & small pyramidal cells; can be found in the cortex of the lips of the calcarine fissure & striate area
striate area
also known as Stria of Genari
projection fibers
fibers that arise or terminate in the cerebral cortex & terminating or arising in subcortical regions
sensory projection system
from the thalamus w/ widespread distribution in the cortex
motor projection system
from the motor & premotor areas and other areas of the cortex; corticospinal, corticobulbar, corticopontine & corticothalamic tracts
diffuse thalamic projection system
from certain thalamic nuclei to all areas of the cortex concerned with arousal reactions, wakefulness and attention
internal capsule
a fan-like mass of projection fibers bounded medially by the caudate nucleus and the thalamus & lentiform nucleus
corona radiata
portions of the projection fibers extending between basal ganglia and thalamus and the cerebral cortex
anterior limb
part of the internal capsule that lies between the head of the caudate nucleus & lenticular nucleus & by fusion of these nuclei
genu
bounded ROS by head of the caudate, POST by thalamus, LAT by apex of lentiform nucleus & DOR tail of caudate
posterior limb
bounded ROS by lentiform nucleus & caudomedially by thalamus
thalamolenticular
lies between the thalamus and lenticular nucleus
retrolenticular
consists of fiber bundles which fan out posterior to the lenticular nucleus
sublenticular
runs lateralwards beneath the lenticular nucleus towards the temporal region of the hemisphere
frontopontine fibers
from frontal cortex to nuclei pontis in the pars basalis of the pons