Cerebral Cortex Medical Neuroscience Dr. Wiegand

Cerebral Cortex Medical Neuroscience Dr. Wiegand

Comparative Anatomy human cat rat Humancortical cortical expansion expansionnot not strictly strictlydue due Human toenlarged enlargedmotor motoror orprimary primarysensory sensoryareas areas to

Longitudinalfissure fissure Longitudinal Gyri& & Gyri sulci sulci Lateral Lateralor or Sylvian Sylvian fissure fissure

Landmarks Precentral & postcentral gyri Lateral Lateralor or Sylvian Sylvian fissure fissure Centralsulcus sulcus Central ParietoParietooccipital occipital sulcus sulcus Preoccipital Preoccipitalnotch notch

Lobes poles Frontal lobe Parietal lobe operculum Temporal lobe Occipital lobe

Medial Surface Centralsulcus sulcus Central Frontal lobe Parietal lobe ParietoParietooccipital occipital sulcus sulcus Occipital lobe

Frontal lobe Sup./mid./inf. gyri Precentral gyrus/sulcus Pars orpercularis, triangularis, orbitalis Parietal Lobe Post central gyrus Supramarginal and angular gyri Superior parietal lobule Temporal Lobe Sup./mid./inf. gyri Transverse gyri

Corpus callosum Callosal sulcus Cingulate gyrus/sulcus Anterior commissure Superior frontal gyrus Paracentral lobule Precuneus Cuneus Calcarine sulcus Lingual gyrus Fornix Septum pellucidum

Gyrus rectus Olfactory sulcus/tract/bulb Olfactory stria Orbital gyri Occipitotemporal gyrus Parahippocampal gyrus & uncus Collateral & rhinal sulci Ant./post. perforated substance

Deep Telencephalic Nuclei claustrum

Gray Matter of the Cerebral Cortex Archicortex – 3 layers (hippocampus) Neocortex – 6 cellular layers Hippocampal formation hippocampus dentate gyrus

Neocortex Neocortex – 6 cellular layers I. II. III. IV. V. VI. Molecular layer – mostly neuropil External granular layer – stellate cells External pyramidal layer – small pyramidal cells Internal granular layer – stellate cells Internal pyramidal layer – large pyramidal cells Multiform layer – multiple cell types

I II III IV V VI sensory association motor Association & Commissural Thalamocortical afferents Corticofugal efferents Corticothalmic efferents

Brodmann Areas Area 4 primary motor cortex Areas 3, 1,2 primary somatosensory cortex Area 17 primary visual cortex Areas 41, 42 primary auditory cortex

White Matter intracortical intercortical projection fibers

Commissural Fibers Anterior Commissure Posterior Commissure Preoptic nuclei (vision) Habenular Commissure Inf. & mid. temporal gyri, olfactory areas Habenular nuclei (olfaction) Corpus Callosum Connects hemispheres Rostrum, genu, body & splenium

Commissural Fibers Anterior Commissure Posterior Commissure Preoptic nuclei (vision) Habenular Commissure Inf. & mid. temporal gyri, olfactory areas Habenular nuclei (olfaction) Corpus Callosum Connects hemispheres Rostrum, genu, body & splenium

Association Fibers Short fibers – connect adjacent gyri Long fibers Superior longitudinal fasc. Arcuate fasciculus Inferior longitudinal fasc. Cingulum – septal area, cingulate and parahippocampal gyri Uncinate fasc. – orbital frontal gyri to temporal pole

Projection Fibers

Internal Capsule Organization medial lateral

Cortical Functional Organization Precentral gyrus Similar organization in visual, auditory and somatosensory cortices