Layers of the cerebral cortex from outside to inside
Molecular or plexiform layer
External granular layer
Outer pyramidal layer
Internal granular layer
Ganglionic layer or inner pyramidal area
Fusiform cell layer
Phylogenetic divisions of cerebral cortex
Neocortex -has all six layers of structure
Allocortex-lt has less than six layers of structure .It is divided into two divisions namely :archicortex and paleocortex which forms part of the limbic system
Lobes of cerebral cortex -neocortex of each cerebral cortex constists of 4 lobes which are:
Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe
Fissures and Sulci in cerebral cortex
Central sulcus/rolandic fissure-between the frontal and parietal
Parieto-occipital-between parietal lobe and occipital lobe
Sylvian fissure/lateral sulcus -between parietal and temporal
Callosomarginal fissure-between temporal lobe and limbic area
Lesion in dominant hemisphere leads to…
Language disorder
Lesion in representational hemispheres leads to
astereognosis
Parts of the frontal lobe of the cerebral cortex
Precentral Cortex -situated posteriorly
Prefrontal Cortex -situated anteriorly
Precentral cortex is divided into three parts
Primary motor area -has giant pyramidal cells called betz cells in the ganglionic layer .concerned with the initiation of voluntary movement abd speech
Premotor area .concerned with postural movements by sending motor impulses to the axial muscles (muscles near the midline of the body )
Supplementary motor area
Functional areas of parietal lobe
Somesthetic area I
Somesthetic area II
Somesthetic association area
Sensory motor area
Area of the cerebral cortex where the Precentral gyrus of frontal lobe (where motor areas are located ) and post central gyrus of parietal lobe (where sensory areas are located ) are knit together by association nerve fibers
Function of this area is to store the timing and programming of various sequential movements of complicated skill movements which are planned by the neocerebellum
Functional areas of the temporal lobe
Primary Auditory area
Secondary auditory area or auditophysic area
Area for equilibrium
Primary auditory area include
Area 41
42
Wernicke’s area
Functional areas of occipital lobe
Primary visual area
Secondary visual area or visuophychotic
Occipital eye field
Supraspinal areas which increase muscle tone
Motor area 4 in cerebral cortex
Cerebellum
Descending fascilitatory reticular system
Red nucleus
Vestibular nucleus
Supraspinal centers which decrease muscle tone
Basal ganglia
Suppressor areas of cerebral cortex
Descending inhibitory reticular system
Lesion of the parietal lobe
Contra lateral disturbance of cutaneous disturbance
Disturbance in kinesthetic sensations
Loss of tactile localization and discrimination
Frontal lobe syndrome
Disorder caused by damage due to head injury or ablation of prefrontal cortex
Temporal lobe syndrome
Kluver-bucy syndrome -bilateral lesions of amygdala and uncus
