Higher Cortical Dysfunction

Specific parts of the cerebral hemispheres are responsible for a certain aspect of function. In normal circumstances these functions are integrated and the patient operates as a whole. Damage to part of the cortex will result in a characteristic disturbance of function. Interruption by disease of 'connections' between one part of the cortex and another will 'disconnect' function.

GENERAL ANATOMY

Brodmann, on the basis of histological differences, divided the cortex into 47 areas. Knowledge of these areas is not practical, though they are referred to often in some texts.

Six layers can be recognised in the cerebral cortex superficial to the junction with the underlying white matter.

The relative preponderance of each layer varies in different regions of the cortex and appears to be related to function.

6 layers

Molecular External granular

Pyramidal

Internal granular Ganglionic

Fusiform

Grey matter

White matter

Each cerebral hemisphere is divided into lobes

Temporal lobe / 0c.ciPital ' ' lobe

6 layers

The frontal motor cortex, dominated by pyramidal rather than granular layers, is termed the AGRANULAR CORTEX

The parietal sensory cortex, dominated by granular layers, is termed the GRANULAR CORTEX.

The largest cells of the agranular cortex are the giant cells of Betz. These give rise to some of the motor fibres of the corticospinal tract.

RIGHT AND LEFT HEMISPHERE FUNCTION

Unilateral brain damage reveals a difference in function between hemispheres. The left hemisphere is 'dominant' in right-handed people. In left-handed subjects the left hemisphere is dominant in the majority (up to 75%).

Hand preference may be hereditary, but in some cases disease of the left hemisphere in early life determines left-handedness.

Was this article helpful?

0 0
Peripheral Neuropathy Natural Treatment Options

Peripheral Neuropathy Natural Treatment Options

This guide will help millions of people understand this condition so that they can take control of their lives and make informed decisions. The ebook covers information on a vast number of different types of neuropathy. In addition, it will be a useful resource for their families, caregivers, and health care providers.

Get My Free Ebook


Post a comment