Una ipotesi neurofisiologica sulle asimmetrie funzionali degli emisferi cerebrali dell'uomo / A neurophysiological hypothesis about the functional asymmetry of the human cerebral hemispheres

Hypothesizes that corresponding cytoarchitectural areas of the cortex of the 2 hemispheres work normally as a functional unit because of the equalizing activity of their connections. Hemispheric asymmetry is thought to arise when 2 areas constituting a bilateral functional unit are asymmetrical--when the area on one side is larger or has a higher neuronal density than the corresponding area on the other side. The commissural projections are then likely to be asymmetrical also. Right^left differences in perception and memory are seen simply as the consequences of an asymmetrical activation of a bilateral cortical substrate. Support for this theory is provided by studies of regional cerebral blood flow, which show that in various behavioral or mental tasks local activation of the cortex is usually bilateral. Differences in symptoms following right or left brain damage are accounted for by differential distance effects resulting from lesions impinging on the larger or smaller area of a bilateral asymmetrical substrate. (99 ref) ((c) 1997 APA/PsycINFO, all rights reserved