[Hemispheric interaction during the processing of spatial information]

Abstract

As a result studying the features of single neurons of prestrial cortex (field 21) of a cat the interhemispheric differences are revealed. It is found that the sizes of receptive fields (RF) of the neurons of this region in the left hemisphere is 1.5 larger as in the right one. The RFs of the left hemisphere consist of zones (mainly 5-9) than the RFs of the right hemisphere which in turn consist of 1-4 zones. About 70% of neurons of the left hemisphere are invariant to a direction of the movement of stimulus, the similar number of the right hemisphere neurons are selective with respect to orientation of a stimulus. The study of the spatial-frequency characteristics of RTs of this region indicated that the left hemisphere neurons are tuned to more lower frequencies (0.05-0.89 cycle/grade) than neurons of the right hemisphere (0.11-3.5 cycle/grade). The study of an activity of the neurons of field 21 after commissurotomy has demonstrated that in this case the hemispheres are fully lost the possibility to receive information from contralateral semifield of the vision. The sizes of RFs are significantly less and become equal in the both hemispheres. The neurons of this region become selective to an orientation of stimulus both in the left and right hemispheres. On the basis of the results of clinical and psychophysical studies it is customary to assume that the two sides of the visual perception--concrete and abstract--to a certain extent are disintegrated between each other and are supplied chiefly by different hemispheres.(ABSTRACT TRUNCATED AT 250 WORDS)