Representation activity of the right and left hemispheres of the brain

Drawings by psychiatric patients were studied in various states (i) in depression; (ii) after neuroleptic injection; and (iii) during left hemisphere suppression induced by unilateral electroconvulsive seizure (UES). In these states, right hemisphere activation predominates. The results of the study demonstrate that, under the predominance of right hemisphere activation over the left hemisphere, there is a tendency to reproduce the image of the object and to represent it in near space. Drawings by psychiatric patients were also investigated in (i) the manic state; (ii) after injection of psychotropic drugs which improved the mood; and (iii) during right hemisphere suppression following right-sided UES. Under these conditions, left hemisphere activation predominates and the drawings loose the illusion of three-dimensional space. A tendency to reproduce the knowledge and the ideas of the object and to represent it in distant space was observed. Thus, both hemispheres may represent space and elaborate perceptive and conceptional models of the world in different ways. It is probable that different types of representation are based on global (right-hemispheric) in comparison with focal (left-hemispheric) attention to space.