Left/right and cortical/subcortical dichotomies in the neuropsychological study of human emotions

Abstract

Two main dichotomies have been put forth in the study of the anatomical substrates of emotional behaviour. The first, more classical and more firmly established, claims that the basic brain mechanisms for emotions are located in subcortical rather than in cortical structures. The second, more recent and still more hypothetical dichotomy, maintains that the right and the left hemispheres are not equally involved in emotional behaviour and that the right hemisphere plays a critical role in this regard. It is not clear, however, if these two dichotomies are independent or are somehow interconnected. The aim of this article is to discuss some aspects of the neuropsychology of human emotions, taking into account both the cortical/subcortical and the left/right dichotomy. First, we will review some well-established facts and some more recent models and data concerning the role played by cortical and subcortical structures in various aspects of emotional behaviour. Secondly, we will present a short summary of current concepts of the relationship between emotions and hemispheric specialisation. In the second part of this paper, we will pay special attention to the components of emotional behaviour which may be more specifically linked to the right and left hemispheres, to see if some similarity exists between the cortical/subcortica1 and the left/right dichotomy. Our main thesis will be that some interconnection may indeed exist between these two dichotomies because right hemisphere superiority for emotional functions concerns more the basic (“subcortical”) levels of emotional arousal and of autonomic response to emotional stimuli than the “cortical” (cognitive and communicative) aspects of emotions. The left hemisphere, by contrast, may be more involved in “cortical” functions of inhibition and control of the subcortical emotional mechanisms.