EMOTION AND HEMISPHERIC DYSFUNCTION

尽管大量文献表明人类的两个半球

Although a large literature suggests that the two hemispheres of man differ in their contributions to emotional processing, the bases for such differences remain unclear. We propose that patients with right hemispheric dysfunction (RHD) may have diminished ability to consciously experience emotional states, and that this defect may exist above and beyond their known difficulties in the perception/expression of nonverbal affective signals. Specifically, RHD patients may be impaired in their self perception/monitoring of autonomic-visceral activity and/or be impaired in becoming autonomically aroused to "in vivo" emotional situations. To assess these possibilities, patients with focal lesions of the right or left hemisphere (and normal controls) will participate in a series of experiments which will assess their ability: (a) to monitor their own visceral activity (i.e., heartbeat); (b) to interpret "offline" false feedback cues about their physiologic state; (c) to become autonomically aroused in emotional situations involving anxiety (shock-induced anticipatory anxiety) or reward; and (d) to assess their emotional experience while participating in an anticipatory anxiety task and a reward situation. Our theoretical framework is derived from William James (1891), who proposed that emotion provoking stimuli induce bodily changes and the perception of these changes as they occur results in the experience of emotion. In our view, it is the cortex (in humans) that plays a critical role in the analysis and interpretation of various stimuli, including those that induce emotional feeling and autonomic visceral responses. Consequently, "feedforward" systems must exist whereby the cortex has the ability to control the autonomic nervous system and hence the viscera such as the heart (visceral afferents). Conversely, because visceral activity can be detected by normals, there must be "feedback" systems whereby neuronal pathways bring information about visceral/somatic activity back to the brain (visceral efferents) for further analysis. It is possible that lesions of the right hemisphere may disrupt either or both the "feedforward" or "feedback" systems, which in turn may impact the conscious emotional experience of RHD patients. Our proposed studies are designed to assess these possibilities.