Neurology #199904025

Dr. A. Damasio

Generation of emotional states from mental imagery project E

Abstract:

We propose to investigate the neurobiology of human emotion with positron emission tomography (P.E.T.), and concurrent measurements of autonomic nervous system activity. Recent work in our laboratory has suggested that emotion can be understood in cognitive terms and, moreover, that adaptive social decision-making also depends on the neural substrates of emotional cognition. Patients with bilateral lesions of the ventromedial prefrontal cortex suffer from severe impairments in decision-making in real-life, and we have interpreted their decision-making deficit as the result of a failure to generate “emotional” states from imagined scenarios of possible future consequences of their actions. Here we propose to demonstrate that the ventromedial frontal cortex is a part of the neural substrate engaged during the process of imagining emotional situations in normal subjects.

The specific hypothesis under investigation is that internal generation of emotional states, i.e., the recall and re-experience of personal, highly emotional events, will activate the same neural structures that are activated by the internal generation of emotional states from imagined scenarios (non-personal events). These neural structures include the brainstem, tegmentum, hypothalamus, cingulated, and insular cortex. The critical difference between the two experiences is that the ventromedial prefrontal cortex will be activated only during the latter (non-personal), but not the former (personal), condition. As an example, we expect that evoking an emotional state of anger by recalling a personal experience of anger, e.g., with the babysitter after discovering that she had abused the kids, will activate neural structures mentioned above. However, if another subject was asked to imagine him/herself in that same situation and to feel angry, we believe that the internal generation of anger in this case would activate the ventromedial prefrontal cortex, in addition to the neural structures activated during the first experiment.

The investigation of this hypothesis will allow us to further the theoretical framework for the understanding of human emotion that has resulted from the careful study of patients with acquired focal brain lesions, and from the previous P.E.T. studies we carried out to study the neurobiology of emotion.