Lateralization of hedonic responses to odors in individuals with unilateral hemispheric lesions.
Item
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Title
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Lateralization of hedonic responses to odors in individuals with unilateral hemispheric lesions.
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Identifier
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AAI9820562
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identifier
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9820562
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Creator
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Madigan, Nancy Kay.
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Contributor
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Advisers: Joan Borod | Howard Ehrlichman
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Date
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1998
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Physiological | Psychology, Behavioral
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Abstract
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Although there is evidence suggesting the existence of hemispheric asymmetries for emotion, the nature of cerebral lateralization has been the source of much debate. Several theories have emerged, suggesting different roles of the right and left hemispheres in emotional processing. In the current study, affective behaviors elicited in response to pleasant and unpleasant odors were examined in individuals with left hemisphere lesions (LHD) and right hemisphere lesions (RHD), and in demographically-matched normal control participants (NC). Responses to odors consisted of: (1) spontaneous facial expressions; (2) prompted facial expressions (representing the participant's odor experience); (3) presence of avoidant/withdrawal responses (e.g., head turning behaviors); (4) subjective ratings of the odors' pleasantness/unpleasantness; and (5) a behavioral choice measure.;Facial expression evoked by odors were compared to expressions elicited without odors, including posed hedonic expressions and emotional expressions. All expressions were evaluated by naive judges. Non-emotional facial factors, such as paralysis and buccofacial apraxia, were also examined to control for these factors.;Ratings of both spontaneous and prompted facial expressions evoked to odors, as well as posed hedonic expressions elicited without odors, indicated that no compelling differences emerged between LHDs, RHDs, and NCs. However, for posed emotional facial expressions, RHD's expressions were rated as less accurate and less intense than expressions produced by NCs. Subjective ratings of odors suggested that RHDs perceived odors presented to the right nostril as less intense in comparison to NCs. Lastly, more avoidant responses were reproduced by LHDs than by RHDs and NCs.;For facial expressions, comparisons among the different elicitation methods suggest that right neocortical regions may be involved in higher level, symbolic aspects of emotional processing. Findings for hedonic experience, assessed by subjective aspects of emotional processing. Findings for hedonic experience, assessed by subjective ratings, also indicated that the importance of the right hemisphere in experience of hedonic intensity. Finally, findings regarding the enhanced presence of avoidant responses in the LHD group might be explained b a possible contralateral disinhibition of right hemisphere functions (i.e., withdrawal action tendencies) following left-hemisphere lesions. Overall, these findings support the notion of right-hemisphere predominance in certain aspects of emotional processing, but suggest that affective information may not be lateralized along a hedonic dimension.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
