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Published October 2013 | public
Journal Article

A selective role for right insula—basal ganglia circuits in appetitive stimulus processing


Hemispheric lateralization of hedonic evaluation ('liking') and incentive motivation ('wanting') in neural networks connecting the basal ganglia and insula (BG-I) in humans was examined. Participants with brain damage restricted to the BG-I of the right (n = 5) or left (n = 5) hemisphere, and 26 healthy participants matched on age, sex and intelligence quotient were tested on positively and negatively valenced pictures drawn from varied stimulus categories (Vijayaraghavan et al., 2008). Liking was assessed with explicit ratings of pleasantness using a nine-point Likert scale. Wanting was quantified as the amount of work (via repeated keypresses) that participants expended to increase (approach) or decrease (withdraw) viewing time. Right-lesion patients showed abnormally low viewing times and liking ratings for positive images. For a subset of positive images depicting sexual content, right-lesion patients exhibited active withdrawal, while the other two groups approached such stimuli. These results suggest that the right basal ganglia–insula complex plays a greater role than the left in supporting hedonic evaluation and motivational approach to positively valenced stimuli. The finding that active avoidance of stimuli that were not 'liked' was spared in both right- and left-sided lesion subjects suggests that unilateral damage to insula/basal ganglia circuits may not be sufficient to affect general incentive motivation independent of preference.

Additional Information

© 2012 The Author. Published by Oxford University Press. Received 15 February 2012; Accepted 8 July 2012; Advance Access publication 13 July 2012. Drs. L.V. and S.P. contributed equally to this research. S.P. was supported by the Dana foundation, the Mallinckrodt foundation, NARSAD and the National Institute on Aging (5K23AG027837). L.V. is currently supported by the Institute of Neurological Sciences, Voluntary Health Services Medical Centre and The TS Srinivasan Charitable Trust. D.T. was supported by the National Institute on Drug Abuse (R01 DA022549) and the National Institute of Neurological Disorders and Stroke (P50 NS19632). Thanks to Thomas Grabowski, MD, for his expert evaluation of the MRI scans.

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