Social Cognitive and Affective Neuroscience Advance Access originally published online on January 31, 2008
Social Cognitive and Affective Neuroscience 2008 3(1):47-54; doi:10.1093/scan/nsn001
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The left amygdala knows fear: laterality in the amygdala response to fearful eyes
1Center for Advanced Imaging, 2Department of Radiology, 3Department of Neurobiology and Anatomy, West Virginia University, Morgantown, WV, and 4Department of Psychology and Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, USA
The detection of threat is a role that the amygdala plays well, evidenced by its increased response to fearful faces in human neuroimaging studies. A critical element of the fearful face is an increase in eye white area (EWA), hypothesized to be a significant cue in activating the amygdala. However, another important social signal that can increase EWA is a lateral shift in gaze direction, which also serves to orient attention to potential threats. It is unknown how the amygdala differentiates between these increases in EWA and those that are specifically associated with fear. Using functional magnetic resonance imaging, we show that the left amygdala distinguished between fearful eyes and gaze shifts despite similar EWA increases whereas the right amygdala was less discriminatory. Additional analyses also revealed selective hemispheric response patterns in the left fusiform gyrus. Our data show clear hemispheric differences in EWA-based fear activation, suggesting the existence of parallel mechanisms that code for emotional face information.
Keywords: amygdala; fMRI; fusiform gyrus; fear; eye gaze
Correspondence should be addressed to Aina Puce, Center for Advanced Imaging, PO Box 9236, West Virginia University School of Medicine, Morgantown, WV 26506-9236, USA. E-mail: apuce{at}hsc.wvu.edu.
Received May 22, 2007. Accepted January 8, 2008.