Social Cognitive and Affective Neuroscience Advance Access published online on October 17, 2006
Social Cognitive and Affective Neuroscience, doi:10.1093/scan/nsl023
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1 Duke-UNC Brain Imaging and Analysis Center, Duke University, North Carolina, USA
* To whom correspondence should be addressed. We investigated the influence of experimentally guided saccades and fixations on fMRI activation in brain regions specialized for face and object processing. Subjects viewed a static image of a face while a small fixation cross made a discrete jump within the image every 500 ms. Subjects were required to make a saccade and fixate the cross at its new location. Each run consisted of alternating blocks in which the subject was guided to make a series of saccades and fixations that constituted either a Typical or an Atypical face scanpath. Typical scanpaths were defined as a scanpath in which the fixation cross landed on the eyes or the mouth in 90% of all trials. Atypical scanpaths were defined as scanpaths in which the fixation cross landed on the eyes or mouth on 12% of all trials. The average saccade length was identical in both typical and atypical blocks, and both were preceded by a baseline block where the fixation cross made much smaller jumps in the middle of the screen. Within the functionally predefined face area of the ventral occipitotemporal cortex (VOTC), typical scanpaths evoked significantly more activity when compared to atypical scanpaths. A voxel-based analysis revealed a similar pattern in clusters of voxels located within VOTC, frontal eye fields, superior colliculi, intraparietal sulcus, and inferior frontal gyrus. These results demonstrate that fMRI activation is highly sensitive to the pattern of eye movements employed during face processing, and thus illustrates the potential confounding influence of uncontrolled eye movements for neuroimaging studies of face and object perception in normal and clinical populations.
Received June 23, 2006
Accepted August 31, 2006
Original Papers
Controlled scanpath variation alters fusiform face activation
James P. Morris 1, Kevin A. Pelphrey 2, and Gregory McCarthy 3 *
2 Duke-UNC Brain Imaging and Analysis Center, Duke University, USA; Department of Psychological and Brain Sciences, North Carolina, USA
3 Duke-UNC Brain Imaging and Analysis Center, Duke University, North Carolina, USA; Department of Psychological and Brain Sciences, North Carolina, USA; Department of Veterans Affairs Medical Center, Durham, North Carolina, USA
Gregory McCarthy, E-mail: gregory.mccarthy{at}duke.edu
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