Abstract
Early visual areas respond preferentially to the contralateral visual field, whereas this contralateral preference becomes weaker at higher levels of visual cortex. Here we used fMRI to test whether a contralateral preference exists in object-selective and face-selective regions generally considered to be ‘high-level’ visual regions. Subjects (N=9) fixated on a central spot while blocks of faces, objects, scenes, and scrambled images were presented in the right or left visual field (with the closest edge of stimuli being 1.3 degrees from the vertical meridian). These images were slightly colored, and subjects performed a color change detection task. We compared responses to ipsilaterally and contralaterally presented images in primary visual cortex (V1), in two face-selective areas - the occipital face area (OFA) and fusiform face area (FFA) - and two object-selective areas - the lateral occipital gyrus (LO) and posterior fusiform gyrus (PF). V1 showed the expected absence of ipsilateral responses. Regions in the two lateral occipital regions showed more graded contralateral preference, with a response to ipsilateral stimuli that was 45% and 36% the magnitude of the response to contralateral stimuli in OFA and LO, respectively. The contralateral preference was smallest in fusiform gyrus, with a response to ipsilateral stimuli that was 75% and 67% the response to contralateral stimuli in FFA and PF, respectively. Nevertheless, the contralateral preference was significant in each region (p<0.01). Overall, our results show that a preference for contralateral over ipsilateral stimuli is still present in high-level object-selective and face-selective cortex, albeit weaker than found in ‘earlier’ cortical areas.