Visuo-tactile integration of 3D objects in fusiform gyrus

Marcus J. Naumer, Institute of Medical Psychology, Frankfurt Medical School, Frankfurt/Main, Germany

Abstract
Functional imaging studies of visuo-tactile (VT) processing revealed LOtv and IPS as the prime candidate regions for object-related VT integration (Amedi et al., 2005; Sathian, 2005). However, most of these studies computed conjunctions of unimodal visual and tactile activations. To test more strictly for VT integration (Beauchamp, 2005; Laurienti et al., 2005), we searched for regions that were activated by each of the unimodal conditions (V; T), and additionally responded more strongly to bimodal VT stimulation than to each of the unimodal conditions. Using fMRI, we assessed VT integration of natural (animals) and artificial 3D objects (“fribbles”; www.cog.brown.edu/~tarr/), while controlling for potential motor, naming, and imagery confounds. During natural stimulation, animal photographs were either presented canonically or mirrored horizontally. We mainly revealed four cortical regions that showed VT integration effects for 3D objects: right and left fusiform gyrus (FG), left LOtv, and left IPS. Interestingly, right FG showed the most robust VT integration effect that neither depended on the particular stimulus material (animals or fribbles) nor on orientation congruency. While VT integration of natural material involved rather anterior portions of right FG, abstract 3D material was integrated in a more posterior part of FG.

Not available

Back to Abstract