Poster D125, Monday, March 27, 8:00 – 10:00 am, Pacific Concourse
The ventral and dorsal visual pathways exchange information during configural face processing.
Valentinos Zachariou1, Nicole Mlynaryk1, Christine Gou1, Leslie Ungerleider1; 1Laboratory of brain and cognition, NIMH, NIH
Configural face processing, the processing of the spatial relationships among the features of a face, is a vital component of face perception. If configural processing depends on spatial information, might this process involve interactions between the face-processing regions of the ventral stream and visuospatial processing regions of the dorsal stream? We explored this question in healthy adults within the context of a thetaburst TMS experiment (TBS). First, using independent face and location localizer tasks, we identified dorsal location and ventral face-processing brain regions, separately for each participant. The dorsal, location-processing regions acted as the active TBS sites and the vertex acted as the control site. Participants were then presented with pairs of face exemplars that could differ in terms of the shape (featural) or the spatial configuration of their shape features (configural). Differences (featural/configural) were matched in RT and accuracy separately for each participant. Each participant was then exposed to two scan sessions (pre and post TBS) per TBS site, with TBS delivered on a single brain region in between the two fMRI sessions. BOLD activity within the face-processing regions decreased in the post TBS session, in comparison to the pre TBS session, but only for configural face differences and only when TBS was applied on the location-processing regions of the dorsal stream. The above effect was not observed for the vertex, the control site. We conclude that the location-processing substrates of the dorsal visual pathway exchange information with face-processing regions of the ventral visual pathway during configural face processing.
Topic Area: PERCEPTION & ACTION: Vision