Funded Grants

Shape Processing in the Ventral and Dorsal Visual pathways

This proposal is for support of my postdoctoral training to conduct an interdisciplinary research project on the processing of visual shape information. The proposed research primarily focuses on the study of visual processing in normal human observers with functional magnetic resonance imaging (fMRI) and psychophysical techniques, but extends also to studies of human patients and monkeys with the same techniques.

Specifically, the proposed studies investigate shape processing in both the ventral occipitotemporal) and the dorsal visual (occipitoparietal) pathways, known to mediate dissociable processes. The goal of the proposed project is threefold: (i) to characterize shape representations extracted by the human visual system, (ii) to determine whether shape information is extracted in both the ventral and the dorsal pathway, and (iii) to examine how shape representations differ in the two pathways.

To this end the first set of studies tests whether the two pathways process different kinds of shape information such as: (i) high versus low spatial frequency components of object images (Study 1), (ii) depth information (Studies 2 & 3), and (iii) relations between object parts and between objects in space (Study 4). The second set of studies tests whether the two visual pathways differ in shape representations as a function of (i) changes in location, size, and orientation (Study 5), (ii) the observer's goals (Study 6), (ii) updating of the shape information during object motion (Study 7), and (iv) temporal properties of the constructed representations (Study 8). Further work in collaboration with Nikos Logothetis will test monkeys on fMRI experiments closely matched to the proposed human fMRI studies, and work in collaboration with Mel Goodale will test patients with dorsal versus ventral damages on the proposed psychophysical experiments.

This proposal will extend my current psychophysical and fMRl research on visual perception and ask new interdisciplinary questions on how visual processing mechanisms mediate higher cognitive functions.