Delineating neural mechanisms underlying human 3D object and space perception: phenomenology, psychophysics, neuroimaging

Supervisors: Dhanraj Vishwanath, Justin Ales

Project Description:

Early studies in the neurophysiology of 3D perception focussed on identifying mechanisms of binocular disparity processing.  Later work focussed primarily on disparity derived depth and 3D structure. These studies have provided important insight on the nature of neural responses to stimuli depicting 3D structure via binocular disparity. They demonstrate that 3D visual information is processed in both dorsal and ventral visual streams, but different information is processed in each stream. It is suggested that the dorsal regions of the extrastriate cortex and aspects of the parietal cortex are involved in integrating signals to derive the 3D structure of viewed surfaces, as well as representations required for visually guided action whereas the ventral regions of the extrastriate cortex and aspects of the temporal cortex store representations of 3D scenes, object configurations and features required for recognition and categorization.  More generally, ventral regions have been implicated with conscious perception of 3D object and space, while dorsal regions are involved in non-conscious representations guiding action.  However, more recent work has challenged this strict dichotomy.  Our own current work in neuroimaging suggests that an important component of the conscious experience of 3D structure may be linked to processing in the dorsal visual stream.

This project will be part of ongoing research in which we aim to more clearly delineate the functional and perceptual distinctions in processing in these two pathways using psychophysical and neuroimaging methods (EEG, fMRI). In contrast to previous approaches that primarily interrogated the processing of specific depth cues. This project, and wider research program, approaches the problem first from understanding the variety of phenomenological and psychophysical aspects of the human experience of 3D objects and space. For example: the characteristic perceptual differences between viewing a picture of a 3D scene and the real scene itself; the distinction between perceiving 3D with scale (absolute depth) and without scale (relative depth); the difference in functional and experiential characteristics of near and far 3D space perception.

This project will be most suited to a candidate that has strong quantitative and experimental skills, some rudimentary programming experience, as well as scientific interest that spans from neurobiology through psychology to philosophy. The student will gain training in both psychophysical and neurophysiological methods (EEG, fMRI) of 3D perception as well as associated technical skills such as 3D graphics, programming, psychophysical and neuroimaging data analysis.

To apply for this project, please go to this link.