Redwood Neuroscience
Title: “Visual Object Size and Viewpoint Tuning
Across Human Visual Cortex”
David Andresen
Psychology Department
Abstract:
The human visual system provides us with the
incredible ability to recognize a familiar object even after changes in viewing
distance and viewpoint that can produce vastly different retinal projections.
What is the system of representations in visual cortex that supports this
ability? I will discuss a recent fMRI adaptation
study in which we examined neural tuning to parametrically varied
transformations of object size and viewpoint while subjects performed two
different tasks. The results revealed size and viewpoint tuning across visual
cortex that became more invariant along the ventral processing stream.
Interestingly, size tuning was found to be independent of the adapted image
size, whereas viewpoint tuning was relative to the degree of change from the adapted
viewpoint.
Furthermore, size tuning was modulated by task
demands, with high level visual areas being sensitive to size when it was task-relevant, and largely invariant to size when it was
task-irrelevant. These findings shed light on the dynamic system of
representations underlying object recognition.