Rory Sayres, phd
Education
B.S. Biology, California Institute of Technology, 2000
Ph.D. Neurosciences, Stanford University, 2007
Research Interests
If we know what someone is looking at, how well can we predict what's going on in that person's visual cortex? My research focuses on using functional MRI data and computational modeling to understand functional specializations in visual cortex. I am examining functional specializations for different color and luminance contrasts, and different temporal frequencies, in area V2. I am also working on developing the population receptive field model created by Serge Dumoulin, examining how best to create a forward model of fMRI response predictions based on a representation of a visual stimulus. Finally, I am interested in the organization of visual field maps in relatively anterior dorsal and ventral visual regions.
About Rory
My professional goal is to produce research that offers substantial, quantitative insight into how the brain works. I am particularly interested in the organization and function of cerebral cortex at the "systems-level" scale, ranging from simple circuits to the organization of cortical regions.
By "quantitative", I mean that I feel it is not enough to understand the general principles to how the brain might compute something, but to try and apply that understanding to particular cases. For intance, in understanding sensory perception, I am interested not only in which cortical regions may correlate to a subject's sensations, but in how well we can predict a subject's perception given a particular pattern of neural acitivity.
My present focus is on the visual system. By the standards of modern computer vision, this part of the brain achieves some astounding recognition behaviors, which are rapid (find your relatives in a crowd), nuanced (do they look happy? Hungry? Tired?), and robust (do the same thing by daylight or candlelight). Currently I am using a combination of functional MRI, psychophysics and modeling to understand aspects of visual recognition in humans.
My current projects involve: (1) understanding how cortex takes information organized according to retinotopic position in early areas, and produces object representations that are robust to different positions; (2) examining functional specialization for color, luminance, and temporal frequency information in early visual cortex; (3) building quantitative models of visual population receptive field properties which incorporate position, orientation, and spatial frequency information; (4) understanding how short-term experience with an object affects both the neural response ('repetition suppression' / 'adaptation') and recognition behavior.
Recent Publications
Sayres R, Grill-Spector K. Relating retinotopic and object-selective responses in human lateral occipital cortex. J Neurophysiol. 2008 In press.
Grill-Spector K, Sayres R. Object Recognition: Insights From Advances in fMRI Methods. Current Directions in Psychological Sciences. 2008 Apr; 17(2): 61-176.
Sayres R, Grill-Spector K. Object-selective cortex exhibits performance-independent repetition suppression. J Neurophysiol. 2006 Feb; 95(2):995-1007. Epub 2005 Oct 19
Sayres R, Ress D, Grill-Spector K. Identifying distributed object representations in human extrastriate cortex. Proceeding of Neural Information Processing Systems (NIPS). Vancouver. Dec. 5th-9th, 2005.
