Natural scene perception, form vision, and attention
We study the neural mechanisms underlying vision and visual perception, particularly perception of natural scenes, object recognition and selective attention. We use four distinct approaches to address these questions: functional neuroimaging (fMRI); studies of neurological patients with specific brain lesions; neurophysiology; and quantitative computational modeling. These convergent approaches allow us to use the best tools to address our questions and circumvents the limitations of any single technique.
Current research in the laboratory focuses on several specific aspects of visual perception. First, we are examining the role of an important human extrastriate visual area, V4, in scene analysis. These experiments involve both studies of neurological V4 lesion patients and functional neuroimaging. We have already demonstrated that human V4 is functionally (and to a lesser degree structurally) homologous to V4 in animal models, and we are now assessing the function of human V4 in more detail.
Second, we are using neurophysiological methods to investigate the function of early and intermediate cortical visual areas during natural vision. These studies address both how the visual system responds to complex scenes during natural vision, and how it is affected by top-down processes such as scene segmentation and grouping.
Finally, we are using quantitative nonlinear systems identification methods to objectively characterize the way natural scenes and complex objects are represented in intermediate visual areas, and to determine how these representations are modulated by attention. These experiments involve functional neuroimaging, neurophysiology, and computational modeling of visual processing.
Selected Publications
Vinje, W. E., & Gallant, J. L. (2000). Sparse coding and decorrelation in primary visual cortex
during natural vision. Science, 287, 1273-1276.
Gallant, J. L., Shoup, R. E., Mazer, J. A. (2000). A human extrastriate cortical area that is functionally
homologous to Macaque area V4. Neuron.
Gallant, J. L. (2000). The neural representation of
shape. In K. K. DeValois and R. L. DeValois (Ed.), Seeing. San Diego, CA: Academic Press.
Connor, C. E., Gallant, J. L., Preddie, D. C., & Van Essen, D. C. (1996). Responses in area V4 depend on the
spatial relationship between stimulus and attention. Journal of Neurophysiology, 75, 1306-1308.
Links
Helen Wills Neuroscience Institute
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