Natural Images, Natural Percepts and Primary Visual Cortex

Tuesday, March 7, 2006 - 10:30am - 11:30am
EE/CS 3-180
Daniel Kersten (University of Minnesota, Twin Cities)
The traditional model of primary visual cortex (V1) is in terms of a
retinotopically organized set of spatio-temporal filters. This
model has been extraordinarily fruitful, providing explanations of a
considerable body of psychophysical and neurophysiological results.
It has also produced compelling linkages between natural image
statistics, efficient coding theory, and neural responses.
However,there is increasing evidence that V1 is doing a whole lot more. We
can get insight into early cortical processing by studying not only
the relationship between image input and neural activity, but also
between human visual percepts and early cortical activity. Natural
percepts (in the sense of tapping into natural modes of processing)
are as important as understanding natural images when trying to
find out what primary visual cortex is doing. I will describe several
results from functional magnetic resonance imaging (fMRI) studies which
show that human V1 blood oxygenation level dependent (BOLD)
response to patterns perceived as well-organized is less than to
patterns perceived as less organized, V1 response to natural
image contrast is correlated with perceived contrast, and apparent size
modulates the spatial extent of V1 activity.
MSC Code: