BOLD response to images formed from random placement of Gabor patches.
This project was motivated by the following question: is specification of RMS contrast
and spatial frequency content sufficient to predict the V1 BOLD response?
A simple thought experiment, illustrated by the images shown below (which all have the
same RMS contrast and spatial frequency content), gives the answer - no! The problem is
in the posing of the question: global contrast and global BOLD response are the wrong
questions to be asking in V1. In V1, it's all about local contrast.
At VSS 2004 I presented preliminary work testing our ability to predict and quantify
local BOLD responses to local image features (abstract published in
JOV). This line of research has
progressed in two directions. One direction is my obsession with localized responses to
individual Gabor patches, with and
neighbors. The other direction is a collaboration with Katja Doerschner, looking at
V1 responses to positive and negative contrast. Part of this experiment manipulates
the density of the patterns (VSS 2009).
tutorials & data
hall of shame
© 2008, C. A. Olman
date of last update: June 25, 2011