Abstract #4204
Intra and cross-modal negative BOLD responses in grey matter regions and large draining veins under contrast-varying visual stimulation
Joao Jorge 1,2 , Patricia Figueiredo 2 , Rolf Gruetter 1 , and Wietske van der Zwaag 1
1
Center for Biomedical Imaging, University of
Lausanne/Ecole Polytechnique Federale de Lausanne,
Lausanne, Switzerland,
2
Institute
for Systems and Robotics, Instituto Superior Tecnico,
Universidade Tecnica de Lisboa, Lisbon, Portugal
During presentation of a stimulus, positive BOLD
responses are generally attributed to local increases in
neuronal activity. Sustained negative BOLD responses are
also frequently observed, but their underlying
neurovascular coupling mechanisms are less well
understood. Here, we studied the negative BOLD response
(both intra- and cross-modal) to contrast-varying visual
stimuli. In grey matter, negative responses consistently
decreased with increasing stimulus contrast in both
visual and auditory regions. Although of larger
amplitude, responses observed in draining veins tended
to be less contrast-dependent.
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