Contrast and duration dependence of the negative BOLD response to visual stimulation in visual and auditory cortical regions at 7T
Joo Jorge 1,2 , Patrcia Figueiredo 2 , Rolf Gruetter 1,3 , and Wietske van der Zwaag 4
Laboratory for Functional and Metabolic
Imaging, cole Polytechnique Fdrale de Lausanne,
of Bioengineering, Instituto Superior Tcnico, Lisbon,
of Radiology, University of Lausanne and University of
Geneva, Lausanne, Switzerland,
Imaging Research Center, cole Polytechnique Fdrale de
Lausanne, Lausanne, Switzerland
Negative BOLD responses to stimulation are often found
in various brain regions, and growing evidence supports
their association with neuronal deactivation. The aim of
this study was to characterize, in humans, positive (PBRs)
and negative BOLD responses (NBRs) to visual
checkerboard stimulation of varying contrast and
duration, focusing on NBRs occurring in both visual and
auditory cortical regions. Across subjects, visual PBRs
and both visual and auditory NBRs were found to
significantly depend on stimulus contrast and duration.
Interestingly, for stimulation periods above 16s, visual
and auditory NBRs tended to exhibit earlier returns to
baseline than the visual PBR.
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