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キーワード:
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要旨:
Negative BOLD responses (NBRs; i.e. below baseline) are pervasive in human fMRI experiments, but commonly
ignored. A recent study characterized a robust sustained NBR in the human occipital cortex, triggered by
stimulating part of the visual-field (Shmuel et al., 2002). The NBR depends on the pattern of neuronal activity and
is coupled to the positive BOLD response (PBR). The NBR is correlated with reductions in cerebral blood flow
(CBF) and with decreases in oxygen consumption. The findings from this human study corroborate contributions
to the NBR by 1) a significant component of reduction in neuronal activity and possibly 2) a component of
hemodynamic changes independent of the local changes in neuronal activity.
