Spatial homogeneity and task-synchrony of the trial-related hemodynamic signal.

ABSTRACT: There is growing evidence that functional brain images in alert task-engaged subjects contain task-related but stimulus-independent signals in addition to stimulus-evoked responses. It is important to separate these different components when analyzing the neuroimaging signal. Using intrinsic-signal optical imaging combined with electrophysiology we had earlier reported a particular 'trial-related signal' in the primary visual cortex (V1) of alert monkeys performing periodic fixation tasks. This signal periodically modulated V1 tissue blood volume, in time with anticipated trial onsets. Unlike visually evoked blood volume changes, however, this signal was present even in total darkness. Further, it could not be predicted by concurrently recorded spiking or local field potentials. Here we us

SUBMITTER: Sirotin YB 

PROVIDER: S-EPMC3254827 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature