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

► Large, stim-independent neuroimaging signal in task-engaged monkeys. ► For visual tasks, this signal time course and amplitude is uniform over V1. ► Signal is independent of neural (electrode) recordings, even locally. ► Signal entrains like clockwork to all trial periods, but only for correct trials. ► Likely distinct from attention but like earlier-reported 'task-related' signal.