Extensive studies have shown that the stimulus-evoked neuronal activity in area MT is causally related to motion perception. Yet little is known about how ongoing (pre- and inter-stimulus) activity in area MT influences the subjects’ ability to perceive and respond to stimuli. Here we ask whether the activity level of area MT preceding stimulus onset has an influence on the subject’s psychophysical performance during physically identical, but perceptually ambiguous visual stimulation. Two rhesus monkeys were well trained to indicate the perceived direction of rotation of bistable structure-from-motion (SFM) stimuli by pulling one of two levers. During this task, multi-channel multi-unit activity (MUA) and local field potentials (LFP) were recorded f