Internal state of monkey primary visual cortex (V1) predicts figure-ground perception

When stimulus information enters the visual cortex, it is rapidly processed for identification. However, sometimes the processing of thestimulus is inadequate and the subject fails to notice the stimulus. Human psychophysical studies show that this occurs during states ofinattention or absent-mindedness. At a neurophysiological level, it remains unclear what these states are. To study the role of corticalstate in perception, we analyzed neural activity in the monkey primary visual cortex before the appearance of a stimulus. We show that,before the appearance of a reported stimulus, neural activity was stronger and more correlated than for a not-reported stimulus. Thisindicates that the strength of neural activity and the functional connectivity between neurons in the primary visual cortex participate inthe perceptual processing of stimulus information. Thus, to detect a stimulus, the visual cortex needs to be in an appropriate state.