Oscillatory modulations in human fusiform cortex during motion-induced blindness: Intracranial recording

ObjectiveMotion-induced blindness (MIB) is an illusory phenomenon, in which a static target surrounded by moving distracters is perceived to disappear. We determined the electrocorticographic (ECoG) correlates of MIB.MethodsWhile undergoing intracranial ECoG recording, a patient with focal epilepsy was instructed to report the transitions of a visual target, which was designed to illusorily or physically disappear and reappear. We then determined the neural modulations associated with illusory and physical transitions of the target. We also tested whether the phase of local delta activity could predict exclusively illusory transitions.ResultsHigh-gamma activity at 80–150 Hz was attenuated in the fusiform region prior to the reports of illusory and real visual target disappearance. Conversely, such high-gamma activity was augmented prior to the report of real target reappearance. Exclusively around illusory disappearance but not around real one, the delta phases in the fusiform region showed a highly skewed distribution with preference of the negative peak.ConclusionsNeuronal modulations in the fusiform region may be involved in visual awareness, while spontaneous fluctuations of neural states entrained on delta rhythm may be involved in generation of MIB.SignificanceOur study increases our understanding of the mechanisms of visual awareness.

► High-gamma activity at 80–150 Hz was attenuated in a fusiform site around illusory disappearance of a visual target. ► The distribution of delta phases in the fusiform site became skewed immediately prior to the illusory disappearance of the visual target. ► High-gamma activity was augmented in the fusiform site around reappearance of the visual target.