Abstract
To make a covert decision or initiate a motor act, executive systems in our brains fluidly reorganize to find a stable neural state corresponding to the decision or movement. It is unclear whether sensory systems can endogenously reorganize in similar ways, or whether executive input is needed for sensory systems to shift from one stable state to another. We developed a procedure in which perceptual state demonstrably switches between dominance of different input patterns, yet the switches themselves are so inconspicuous as to become unreportable, minimizing their executive consequences. We used binocular rivalry, a paradigm in which sensory ambiguity arises from the presentation of markedly different visual input to each eye. In our case, the two eyes were stimulated by perceptually similar, dynamic random dot kinematograms, in which we maintained the interocular conflict that causes binocular rivalry. Using this stimulus paradigm, observers perceive virtually no switches. But, by periodically presenting opposite motion directions to the two eyes, motion direction reports allow us to reconstruct the time course of eye-dominance. This implicit reconstruction shows that switches do occur when imperceptible, with time-courses comparable to fully visible binocular rivalry switches. We find fMRI and pupil evidence for engagement of executive functions on fully visible switches, but negligible activations if the perceptual switch is unreportable. Thus, the ability to rapidly and autonomously reorganize, commonly observed in higher-order cortical areas, is also present within sensory regions, and may be ubiquitous among neural networks across the human brain.
Meeting abstract presented at VSS 2016