Intra- and interareal covariation of neural activity during multistable perception in the monkey

Previous neurophysiological recordings in monkeys used the paradigm of binocular rivalry to investigate activity of single neurons in the visual cortex during multistable perception. These studies revealed that a subset of cells throughout visual cortex, including the striate and extrastriate areas, is directly involved in spontaneous perceptual reorganizations of an unchanging sensory stimulus. In the present study, the role of perception-related networks is further examined using simultaneous multiple electrode measurements in several visual cortical areas. As in previous studies, monkeys were trained to report their changing percept during rivalry by pressing levers, with optokinetic responses to moving stimuli serving as an additional behavioral control. Rivalry-inducing stimuli consisted of a variety of relatively large (>5 deg) patterns, including images, gratings and moving random dots. Multiple electrodes measured extracellular activity simultaneously in striate and extrastriate visual cortex. In addition to isolated neural responses, local field potential (LFP) as well as multiunit activity (MUA) was measured and analyzed. During rivalry, perceptual changes were reflected not only in the spiking of individual cells, but also in MUA as well as several frequency ranges of the LFP at individual sites. In an effort to better understand the overall flow and organization of perception-related activity in the visual cortex, the temporal covariation between the various neural signals was evaluated with respect to the animal’s changing percept, its state of arousal, as well as its pattern of spontaneous eye movements