INM-6 Seminar: Talk by Dr. Christ Devia

BNI & CENEM, Facultad de Medicina. Universidad de Chile, Santiago, Chile.

Laboratorio de Neurodinámica, Escuela de Psicología,

Pontificia Universidad Católica de Chile.

Sustained visual perception in humans correlates with transient events of large-scale phase coupling

Daily perceptual experience consists of a succession of transient and sustained perceptual experiences. Over the last decades, several lines of studies have shown that neuronal synchronization occurs soon after the presentation of visual, auditory or somatosensory stimuli. Most of these studies have employed long-range phase synchronization as the electrophysiological correlate of synchronous neuronal ensembles considered to underlie perception. However, in these studies, phase synchronization is modulated immediately after briefly presented stimuli (~400ms). Still, during natural vision, visual percepts can be sustained for long periods of time. It is unknown whether spatio-temporal patterns of phase synchrony can account for this sustained perception or only indicate perceptual transitions. In this work, we examined patterns of phase synchronization in a classical bistable visual task, the Necker's cube. In this paradigm, one lasting physical stimulus has two possible interpretations, and the subject reported his perception changes from one to the other interpretation, by a button press (BP). Results demonstrate that sustain perception correlates with a discontinuous large-scale pattern of phase coupling, with synchrony events restricted in time, frequency and location. This pattern exhibits synchrony events already reported as stimulus sensing and binding. Overall, our results show that large-scale synchrony varies on time during the individual's perception experience. This result suggests that large-scale synchrony may participate in perceptual transition, but are not necessarily required to remain stationary during sustained perception.