BME házi kollokvium sorozat: emlékeztető

Ma ötkor a BME-n. ST ép. 320. *Előadás a BME Kognitív Tudományi Központ* *házi kollokvium sorozata keretében:* *Előadó: Zsóri Adrienn, *Magdeburgi Egyetem, Németország *Cím:* Temporal dynamics of visual processing during binocular rivalry * * During binocular rivalry different images simultaneously presented to both eyes compete for perceptual dominance. The result of this competition is an unstable, changing percept that offers a unique opportunity to investigate the neural correlates during conscious and unconscious perception. In a combined MEG/EEG-study subjects were presented with a squared aperture in which 100 red dots moved coherently to the left while other 100 blue dots moved rightwards thereby defining two transparent surfaces. The subjects viewed the stimuli through red-blue glasses guaranteeing that each transparent surface was seen by a different eye and were instructed to press a button to indicate which percept (left or right moving surface) was dominant. Small vertical translations of the dots served as a probe and randomly occurred in either the leftwards or the rightwards moving surface. The event-related electric (ERP) and magnetic (ERF) responses to the probes on each surface were compared as a function of whether the surface on which the probe occurred was the dominant percept or not. This made it possible to compare ERP and ERF responses elicited by exactly the same physical stimulus in two different states of awareness. This comparison revealed a significant difference in the electrophysiological responses starting at 110 ms post-stimulus. Source analysis of this difference indicated that the earliest sources were located in the medial superior occipital cortex. At 130 ms estimates of activity could also be observed in the primary visual cortex around the occipital pole. Importantly, the source strength of the superior medial occipital cortex was higher during unconscious than during conscious perception. This temporal pattern of activation is consistent with the idea of top-down control of the primary visual cortex by higher order extrastriate regions. The higher strength of the superior medial occipital sources during unconscious perception suggests that the top-down is of inhibitory nature. *Idő:* 2005 október 24, 17 óra *Hely:* BME, St. épület 320 Minden érdeklődőt szeretettel várunk. Jakab Zoltán