BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:Top-down vs. bottom-up? Effects of prediction and attention on sen sory processing and perception - Heleen A. Slagter\, PhD\, Professor of C ognitive Neuroscience VU University Amsterdam DTSTART:20190308T163000Z DTEND:20190308T173000Z UID:TALK116146@talks.cam.ac.uk CONTACT:Louise White DESCRIPTION:\nPerception is more than meets the eye: how we see the world is critically shaped by attention (what is relevant) and as a growing body of work indicates\, by expectations derived from past experience (what is likely). Overturning the classical notion of perception as a largely bott om-up process of feature detection and evidence accumulation\, the idea th at our brain is a prediction machine\, continually trying to predict what is ‘out there’ based on past experience\, is quickly growing in statur e and influence. Yet\, little is still known about how predictions shape p erceptual experience\, independently and/or in interaction with attention. In my talk\, I will present results from several behavioral and EEG exper iments to address two specific outstanding issues. First\, predictive proc essing theories propose that predictions reduce sensory signals as early a s primary visual cortex (V1)\, and that attention can modulate these effec ts. Indeed\, both prediction and attention have been shown to modulate V1 activity\, albeit with fMRI\, which has low temporal resolution. This leav es it unclear whether these effects reflect a modulation of the first feed forward sweep of visual information processing and/or later\, feedback-rel ated activity. In two experiments\, we used EEG and orthogonally manipulat ed spatial predictions and attention to address this outstanding question. Although clear top-down biases were found\, as reflected in pre-stimulus alpha-band activity\, no evidence was found for top-down effects on the ea rliest visual cortical processing stage (<80ms post-stimulus)\, as indexed by the amplitude of the C1 ERP component and multivariate pattern analyse s. Later processing stages did show clear modulations by attention and pre diction. Second\, recent work indicates that distractor suppression may on ly emerge when information about the distractor can be derived directly fr om experience\, suggesting that suppression of distracting information is expectation dependent rather than controlled by top-down inhibitory mechan isms. Indeed\, across several EEG studies\, using ERPs and decoding and in verted encoding analyses\, we found that as subjects learned about distrac tor features and/or locations\, the brain stopped regarding the distractor as a distractor\, as indicated in behavior and by the elimination of neur al responses previously associated with active distractor suppression. Col lectively\, these findings shed novel light on how prediction and attentio n interact to bias visual processing and perception.\n\nBio\n\nHeleen Slag ter is Professor of Cognitive Neuroscience at the VU University of Amsterd am. She received a PhD in cognitive neuroscience in 2005 from the Universi ty of Amsterdam. After a 4-year postdoc at the University of Wisconsin-Mad ison\, USA\, she returned to Amsterdam to set up her own lab. Her research focuses on (the neural basis of) core cognitive functions\, such as atten tion\, and the plasticity of these functions. What are the mechanisms that allow us to perceive\, select\, suppress\, and become aware of informatio n in the environment? How does learning based on prior experience or menta l training as cultivated by meditation influence these mechanisms that ada ptively control information processing? Dr. Slagter’s work has garnered awards and funding\, including a prestigious VIDI grant by the Netherlands Organization for Scientific research\, an ERC starting grant\, and an ear ly career award by the Society for Psychophysiological Research. LOCATION:Ground Floor Lecture Theatre\, Department of Psychology END:VEVENT END:VCALENDAR