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Symposium at NVP on "Top-down perceptual decision-making"

posted Aug 15, 2011, 11:39 AM by Floris de Lange

On December 16-17, the NVP Winter Conference on Cognition, Brain, and Behaviour of the Dutch Psychonomic Society will be held in Egmond aan Zee, at Hotel Zuiderduin.There will be a symposium on top-down influences on visual perception.

Chairs: Floris de Lange (Donders Institute, Nijmegen) and Simon van Gaal (Neurospin institute, Paris)

Title: Changing views: How top-down factors alter perception and decision-making

Symposium abstract:

Perception is not simply a passive process of accumulation of sensory evidence, but it is strongly shaped by internal brain states, which incorporate our goals, attention, expectations, and knowledge about the world. Although great progress has been made, the exact mechanisms by which these “top-down factors” affect perception, cognition, and behavior are still largely unknown. Where do the neuronal top-down signals come from? How do they change communication between sensory and decision-related brain regions ? And how do these factors affect our perception and decision-making?

In this symposium, we will present recent developments in the field of top-down effects on perception and decision-making, which are rooted in perceptual psychophysics, computational modeling, and neurophysiology (EEG/MEG and fMRI). We will address different perspectives and viewpoints, all based on novel conceptual frameworks and experimental approaches. Specifically, we will discuss novel fMRI approaches highlighting how sensory representations in the visual cortex change with top-down attention (Jehee). We will show how non-invasive neurophysiological methods dissociate between the neural consequences of top-down attention and stimulus expectation (MEG, fMRI: de Lange). We will discuss recent neurophysiological and psychophysical evidence for a novel feedback signal in visual cortex triggered by perceptual decisions (Donner). Finally, we will present new neurophysiological evidence that questions the dependence of top-down control signals on consciousness (van Gaal). Together, these presentations will reveal that top-down control of perception and decision-making is multifaceted and versatile, rather than unitary and fixed.

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