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Seminar Abstract

Evaluating optimal models of information processing in visual cortex.

Speaker : Associate Professor John Serences, Perception and Cognition Lab, Department of Psychology, University of California, San Diego, USA.
Date : 26th of November 2012, 1:00PM until 2:00PM
Location : C5C498, Macquarie University.

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Current behavioral goals and motivational drives play a critical role in shaping and refining information processing so that only the most relevant sensory stimuli are perceived and allowed to influence decision making. Traditional accounts hold that these ‘top-down’ attentional factors are critically important in information processing precisely because attention enhances the gain of the sensory neurons that are selectively tuned to relevant stimulus features. These models are intuitively appealing, and suggest that attention effectively increases the intensity of important stimuli in a manner analogous to turning up the volume knob on a stereo. Using the early visual system as a model, I will use fMRI and a novel analytic approach to show that attention modulates the gain of the most informative sensory neurons given whatever specific perceptual task confronts the observer. Counter-intuitively, enhancing the gain of the most informative sensory neurons often means biasing patterns of neural activity away from the patterns evoked by sensory stimuli. Thus, contrary to most traditional accounts, these observations suggest that the primary function of attention is not simply to enhance the gain of stimulus-driven responses, but to optimize performance on the current perceptual task.