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Title:Cortical competition: a neurally plausible account of hemisphere-specific processing resources?
Author(s):Clevenger, John H
Advisor(s):Beck, Diane M.
Contributor(s):Simons, Daniel J.
Department / Program:Psychology
Degree Granting Institution:University of Illinois at Urbana-Champaign
Abstract:Recent studies have shown performance advantages in visual tasks when task-relevant stimuli are presented in different visual hemifields as opposed to a single hemifield. A common interpretation of these findings is that each cortical hemisphere has an independent tank of processing resources and that overloading a single hemisphere leads to performance degradation. However, it is not clear what such processing resources might be. We explore three ways of interpreting processing resources and their relationship to hemifield independence: resources as a kind of neural fuel, as a limitation on the coordination of attentional deployment, and as competition (interference) between representations in visual cortex. We report three experiments centered on hemifield independence that provide constraints on each of the three models. Experiments 1 and 2 show that, while fixing hemifield-level display density, local display density seems to drive hemifield independence. We argue that the competition model a priori predicts this effect and offer suggestions for how the other models can be adapted to account for it. Experiment 3 shows that hemifield independence can be modulated by attention: when the location of target is validly cued hemifield independence disappears. Once again, this effect is predicted by the competition model but is not inconsistent with the other two models. Taken as a whole, we argue that these three experiments provide constraints on any successful explanation of hemifield independence and suggest that the competition model naturally satisfies these constraints.
Issue Date:2016-10-13
Rights Information:Copyright 2016 John Clevenger
Date Available in IDEALS:2017-03-01
Date Deposited:2016-12

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