a normalization model of attentional modulation of single unit responses注意力调制的规范化模型的单一单元反应.pdfVIP

A Normalization Model of Attentional Modulation of Single Unit Responses 1 2 Joonyeol Lee , John H. R. Maunsell * 1 Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America, 2 Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, United States of America Abstract Although many studies have shown that attention to a stimulus can enhance the responses of individual cortical sensory neurons, little is known about how attention accomplishes this change in response. Here, we propose that attention-based changes in neuronal responses depend on the same response normalization mechanism that adjusts sensory responses whenever multiple stimuli are present. We have implemented a model of attention that assumes that attention works only through this normalization mechanism, and show that it can replicate key effects of attention. The model successfully explains how attention changes the gain of responses to individual stimuli and also why modulation by attention is more robust and not a simple gain change when multiple stimuli are present inside a neuron’s receptive field. Additionally, the model accounts well for physiological data that measure separately attentional modulation and sensory normalization of the responses of individual neurons in area MT in visual cortex. The proposal that attention works through a normalization mechanism sheds new light a broad range of observations on how attention alters the representation of sensory information in cerebral cortex. Citation: Lee J, Maunsell JHR (2009) A Normalization Model of Attentional Modulation of Single Unit Responses. PLoS ONE 4(2): e4651. doi:10.1371/ journal.pone.0004651 Editor: Jan La