Our perceptions are often shaped by focusing our attention towards specific features or periods of time irrespective of location. Here we explore the physiological bases of these non-spatial forms of attention by imaging brain activity while subjects perform a challenging change-detection task. The task employs a continuously varying visual stimulus that, for any moment in time, selectively activates functionally distinct subpopulations of primary visual cortex (V1) neurons. When subjects are cued to the timing and nature of the change, the mapping of orientation preference across V1 systematically shifts towards the cued stimulus just prior to its appearance. A simple linear model can explain this shift: attentional changes are selectively targeted towards neural subpopulations, representing the attended feature at the times the feature was anticipated. Our results suggest that featural attention is mediated by a linear change in the responses of task-appropriate neurons across cortex during appropriate periods of time.
Bibliographical noteFunding Information:
We thank Cheryl Olman and Andrea Grant for assistance with image pre-processing and retinotopic mapping; Zheng Wu and Bradley Edelman for assistance in data analysis; Blaine Schneider, Thomas Nelson, Pantea Moghimi and Zheng Wu for assistance during data collection; Jimmy Shen and Rody Oldenhuis for their publicly available MATLAB toolboxes; Federico De Martino, Stephen Engel and members of the Engel and Olman labs for substantial analysis advice; Michael Beauchamp, Katherine Weiner, Pantea Moghimi, Cheryl Olman and Federico De Martino for comments on the manuscript and subject volunteers for their time. S.G.W. was supported by T32-GM8471, T32-GM8244, T32-HD007151 and the University of Minnesota’s MnDRIVE initiative. This work was also supported by P30-EY011374, P30-NS076408, R01-EY014989, P41-RR008079, P41-EB015894 and S10-RR026783.
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