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Abdurahman Elkhetali, Ryan Vaden, Sean Pool, Kristina Visscher; Three measures of ongoing neural activity examined in retinotopically mapped visual cortex. Journal of Vision 2012;12(9):384. doi: https://doi.org/10.1167/12.9.384.
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© ARVO (1962-2015); The Authors (2016-present)
The brain is constantly active; neurons signal to each other even in the absence of external stimuli. Fluctuations in ongoing, non-stimulus-driven activity may modulate the brain's interaction with the external environment, and may reflect processes associated with task preparation and task maintenance. Here, we examine changes in non-stimulus-driven neural activity that reflect task maintenance and task preparation. Nineteen subjects performed auditory and visual tasks. The auditory task required discrimination between two successive sounds. The visual task required discrimination between two centrally-presented gray scale images (Gabor patches). The tasks were presented in four different behavioral conditions designed to test the effects of attention and ignoring: 1) visual task alone, 2) auditory task alone, 3) auditory task with visual distracter, 4) visual task with auditory distracter. Three types of non-stimulus-driven neural activity were measured: activity associated with maintenance of a task set, activity associated with the onset of a task block, and cue-driven activity associated with preparation for a trial of the task. Regions of interest (ROI) were created for each subject based on retinopic maps of the visual cortex. Each visual area (V1,V2, and extrastriate areas) were divided into central and peripheral ROIs depending on eccentricity. Our data show that non-stimulus-driven neural activity in the visual cortex depends on task. The pattern of these results depends on the visual cortical region and on eccentricity. Different regions show different patterns of preparation-related vs. maintenance-related ongoing activity. This indicates that these various measures reflect different mechanisms by which ongoing activity influences information processing.
Meeting abstract presented at VSS 2012
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