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Miranda Scolari, Newton A. Abuyo, John T. Serences; Switching between optimal feature-based attentional gain patterns according to task demands. Journal of Vision 2012;12(9):916. doi: https://doi.org/10.1167/12.9.916.
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Several recent studies have demonstrated that feature-based attentional gain is deployed to the most informative sensory neurons during discrimination tasks (e.g. Navalpakkam & Itti, 2007; Scolari & Serences, 2009). When making a coarse discrimination (e.g., identifying a 90° target among 180° distractors), attention enhances the response of neurons tuned to the target (on-channel gain) because these neurons reliably signal the difference between stimulus alternatives. However, when making a fine discrimination (e.g., identifying a 90° target among 95° distractors), attention enhances the response of neurons tuned to flanking orientations (off-channel gain) because these neurons undergo a larger firing rate change between target and distractors. While these two task-dependent patterns have been observed in discrete studies, here we explore whether subjects can appropriately switch between strategies in response to changes in the degree of target-distractor similarity. We estimated the shape of the feature-based attentional gain function during both fine and coarse orientation discrimination tasks (all subjects completed both task types in separate sessions, N=26). Following the methods of Scolari & Serences (2009), subjects indicated the location of a target Gabor patch that was rotated ±5° (fine) or ±90° (coarse) from three uniform distractors. On 33% of trials, we probed the distribution of gain by measuring detection accuracy for a single Gabor offset from the expected discrimination target by 0°, ±5°, ±10°, ±20°, or ±90°. Overall, we observed more on-channel gain during the coarse discrimination and more off-channel gain during the fine discrimination task. Furthermore, the best subjects showed the greatest difference in gain at the target orientation between task types. This suggests that individuals who most effectively deploy gain in one discrimination task are also likely to be most effective at switching gain patterns in accordance with altered perceptual demands.
Meeting abstract presented at VSS 2012
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