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Jennifer Anderson, Michael Levine; Noise Modulation in the Dorsal and Ventral Visual Pathways. Journal of Vision 2010;10(7):1075. doi: 10.1167/10.7.1075.
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© ARVO (1962-2015); The Authors (2016-present)
The human visual system responds differently to the same stimulus depending on type of task. These differences may be due to how the stimulus is encoded; action-tasks utilizing an observer-based encoding, and perceptual-tasks utilizing an object-based encoding. We are interested in how the systems modulating these different outputs process extrinsic noise. Previously, we demonstrated a method allowing subjects to respond to the same visual display via hand-eye coordination or via perceptual-awareness. In the current study, we examined response variance in the two tasks given increasing levels of noise. Noise was defined as a random displacement applied to each frame of a moving target as it traversed the visual display. The magnitude of the displacement corresponded to the standard deviation of the sampled normal distribution. We hypothesized that response variance would be the sum of the intrinsic noise of the system and the applied extrinsic noise. We tested video-game experts and non-experts. All data follow the expected trend in the action-task. Data from non-experts also follow this trend in the perceptual-task, however data from video-game experts show less variability in responses compared to the predicted model, especially at high levels of extrinsic noise. This may suggest that experts are better able to “ignore” noise than non-experts. Further analysis using a LAMSTAR neural network, trained on subject data, was able to determine the threshold at which noise overwhelmed the mechanism for “ignoring” noise in the perceptual-task. We found that the two systems would begin to treat the sum of the intrinsic and extrinsic noise similarly at much higher levels of noise in video-game experts. In sum, these findings suggest that noise may be processed differently according to the type of visual task.
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