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Mark W. Greenlee, Katharina Rosengarth, Tina Plank; Brain plasticity associated with supervised and unsupervised learning in a coherent-motion detection task. Journal of Vision 2010;10(7):1108. doi: https://doi.org/10.1167/10.7.1108.
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We investigated the role of trial-by-trial feedback during training on the neural correlates of perceptual learning in a coherent-motion detection paradigm. Stimuli were four patches of randomly moving dots were presented simultaneously, one in each visual quadrant. Over six training sessions (with a total of 5340 trials per observer) subjects learned to detect coherent motion in a predefined quadrant. During training, half of our subjects received feedback after each response, indicating whether they were correct or incorrect on that trial, whereas the other subjects did not get feedback. We investigated whether the presence of feedback during training had an effect on learning success (performance, reactions times) and on the resultant BOLD response to motion stimuli presented within the trained quadrant (measured in three separate sessions). Behavioral data of 4 subjects showed improved performance with increasing practice. Feedback led a significant benefit in performance and to lower reactions times. After training with feedback, subjects exhibited bilateral BOLD responses in hMT+ that first increased (from session 1 to 2) and then decreased (from session 2 to 3). Without feedback during training the BOLD signal in hMT+ was reduced and showed a shallower, monotonic learning curve. These results point to a learning-specific alteration in the activity of MT neurons that selectively respond to coherent-motion stimuli. Trial-by-trial feedback enhanced performance and led to a different time course of the BOLD response over training.
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