Trained to silence: Progressive signal inhibition during short visuo-motor training

- Short training reduces task-related signals across task positive and task negative areas.
- Neural effects span both default-mode network and peripheral visual representations.
- Cortical signals correlated to reported automaticity and boredom, not performance.
- Task-negative training effects apparent in subsequent resting-state activity.
- Slow progressive reductions constitute a new type of cortical adaptation.

Short training is often sufficient for human individuals to become adept at performing a complex new task. However, the precise nature of the changes in cortical activity during short-term training of under an hour is still not fully understood. In this study, we have examined the effects of such short training in a visual recognition task on cortical activity using functional imaging (BOLD fMRI). Participants performed a gender/age discrimination task on face images for 28 min, preceded and followed by resting state scans. Our results reveal a consistent and progressive signal reduction during stimuli presentation compared to a fixation baseline, which was reflected in participant's subjective experience as evaluated by post-scan questionnaires. The BOLD reduction surprisingly included both task-positive and task-negative regions. While higher order face-selective regions showed a reduced positive peak response, negatively-responding areas - including the peripheral visual representations as well as the Default Mode Network - showed deeper negative BOLD responses during the visual stimulation periods. Interestingly, these training effects have left significant traces in the spontaneous resting-state fluctuations following the training period in areas that partially correspond to those that showed response changes during task performance. The results reveal the widespread cortical changes underlying short-term training.