Abstract
Our ability to flexibly adapt to changing demands is supported by flexible coding of task-relevant information in frontal and parietal brain regions. Converging evidence suggest that coding of stimuli and task rules in these regions become stronger as task difficulty increases. Here, we tested whether there is a corresponding change in the representational format as well, an issue that has rarely been addressed directly in past research. Participants performed a visual classification task under varying levels of perceptual difficulty, while we acquired fMRI. Using a model-based representational similarity approach, we tested whether stimulus representations retain exemplar-level information. We expected representations to drop such exemplar-level information as perceptual difficulty increases, which would indicate a focus on representing behaviorally relevant category information. Counter to these expectations, and in contrast to previous research, we found frontal and parietal brain regions contained exemplar-level stimulus information. Interestingly, the anterior intraparietal sulcus (aIPS) retained exemplar-level stimulus information even in perceptually difficult trials, and these representations were directly related to performance. Overall, these findings call for a reassessment of the neural mechanisms underlying human adaptive behavior during visual classification.
Competing Interest Statement
The authors have declared no competing interest.
