Poster B50, Sunday, March 26, 8:00 – 10:00 am, Pacific Concourse
Decoding the content and the rule during visuomotor working memory
Romain Quentin1, Jean-Remi King2, Etienne Sallard1, Nathan Fishman1, Ethan Buch1, Ryan Thompson1, Leonardo Cohen1; 1National Institute of Neurological Disorders and Stroke (NINDS/NIH), 2New York University (NYU)
Working memory is required for learning, reasoning, updating information, and performing everyday visuomotor tasks. Intra-cortical recordings in nonhuman primates and fMRI studies in humans demonstrated the involvement of the frontal cortex during working memory. However, whether such frontal involvement reflects the encoding of information content itself or the rule allowing one to recall this content is unknown. We developed an original working memory task in which two visual stimuli with different orientations and spatial frequencies were presented to the participant. After a short delay, a post-cue instruction indicated which visual feature (spatial frequency or orientation) of which stimulus (left or right) the participant had to remember. A group of 20 healthy adults performed this task while MEG signal was recorded. Multivariate pattern analysis showed first that both spatial frequency and orientation could be decoded from MEG early visual responses. In addition, we observed how trained classifiers generalized across time to get information on the dynamic representations of working memory states. Our results demonstrate that both the cued item and the type of cue (rule) can be decoded more than one second after their presentation. Moreover, the generalization across time showed a stable representation. These results demonstrate our ability to observe the dynamics of these representations and emphasize the crucial role of the rule maintenance during working memory task.
Topic Area: EXECUTIVE PROCESSES: Working memory