Poster D47, Monday, March 27, 8:00 – 10:00 am, Pacific Concourse
Visual field maps limit working memory precision
Xingyu Ding1,2, Wayne E. Mackey1, Clayton E. Curtis1, Xiao-Jing Wang1,2, Jonathan Winawer1; 1NYU, 2NYU Shanghai
The storage capacity of working memory (WM) is severely limited, and this limitation varies greatly both between individuals and across the lifespan. Currently, the neurobiological basis of this limitation is unknown. Here, we show that the sizes of select visual field maps in early visual cortex and frontoparietal cortex limit the precision of WM representations. First, we used a recurrent (attractor) network model of spatial working memory to investigate how the size of the neural population affected the fidelity of the WM representation. Results show that with a larger population size, the precision of the decoded WM representation is enhanced. Second, we carried out nonlinear population receptive field mapping to identify visual field maps in early visual and frontoparietal cortex of human subjects. This allowed us to quantify the size of specific populations in individual subjects. We then correlated the size of visual field maps with individual performance during a spatial working memory task and found that the size of select visual field maps predicted WM precision. Finally, using our measurements of visual field maps for each individual subject, we simulated population level activity in each visual field map with our neural network model. This simulation demonstrates that the precision of the WM representation in the population activity correlates with WM accuracy. Together, these results support the hypothesis that WM resources are limited by neural architecture in visual and frontoparietal cortex known to be critical for WM performance.
Topic Area: EXECUTIVE PROCESSES: Working memory