Dynamic task-based reorganization of sensory-biased and supramodal working memory networks in the human cerebral cortex

Sensory working memory is supported by a distributed set of brain regions. Visual working memory and auditory working memory recruit different networks, which include posterior sensory cortices and multiple sensory-biased regions interleaved across frontal cortex. Additionally, a fronto-parietal network of supramodal regions is robustly recruited by working memory in both modalities. Here we examined functional connectivity among visual-biased, auditory-biased, and supramodal working memory networks by collecting fMRI data from 24 human participants (aged 18-43; 11 men and 13 women). Replicating and extending prior work from our laboratory (Tobyne et al., 2017; Noyce et al., 2022), resting-state fMRI (N=18) analysis revealed that the visual-biased WM network exhibits stronger functional connectivity with supramodal regions than does the auditory-biased network. These findings point to a potential functional asymmetry between visual and auditory working memory mechanisms; visual cognition may have more direct access to supramodal WM brain structures. Therefore, we hypothesized that auditory working memory task performance would evoke more robust changes in functional connectivity than would visual working memory task performance. To test this hypothesis, we examined changes in functional connectivity that occur when participants (N=21) perform visual or auditory working memory tasks equated for difficulty. Auditory working memory produced substantial network changes that increased the connectivity of the auditory-biased network to supramodal regions and visual-biased frontal regions. At the same time, connectivity from posterior visual areas to supramodal and frontal visual regions decreased. In contrast, the visual task produced more modest changes in functional connectivity. Moreover, we observed that the strength of auditory-biased network connectivity changes correlated with subject behavioral performance on the auditory task, with higher working memory precision observed in participants with greater connectivity changes. Therefore, the visual working memory network appears to have more robust connectivity to supramodal working memory cortical structures at rest, but during auditory working memory, dynamic network changes permit the auditory working memory network to increase connectivity to the supramodal and frontal visual working memory networks.