Sensory Bias and Working-Memory Recruitment Are Multiplexed In Human Frontal Cortex

Abigail Noyce¹, Barbara G. Shinn-Cunningham², David C. Somers³
¹Boston University, ²Boston University, ³Boston University

Large swathes of human lateral frontal cortex (LFC) are recruited for attention, working memory, and flexible cognitive control. Recently, subject-by-subject mapping of visual and auditory selective attention resulted in the identification of interleaved visual-biased and auditory-biased areas in LFC (Michalka et al., under review). Here, we used fMRI to measure BOLD activity in auditory and visual 2-back tasks (n=9). Visual stimuli were monochrome photos of younger adult faces; auditory stimuli were recorded cat and dog calls. By contrasting auditory and visual working memory, we are able to identify two visual-biased areas and two auditory-based areas in individual subjects, replicating the results of Michalka et al. The superior and inferior precentral sulcus (sPCS and iPCS) are visual-biased; the transverse gyrus intersecting precentral sulcus (tgPCS) and inferior frontal gyrus (IFG) are auditory based. Conversely, when contrasting working memory to sensorimotor control within each modality, we see activation that extends substantially beyond the significant sensory-biased areas. Combing these two contrasts, we quantified the degree of working memory recruitment and the preference for sensory modality of each vertex on individual subjects’ cortical surfaces. Visual-biased regions of the LFC tend to be recruited for both working memory tasks, while auditory-biased regions are more likely to maintain an auditory preference. This may suggest that human visual attention architectures are recruited to support performance even in tasks that are not explicitly visuospatial, while auditory architectures are more specialized.

Keywords: Working Memory, Auditory, Visual, fMRI


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