Poster C47, Sunday, March 25, 1:00-3:00 pm, Exhibit Hall C
Common recruitment of neural resources for phonological working memory regardless of behavioral demands.
Terri L. Scott1, Sara C. Dougherty1, Ja Young Choi2, Tyler K. Perrachione1; 1Boston University, 2Harvard University
Phonological working memory is the process by which we maintain representations of sounds important for speech and language in short-term memory. This ability is believed to be critical for language and reading acquisition and is often assessed clinically using nonword repetition tasks. Inconsistencies exist in the neuroimaging literature as to whether phonological working memory is supported by fronto-parietal brain regions classically associated with short-term memory storage or perisylvian brain structures canonically implicated in speech perception and production. In this study, we used fMRI to assess neurophysiological responses while individuals performed two tasks—nonword repetition and nonword discrimination—at two levels of working memory load. These tasks closely reflect the clinical operationalization of phonological working memory, though the behavioral demands of nonword discrimination more closely parallel classic working memory tasks. Using group-constrained subject-specific functional analysis, a method specifically employed to address individual subject variability, we found significant neural responses to the critical contrast of high vs. low phonological working memory load in both tasks were supported by a similar set of regions closely resembling those involved in speech (i.e., superior temporal gyrus, planum temporale, motor cortex, and cerebellum). Moreover, within those regions, the voxel-wise patterns of load-related activation were highly correlated between the two tasks. These results suggest that processing increased phonological load involves recruitment of a consistent set of neural regions known to be integrally involved in speech, regardless of the specific behavioral demands of the working memory task.
Topic Area: LANGUAGE: Other