A working memory role for superior temporal cortex in deaf individuals independently of linguistic content
2015 (English)Conference paper, Abstract (Refereed)
Studies of sign languages have been used to test traditional cognitive models of working memory (WM) that distinguish between verbal and visuospatial WM (e.g. Baddeley, 2003), without considering that sign languages operate in the visuospatial domain. Previous studies have shown that WM mental representations and processes are largely similar for signed and spoken languages (e.g. Rönnberg et al., 2004). However, it is not clear to what extent visual WM processes aid and support sign language WM.
Here we characterise the neural substrates supporting sign language and visual WM, and the mechanisms that subserve differential processing for signers and for deaf individuals. We conducted a functional magnetic resonance imaging (fMRI) experiment with three groups of participants: deaf native signers, hearing native signers and hearing non-signers. Participants performed a 2-back WM task and a control task on two sets of stimuli: signs from British Sign Language or non-sense objects. Stimuli were composed of point-lights to control for differences in visual features.
Our results show activation in a fronto-parietal network for WM processing in all groups, independently of stimulus type, in agreement with previous literature. We also replicate previous findings in deaf signers showing a stronger right posterior superior temporal cortex (STC) activation for visuospatial processing, and stronger bilateral STC activation for sign language stimuli.
Group comparisons further reveal stronger activations in STC for WM in deaf signers, but not for the groups of hearing individuals. This activation is independent of the linguistic content of the stimuli, being observed in both WM conditions: signs and objects. These results suggest a cognitive role for STC in deaf signers, beyond sign language processing.
Place, publisher, year, edition, pages
General Language Studies and Linguistics
IdentifiersURN: urn:nbn:se:liu:diva-123240OAI: oai:DiVA.org:liu-123240DiVA: diva2:878476
Conference on Cognitive Hearing Science for Communication (CHCCOM2015), Linköping, June 14-17, 2015