Cerebral Cortex Advance Access published online on January 31, 2008
Cerebral Cortex, doi:10.1093/cercor/bhm248
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Encoding, Rehearsal, and Recall in Signers and Speakers: Shared Network but Differential Engagement
1 Department of Brain and Cognitive Sciences, 2 Rochester Center for Brain Imaging, University of Rochester, Rochester, NY 14627-0268, USA, Departments of, 3 Psychology, 4 Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J1, 5 Department of Research and Teacher Education, National Technical Institute for the Deaf, Rochester, NY 14623, USA, 6 National Institute of Deafness and Communication Disorder, Bethesda, MD 20892, USA
Address corresponding to Daphne Bavelier, RC Box 270268, Brain and Cognitive Sciences Department, University of Rochester, Rochester, NY 14627-0268, USA. Email: daphne{at}bcs.rochester.edu.
Short-term memory (STM), or the ability to hold verbal information in mind for a few seconds, is known to rely on the integrity of a frontoparietal network of areas. Here, we used functional magnetic resonance imaging to ask whether a similar network is engaged when verbal information is conveyed through a visuospatial language, American Sign Language, rather than speech. Deaf native signers and hearing native English speakers performed a verbal recall task, where they had to first encode a list of letters in memory, maintain it for a few seconds, and finally recall it in the order presented. The frontoparietal network described to mediate STM in speakers was also observed in signers, with its recruitment appearing independent of the modality of the language. This finding supports the view that signed and spoken STM rely on similar mechanisms. However, deaf signers and hearing speakers differentially engaged key structures of the frontoparietal network as the stages of STM unfold. In particular, deaf signers relied to a greater extent than hearing speakers on passive memory storage areas during encoding and maintenance, but on executive process areas during recall. This work opens new avenues for understanding similarities and differences in STM performance in signers and speakers.
Key Words: American Sign Language • deafness • fMRI • short-term memory