Neural substrates for verbal working memory in deaf signers: fMRI study and lesion case report.
The nature of the representations maintained in verbal working memory is a topic of debate. Some authors argue for a modality-dependent code, tied to particular sensory or motor systems. Others argue for a modality-neutral code. Sign language affords a unique perspective because it factors out the effects of modality. In an fMRI experiment, deaf participants viewed and covertly rehearsed strings of non-sense signs; analyses focused on regions responsive in both sensory and rehearsal phases. Compared with previous findings in hearing subjects, deaf subjects showed a significantly increased involvement of parietal regions. A lesion case study indicates that this network is left-dominant. The findings support the hypothesis that linguistic working memory is supported by modality-specific neural systems, but some modality-neutral systems may also be involved.
Buchsbaum
Bradley
B
Laboratory for Cognitive Brain Research, Department of Cognitive Sciences, University of California, Irvine, USA.
Pickell
Bert
B
Love
Tracy
T
Hatrak
Marla
M
Bellugi
Ursula
U
Hickok
Gregory
G
D001931:Brain Mapping; D003638:Deafness / Q000503:physiopathology*; D004292:Dominance, Cerebral / Q000502:physiology; D006801:Humans; D008037:Linguistics; D008279:Magnetic Resonance Imaging; D008570:Memory, Short-Term / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology*; D012813:Sign Language