Increased neural efficiency in the temporal association cortex as the result of semantic task repetition

Authors

  • Christine Whatmough,

    Corresponding author
    1. Department of Neurology and Neurosurgery, McGill University, Montréal, Canada
    2. Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, Montréal, Canada
    3. Centre de Recherche Institute Universitaire de Gériatrie de Montréal, Université de Montréal, Montréal, Canada
    • Lady Davis Institute for Medical Research, Tr-1, 3755 Cote-Ste-Catherine Road, Montreal, QC, Canada H3T 1E2
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  • Jim Nikelski,

    1. Department of Neurology and Neurosurgery, McGill University, Montréal, Canada
    2. Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, Montréal, Canada
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  • Oury Monchi,

    1. Centre de Recherche Institute Universitaire de Gériatrie de Montréal, Université de Montréal, Montréal, Canada
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  • Howard Chertkow

    1. Department of Neurology and Neurosurgery, McGill University, Montréal, Canada
    2. Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, Montréal, Canada
    3. Centre de Recherche Institute Universitaire de Gériatrie de Montréal, Université de Montréal, Montréal, Canada
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Abstract

We examined the effect of semantic task repetition and of alternating between tasks on cerebral blood flow in three H215O positron emission tomography experiments. We found that repeatedly performing semantic tasks resulted in a reduction in cerebral blood flow to the left temporal association cortex similar to that found in priming experiments even though here there was no repetition of stimuli. Although the same effect was found in two different tasks (word meaning judgments and picture naming), it was only present when the same task was repeated on consecutive scans and not when the subjects alternated from scan to scan between tasks. We propose that there is a neural efficiency which develops in the association cortex of the temporal lobe as a result of repeatedly performing a semantic task. This efficiency is abolished by interruptions such as performing a different task. Hum Brain Mapp, 2008. © 2007 Wiley-Liss, Inc.

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