Right-hemisphere motor facilitation by self-descriptive personality-trait words

Authors

  • Istvan Molnar-Szakacs,

    1. UCLA Ahmanson-Lovelace Brain Mapping Center
    2. FPR-UCLA Center for Culture, Brain and Development
    3. Brain Research Institute and
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  • Lucina Q. Uddin,

    1. Department of Psychology,
    2. Brain Research Institute and
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  • Marco Iacoboni

    1. UCLA Ahmanson-Lovelace Brain Mapping Center
    2. FPR-UCLA Center for Culture, Brain and Development
    3. Department of Psychiatry and Biobehavioural Sciences
    4. Brain Research Institute and
    5. Neuropsychiatric Institute, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
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Istvan Molnar-Szakacs, 1UCLA Ahmanson-Lovelace Brain Mapping Center, as above.
E-mail: imolnar@ucla.edu

Abstract

The emergent picture from the literature on the processing of self-related information suggests that in addition to the neural mechanisms involved in recognizing one's own face, there may also be neural representations of the self that are modality independent and favour the right hemisphere. We used focal, single-pulse transcranial magnetic stimulation in human subjects to assess cortical excitability during covert reading of self-descriptive personality-trait words. We hypothesized that the right hemisphere would show a greater overall facilitation to personality-trait words than the left hemisphere. Overall, personality-trait words led to significantly greater motor facilitation in the right hemisphere than in the left hemisphere. In addition, words rated as ‘never’ self-characteristic yielded significant right hemisphere facilitation, and words rated as ‘always’ self-characteristic showed a similar trend. The results are discussed in terms of the notion that the right hemisphere plays a dominant role in both self-relevant processing and the processing of affective stimuli.

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