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Brain State-dependent Functional Hemispheric Specialization in Men but not in Women

Mohr, Christine ; Michel, Christoph M. ; Lantz, Goran ; Ortigue, Stephanie ; Viaud-Delmon, Isabelle ; Landis, Theodor

In: Cerebral Cortex, 2005, vol. 15, no. 9, p. 1451-1458

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    Title
    • Brain State-dependent Functional Hemispheric Specialization in Men but not in Women
    Author
    • Mohr, Christine. The Functional Brain Mapping Laboratory of the Neurology Clinic, University Hospital Geneva, Geneva, Switzerland
    • Michel, Christoph M.. The Functional Brain Mapping Laboratory of the Neurology Clinic, University Hospital Geneva, Geneva, Switzerland
    • Lantz, Goran. The Functional Brain Mapping Laboratory of the Neurology Clinic, University Hospital Geneva, Geneva, Switzerland
    • Ortigue, Stephanie. The Functional Brain Mapping Laboratory of the Neurology Clinic, University Hospital Geneva, Geneva, Switzerland
    • Viaud-Delmon, Isabelle. CNRS UMR 7593, Hopital de la Salpetriere, Paris, France
    • Landis, Theodor. The Functional Brain Mapping Laboratory of the Neurology Clinic, University Hospital Geneva, Geneva, Switzerland
    Document Type
    • Postprint
    Language
    • English
    Published in
    • Cerebral Cortex, 2005, vol. 15, no. 9, p. 1451-1458. Oxford University Press
    Other Version
    OAI-PMH Identifier
    • oai:doc.rero.ch:298079
    Summary
    Hemispheric specialization is reliably demonstrated in patients with unilateral lesions or disconnected hemispheres, but is inconsistent in healthy populations. The reason for this paradox is unclear. We propose that functional hemispheric specialization in healthy participants depends upon functional brain states at stimulus arrival (FBS). Brain activity was recorded from 123 surface electrodes while 22 participants (11 women) performed lateralized lexical decisions (left hemisphere processing) on neutral and emotional (right hemisphere processing) words. We determined two classes of stable FBS, one with right anterior-left posterior orientations (RA-LP maps) and one with left anterior-right posterior orientations (LA-RP maps). Results show that functional hemispheric specialization is dependent upon the class of FBS and gender. Of those with LA-RP maps, only men showed a strong emotional word advantage (EWA) after left visual field (right hemisphere) presentation, but no EWA after right visual field (left hemisphere) presentation. Subsequent to all other brain states, there was an almost equal EWA after presentation to either visual field. Only about half of the FBS in men led to the pattern of functional hemispheric specialization. We suggest that ‘split-brain' research may be marginally describable by a model, but only in exceptional situations, while in connected brains this functional hemispheric specialization is only one of many dynamic states