Unbound MEDLINE

Dynamic causal modeling of spatiotemporal integration of phonological and semantic processes: an electroencephalographic study.

Abstract

Integration of phonological and lexicosemantic processes is essential for visual word recognition. Here we used dynamic causal modeling of event-related potentials, combined with group source reconstruction, to estimate how those processes translate into context-dependent modulation of effective connectivity within the temporal-frontal language network. Fifteen healthy human subjects performed a phoneme detection task in pseudo-words and a semantic categorization task in words. Cortical current densities revealed the sequential activation of temporal regions, from the occipital-temporal junction toward the anterior temporal lobe, before reaching the inferior frontal gyrus. A difference of activation between phonology and semantics was identified in the anterior temporal lobe within the 240-300 ms peristimulus time window. Dynamic causal modeling indicated this increase of activation of the anterior temporal lobe in the semantic condition as a consequence of an increase of forward connectivity from the posterior inferior temporal lobe to the anterior temporal lobe. In addition, fast activation of the inferior frontal region, which allowed a feedback control of frontal regions on the superior temporal and posterior inferior temporal cortices, was found to be likely. Our results precisely describe spatiotemporal network mechanisms occurring during integration of phonological and semantic processes. In particular, they support the hypothesis of multiple pathways within the temporal lobe for language processing, where frontal regions would exert a top-down control on temporal regions in the recruitment of the anterior temporal lobe for semantic processing.

Links

  • Publisher Full Text
  • Authors

    Yvert G, Perrone-Bertolotti M, Baciu M, David O

    Institution

    Laboratoire de Psychologie et Neurocognition, UMR CNRS 5105, Grenoble, France.

    Source

    The Journal of neuroscience : the official journal of the Society for Neuroscience 32:12 2012 Mar 21 pg 4297-306

    MeSH

    Adult
    Brain Mapping
    Cerebral Cortex
    Electroencephalography
    Evoked Potentials
    Female
    Humans
    Image Processing, Computer-Assisted
    Magnetic Resonance Imaging
    Male
    Models, Neurological
    Nonlinear Dynamics
    Phonetics
    Photic Stimulation
    Reaction Time
    Semantics
    Young Adult

    Pub Type(s)

    Journal Article
    Research Support, Non-U.S. Gov't

    Language

    eng

    PubMed ID

    22442091