From perceptual to lexico-semantic analysis - cortical plasticity enabling new levels of processing

Lara Schlaffke, Naima N. Rüther, Stefanie Heba, Lauren M. Haag, Thomas Schultz, Katharina Rosengarth, Martin Tegenthoff, Christian Bellebaum, and Tobias Schmidt-Wilcke
In: Human Brain Mapping (2015)
 

Abstract

Certain kinds of stimuli can be processed on multiple levels. While the neural correlates of different levels of processing (LOPs) have been investigated to some extent, most of the studies involve skills and/or knowledge already present when performing the task. In this study we specifically sought to identify neural correlates of an evolving skill that allows the transition from perceptual to a lexico-semantic stimulus analysis. Eighteen participants were trained to decode 12 letters of Morse code that were presented acoustically inside and outside of the scanner environment. Morse code was presented in trains of three letters while brain activity was assessed with fMRI. Participants either attended to the stimulus length (perceptual analysis), or evaluated its meaning distinguishing words from nonwords (lexico-semantic analysis). Perceptual and lexico-semantic analyses shared a mutual network comprising the left premotor cortex, the supplementary motor area (SMA) and the inferior parietal lobule (IPL). Perceptual analysis was associated with a strong brain activation in the SMA and the superior temporal gyrus bilaterally (STG), which remained unaltered from pre and post training. In the lexico-semantic analysis post learning, study participants showed additional activation in the left inferior frontal cortex (IFC) and in the left occipitotemporal cortex (OTC), regions known to be critically involved in lexical processing. Our data provide evidence for cortical plasticity evolving with a learning process enabling the transition from perceptual to lexico-semantic stimulus analysis. Importantly, the activation pattern remains task-related LOP and is thus the result of a decision process as to which LOP to engage in.

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Bibtex

@ARTICLE{SchlaffkeHBM2015,
    author = {Schlaffke, Lara and R{\"u}ther, Naima N. and Heba, Stefanie and Haag, Lauren M. and Schultz, Thomas and
              Rosengarth, Katharina and Tegenthoff, Martin and Bellebaum, Christian and Schmidt-Wilcke, Tobias},
     title = {From perceptual to lexico-semantic analysis - cortical plasticity enabling new levels of processing},
   journal = {Human Brain Mapping},
      year = {2015},
      note = {Early View.},
  abstract = {Certain kinds of stimuli can be processed on multiple levels. While the neural correlates of
              different levels of processing (LOPs) have been investigated to some extent, most of the studies
              involve skills and/or knowledge already present when performing the task. In this study we
              specifically sought to identify neural correlates of an evolving skill that allows the transition
              from perceptual to a lexico-semantic stimulus analysis. Eighteen participants were trained to decode
              12 letters of Morse code that were presented acoustically inside and outside of the scanner
              environment. Morse code was presented in trains of three letters while brain activity was assessed
              with fMRI. Participants either attended to the stimulus length (perceptual analysis), or evaluated
              its meaning distinguishing words from nonwords (lexico-semantic analysis). Perceptual and
              lexico-semantic analyses shared a mutual network comprising the left premotor cortex, the
              supplementary motor area (SMA) and the inferior parietal lobule (IPL). Perceptual analysis was
              associated with a strong brain activation in the SMA and the superior temporal gyrus bilaterally
              (STG), which remained unaltered from pre and post training. In the lexico-semantic analysis post
              learning, study participants showed additional activation in the left inferior frontal cortex (IFC)
              and in the left occipitotemporal cortex (OTC), regions known to be critically involved in lexical
              processing. Our data provide evidence for cortical plasticity evolving with a learning process
              enabling the transition from perceptual to lexico-semantic stimulus analysis. Importantly, the
              activation pattern remains task-related LOP and is thus the result of a decision process as to which
              LOP to engage in.}
}