Modulation of early cortical processing during divided attention to non-contiguous locations

Authors

  • Hans-Peter Frey,

    Corresponding author
    1. The Sheryl and Daniel R. Tishman Cognitive Neurophysiology Laboratory, Children's Evaluation and Rehabilitation Center (CERC), Departments of Pediatrics and Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
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  • Anita M. Schmid,

    1. Brain and Mind Research Institute, Division of Systems Neurology and Neuroscience, Weill Cornell Medical College, New York, NY, USA
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  • Jeremy W. Murphy,

    1. The Sheryl and Daniel R. Tishman Cognitive Neurophysiology Laboratory, Children's Evaluation and Rehabilitation Center (CERC), Departments of Pediatrics and Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
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  • Sophie Molholm,

    1. The Sheryl and Daniel R. Tishman Cognitive Neurophysiology Laboratory, Children's Evaluation and Rehabilitation Center (CERC), Departments of Pediatrics and Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
    2. The Cognitive Neurophysiology Laboratory, Program in Cognitive Neuroscience, Departments of Psychology & Biology, City College of the City University of New York, New York, NY, USA
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  • Edmund C. Lalor,

    1. Trinity Centre for Bioengineering, School of Engineering, Trinity College Dublin, Dublin, Ireland
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  • John J. Foxe

    Corresponding author
    1. The Sheryl and Daniel R. Tishman Cognitive Neurophysiology Laboratory, Children's Evaluation and Rehabilitation Center (CERC), Departments of Pediatrics and Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
    2. The Cognitive Neurophysiology Laboratory, Program in Cognitive Neuroscience, Departments of Psychology & Biology, City College of the City University of New York, New York, NY, USA
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Abstract

We often face the challenge of simultaneously attending to multiple non-contiguous regions of space. There is ongoing debate as to how spatial attention is divided under these situations. Whereas, for several years, the predominant view was that humans could divide the attentional spotlight, several recent studies argue in favor of a unitary spotlight that rhythmically samples relevant locations. Here, this issue was addressed by the use of high-density electrophysiology in concert with the multifocal m-sequence technique to examine visual evoked responses to multiple simultaneous streams of stimulation. Concurrently, we assayed the topographic distribution of alpha-band oscillatory mechanisms, a measure of attentional suppression. Participants performed a difficult detection task that required simultaneous attention to two stimuli in contiguous (undivided) or non-contiguous parts of space. In the undivided condition, the classic pattern of attentional modulation was observed, with increased amplitude of the early visual evoked response and increased alpha amplitude ipsilateral to the attended hemifield. For the divided condition, early visual responses to attended stimuli were also enhanced, and the observed multifocal topographic distribution of alpha suppression was in line with the divided attention hypothesis. These results support the existence of divided attentional spotlights, providing evidence that the corresponding modulation occurs during initial sensory processing time-frames in hierarchically early visual regions, and that suppressive mechanisms of visual attention selectively target distracter locations during divided spatial attention.

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