Frontiers in Neuroscience (Jan 2020)

The Impact of Cognitive Load on the Spatial Deployment of Visual Attention: Testing the Role of Interhemispheric Balance With Biparietal Transcranial Direct Current Stimulation

  • Rebecca E. Paladini,
  • Fluri A. M. Wieland,
  • Lien Naert,
  • Mario Bonato,
  • Urs P. Mosimann,
  • Tobias Nef,
  • Tobias Nef,
  • René M. Müri,
  • René M. Müri,
  • Thomas Nyffeler,
  • Thomas Nyffeler,
  • Thomas Nyffeler,
  • Dario Cazzoli,
  • Dario Cazzoli,
  • Dario Cazzoli

DOI
https://doi.org/10.3389/fnins.2019.01391
Journal volume & issue
Vol. 13

Abstract

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In healthy individuals, increasing cognitive load induces an asymmetric deployment of visuospatial attention, which favors the right visual space. To date, the neural mechanisms of this left/right attentional asymmetry are poorly understood. The aim of the present study was thus to investigate whether a left/right asymmetry under high cognitive load is due to a shift in the interhemispheric balance between the left and right posterior parietal cortices (PPCs), favoring the left PPC. To this end, healthy participants completed a visuospatial attention detection task under low and high cognitive load, whilst undergoing biparietal transcranial direct current stimulation (tDCS). Three different tDCS conditions were applied in a within-subjects design: sham, anodal left/cathodal right, and cathodal left/anodal right stimulation. The results revealed a left/right attentional asymmetry under high cognitive load in the sham condition. This asymmetry disappeared during cathodal left/anodal right tDCS, yet was not influenced by anodal left/cathodal right tDCS. There were no left/right asymmetries under low cognitive load in any of the conditions. Overall, these findings demonstrate that attentional asymmetries under high cognitive load can be modulated in a polarity-specific fashion by means of tDCS. They thus support the assumption that load-related asymmetries in visuospatial attention are influenced by interhemispheric balance mechanisms between the left and right PPCs.

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