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A systematic review of transcranial direct current stimulation on eye movements and associated psychological function

  • Ashwin Subramaniam , Sicong Liu , Liam Lochhead and Lawrence Gregory Appelbaum ORCID logo EMAIL logo

Abstract

The last decades have seen a rise in the use of transcranial direct current stimulation (tDCS) approaches to modulate brain activity and associated behavior. Concurrently, eye tracking (ET) technology has improved to allow more precise quantitative measurement of gaze behavior, offering a window into the mechanisms of vision and cognition. When combined, tDCS and ET provide a powerful system to probe brain function and measure the impact on visual function, leading to an increasing number of studies that utilize these techniques together. The current pre-registered, systematic review seeks to describe the literature that integrates these approaches with the goal of changing brain activity with tDCS and measuring associated changes in eye movements with ET. The literature search identified 26 articles that combined ET and tDCS in a probe-and-measure model and are systematically reviewed here. All studies implemented controlled interventional designs to address topics related to oculomotor control, cognitive processing, emotion regulation, or cravings in healthy volunteers and patient populations. Across these studies, active stimulation typically led to changes in the number, duration, and timing of fixations compared to control stimulation. Notably, half the studies addressed emotion regulation, each showing hypothesized effects of tDCS on ET metrics, while tDCS targeting the frontal cortex was widely used and also generally produced expected modulation of ET. This review reveals promising evidence of the impact of tDCS on eye movements and associated psychological function, offering a framework for effective designs with recommendations for future studies.


Corresponding author: Lawrence Gregory Appelbaum, Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC 27710, USA; and Department of Psychiatry, University of California, 106 Guava Hall, 9500 Gillman Dr, San Diego, CA 92093, USA, E-mail:

Funding source: Army Research Office

Award Identifier / Grant number: W911NF-15-1-0390

Acknowledgments

The authors would like to thank Elly Daskalakis for her valuable comments on this manuscript.

  1. Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

  2. Research funding: This research was funded by grant support to L.G.A. through the United States Army Research Office [W911NF-15-1-0390].

  3. Conflict of interest statement: All authors declare that they have no conflict of interest related to the research presented in this article.

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Received: 2022-07-05
Accepted: 2022-09-07
Published Online: 2022-10-31
Published in Print: 2023-04-25

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