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Curr Biol. 2016 Jul 25;26(14):1867-72. doi: 10.1016/j.cub.2016.05.019. Epub 2016 Jun 30.

Electrical Stimulation of Visual Cortex Can Immediately Improve Spatial Vision.

Author information

1
Department of Psychological and Brain Sciences, Boston University, Boston, MA 02215, USA.
2
Department of Psychology, Center for Integrative and Cognitive Neuroscience, Vanderbilt Vision Research Center, Vanderbilt University, Nashville, TN 37240, USA.
3
Department of Psychology, Center for Integrative and Cognitive Neuroscience, Vanderbilt Vision Research Center, Vanderbilt University, Nashville, TN 37240, USA. Electronic address: geoffrey.f.woodman@vanderbilt.edu.

Abstract

We can improve human vision by correcting the optics of our lenses [1-3]. However, after the eye transduces the light, visual cortex has its own limitations that are challenging to correct [4]. Overcoming these limitations has typically involved innovative training regimes that improve vision across many days [5, 6]. In the present study, we wanted to determine whether it is possible to immediately improve the precision of spatial vision with noninvasive direct-current stimulation. Previous work suggested that visual processing could be modulated with such stimulation [7-9]. However, the short duration and variability of such effects made it seem unlikely that spatial vision could be improved for more than several minutes [7, 10]. Here we show that visual acuity in the parafoveal belt can be immediately improved by delivering noninvasive direct current to visual cortex. Twenty minutes of anodal stimulation improved subjects' vernier acuity by approximately 15% and increased the amplitude of the earliest visually evoked potentials in lockstep with the behavioral effects. When we reversed the orientation of the electric field, we impaired resolution and reduced the amplitude of visually evoked potentials. Next, we found that anodal stimulation improved acuity enough to be measurable with the relatively coarse Snellen test and that subjects with the poorest acuity benefited the most from stimulation. Finally, we found that stimulation-induced acuity improvements were accompanied by changes in contrast sensitivity at high spatial frequencies.

KEYWORDS:

direct-current stimulation; electrophysiology; spatial vision; visual acuity

PMID:
27374337
PMCID:
PMC4961578
DOI:
10.1016/j.cub.2016.05.019
[Indexed for MEDLINE]
Free PMC Article

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