title: Contrasting effects of transcranial direct current stimulation on central and peripheral visual fields.
abstract: Recent research suggested that transcranial direct current stimulation (tDCS) can affect visual processing and that it can be useful in visual rehabilitation. Nevertheless, there are still few investigations on the subject. tDCS selectivity and the extent of its outcomes on visual perception are still to be assessed. Here, we investigate whether central and peripheral visual fields are equally affected by tDCS. We also tried to reproduce a previous work that has evaluated tDCS effects on the central visual field only (Kraft et al. 207:283-290, 2010). Fifteen healthy subjects participated in this randomized repeated-measure design study and received 1.5-mA anodal, cathodal and sham stimulation in different sessions, while performing 10-2 and 60-4 protocols in an automated perimeter. Anodal tDCS significantly decreased thresholds, but was limited to the most eccentric regions of the visual field measured (60°). This suggests that tDCS might be used for rehabilitation of peripheral visual field losses. We did not replicate the excitatory tDCS effect in the central visual field as previously reported by another group. Instead, we observed a trend toward an inhibitory (yet not statistically significant) effect of anodal tDCS on the central field. This might be explained by methodological differences. These results highlight that although tDCS is a technique with a low focality in the spatial domain, its effects might be highly focal in a functional domain. When taken together with previous findings, this also suggests that tDCS may have a differential effect on different retinotopic areas in the brain.
authors: Departamento de Psicologia Experimental, Instituto de Psicologia da Universidade de São Paulo, São Paulo, Brazil, e.thiagocosta@gmail.com.
authors: Thiago L
authors: TL
authors: Costa
authors: Mirella
authors: M
authors: Gualtieri
authors: Mirella T S
authors: MT
authors: Barboni
authors: Rafael K
authors: RK
authors: Katayama
authors: Paulo S
authors: PS
authors: Boggio
authors: Dora F
authors: DF
authors: Ventura
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D008297:Male; D016037:Single-Blind Method; D065908:Transcranial Direct Current Stimulation; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology*; D055815:Young Adult
references: Neurorehabil Neural Repair. 2012 Jul-Aug;26(6):616-26
references: 22291042
references: Clin EEG Neurosci. 2012 Jul;43(3):176-83
references: 22956646
references: PM R. 2011 Sep;3(9):825-35
references: 21944300
references: Vision Res. 1977;17(9):1057-65
references: 595415
references: Arch Ophthalmol. 1989 Jan;107(1):81-6
references: 2642703
references: Exp Brain Res. 2007 Apr;178(2):261-6
references: 17051377
references: Front Psychiatry. 2012 Sep 12;3:78
references: 22988446
references: J Neurosci. 2013 Mar 6;33(10):4482-6
references: 23467363
references: Eur J Neurosci. 2010 May;31(10):1800-6
references: 20584184
references: Exp Brain Res. 2015 Apr;233(4):1213-23
references: 25600818
references: Neuropsychologia. 2013 Jun;51(7):1234-9
references: 23562964
references: Neuroreport. 2001 Nov 16;12(16):3553-5
references: 11733710
references: Front Hum Neurosci. 2013 Oct 21;7:688
references: 24155708
references: J Cogn Neurosci. 2009 Feb;21(2):207-21
references: 18823235
references: Invest Ophthalmol Vis Sci. 2004 Feb;45(2):702-7
references: 14744917
references: Exp Brain Res. 2010 Dec;207(3-4):283-90
references: 21046369
references: Clin Neurophysiol. 2006 Jul;117(7):1623-9
references: 16762592
references: Neuromodulation. 2012 Jul;15(4):367-73
references: 22376226
references: Neurosci Lett. 2015 Feb 19;588:78-82
references: 25556682
references: Ophthalmologica. 2001 Mar-Apr;215(2):87-90
references: 11244336
references: Neurorehabil Neural Repair. 2013 Oct;27(8):760-9
references: 23774122
references: Brain Res. 2010 Aug 19;1349:76-89
references: 20599813
references: Front Hum Neurosci. 2013 Jun 06;7:256
references: 23761755
references: Neuroreport. 2004 Nov 15;15(16):2491-4
references: 15538181
references: Restor Neurol Neurosci. 2011;29(6):453-61
references: 22278016
references: Clin Neurophysiol. 2006 Apr;117(4):845-50
references: 16427357