Transcranial direct current stimulation accelerates allocentric target detection.
BACKGROUND
Previous research on hemispatial neglect has provided evidence for dissociable mechanisms for egocentric and allocentric processing. Although a few studies have examined whether tDCS to posterior parietal cortex can be beneficial for attentional processing in neurologically intact individuals, none have examined the potential effect of tDCS on allocentric and/or egocentric processing.


OBJECTIVE
Our objective was to examine whether transcranial direct current stimulation (tDCS), a noninvasive brain stimulation technique that can increase (anodal) or decrease (cathodal) cortical activity, can affect visuospatial processing in an allocentric and/or egocentric frame of reference.


METHODS
We tested healthy individuals on a target detection task in which the target--a circle with a gap--was either to the right or left of the viewer (egocentric), or contained a gap on the right or left side of the circle (allocentric). Individuals performed the task before, during, and after tDCS to the posterior parietal cortex in one of three stimulation conditions--right anodal/left cathodal, right cathodal/left anodal, and sham.


RESULTS
We found an allocentric hemispatial effect both during and after tDCS, such that right anodal/left cathodal tDCS resulted in faster reaction times for detecting stimuli with left-sided gaps compared to right-sided gaps.


CONCLUSIONS
Our study suggests that right anodal/left cathodal tDCS has a facilitatory effect on allocentric visuospatial processing, and might be useful as a therapeutic technique for individuals suffering from allocentric neglect.
Department of Neurology, Center for Cognitive Neuroscience, University of Pennsylvania, 3 West Gates, 3400 Spruce Street, Philadelphia, PA 19104, USA. jared.medina@uphs.upenn.edu
Jared
J
Medina
Jacques
J
Beauvais
Abhishek
A
Datta
Marom
M
Bikson
H Branch
HB
Coslett
Roy H
RH
Hamilton
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual / Q000502:physiology; D010775:Photic Stimulation; D017603:Signal Detection, Psychological / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult