Article

The general population shows an attentional bias to the left, known as
pseudoneglect. This bias is thought to be driven by higher levels of activation
in right parietal areas. Using transcranial direct current stimulation (tDCS) to
manipulate activation, this study examined whether tDCS over the left and right
posterior parietal cortices (PPC) affects pseudoneglect. Normal participants
received tDCS over the left or right PPCs (15 in each group). Pseudoneglect was
measured using the greyscales task, which requires a forced-choice discrimination
of luminance between two opposing luminance gradients. The greyscales task was
administered both before and after; (a) anodal (b) cathodal and (c) sham tDCS.
Participants who received tDCS over the left PPC demonstrated pseudoneglect for
the greyscales task, which was significantly reduced by anodal tDCS, but was
unaffected by sham or cathodal tDCS. In contrast, for those participants who
received right PPC tDCS, pseudoneglect for the greyscales task was unaffected by
tDCS. Anodal tDCS, which is known to elevate neural excitation, may have overcome
lower levels of activation in the left PPC, resulting in decreased pseudoneglect.
These findings provide convincing evidence in support of an
activation-orientation model of pseudoneglect and have implications for models of
left neglect.
CI - Copyright (c) 2012 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS