Article

Prism adaptation (PA) has been shown to affect performance on a variety of
spatial tasks in healthy individuals and neglect patients. However, little is still known about the mechanisms through which PA affects spatial cognition. In
the present study we tested the effect of PA on the perceptual-attentional
"where" and motor-intentional "aiming" spatial systems in healthy individuals.
Eighty-four participants performed a line bisection task presented on a computer
screen under normal or right-left reversed viewing conditions, which allows for
the fractionation of "where" and "aiming" bias components (Schwartz et al.,
1997). The task was performed before and after a short period of visuomotor
adaptation either to left- or right-shifting prisms, or control goggles fitted
with plain glass lenses. Participants demonstrated initial leftward "where" and
"aiming" biases, consistent with previous research. Adaptation to left-shifting
prisms reduced the leftward motor-intentional "aiming" bias. By contrast, the
"aiming" bias was unaffected by adaptation to the right-shifting prisms or
control goggles. The leftward "where" bias was also reduced, but this reduction
was independent of the direction of the prismatic shift. These results mirror
recent findings in neglect patients, who showed a selective amelioration of right
motor-intentional "aiming" bias after right prism exposure (Fortis et al., 2009;
C.L. Striemer & J. Danckert, 2010). Thus, these findings indicate that prism
adaptation primarily affects the motor-intentional "aiming" system in both
healthy individuals and neglect patients, and further suggest that improvement in
neglect patients after PA may be related to changes in the aiming spatial system.
CI - Copyright (c) 2011 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS