Ocular motor ability and covert attention in patients with Duane Retraction Syndrome

Is orienting of spatial attention dependent on normal functioning of the ocular motor system? We investigated the role of motor pathways in covert orienting (attentional orienting without performing eye movements) by studying three patients suffering from Duane Retraction Syndrome-a congenital impairment in executing horizontal eye movements restricted to specific gaze directions. Patients showed a typical exogenous (reflexive) attention effect when the target was presented in visual fields to which they could perform an eye movement. This effect was not present when the target was presented in the visual field to which they could not perform eye movements. These findings stress the link between eye movements and attention. Specifically, they bring out the importance of the ability to execute appropriate eye movements for attentional orienting. We suggest that the relevant information about eye movement ability is provided by feedback from lower motor structures to higher attentional areas. (C) 2010 Elsevier Ltd. All rights reserved.