Reaching affects saccade trajectories

The pre-motor theory suggests that, when attention is oriented to a locatio n, the motor systems that are involved in achieving current behavioural goa ls are activated. For example, when a task requires accurate reaching, atte ntion to a location activates the motor circuits controlling saccades and m anual reaches. These actions involve separate neural systems for the contro l of eye and hand, but we believe that the selection processes acting on ne ural population codes within these systems are similar and can affect each other. The attentional effect can be revealed in the subsequent movement. T he present study shows that the path the eye takes as it saccades to a targ et is affected by whether a reach to the target is also produced. This effe ct is interpreted as the influence of a hand-centred frame used in reaching on the spatial frame of reference required for the saccade.