The accuracy of reaching movements in brief delay conditions.

We tested the hypothesis that a highly accurate target representation is available to the visuomotor system in brief (< 2 s) delay conditions. Participants reached to single midsagittal targets (20, 25, 30, 35, 40 cm amplitude) in full vision, open-loop and delay conditions (500, 1,000, 1,500 or 2,000 ms). Radial endpoint error was significantly greater for open-loop than full vision reaches, and was greater still for all delay conditions, which did not differ from one another. Radial error was greater for farther targets, although this tended to hold only for delayed reaches. These data suggest that the visuomotor system switches from on-line visual information to a degraded, stored representation very soon (< 500 ms) if not immediately after target occlusion.