Lateral interactions in the superior colliculus, not an extended fixation zone, can account for the remote distracter effect

Recordings of neuronal activity in the monkey superior colliculus (SC) sugg est that the two apparently independent effects of a visual distracter on b oth temporal (latency) and spatial (metrics) saccade parameters may be the result of lateral interactions between subpopulations of saccade-related ne urons located at different sites on the motor map of the superior colliculu s. One subpopulation is activated during the planing and initiation of a sa ccade; the other is activated by the appearance of a distractor. The inhibi tory or facilitative nature of this interaction depends on the distance bet ween the distracter and the target and is consistent with the complex patte rn of intrinsic and commissural collicular connections.