Automatic and strategic volitional saccadic eye movements in psychotic patients
Drug-free schizophrenics were compared with depressive psychotics and normal controls on two saccade initiation tasks which differed with respect to the type of stimulus that initiated a saccadic response. Strategic initiation (SIS) appears to use a route different from that in automatic initiation (AIS). The SIS task revealed slowed responding in psychiatrically ill patients if their cognition was impaired, but all groups responded similarly on the AIS task. Schizophrenics could be separated from depressed psychotics by their inability to utilize temporal redundancy to speed up saccade initiation on the SIS task. Neurophysiological evidence implicates specific impairments in the frontal eye field (FEF) and/or basal ganglia.