Two experiments were conducted to investigate the ability of schizophrenia
patients to maintain internal representation over time and space. It has be
en hypothesized that the ability to guide behavior by internal representati
on, mediated by the dorsolateral prefrontal cortex (DLPFC), is impaired in
schizophrenia [e.g. Goldman-Rakic, P.S., 1996. The functional parcellation
of dorsolateral prefrontal cortex and the heterogeneous facets of schizophr
enia. In: Matthysse, S., Levy, D.L. (Eds.), Psychopathology: Evolution of a
New Science. Cambridge University Press, Cambridge]. In Experiment 1, subj
ects observed a target, which traveled behind an opaque wall during a part
of its trajectory. The task was to accurately assess the speed of the targe
t by predicting when the target would re-emerge on the other side of the wa
ll. In Experiment 2, subjects were asked to estimate the spatial trajectory
of an established target path when it was partially occluded from view by
another object. Schizophrenia patients were impaired in estimating the spee
d of a moving target and in estimating the spatial trajectory, without show
ing deficits in the control tasks. These results suggest that schizophrenia
patients may not be able to accurately maintain the internal representatio
n of a target over time and space. Such deficits may have deleterious conse
quences in goal-directed behavior. (C) 2000 Elsevier Science B.V. All right
s reserved.