Neuropsychological research on frontal lobe function in schizophrenia: A relationship between visual cognitive context and eye movements.

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The purpose of this study is to investigate the frontal lobe function being reflected as a strategy or a process of 'context-updating' which is performed by schizophrenics, recording eye movements during the visual cognitive tasks. In the first step, we prepared a paradigm in which eye movements can be led to tracing strategies employed in processing visual stimuli, and devised the recording and analyzing system for the data of eye movements using the appratus (NAC, model V) and micro-computer (NEC, PC9801, VM2). Specifically, in order to explore the trends of visual information processing, we newly developed the computerized method by which on a screen we can examine the data of eye movements accumulated trial by trial, or subject by subject within a given stimulus pattern. In the second step, we conducted two kinds of experiments in which eye movements were recorded during tasks. Sixteen schizophrenic outpatients (mean age 39. 1 years) and 7 normal volunteers served as subjects. All … More schizophtrenics met the diagnostic criteria of DSM-III for schizophrenic disorders. In experiment I, the two kinds of ambiguous figures, i.e., "Duck and Rabbit" drawn by Jastrow and "Young Woman and Old Women" drawn by Boring, were employed as a stimuli. In one condition of this experiment I, subjects were required to perceive only the one aspect of each of ambiguous figures. In another condition, they were instructed to make an alternation between two different images evoked by a given figure, as correctly and quickly as possible. In experiment II, we employd the Neisser's visual search task and modified for this experiment. Prior to these experiments, Benton Visual Retention Test were administered for all subjects. As a result, we found that schizophrenic patients were mainly divided into the poor-performed group and the well-perrformed group. Especially, several of the schizophrenic subjects included in the latter group performed the tasks as well as normal subjects. These results claimed that neither the frontal lobe dysfunction nor the cognitive dysfunction in schizophrenics should be assesed collectively. Less