This project uses experimental psychological techniques to examine whether schizophrenic deficits in ocular-motor, cognitive and social tasks result from an impaired ability to suppress inappropriate responses linked to dysfunction of the prefrontal cortex and related brain areas. Data collection from our core sample of 65 medicated schizophrenics and 44 matched normals is complete. We are, however, continuing to test subjects available in both a medicated and a drug free state. This year, in order to elucidate the nature of the psychological effects of pharmacological treatments and to explore differences between typical and atypical neuroleptics, we developed some new experimental procedures that finely examine the temporal dimensions of selective attention and negative priming. We have also modified for use by schizophrenics an important new experimental measure of working memory capacity. In addition, we continued the tasks of preparing our data for analysis and carrying out analyses of already prepared data. This year we paid particular attention to the complex issues involved in eye-movement measurement. The first paper based on our eye-movement data was accepted for publication in a major journal. It compared the effects of foreperiod variations in saccadic and manual reaction time (RT) tests. Although manual RT showed the characteristic schizophrenic slowness and exaggerated foreperiod effects, no differences were found between our schizophrenic and normal subjects in saccadic RT performance. These results raise major questions about the locus of the RT deficits seen as characteristic of schizophrenia. Earlier results of substantial theoretical import were published this year in a major journal. These findings suggest that """"""""out of sight"""""""" is """"""""out of mind"""""""" for schizophrenic individuals and confirm conjectures by Goldman-Rakic about the effects of prefrontal cortex dysfunction on the working memory of schizophrenic individuals.
