Amphetamine-produced attenuation of latent inhibition is modulated by stimulus preexposure duration: Implications for schizophrenia

The relationship between amphetamine-produced dopamine overreactivity and attention to irrelevant stimuli is reflected in an attenuated latent inhibition (LI) effect. This occurs in both animal and human subjects. The present study examines the manner in which this effect in rats is modulated by the duration of stimulus preexposure. A factorial design was used with three levels of stimulus preexposure duration and either amphetamine or saline administration. In addition, there were corresponding groups that did not receive stimulus preexposure. It was found that although amphetamine did indeed abolish LI at short exposure intervals (30 sec), the LI effect was normal for long stimulus preexposure durations (150 sec). The data were discussed in terms of the affects of amphetamine on the processing of irrelevant stimuli and the relationship of such a dysfunctional attentional process to schizophrenia.