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Rats with combined lesions of the perirhinal and postrhinal cortices were trained on a complex discrimination task, the simultaneous feature-positive and feature-negative discrimination task. In this task, a panel light (L) paired with an auditory stimulus determined whether a tone (T) or white noise (N) would be rewarded (+) or not rewarded (−). Thus, the light feature determined whether the target auditory stimuli were rewarded or not. In each session, trial types were LT+, T−, N+, and LN−. We had hypothesized that damage to the target regions would impair performance on this task. Acquisition was altered in the lesioned rats, but not in the predicted direction. Instead, lesioned rats exhibited significantly enhanced acquisition of the discrimination. Manipulation of intertrial intervals indicated that reduction of proactive interference did not explain the enhancement. Lesioned rats were not different from controls on a multiple cued-interval timing task, providing evidence that the enhancement does not extend to all types of discriminations and is not due to a deficit in timing. Other research shows that rats with perirhinal lesions are impaired on similar tasks, thus the enhancement is likely due to the effects of postrhinal damage. Normally in this task, context is thought to accrue inhibitory control over other cues. Without this inhibitory control, animals might be expected to learn the task more efficiently. Our conclusion is that deficits in processing contextual information underlie the enhanced acquisition observed in rats with combined perirhinal and postrhinal damage on this complex discrimination task.

Today, psychiatry residents learn multiple psychotherapeutic techniques during their training. Learning these different modalities at the same time can cause confusion in the areas of assessment, making a psychotherapeutic recommendation, and conducting a treatment. To investigate these issues, we presented a complex training case to three psychotherapy experts. Although they had somewhat different ideas about how to treat the patient, there was general consensus that adhering to a single conceptual formulation is key to treating individual patients in psychotherapy. A final discussion addresses the pedagogical implications of this perspective.

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