Associative learning in deficit and nondeficit schizophrenia.

When two stimuli are associated and treated as equivalent, generalization occurs between them (acquired equivalence). The feedback-guided learning of associations is related to the basal ganglia, whereas the medial temporal lobe participates in acquired equivalence learning. In this study, we investigated feedback-guided associative learning and acquired equivalence in deficit and nondeficit schizophrenia. Results revealed that acquired equivalence learning was similarly impaired in deficit and nondeficit patients, whereas feedback-guided associative learning was impaired only in deficit patients. Associative learning and acquired equivalence were not related to frontal lobe tests. These results suggest that the enduring negative symptoms of deficit patients may be related to decreased response to cognitive feedback and deficient basal ganglia functioning.