Rule-based And Information-integration Category Learning In Schizophrenia

A substantial and growing body of evidence from functional neuroimaging, neuropsychological and behavioral studies support the concept of multiple category learning systems. Previous research revealed that successful rule-based (RB) categorization depend on the medial temporal lobe and non-verbalizable information-integration (Ⅱ) category learning depend on the posterior caudate selectively. These structures, which are prefrontal cortex and medial temporal lobe, are critical in the pathophysiology of schizophrenia. Because of the impairs of prefrontal cortex and medial temporal lobe, schizophrenia seems to be impaired performance on most tests of explicit or declarative learning. However, owning to the striatum which was influenced by the stage of their illness and antipsychotics, the schizophrenia displayed different performance. So there have been conflicting results for implicit learning in schizophrenia. And the striatum was the critical brain structures of information-integration category learning. The studies investigating the cognitive of schizophrenia with rule-based and information-integration category learning could add to growing evidence that information-integration category learning depend on the striatum. The present study, was the first study investigating the cognitive of schizophrenia with rule-based and information-integration category learning, which was one of the the innovation.Thus it raised two questions that whether the performance in schizophrenia varies on the rule-based and information-integration categorization and whether the first-generation drugs affect the performance on information-integration categorization. This research was designed to throw some light on these questions.20 health control partitions, and 40 patients with schizophrenia, who didn't be suffered from other nervous system diseases, were asked to complete both rule-based tasks and information-integration tasks based on feedback. In patients groups, there are 18 patients taking the first-generation drugs and 22 other patients taking the second-generation drugs. In two tasks, the participants were asked to learn to put all materials into two categories. To avoid the influence between two tasks, two tasks were completed in every other day. The order of two tasks was ordered with ABBA to avoid the order effect.The results showed that:in rule-based tasks, the health control group preformed significantly higher accuracy than the patients group, and the patients receiving first-generation drugs didn't exhibit significantly differently from those receiving second-generation drugs. However, in information-integration category learning, the patients receiving first-generation drugs preformed significantly higher accuracy than those receiving second-generation drugs, but didn't exhibit significantly differently from the health control group.In conclusion, the present findings indicated that two category learning tasks were mediated by functionally separate systems. Besides, the first generation antipsychotics may disrupt information-integration category learning depending on inhibiting dopamine D2 receptors in the striatum.