Probabilistic and Deductive Reasoning in the Human Brain

Neural Correlates of Cognitive Dysfunction in Conditional Reasoning in Schizophrenia: An Event-related Potential Study

Purpose

Schizophrenia patients show impaired conditional reasoning. This study was to investigate event-related potential (ERP) characteristics of the conditional reasoning in schizophrenia.

Patients and methods

Participants included 24 schizophrenia patients and 30 normal controls (NCs), and the measurements of ERPs were conducted during the Wason selection task.

Results

Results showed that NCs consistently outperformed schizophrenia patients in terms of accuracy. Among the different rule types of the task, the precautionary type experiment yielded the highest accuracy rates. In contrast, both the descriptive and abstract type experiments resulted in lower accuracy. The RTs of the abstract type experiment were the shortest among the four experiments. In the abstract type of the Wason selection task, the NCs exhibited higher amplitudes for both the N1 and P2 components compared to the schizophrenia patients. At the parietal lobe, the N2 amplitudes were higher for the social contract type of the task compared to the precautionary version. At the frontal lobe, the N2 amplitudes were highest for the abstract type of the task. In the abstract type, the N2 amplitude at the parietal lobe was higher than that at the central lobe. The NCs displayed lower amplitudes for both the P3 and slow wave compared to the schizophrenia patients. Differences were observed between the NC and schizophrenia groups in terms of the latencies for N1, P2, N2, P3 and slow wave components across different experiment types and regions of interest.

Conclusion

In conclusion, the observed ERP patterns provide valuable insights into the neural mechanisms underlying the Wason selection task, highlighting the differences between NCs and patients with schizophrenia.