False memory production in schizophrenia: A neurophysiological investigation

BACKGROUND: The topic of false memory in schizophrenia has been well documented in earlier research contributions. To date, there is no study exploring the implications of specific neural networks during this phenomenon in patients suffering from schizophrenia. METHODS: We compared 17 patients suffering from psychosis (SCZ) to 33 healthy controls (HC) performing a verbal memory task designed to produce false memories, i.e. the Deese–Roediger–McDermott paradigm (DRM). Electroencephalography was used to specifically analyze the P2 and N400 event-related potentials components. RESULTS: The SCZ patients showed a reduced ability to distinguish between true and false memories as assessed by the A′ index which was calculated based on the false and true memory rates. The morphology of the P2 differed in frontal electrode region with a lower amplitude in SCZ. In addition, the amplitude of N400 was more pronounced (more negative) in HC than in SCZ in centro-parietal electrode site. CONCLUSIONS: We suggest that the differences found in P2 amplitude are associated with difficulties of SCZ patients to efficiently compare item-specific features of a mnesic elements to incoming stimuli which impair the subsequent verbal memory information processing reflected by the N400 component amplitude decrease. These results are consistent with the idea that SCZ use a different strategy while they perform the DRM paradigm.