19.3 CAN WE IMPROVE RELATIONAL MEMORY IN SCHIZOPHRENIA AND IF SO, WHAT IS THE IMPACT ON NEURAL ACTIVITY?

Abstract

Background: Semantic information significantly contributes to the organization of relational memory. It is now well-established that people with schizophrenia do not spontaneously self-initiate strategies that use such semantic information to form relational memory. Multiple evidence suggests this deficit may relate in part with the contribution of the dorsolateral prefrontal cortex to relational memory. For instance, in a previous functional magnetic resonance imaging (fMRI) study, we observed decreased brain activity in the left DLPFC in a group of participants with schizophrenia during a memory task involving elaborative semantic encoding. To remediate this selective memory deficit, we have developed a brief cognitive training for people with schizophrenia, named the Strategy for Semantic Association Memory (SESAME), which led to significant relational memory performance improvement. Here, we investigated the neural correlates underlying such memory improvements. Method(s): Fifteen schizophrenia patients with deficits in self-initiation of semantic encoding strategies received two 60-minute SESAME training sessions. Memory performance and brain activity during a relational memory task were measured pre- and post- training using fMRI. In addition, we also investigated if structural preservation measured by the cortical thickness of the DLPFC as assessed prior to the intervention, predicted memory improvement post-training. Result(s): SESAME memory training led to significant improvements in memory performance that were associated with increased activity in the left DLPFC, during a task in which patients had the opportunity to self-initiate semantic encoding strategies. Furthermore, patients with greater cortical reserve, as defined by cortical thickness measurement in the same left DLPFC area, significantly exhibited stronger memory improvement. Conclusion(s): Our findings provide evidence of neural malleability in the left DLPFC in schizophrenia using cognitive strategies training. Moreover, the brain-behavioral changes observed in schizophrenia provide hope that relational memory performance can be improved with a brief cognitive intervention. In the future, we aim to test the clinical efficacy of this training as part of a larger randomized controlled trial, and to develop complementary training focusing on other strategies (e.g. unitization) that could help improving relational memory in people with schizophrenia.