VISUAL WORKING MEMORY REPRESENTATIONS IN PATIENTS WITH SCHIZOPHRENIA

Schizophrenia (SZ) is a severe mental illness that is often associated with significant disability. In addition to the characteristic positive and negative symptoms, patients also exhibit cognitive deficits, particularly in working memory (WM). Impairments in WM are already present early in the disease, are persistent, and have predictive value for the functional outcome. However, the specific nature of these deficits across different WM functions remains poorly understood. Specifically, it is unclear whether WM deficits are uniform across WM subdomains or exhibit subdomain-specific patterns. To address this gap, we conducted three complementary visual WM electroencephalography (EEG) studies with the same stimuli (images of faces and houses) and with the same sample of 30 patients with SZ and 30 healthy controls. We examined visual object representation across three WM subdomains: 1. Capacity (keeping one or two objects in memory), 2. Prioritization (updating memory content after a retro-cue), and 3. Manipulation (mental rotation of memory content). Patients exhibited consistent deficits across the three studies, with large effect sizes. Additionally, neural decoding analyses revealed heterogeneous patterns of WM representation deficits that varied across individual patients and partially also across tasks. These findings suggest that, in addition to a general deficit, WM impairments in SZ are more heterogeneous and complex than previously thought. These results have important implications for cognitive remediation programs, supporting the need for personalized therapeutic interventions that target the subdomain-specific WM vulnerabilities in individual patients.