Abstract

Introduction: Working memory (WM) refers to the capacity of maintaining and storing information in the short term for subsequent goal-directed behavior. An adequate communication between the prefrontal cortex (PFC) and other sensory regions through oscillations in gamma band (GB), would be critical for this cognitive process. Interestingly, GB has shown abnormalities in schizophrenia (SZ) patients, which might explain in part, their WM task related difficulties. However, little is known during early stages of the disease as it is the clinical high-risk state (CHR). Methods: We performed a 64-channel electroencephalogram (EEG) while executing a WM task with three different loads, in 13 CHR and 12 HC. The obtained data was preprocessed and analyzed through a time-frequency analysis focused in the PFC GB activity during the maintenance phase. We also measured task-related behavioral scores. Results: CHR presented worst behavioral scores. HC presented an increased frontal GB response in high WM load conditions. CHR showed a greater GB responses for all conditions compared with HC without a clear load effect. Discussion: These findings in HC and CHR are consistent with previous findings in HC and SZ. GB abnormalities could be proposed as a trait marker of psychosis which is present early on the development of the disease. Lower behavioral scores and their correlation with GB abnormalities might explain in part the functional impairments seen in CHR.