S100B serum levels and word memory processing in remitted major depression as reflected by brain potentials.

Objective: Memory processes, as reflected by 'old/new' effects of event-related potentials (ERPs), have been shown to be impaired in depressed patients. This variability might be partly explained by biological factors. S100B is a glial calcium- binding protein with neuroplastic properties; S100B serum levels have been shown to be increased in depressive patients. The pathophysiologic role of S100B in depression, however, is not yet sufficiently understood. Methods: In the present study, ERPs recorded in a visual continuous word recognition paradigm were therefore investigated in patients with remitted major depression in relation to S100B serum levels. Results: Patients with moderately increased S100B serum levels (n = 6) showed a normal old/new effect in contrast to a reduced old/new effect in patients with normal S100B levels (n = 6) compared to aged-matched controls. Conclusions: These findings provide evidence of an association between S100B levels and memory processes in patients with recurrent depression and further suggest a neuroprotective role of moderately increased S100B serum levels in the course of affective disorders. Copyright (C) 2009 S. Karger AG, Basel