1. ¹Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
2. ²Neuroscience and Psychiatry Unit, The University of Manchester, Manchester, UK
3. ³Imaging Science and Biomedical Engineering, The University of Manchester, Manchester, UK

Correspondence: Dr IM Anderson, Neuroscience and Psychiatry Unit, The University of Manchester, Room G907, Stopford Building, Oxford Road, Manchester M13 9PT, UK. Tel: +44 161 275 7428; Fax: +44 161 275 7429; E-mail: ian.anderson@manchester.ac.uk

Received 13 September 2004; Revised 14 February 2005; Accepted 16 February 2005; Published online 13 April 2005.

Abstract

Changes in serotonin neurotransmission have also been implicated in the etiology and treatment of impulse control disorders, depression, and anxiety. We have investigated the effect of enhancing serotonin function on fundamental brain processes that we have proposed are abnormal in these disorders. In all, 12 male volunteers received citalopram (7.5 mg intravenously) and placebo pretreatment in a single-blind crossover design before undertaking Go/No-go, Loss/No-loss, and covert (aversive) face emotion recognition tasks during functional magnetic resonance imaging (fMRI). Blood oxygenation level dependent responses were analyzed using Statistical Parametric Mapping (SPM2). The tasks activated prefrontal and subcortical regions generally consistent with literature with lateral orbitofrontal cortex (BA47) common to the three tasks. Citalopram pretreatment enhanced the right BA47 responses to the No-go condition, but attenuated this response to aversive faces. Attenuations were seen following citalopram in the medial orbitofrontal (BA11) responses to the No-go and No-loss (ie relative reward compared with Loss) conditions. The right amygdala response to aversive faces was attenuated by citalopram. These results support the involvement of serotonin in modulating basic processes involved in psychiatric disorders but argue for a process-specific, rather than general effect. The technique of combining drug challenge with fMRI (pharmacoMRI) has promise for investigating human psychiatric disorders.