Biological Psychology 52 (2000) 259 – 265 Serotonergic-1a activity and contingent negative variation Michel Hansenne *, William Pitchot, Emmanuel Pinto, Patrick Papart, Marc Ansseau Department of Psychiatry, Uniersity of Lie `ge, CHU du Sart Tilman (B-35), B-4000 Lie `ge, Belgium Received 21 October 1999; received in revised form 18 November 1999; accepted 13 December 1999 Abstract While cholinergic, dopaminergic, noradrenergic, and gabaergic effects on contingent negative variation (CNV) have been largely described, little is known about serotonergic influence. Therefore, the relationship between CNV and serotonergic activity as reflected by prolactin (PRL) response to flesinoxan, a 5-HT 1A full agonist, has been investigated in 28 healthy volunteers. To investigate the clinical implications of the relationship between CNV and serotonergic-1a activity, a group of 43 depressed patients was included in the study. Results among healthy volunteers showed a significant negative relationship between PRL response to flesinoxan and CNV amplitude at Fz, but no relationship for the other electrodes (Cz and Pz). In depressed patients, the relationships were not significant. Overall, this study does not support serotonergic effects on CNV. However, this information is indirect (correlations) and is limited to 5-HT 1A activity. © 2000 Elsevier Science B.V. All rights reserved. Keywords: CNV; Flesinoxan; Serotonin; 5-HT 1A ; Psychopharmacology www.elsevier.com/locate/biopsycho 1. Introduction Previous psychopharmacological studies have provided insights into the neurobi- ological substrates of contingent negative variation (CNV). The influence of cholin- ergic, noradrenergic, dopaminergic and gabaergic systems have been reported in * Corresponding author. Tel.: +32-4-3667960; fax: +32-4-3667283. E-mail address: michel.hansenne@ulg.ac.be (M. Hansenne) 0301-0511/00/$ - see front matter © 2000 Elsevier Science B.V. All rights reserved. PII:S0301-0511(99)00047-2