title: Top-down-directed synchrony from medial frontal cortex to nucleus accumbens during reward anticipation.
abstract: The nucleus accumbens and medial frontal cortex (MFC) are part of a loop involved in modulating behavior according to anticipated rewards. However, the precise temporal landscape of their electrophysiological interactions in humans remains unknown because it is not possible to record neural activity from the nucleus accumbens using noninvasive techniques. We recorded electrophysiological activity simultaneously from the nucleus accumbens and cortex (via surface EEG) in humans who had electrodes implanted as part of deep-brain-stimulation treatment for obsessive-compulsive disorder. Patients performed a simple reward motivation task previously shown to activate the ventral striatum. Spectral Granger causality analyses were applied to dissociate "top-down" (cortex → nucleus accumbens)- from "bottom-up" (nucleus accumbens → cortex)-directed synchronization (functional connectivity). "Top-down"-directed synchrony from cortex to nucleus accumbens was maximal over medial frontal sites and was significantly stronger when rewards were anticipated. These findings provide direct electrophysiological evidence for a role of the MFC in modulating nucleus accumbens reward-related processing and may be relevant to understanding the mechanisms of deep-brain stimulation and its beneficial effects on psychiatric conditions.
authors.affiliation: Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands. mikexcohen@gmail.com
authors.forename: Michael X
authors.initials: MX
authors.lastname: Cohen
authors.forename: Lo
authors.initials: L
authors.lastname: Bour
authors.forename: Mariska
authors.initials: M
authors.lastname: Mantione
authors.forename: Martijn
authors.initials: M
authors.lastname: Figee
authors.forename: Matthijs
authors.initials: M
authors.lastname: Vink
authors.forename: Marina A J
authors.initials: MA
authors.lastname: Tijssen
authors.forename: Anne-Fleur
authors.initials: AF
authors.lastname: van Rootselaar
authors.forename: Pepijn
authors.initials: P
authors.lastname: van den Munckhof
authors.forename: P Richard
authors.initials: PR
authors.lastname: Schuurman
authors.forename: Damiaan
authors.initials: D
authors.lastname: Denys
mesh_terms: D000328:Adult; D001931:Brain Mapping; D004569:Electroencephalography; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009042:Motivation; D009434:Neural Pathways / Q000502:physiology; D009483:Neuropsychological Tests; D009714:Nucleus Accumbens / Q000502:physiology*; D012201:Reward