title: Functional connectivity in healthy subjects is nonlinearly modulated by the COMT and DRD2 polymorphisms in a functional system-dependent manner.
abstract: The dopamine system is known to modulate brain function in an inverted U-shaped manner. Recently, the functional networks of the brain were categorized into two systems, a "control system" and a "processing system." However, it remains unclear whether the inverted U-shaped model of dopaminergic modulation could be applied to both of these functional systems. The catechol-O-methyltransferase (COMT) and dopamine D2 receptor (DRD2) were genotyped in 258 healthy young human subjects. The local and long-range functional connectivity densities (FCDs) of each voxel were calculated and compared in a voxel-wise manner using a two-way (COMT and DRD2 genotypes) analysis of covariance. The resting-state functional connectivity analysis was performed to determine the functional networks to which brain regions with significant FCD differences belonged. Significant COMT × DRD2 interaction effects were found in the local FCDs of the superior portion of the right temporal pole (sTP) and left lingual gyrus (LG) and in the long-range FCDs of the right putamen and left medial prefrontal cortex (MPFC). Post hoc tests showed nonlinear relationships between the genotypic subgroups and FCD. In the control system, the sTP and putamen, components of the salience network, showed a U-shaped modulation by dopamine signaling. In the processing system, however, the MPFC of the default-mode network and the LG of the visual network showed an inverted U-shaped modulation by the dopamine system. Our findings suggest an interaction between COMT and DRD2 genotypes and show a functional system-dependent modulation of dopamine signaling.
authors.affiliation: Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China, Brainnetome Center and National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China, Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China, and Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: Tian
authors.initials: T
authors.lastname: Tian
authors.forename: Wen
authors.initials: W
authors.lastname: Qin
authors.forename: Bing
authors.initials: B
authors.lastname: Liu
authors.forename: Tianzi
authors.initials: T
authors.lastname: Jiang
authors.forename: Chunshui
authors.initials: C
authors.lastname: Yu
mesh_terms: D000293:Adolescent; D000328:Adult; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D002450:Cell Communication / Q000235:genetics / Q000502:physiology; D004298:Dopamine / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009415:Nerve Net / Q000166:cytology / Q000502:physiology*; D009434:Neural Pathways / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D017711:Nonlinear Dynamics; D011110:Polymorphism, Genetic / Q000502:physiology*; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D055815:Young Adult
chemical_list: C581293:DRD2 protein, human; D017448:Receptors, Dopamine D2; D002394:Catechol O-Methyltransferase; D004298:Dopamine