title: GABA concentration in posterior cingulate cortex predicts putamen response during resting state fMRI.
abstract: The role of neurotransmitters in the activity of resting state networks has been gaining attention and has become a field of research with magnetic resonance spectroscopy (MRS) being one of the key techniques. MRS permits the measurement of γ-aminobutyric acid (GABA) and glutamate levels, the central biochemical constituents of the excitation-inhibition balance in vivo. The inhibitory effects of GABA in the brain have been largely investigated in relation to the activity of resting state networks in functional magnetic resonance imaging (fMRI). In this study GABA concentration in the posterior cingulate cortex (PCC) was measured using single voxel spectra acquired with standard point resolved spectroscopy (PRESS) from 20 healthy male volunteers at 3 T. Resting state fMRI was consecutively measured and the values of GABA/Creatine+Phosphocreatine ratio (GABA ratio) were included in a general linear model matrix as a step of dual regression analysis in order to identify voxels whose neuroimaging metrics during rest were related to individual levels of the GABA ratio. Our data show that the connection strength of putamen to the default-mode network during resting state has a negative linear relationship with the GABA ratio measured in the PCC. These findings highlight the role of PCC and GABA in segregation of the motor input, which is an inherent condition that characterises resting state.
authors.affiliation: Institute of Neuroscience and Medicine 4, INM 4, Forschungszentrum Jülich, Jülich, Germany.
authors.forename: Jorge
authors.initials: J
authors.lastname: Arrubla
authors.affiliation: Institute of Neuroscience and Medicine 4, INM 4, Forschungszentrum Jülich, Jülich, Germany.
authors.forename: Desmond H Y
authors.initials: DH
authors.lastname: Tse
authors.affiliation: Institute of Neuroscience and Medicine 4, INM 4, Forschungszentrum Jülich, Jülich, Germany; Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen, Germany.
authors.forename: Christin
authors.initials: C
authors.lastname: Amkreutz
authors.affiliation: Institute of Neuroscience and Medicine 4, INM 4, Forschungszentrum Jülich, Jülich, Germany; Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen, Germany; JARA - BRAIN - Translational Medicine, RWTH Aachen University, Aachen, Germany.
authors.forename: Irene
authors.initials: I
authors.lastname: Neuner
authors.affiliation: Institute of Neuroscience and Medicine 4, INM 4, Forschungszentrum Jülich, Jülich, Germany; JARA - BRAIN - Translational Medicine, RWTH Aachen University, Aachen, Germany; Department of Neurology, RWTH Aachen University, Aachen, Germany.
authors.forename: N Jon
authors.initials: NJ
authors.lastname: Shah
mesh_terms: D000328:Adult; D001931:Brain Mapping; D018698:Glutamic Acid / Q000302:isolation & purification* / Q000378:metabolism; D006179:Gyrus Cinguli / Q000378:metabolism; D064368:Healthy Volunteers; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009415:Nerve Net / Q000000981:diagnostic imaging* / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000378:metabolism*; D011859:Radiography; D005680:gamma-Aminobutyric Acid / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D018377:Neurotransmitter Agents; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid