title: Microstructural and functional correlates of glutamate concentration in the posterior cingulate cortex.
abstract: Glutamate is the major excitatory neurotransmitter in the human brain and has a central role in both intrinsic and stimulus-induced activity. We conducted a study in a cohort of healthy, male volunteers in which glutamate levels were measured in the posterior cingulate cortex (PCC) using 1H magnetic resonance spectroscopy at 3T. The advantages of simultaneous electroencephalography and magnetic resonance imaging (EEG-MRI) were exploited and the subjects were measured in the same session and under the same physiological conditions. Diffusion tensor imaging (DTI), functional MRI (fMRI) and EEG were measured in order to investigate the functional and microstructural correlates of glutamate. The concentration of glutamate (institute units) was calculated and those values were tested for correlation with the metrics of resting state fMRI, DTI, and EEG electrical sources. Our results showed that the concentration of glutamate in the PCC had a significant negative correlation with the tissue mean diffusivity in the same area. The analysis of resting state networks did not show any relationship between the concentration of glutamate and the intrinsic activity of the resting state networks. The concentration of glutamate showed a positive correlation with the electrical generators of α-1 frequency and a negative correlation with the generators of α-2 and β-1 electrical generators. © 2017 Wiley Periodicals, Inc.
authors.affiliation: Institute of Neuroscience and Medicine 4, Forschungszentrum Jülich, Jülich, Germany.|Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen, Germany.
authors.forename: Jorge
authors.initials: J
authors.lastname: Arrubla
authors.affiliation: Institute of Neuroscience and Medicine 4, Forschungszentrum Jülich, Jülich, Germany.
authors.forename: Ezequiel
authors.initials: E
authors.lastname: Farrher
authors.affiliation: Institute of Neuroscience and Medicine 4, Forschungszentrum Jülich, Jülich, Germany.|Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen, Germany.
authors.forename: Johanna
authors.initials: J
authors.lastname: Strippelmann
authors.affiliation: Institute of Neuroscience and Medicine 4, Forschungszentrum Jülich, Jülich, Germany.|Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.
authors.forename: Desmond H Y
authors.initials: DHY
authors.lastname: Tse
authors.affiliation: Institute of Neuroscience and Medicine 4, Forschungszentrum Jülich, Jülich, Germany.|Department of Neurology, RWTH Aachen University, Aachen, Germany.
authors.forename: Farida
authors.initials: F
authors.lastname: Grinberg
authors.affiliation: Institute of Neuroscience and Medicine 4, Forschungszentrum Jülich, Jülich, Germany.|Department of Neurology, RWTH Aachen University, Aachen, Germany.|JARA - BRAIN - Translational Medicine, RWTH Aachen University, Aachen, Germany.|Institute of Neuroscience and Medicine 11, Forschungszentrum Jülich, Jülich, Germany.
authors.forename: N Jon
authors.initials: NJ
authors.lastname: Shah
authors.affiliation: Institute of Neuroscience and Medicine 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
mesh_terms: D000328:Adult; D001923:Brain Chemistry / Q000502:physiology; D038524:Diffusion Magnetic Resonance Imaging; D004569:Electroencephalography; D018698:Glutamic Acid / Q000032:analysis / Q000378:metabolism*; D006179:Gyrus Cinguli / Q000033:anatomy & histology / Q000378:metabolism*; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male
chemical_list: D018698:Glutamic Acid
keywords: EEG; Glutamate; LORETA; MRI; default-mode network; diffusion tensor imaging; posterior cingulate cortex; resting state; spectroscopy