title: The role of GABAergic modulation in motor function related neuronal network activity.
abstract: At rest, the primary motor cortex (M1) exhibits spontaneous neuronal network oscillations in the beta (15-30 Hz) frequency range, mediated by inhibitory interneuron drive via GABA-A receptors. However, questions remain regarding the neuropharmacological basis of movement related oscillatory phenomena, such as movement related beta desynchronisation (MRBD), post-movement beta rebound (PMBR) and movement related gamma synchronisation (MRGS). To address this, we used magnetoencephalography (MEG) to study the movement related oscillatory changes in M1 cortex of eight healthy participants, following administration of the GABA-A modulator diazepam. Results demonstrate that, contrary to initial hypotheses, neither MRGS nor PMBR appear to be GABA-A dependent, whilst the MRBD is facilitated by increased GABAergic drive. These data demonstrate that while movement-related beta changes appear to be dependent upon spontaneous beta oscillations, they occur independently of one other. Crucially, MRBD is a GABA-A mediated process, offering a possible mechanism by which motor function may be modulated. However, in contrast, the transient increase in synchronous power observed in PMBR and MRGS appears to be generated by a non-GABA-A receptor mediated process; the elucidation of which may offer important insights into motor processes.
authors.affiliation: Aston Brain Centre, School of Life and Health Sciences, Aston University, Birmingham, UK. hallsd@aston.ac.uk
authors.forename: S D
authors.initials: SD
authors.lastname: Hall
authors.forename: I M
authors.initials: IM
authors.lastname: Stanford
authors.forename: N
authors.initials: N
authors.lastname: Yamawaki
authors.forename: C J
authors.initials: CJ
authors.lastname: McAllister
authors.forename: K C
authors.initials: KC
authors.lastname: Rönnqvist
authors.forename: G L
authors.initials: GL
authors.lastname: Woodhall
authors.forename: P L
authors.initials: PL
authors.lastname: Furlong
mesh_terms: D000328:Adult; D001611:Beta Rhythm; D003344:Cortical Synchronization; D003627:Data Interpretation, Statistical; D003975:Diazepam / Q000494:pharmacology; D004569:Electroencephalography; D018757:GABA Modulators / Q000494:pharmacology; D006801:Humans; D007395:Interneurons / Q000187:drug effects / Q000502:physiology; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000187:drug effects / Q000502:physiology*; D009068:Movement / Q000187:drug effects / Q000502:physiology*; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology*; D011963:Receptors, GABA-A / Q000187:drug effects; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
chemical_list: D018757:GABA Modulators; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid; D003975:Diazepam