title: Synchrony between neurons with similar muscle fields in monkey motor cortex.
abstract: Synchronous firing of motor cortex cells exhibiting postspike facilitation (PSF) or suppression (PSS) of hand muscle EMG was examined to investigate the relationship between synchrony and output connectivity. Recordings were made in macaque monkeys performing a precision grip task. Synchronization was assessed with cross-correlation histograms of the activity from 144 pairs of simultaneously recorded neurons, while spike-triggered averages of EMG defined the muscle field for each cell. Cell pairs with similar muscle fields showed greater synchronization than pairs with nonoverlapping fields. Furthermore, cells with opposing effects in the same muscles exhibited negative synchronization. We conclude that synchrony in motor cortex engages networks of neurons directly controlling the same muscle set, while inhibitory connections exist between neuronal populations with opposing output effects.
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, UCL, London WC1N 3BG, United Kingdom.
authors.forename: Andrew
authors.initials: A
authors.lastname: Jackson
authors.forename: Veronica J
authors.initials: VJ
authors.lastname: Gee
authors.forename: Stuart N
authors.initials: SN
authors.lastname: Baker
authors.forename: Roger N
authors.initials: RN
authors.lastname: Lemon
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D004566:Electrodes; D004576:Electromyography; D005260:Female; D006225:Hand / Q000294:innervation / Q000502:physiology; D018737:Hand Strength / Q000502:physiology*; D008253:Macaca mulatta; D009044:Motor Cortex / Q000166:cytology* / Q000502:physiology*; D009046:Motor Neurons / Q000502:physiology*; D009068:Movement / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation* / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology