title: Modulatory Effects of the Ipsi and Contralateral Ventral Premotor Cortex (PMv) on the Primary Motor Cortex (M1) Outputs to Intrinsic Hand and Forearm Muscles in Cebus apella.
abstract: The ventral premotor cortex (PMv) is a key node in the neural network involved in grasping. One way PMv can carry out this function is by modulating the outputs of the primary motor cortex (M1) to intrinsic hand and forearm muscles. As many PMv neurons discharge when grasping with either arm, both PMv within the same hemisphere (ipsilateral; iPMv) and in the opposite hemisphere (contralateral; cPMv) could modulate M1 outputs. Our objective was to compare modulatory effects of iPMv and cPMv on M1 outputs to intrinsic hand and forearm muscles. We used paired-pulse protocols with intracortical microstimulations in capuchin monkeys. A conditioning stimulus was applied in either iPMv or cPMv simultaneously or prior to a test stimulus in M1 and the effects quantified in electromyographic signals. Modulatory effects from iPMv were predominantly facilitatory, and facilitation was much more common and powerful on intrinsic hand than forearm muscles. In contrast, while the conditioning of cPMv could elicit facilitatory effects, in particular to intrinsic hand muscles, it was much more likely to inhibit M1 outputs. These data show that iPMv and cPMv have very different modulatory effects on the outputs of M1 to intrinsic hand and forearm muscles.
authors.affiliation: Département de Neurosciences, Faculté de Médecine, Université de Montréal, Québec, Canada.
authors.forename: Stephan
authors.initials: S
authors.lastname: Quessy
authors.affiliation: Département de Neurosciences, Faculté de Médecine, Université de Montréal, Québec, Canada.
authors.forename: Sandrine L
authors.initials: SL
authors.lastname: Côté
authors.affiliation: Département de Neurosciences, Faculté de Médecine, Université de Montréal, Québec, Canada Groupe de recherche sur le système nerveux central (GRSNC), Université de Montréal, Québec, Canada.
authors.forename: Adjia
authors.initials: A
authors.lastname: Hamadjida
authors.affiliation: Department of Physical Therapy, School of Medicine, Emory University, Atlanta, GA.
authors.forename: Joan
authors.initials: J
authors.lastname: Deffeyes
authors.affiliation: Département de Neurosciences, Faculté de Médecine, Université de Montréal, Québec, Canada Groupe de recherche sur le système nerveux central (GRSNC), Université de Montréal, Québec, Canada.
authors.forename: Numa
authors.initials: N
authors.lastname: Dancause
mesh_terms: D000818:Animals; D002428:Cebus; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D005542:Forearm / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology*; D006225:Hand / Q000502:physiology*; D008839:Microelectrodes; D009043:Motor Activity / Q000502:physiology; D009044:Motor Cortex / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000502:physiology*
keywords: cortical network; interaction; interhemispheric; motor-evoked potential; stimulation