title: Task dependency of the long-latency facilitatory effect on the soleus H-reflex by cerebellar transcranial magnetic stimulation.
abstract: We investigated whether cerebellar transcranial magnetic stimulation (C-TMS) facilitates the excitability of the ipsilateral soleus motoneuron pool in resting humans, and whether the facilitation is modulated by a task that promotes cerebellar activity. A test tibial nerve stimulus evoking the H-reflex from the right soleus muscle was delivered before or after conditioning C-TMS in prone individuals. The amplitude of the H-reflex was significantly increased at conditioning-test interstimulus intervals of 110, 120, and 130 ms. Furthermore, we revealed that this facilitation effect was inhibited while the individuals tapped their right index finger. These findings indicate that C-TMS facilitates spinal motoneuronal excitability with an ∼100 ms latency in resting humans, and that this cerebellar spinal facilitation is modulated by a task that might increase cerebellar activity. Cerebellar spinal facilitation could thus be useful for assessing the excitability of the cerebellum, or the cerebellar output to spinal motoneurons.
authors.affiliation: aFaculty of Rehabilitation, Shijonawate Gakuen University bCenter for Information and Neural Networks, National Institute of Information and Communications Technology cRehabilitation Unit, Osaka University Hospital, Osaka dDepartment of Rehabilitation, Yamamoto Hospital, Wakayama eJapan Society for the Promotion of Science, Tokyo fDepartment of Rehabilitation, Hannachuo Hospital, Nara, Japan.
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Matsugi
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Mori
authors.forename: Shintaro
authors.initials: S
authors.lastname: Uehara
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Kamata
authors.forename: Kosuke
authors.initials: K
authors.lastname: Oku
authors.forename: Kouichi
authors.initials: K
authors.lastname: Mukai
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Nagano
mesh_terms: D002531:Cerebellum / Q000502:physiology*; D005385:Fingers / Q000502:physiology; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D009043:Motor Activity / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology; D013979:Tibial Nerve / Q000502:physiology; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult