title: Acute changes in soleus H-reflex facilitation and central motor conduction after targeted physical exercises.
abstract: We tested the acute effect of exercises targeted simultaneously at cortical and brainstem circuits on neural transmission through corticobulbar connections. Corticobulbar pathways represent a potential target for rehabilitation after spinal cord injury (SCI), which tends to spare brainstem circuits to a greater degree than cortical circuits. To explore this concept, able-bodied volunteers (n=20) underwent one session each of three exercises targeted at different nervous system components: treadmill walking (spinal locomotor circuits), isolated balance exercise (brainstem and other pathways), and multimodal balance plus skilled hand exercise (hand motor cortex and corticospinal tract). We found that short-interval soleus H-reflex facilitation increased after one session of balance and multimodal exercise by 13.2±4.0% and 8.3±4.7%, and slightly decreased by 1.9±4.4% after treadmill exercise (p=0.042 on ANOVA across exercise type). Increases in long-interval H-reflex facilitation were not significantly different between exercises. Both balance and multimodal exercise increased central motor conduction velocity by 4.3±2.6% and 4.5±2.8%, whereas velocity decreased by 4.3±2.7% after treadmill exercise (p=0.045 on ANOVA across exercise type). In conclusion, electrophysiological transmission between the motor cortex and spinal motor neurons in able-bodied subjects increased more following one session of balance exercise than treadmill exercise.
authors.affiliation: RR&D National Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center, Bronx, NY, United States; Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States. Electronic address: noam.harel@mssm.edu.
authors.forename: Noam Y
authors.initials: NY
authors.lastname: Harel
authors.affiliation: RR&D National Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center, Bronx, NY, United States.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Martinez
authors.affiliation: RR&D National Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center, Bronx, NY, United States.
authors.forename: Steven
authors.initials: S
authors.lastname: Knezevic
authors.affiliation: RR&D National Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center, Bronx, NY, United States.
authors.forename: Pierre K
authors.initials: PK
authors.lastname: Asselin
authors.affiliation: RR&D National Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center, Bronx, NY, United States; Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States.
authors.forename: Ann M
authors.initials: AM
authors.lastname: Spungen
mesh_terms: D000328:Adult; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*; D009046:Motor Neurons / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D009431:Neural Conduction / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D011712:Pyramidal Tracts / Q000502:physiology; D016138:Walking / Q000502:physiology; D055815:Young Adult
keywords: Balance exercise; Corticospinal; H-reflex facilitation; Reticulospinal; Transcranial magnetic stimulation