title: Remote limb ischemic conditioning enhances motor learning in healthy humans.
abstract: Brief bouts of sublethal ischemia have been shown to protect exposed tissue (ischemic conditioning) and tissues at remote sites (remote ischemic conditioning) against subsequent ischemic challenges. Given that the mechanisms of this protective phenomenon are multifactorial and epigenetic, we postulated that remote limb ischemic conditioning (RLIC) might enhance mechanisms responsible for neural plasticity, and thereby facilitate learning. Specifically, we hypothesized that conditioning of the nervous system with RLIC, achieved through brief repetitive limb ischemia prior to training, would facilitate the neurophysiological processes of learning, thus making training more effective and more long-lasting. Eighteen healthy adults participated in this study; nine were randomly allocated to RLIC and nine to sham conditioning. All subjects underwent seven consecutive weekday sessions and 2-wk and 4-wk follow-up sessions. We found that RLIC resulted in significantly greater motor learning and longer retention of motor performance gains in healthy adults. Changes in motor performance do not appear to be due to a generalized increase in muscle activation or muscle strength and were not associated with changes in serum brain-derived neurotrophic factor (BDNF) concentration. Of note, RLIC did not enhance cognitive learning on a hippocampus-dependent task. While future research is needed to establish optimal conditioning and training parameters, this inexpensive, clinically feasible paradigm might ultimately be implemented to enhance motor learning in individuals undergoing neuromuscular rehabilitation for brain injury and other pathological conditions.
authors: Program in Physical Therapy, Washington University School of Medicine, St. Louis, Missouri;
authors: Kendra M
authors: KM
authors: Cherry-Allen
authors: Department of Neurological Surgery, Washington University School of Medicine, St. Louis, Missouri; Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri; Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri;
authors: Jeff M
authors: JM
authors: Gidday
authors: Department of Neurology, Washington University School of Medicine, St. Louis, Missouri;
authors: Jin-Moo
authors: JM
authors: Lee
authors: Department of Neurology, Washington University School of Medicine, St. Louis, Missouri; Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri; Department of Radiology, Washington University School of Medicine, St. Louis, Missouri; and.
authors: Tamara
authors: T
authors: Hershey
authors: Program in Physical Therapy, Washington University School of Medicine, St. Louis, Missouri; Department of Neurology, Washington University School of Medicine, St. Louis, Missouri; Program in Occupational Therapy, Washington University School of Medicine, St. Louis, Missouri langc@wustl.edu.
authors: Catherine E
authors: CE
authors: Lang
mesh_terms: D000293:Adolescent; D000328:Adult; D004576:Electromyography; D005121:Extremities / Q000098:blood supply*; D005500:Follow-Up Studies; D006801:Humans; D007511:Ischemia / Q000503:physiopathology*; D007858:Learning / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology; D011930:Reaction Time; D012153:Retention, Psychology / Q000502:physiology; D055815:Young Adult
keywords: behavioral training; motor learning; remote limb ischemic conditioning