title: Soleus H-reflex operant conditioning changes the H-reflex recruitment curve.
abstract: BACKGROUND
  Operant conditioning can gradually change the human soleus H-reflex. The protocol conditions the reflex near M-wave threshold. In this study we examine its impact on the reflexes at other stimulus strengths.
  
  
  METHODS
  H-reflex recruitment curves were obtained before and after a 24-session exposure to an up-conditioning (HRup) or a down-conditioning (HRdown) protocol and were compared.
  
  
  RESULTS
  In both HRup and HRdown subjects, conditioning affected the entire H-reflex recruitment curve. In 5 of 6 HRup and 3 of 6 HRdown subjects, conditioning elevated (HRup) or depressed (HRdown), respectively, the entire curve. In the other HRup subject or the other 3 HRdown subjects, the curve was shifted to the left or to the right, respectively.
  
  
  CONCLUSIONS
  H-reflex conditioning does not simply change the H-reflex to a stimulus of particular strength; it also changes the H-reflexes to stimuli of different strengths. Thus, it is likely to affect many actions in which this pathway participates.
authors.affiliation: Helen Hayes Hospital, New York State Department of Health, Route 9W, West Haverstraw, New York 10993, USA. thompsona@helenhayeshosp.org
authors.forename: Aiko K
authors.initials: AK
authors.lastname: Thompson
authors.forename: Xiang Yang
authors.initials: XY
authors.lastname: Chen
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Wolpaw
mesh_terms: D000328:Adult; D003216:Conditioning, Operant / Q000502:physiology*; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000294:innervation / Q000502:physiology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology; D011999:Recruitment, Neurophysiological / Q000502:physiology*; D013979:Tibial Nerve / Q000502:physiology*; D055815:Young Adult