title: Operant conditioning of a spinal reflex can improve locomotion after spinal cord injury in humans.
abstract: Operant conditioning protocols can modify the activity of specific spinal cord pathways and can thereby affect behaviors that use these pathways. To explore the therapeutic application of these protocols, we studied the impact of down-conditioning the soleus H-reflex in people with impaired locomotion caused by chronic incomplete spinal cord injury. After a baseline period in which soleus H-reflex size was measured and locomotion was assessed, subjects completed either 30 H-reflex down-conditioning sessions (DC subjects) or 30 sessions in which the H-reflex was simply measured [unconditioned (UC) subjects], and locomotion was reassessed. Over the 30 sessions, the soleus H-reflex decreased in two-thirds of the DC subjects (a success rate similar to that in normal subjects) and remained smaller several months later. In these subjects, locomotion became faster and more symmetrical, and the modulation of EMG activity across the step cycle increased bilaterally. Furthermore, beginning about halfway through the conditioning sessions, all of these subjects commented spontaneously that they were walking faster and farther in their daily lives, and several noted less clonus, easier stepping, and/or other improvements. The H-reflex did not decrease in the other DC subjects or in any of the UC subjects; and their locomotion did not improve. These results suggest that reflex-conditioning protocols can enhance recovery of function after incomplete spinal cord injuries and possibly in other disorders as well. Because they are able to target specific spinal pathways, these protocols could be designed to address each individual's particular deficits, and might thereby complement other rehabilitation methods.
authors: Helen Hayes Hospital, New York State Department of Health, West Haverstraw, New York 10993, USA. thompsona@helenhayeshosp.org
authors: Aiko K
authors: AK
authors: Thompson
authors: Ferne R
authors: FR
authors: Pomerantz
authors: Jonathan R
authors: JR
authors: Wolpaw
mesh_terms: D000328:Adult; D000368:Aged; D003216:Conditioning, Operant / Q000502:physiology*; D004576:Electromyography / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D008124:Locomotion / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D020127:Recovery of Function / Q000502:physiology*; D012018:Reflex / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology; D013119:Spinal Cord Injuries / Q000503:physiopathology* / Q000534:rehabilitation*
references: J Neurophysiol. 2006 Oct;96(4):1718-27
references: 16837659
references: Eur J Appl Physiol Occup Physiol. 1993;66(2):116-21
references: 8472692
references: J Appl Physiol (1985). 2004 May;96(5):1969-77
references: 14660502
references: J Neurosci. 2005 Jul 20;25(29):6898-906
references: 16033899
references: J Neurosci. 2006 Nov 29;26(48):12537-43
references: 17135415
references: Muscle Nerve. 2013 Apr;47(4):539-44
references: 23281107
references: J Neurosci. 1986 May;6(5):1308-13
references: 3711981
references: Exp Neurol. 1994 Dec;130(2):202-13
references: 7867751
references: Neuroscientist. 2010 Oct;16(5):532-49
references: 20889964
references: Prog Brain Res. 2000;128:89-97
references: 11105671
references: J Neurophysiol. 1987 Feb;57(2):443-59
references: 3559687
references: J Neurosurg Sci. 2004 Dec;48(4):177-81
references: 15876986
references: J Neurosci. 2010 Dec 1;30(48):16128-36
references: 21123559
references: Exp Brain Res. 2006 Mar;170(1):1-6
references: 16328299
references: Muscle Nerve. 2012 Jan;45(1):116-25
references: 22190317
references: Neurorehabil Neural Repair. 2008 Jan-Feb;22(1):22-30
references: 17507641
references: Physiol Res. 2002;51(4):395-400
references: 12449438
references: Annu Rev Neurosci. 2011;34:413-40
references: 21469957
references: Brain Res Brain Res Rev. 2002 Oct;40(1-3):178-91
references: 12589916
references: Acta Physiol (Oxf). 2007 Feb;189(2):171-80
references: 17250567
references: J Neurotrauma. 1999 Feb;16(2):175-86
references: 10098962
references: J Rehabil Med. 2003 May;(41 Suppl):34-40
references: 12817655
references: J Appl Physiol (1985). 2006 Dec;101(6):1783-94
references: 16809627
references: J Neurophysiol. 1983 Dec;50(6):1296-311
references: 6663327
references: Neurorehabil Neural Repair. 2004 Dec;18(4):230-49
references: 15537994
references: J Neurophysiol. 2002 Feb;87(2):645-52
references: 11826033
references: JAMA. 2006 Nov 1;296(17):2095-104
references: 17077374
references: J Neurosci. 2009 May 6;29(18):5784-92
references: 19420246
references: Exp Brain Res. 2003 Aug;151(3):420-5
references: 12827331
references: Trends Neurosci. 1988 Jul;11(7):328-32
references: 2465639
references: Clin Neurophysiol. 2012 Apr;123(4):796-807
references: 21945456
references: J Rehabil Res Dev. 1999 Jul;36(3):237-51
references: 10659807
references: Drug Saf. 2004;27(11):799-818
references: 15350152
references: J Physiol. 2001 May 15;533(Pt 1):15-22
references: 11351008
references: Brain Res. 1982 Jul 29;244(2):365-9
references: 6889452
references: J Neurosci. 1984 Nov;4(11):2718-24
references: 6502200
references: Brain Res Rev. 2008 Jan;57(1):241-54
references: 18022244
references: J Neurotrauma. 2002 Oct;19(10):1217-29
references: 12427330
references: J Neurotrauma. 1996 Dec;13(12):755-66
references: 9002061
references: J Neurosci. 2011 Aug 3;31(31):11370-5
references: 21813696
references: Drug Saf. 2006;29(1):31-48
references: 16454533
references: J Physiol. 2001 Dec 15;537(Pt 3):1033-45
references: 11744775
references: Acta Physiol (Oxf). 2007 Feb;189(2):111-21
references: 17250563
references: J Neurophysiol. 1995 Jan;73(1):411-5
references: 7714584
references: Lancet Neurol. 2007 Aug;6(8):725-33
references: 17638613
references: Muscle Nerve. 2012 Sep;46(3):443-8
references: 22907238
references: Exp Brain Res. 2002 May;144(1):88-94
references: 11976762
references: Brain Res. 1994 Jun 13;648(1):167-70
references: 7922520
references: Can J Physiol Pharmacol. 2004 Apr;82(4):238-48
references: 15181462
references: Paraplegia. 1992 Apr;30(4):229-38
references: 1625890
references: J Neurophysiol. 2006 Oct;96(4):2144-50
references: 16807351
references: J Neurophysiol. 1996 Apr;75(4):1637-46
references: 8727402
references: J Neural Transm (Vienna). 2008;115(4):607-16
references: 18389166
references: Brain Res Brain Res Rev. 2002 Oct;40(1-3):192-201
references: 12589917
references: Clin Neurophysiol. 2004 Sep;115(9):2144-50
references: 15294217
references: J Neurophysiol. 1997 Feb;77(2):797-811
references: 9065851
references: J Neurophysiol. 2005 Oct;94(4):2844-55
references: 16000519
references: Adv Neurol. 1997;72:233-47
references: 8993702
references: Exp Brain Res. 2006 Jan;168(4):517-28
references: 16151781