@article {4108, title = {Retraining Reflexes: Clinical Translation of Spinal Reflex Operant Conditioning}, journal = {Neurotherapeutics}, volume = {15}, year = {2018}, month = {07/2018}, pages = {669-683}, abstract = {Neurological disorders, such as spinal cord injury, stroke, traumatic brain injury, cerebral palsy, and multiple sclerosis cause motor impairments that are a huge burden at the individual, family, and societal levels. Spinal reflex abnormalities contribute to these impairments. Spinal reflex measurements play important roles in characterizing and monitoring neurological disorders and their associated motor impairments, such as spasticity, which affects nearly half of those with neurological disorders. Spinal reflexes can also serve as therapeutic targets themselves. Operant conditioning protocols can target beneficial plasticity to key reflex pathways; they can thereby trigger wider plasticity that improves impaired motor skills, such as locomotion. These protocols may complement standard therapies such as locomotor training and enhance functional recovery. This paper reviews the value of spinal reflexes and the therapeutic promise of spinal reflex operant conditioning protocols; it also considers the complex process of translating this promise into clinical reality.}, keywords = {clinical translation, H-Reflex, neurological disorders, operant conditioning, plasticity, Rehabilitation, spinal reflex}, issn = {1878-7479}, doi = {https://doi.org/10.1007/s13311-018-0643-2}, url = {https://link.springer.com/article/10.1007/s13311-018-0643-2}, author = {Eftekhar, A and Norton, JJS and McDonough, CM and Jonathan Wolpaw} } @inbook {3380, title = {Targeted neuroplasticity for rehabilitation.}, booktitle = {Progress in Brain Research}, volume = {218}, year = {2015}, month = {03/2015}, pages = {157-72}, abstract = {

An operant-conditioning protocol that bases reward on the electromyographic response produced by a specific CNS pathway can change that pathway. For example, in both animals and people, an operant-conditioning protocol can increase or decrease the spinal stretch reflex or its electrical analog, the H-reflex. Reflex change is associated with plasticity in the pathway of the reflex as well as elsewhere in the spinal cord and brain. Because these pathways serve many different behaviors, the plasticity produced by this conditioning can change other behaviors. Thus, in animals or people with partial spinal cord injuries, appropriate reflex conditioning can improve locomotion. Furthermore, in people with spinal cord injuries, appropriate reflex conditioning can trigger widespread beneficial plasticity. This wider plasticity appears to reflect an iterative process through which the multiple behaviors in the individual{\textquoteright}s repertoire negotiate the properties of the spinal neurons and synapses that they all use. Operant-conditioning protocols are a promising new therapeutic method that could complement other rehabilitation methods and enhance functional recovery. Their successful use requires strict adherence to appropriately designed procedures, as well as close attention to accommodating and engaging the individual subject in the conditioning process.

}, keywords = {activity-dependent plasticity, H-Reflex, operant conditioning, Rehabilitation, spinal cord injury, spinal reflex}, issn = {1875-7855}, doi = {10.1016/bs.pbr.2015.02.002}, url = {http://www.ncbi.nlm.nih.gov/pubmed/25890136}, author = {Thompson, Aiko K and Jonathan Wolpaw} } @article {3088, title = {H-reflex modulation in the human medial and lateral gastrocnemii during standing and walking.}, journal = {Muscle \& nerve}, volume = {45}, year = {2012}, month = {01/2012}, pages = {116{\textendash}125}, abstract = {INTRODUCTION: The soleus H-reflex is dynamically modulated during walking. However, modulation of the gastrocnemii H-reflexes has not been studied systematically. METHODS: The medial and lateral gastrocnemii (MG and LG) and soleus H-reflexes were measured during standing and walking in humans. RESULTS: Maximum H-reflex amplitude was significantly smaller in MG (mean 1.1 mV) or LG (1.1 mV) than in soleus (3.3 mV). Despite these size differences, the reflex amplitudes of the three muscles were positively correlated. The MG and LG H-reflexes were phase- and task-dependently modulated in ways similar to the soleus H-reflex. CONCLUSIONS: Although there are anatomical and physiological differences between the soleus and gastrocnemii muscles, the reflexes of the three muscles are similarly modulated during walking and between standing and walking. Our findings support the hypothesis that these reflexes are synergistically modulated during walking to facilitate ongoing movement.}, keywords = {Locomotion, phase-dependent modulation, spinal reflex, synergist, task-dependent modulation}, issn = {1097-4598}, doi = {10.1002/mus.22265}, url = {http://www.ncbi.nlm.nih.gov/pubmed/22190317}, author = {Makihara, Yukiko and Segal, Richard L. and Jonathan Wolpaw and Thompson, Aiko K.} } @article {3269, title = {Operant conditioning of H-reflex in freely moving monkeys.}, journal = {Journal of neuroscience methods}, volume = {31}, year = {1990}, month = {02/1990}, pages = {145{\textendash}152}, abstract = {The H-reflex, the electrical analog of the stretch reflex or tendon jerk, is the simplest behavior of the primate CNS. It is subserved by a wholly spinal two-neuron reflex arc. Recent studies show that this reflex can be increased or decreased by operant conditioning, and that such conditioning causes plastic changes in the spinal cord itself. Thus, H-reflex conditioning provides a powerful new model for investigating primate memory traces. The key feature of this model, the conditioning task, originally required animal restraint. This report describes a new tether-based design that allows H-reflex measurement and conditioning without restraint. This design integrates the conditioning task into the life of the freely moving animal.}, keywords = {conditioning, H-Reflex, Memory, plasticity, primate, spinal reflex, stretch reflex}, issn = {0165-0270}, doi = {10.1016/0165-0270(90)90159-D}, url = {http://www.ncbi.nlm.nih.gov/pubmed/2319815}, author = {Jonathan Wolpaw and Herchenroder, P. A.} } @article {3178, title = {Memory traces in spinal cord produced by H-reflex conditioning: effects of post-tetanic potentiation.}, journal = {Neuroscience letters}, volume = {103}, year = {1989}, month = {08/1989}, pages = {113{\textendash}119}, abstract = {Operant conditioning of the wholly spinal, largely monosynaptic triceps surae H-reflex in monkeys causes changes in lumbosacral spinal cord that persist after removal of supraspinal influence. We evaluated the interaction between post-tetanic potentiation and these memory traces. Animals in which the triceps surae H-reflex in one leg had been increased or decreased by conditioning were deeply anesthetized, and monosynaptic reflexes to L6-S1 dorsal root stimulation were recorded before and after tetanization from both legs for 3 days after thoracic cord transection. Animals remained anesthetized throughout and were sacrificed by overdose. Reflex asymmetries consistent with the effect of H-reflex conditioning were present after transection and persisted through the 3 days of study. Tetanization affected conditioned leg and control leg reflexes similarly. This finding suggests that, while post-tetanic potentiation and probably H-reflex conditioning alter Ia synaptic transmission, the two phenomena have different mechanisms.}, keywords = {conditioning, Learning, Memory, motoneuron, potentiation, primate, spinal reflex}, issn = {0304-3940}, doi = {10.1016/0304-3940(89)90495-3}, url = {http://www.ncbi.nlm.nih.gov/pubmed/2779852}, author = {Jonathan Wolpaw and Jonathan S. Carp and Lee, C. L.} } @article {3274, title = {Operant conditioning of primate triceps surae H-reflex produces reflex asymmetry.}, journal = {Experimental brain research. Experimentelle Hirnforschung. Exp{\'e}rimentation c{\'e}r{\'e}brale}, volume = {75}, year = {1989}, month = {03/1989}, pages = {35{\textendash}39}, abstract = {Monkeys are able to increase or decrease triceps surae H-reflex when reward depends on reflex amplitude. Operantly conditioned change occurs over weeks and produces persistent alterations in the lumbosacral spinal cord which should be technically accessible substrates of primate memory. Previous work monitored and conditioned triceps surae H-reflex in one leg. To determine whether H-reflex conditioning in one leg affects the control leg, the present study monitored H-reflexes in both legs while the reflex in one leg underwent HR increases or HR decreases conditioning. Under the HR increases mode, H-reflex increase was much greater in the HR increases leg than in the control leg. Under the HR decreases mode, H-reflex decrease was confined to the HR decreases leg. By showing that conditioning of one leg{\textquoteright}s H-reflex produces H-reflex asymmetry, the data further define the phenomenon and indicate that the other leg can serve as an internal control for physiologic and anatomic studies exploring the sites and mechanisms of the spinal cord memory substrates.}, keywords = {Learning, Memory, monosynaptic reflex, operant conditioning, plasticity, Spinal Cord, spinal reflex}, issn = {0014-4819}, doi = {10.1007/BF00248527}, url = {http://www.ncbi.nlm.nih.gov/pubmed/2707354}, author = {Jonathan Wolpaw and Lee, C. L. and Calaitges, J. G.} } @article {3279, title = {Operant conditioning of primate spinal reflexes: effect on cortical SEPs.}, journal = {Electroencephalography and clinical neurophysiology}, volume = {69}, year = {1988}, month = {04/1988}, pages = {398{\textendash}401}, abstract = {Previous studies have demonstrated operant conditioning of the primate spinal stretch reflex (SSR) and of its electrical analog, the H-reflex. We studied the evoked potential recorded over primary somatosensory cortex (SEP) which accompanies the H-reflex to determine whether the initial cortical response changes in the course of conditioned H-reflex change. When H-reflex amplitude changed, SEP amplitude also changed, but only half as much as the H-reflex. The results indicate that, while operant conditioning of the H-reflex has its largest effect on the spinal pathway of the reflex, it also has some effect on supraspinal pathways of the initial cortical response.}, keywords = {cortical response, H-Reflex, Learning, Memory, operant conditioning, plasticity, somatosensory evoked potential, spinal reflex}, issn = {0013-4694}, doi = {10.1016/0013-4694(88)90012-0}, url = {http://www.ncbi.nlm.nih.gov/pubmed/2450739}, author = {Jonathan Wolpaw and Dowman, R.} } @article {3280, title = {Spinal stretch reflex and cortical evoked potential amplitudes versus muscle stretch amplitude in the monkey arm.}, journal = {Electroencephalography and clinical neurophysiology}, volume = {69}, year = {1988}, month = {04/1988}, pages = {394{\textendash}397}, abstract = {While investigating operant conditioning of the primate spinal stretch reflex (SSR), we studied SSR amplitude and cortical somatosensory evoked potential (SEP) amplitude as stretch amplitude changed in the monkey arm. Initial muscle length and background EMG activity remained constant. With change in stretch amplitude (and proportional change in stretch velocity and acceleration), changes in SSR and SEP amplitudes were respectively 0.75 and 0.66 as great. The lesser change in SSR amplitude may reflect saturation of Ia afferents, while that in SEP amplitude may also reflect participation of other peripheral receptors.}, keywords = {muscle stretch, primate, Somatosensory Cortex, somatosensory evoked potential, spinal reflex, stretch reflex}, issn = {0013-4694}, doi = {10.1016/0013-4694(88)90011-9}, url = {http://www.ncbi.nlm.nih.gov/pubmed/2450738}, author = {Jonathan Wolpaw and Dowman, R.} } @article {3283, title = {Motoneuron response to dorsal root stimulation in anesthetized monkeys after spinal cord transection.}, journal = {Experimental brain research. Experimentelle Hirnforschung. Exp{\'e}rimentation c{\'e}r{\'e}brale}, volume = {68}, year = {1987}, month = {10/1987}, pages = {428{\textendash}433}, abstract = {In preparation for studying the spinal cord alterations produced by operant conditioning of spinal reflexes, we studied peripheral nerve responses to supramaximal dorsal root stimulation in the lumbosacral cord of deeply anesthetized monkeys before and after thoracic cord transection. Except for variable depression in the first few minutes, reflex responses were not reduced or otherwise significantly affected by transection in the hour immediately following the lesion or for at least 50 h. The results suggest that reduction in muscle spindle sensitivity and/or in polysynaptic motoneuron excitation contributes to stretch reflex depression after cord transection.}, keywords = {monosynaptic reflex, primate, Spinal Cord, spinal cord injury, spinal reflex, spinal shock}, issn = {0014-4819}, doi = {10.1007/BF00248809}, url = {http://www.ncbi.nlm.nih.gov/pubmed/3480233}, author = {Jonathan Wolpaw and Lee, C. L.} } @article {3285, title = {Adaptive plasticity in the spinal stretch reflex: an accessible substrate of memory?.}, journal = {Cellular and molecular neurobiology}, volume = {5}, year = {1985}, month = {06/1985}, pages = {147{\textendash}165}, abstract = {The study of the substrates of memory in higher vertebrates is one of the major problems of neurobiology. A simple and technically accessible experimental model is needed. Recent studies have demonstrated long-term adaptive plasticity, a form of memory, in the spinal stretch reflex (SSR). The SSR is due largely to a two-neuron monosynaptic arc, the simplest, best-defined, and most accessible pathway in the primate central nervous system (CNS). Monkeys can slowly change SSR amplitude without a change in initial muscle length or alpha motoneuron tone, when reward is made contingent on amplitude. Change occurs over weeks and months and persists for long periods. It is relatively specific to the agonist muscle and affects movement. The salient features of SSR adaptive plasticity, combined with clinical and laboratory evidence indicating spinal cord capacity for intrinsic change, suggest that SSR change eventually involves persistent segmental alteration. If this is the case, SSR plasticity should be a powerful model for studying the neuronal and synaptic substrates of memory in a primate.}, keywords = {Learning, Memory, plasticity, primate, spinal reflex, stretch reflex}, issn = {0272-4340}, doi = {10.1007/BF00711090}, url = {http://www.ncbi.nlm.nih.gov/pubmed/3161616}, author = {Jonathan Wolpaw} } @article {3286, title = {Reduced day-to-day variation accompanies adaptive plasticity in the primate spinal stretch reflex.}, journal = {Neuroscience letters}, volume = {54}, year = {1985}, month = {03/1985}, pages = {165{\textendash}171}, abstract = {Monkeys can change the amplitude of the spinal stretch reflex (SSR), or M1, when reward is made contingent on amplitude. The present study demonstrates that reduced SSR day-to-day variation accompanies such adaptive SSR change. This finding supports the assumption that initial, phase I, SSR change results from contingency-appropriate stabilization of tonic activity in relevant descending spinal cord pathways.}, keywords = {Learning, Memory, plasticity, primate, spinal reflex, stretch reflex}, issn = {0304-3940}, doi = {10.1016/S0304-3940(85)80073-2}, url = {http://www.ncbi.nlm.nih.gov/pubmed/3991057}, author = {Jonathan Wolpaw and O{\textquoteright}Keefe, J. A. and Kieffer, V. A. and Sanders, M. G.} } @article {3292, title = {Adaptive plasticity in the primate spinal stretch reflex: reversal and re-development.}, journal = {Brain research}, volume = {278}, year = {1983}, month = {11/1983}, pages = {299{\textendash}304}, abstract = {Monkeys can gradually increase or decrease the amplitude of the segmentally mediated spinal stretch reflex (SSR) without change in initial muscle length or background EMG activity. Both increase (under the SSR increases mode) and decrease (under the SSR decreases mode) occur slowly, progressing steadily over weeks. The present study investigated reversal and re-development of SSR amplitude change. Over a period of months, following collection of control data, monkeys were exposed to one mode, then to the other, and then to the first mode again. Development, reversal, and re-development of change all took place over weeks, following very similar courses. These data are consistent with the hypothesis that persistent segmental alteration underlies SSR amplitude change. Such persistent segmental alteration would constitute a technically accessible substrate of memory.}, keywords = {Learning, Memory, plasticity, primate, spinal reflex, stretch reflex}, issn = {0006-8993}, doi = {10.1016/0006-8993(83)90259-7}, url = {http://www.ncbi.nlm.nih.gov/pubmed/6640320}, author = {Jonathan Wolpaw} } @article {3294, title = {Adaptive plasticity in the spinal stretch reflex.}, journal = {Brain research}, volume = {267}, year = {1983}, month = {05/1983}, pages = {196{\textendash}200}, abstract = {Monkeys can change the amplitude of the spinal stretch reflex without change in initial alpha motor neuron tone, as measured by EMG, or in initial muscle length. Change is apparent in 5-10 days, continues to develop over weeks, and persists during inactive periods. Spinal stretch reflex change may be a valuable system for studying the neuronal and synaptic bases of an adaptive change in primate CNS function.}, keywords = {Learning, Memory, plasticity, primate, spinal reflex, stretch reflex}, issn = {0006-8993}, doi = {10.1016/0006-8993(83)91059-4}, url = {http://www.ncbi.nlm.nih.gov/pubmed/6860948}, author = {Jonathan Wolpaw and Kieffer, V. A. and Seegal, R. F. and Braitman, D. J. and Sanders, M. G.} } @article {3329, title = {Diurnal rhythm in the spinal stretch reflex.}, journal = {Brain research}, volume = {244}, year = {1982}, month = {07/1982}, pages = {365{\textendash}369}, abstract = {We studied primate spinal stretch reflex (SSR) amplitude as a function of time of day. SSR amplitude was greatest around midnight and smallest around noon. The diurnal rhythm was not simply a function of number of trials, or of the lighting cycle. This rhythm offers an opportunity to study the neuronal and synaptic mechanisms producing a diurnal change in CNS function. Its existence indicates that the CNS response to a given limb disturbance, and thus the CNS activity underlying a given performance, varies with time of day.}, keywords = {circadian rhythm, diurnal rhythm, muscle stretch, primate, spinal reflex, stretch reflex}, issn = {0006-8993}, doi = {10.1016/0006-8993(82)90099-3}, url = {http://www.ncbi.nlm.nih.gov/pubmed/6889452}, author = {Jonathan Wolpaw and Seegal, R. F.} }