@article {3246,
	title = {The complex structure of a simple memory.},
	journal = {Trends in neurosciences},
	volume = {20},
	year = {1997},
	month = {12/1997},
	pages = {588{\textendash}594},
	abstract = {Operant conditioning of the vertebrate H-reflex, which appears to be closely related to learning that occurs in real life, is accompanied by plasticity at multiple sites. Change occurs in the firing threshold and conduction velocity of the motoneuron, in several different synaptic terminal populations on the motoneuron, and probably in interneurons as well. Change also occurs contralaterally. The corticospinal tract probably has an essential role in producing this plasticity. While certain of these changes, such as that in the firing threshold, are likely to contribute to the rewarded behavior (primary plasticity), others might preserve previously learned behaviors (compensatory plasticity), or are simply activity-driven products of change elsewhere (reactive plasticity). As these data and those from other simple vertebrate and invertebrate models indicate, a complex pattern of plasticity appears to be the necessary and inevitable outcome of even the simplest learning.},
	keywords = {H-Reflex, Learning, Memory, operant conditioning, plasticity, Spinal Cord, stretch reflex},
	issn = {0166-2236},
	doi = {10.1016/S0166-2236(97)01133-8},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/9416673},
	author = {Jonathan Wolpaw}
}
@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 {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 {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 {3288,
	title = {Adaptive plasticity and diurnal rhythm in the primate spinal stretch reflex are independent phenomena.},
	journal = {Brain research},
	volume = {300},
	year = {1984},
	month = {05/1984},
	pages = {385{\textendash}391},
	abstract = {Recent studies have revealed two phenomena producing considerable variation in amplitude of the initial, purely segmental, largely monosynaptic, response to sudden muscle stretch, the spinal stretch reflex (SSR), without change in background EMG activity or initial muscle length. The first is small and short-term, a modest diurnal rhythm in SSR amplitude. The second is large and long-term, marked adaptive change in SSR amplitude which occurs gradually over weeks and months when animals are rewarded for such change. This second phenomenon may involve persistent segmental alteration, and, if so, could constitute a technically accessible substrate of memory. The present study compared the two phenomena and sought evidence of interaction between them. The diurnal rhythm persisted, without change in phase and with only minimal change in amplitude, despite the occurrence of marked adaptive change. Animals did not utilize the rhythm to increase reward percentage by altering daily performance schedules. These results suggest that the mechanisms of the diurnal rhythm and of adaptive plasticity in SSR amplitude are separate and independent. The diurnal rhythm{\textquoteright}s effect on movement was not altered by adaptive change in SSR amplitude. This effect was comparable to adaptive change{\textquoteright}s effect on movement when both were expressed as change in movement/change in SSR amplitude.},
	keywords = {adaptive plasticity, diurnal rhythm, Learning, Memory, primate, stretch reflex},
	issn = {0006-8993},
	doi = {10.1016/0006-8993(84)90852-7},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/6539634},
	author = {Jonathan Wolpaw and Noonan, P. A. and O{\textquoteright}Keefe, J. A.}
}
@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.}
}
