@article {3284,
	title = {Adaptive plasticity in primate spinal stretch reflex: persistence.},
	journal = {Journal of neurophysiology},
	volume = {55},
	year = {1986},
	month = {02/1986},
	pages = {272{\textendash}279},
	abstract = {Monkeys can gradually change the amplitude of the wholly segmental, largely monosynaptic, spinal stretch reflex (SSR) when confronted by a task requiring such change (15-19). Change develops over months and may reverse and redevelop at similarly slow rates. We investigated the persistence of SSR amplitude change over nonperformance periods of up to 38 days. Eight animals with chronic EMG electrodes learned to maintain elbow angle and a given level of biceps background EMG against constant extension torque. At random times, a brief additional extension torque pulse elicited the biceps SSR. In the control mode, reward always followed. Under the SSR increase or SSR decrease mode, reward occurred only if the absolute value of biceps EMG in the SSR interval was above or below a set value. Animals completed 3,000-6,000 trials/day over data-collection periods of 2-17 mo. Animals worked first under the control mode for up to 60 days and then under the SSR increase or SSR decrease mode for up to 274 days. Mode was switched once or twice more (SSR increase to SSR decrease or vice versa) over subsequent months. Animals responded to each SSR increase or SSR decrease mode exposure with gradual mode-appropriate change in SSR amplitude. Mode exposures were interrupted by gaps in performance of 10-38 days. Gaps produced transient 10- to 15\% decreases in SSR amplitude under the control mode. This nonspecific decrease disappeared over the first week of postgap performance. Under the control mode, gaps had no other effects on SSR amplitude.(ABSTRACT TRUNCATED AT 250 WORDS)},
	keywords = {Spinal Cord},
	issn = {0022-3077},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/3950691},
	author = {Jonathan Wolpaw and O{\textquoteright}Keefe, J. A. and Noonan, P. 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.}
}
