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Titolo:
Motor unit properties after operant conditioning of rat H-reflex
Autore:
Carp, JS; Chen, XY; Sheikh, H; Wolpaw, JR;
Indirizzi:
New York State Dept Hlth, Wadsworth Ctr, Albany, NY 12201 USA New York State Dept Hlth Albany NY USA 12201 th Ctr, Albany, NY 12201 USA SUNY Albany, Albany, NY 12201 USA SUNY Albany Albany NY USA 12201SUNY Albany, Albany, NY 12201 USA
Titolo Testata:
EXPERIMENTAL BRAIN RESEARCH
fascicolo: 3, volume: 140, anno: 2001,
pagine: 382 - 386
SICI:
0014-4819(200110)140:3<382:MUPAOC>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
FAST-TWITCH MUSCLE; MEDIAL GASTROCNEMIUS-MUSCLE; LOW-FREQUENCY ACTIVATION; RATE CHRONIC STIMULATION; SPINAL STRETCH REFLEX; SKELETAL-MUSCLE; CONTRACTILE PROPERTIES; MOTONEURON PROPERTIES; PHYSIOLOGICAL AMOUNTS; CAT HINDLIMB;
Keywords:
plasticity; H-reflex; operant conditioning; triceps surae; motor unit type;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
39
Recensione:
Indirizzi per estratti:
Indirizzo: Carp, JS New York State Dept Hlth, Wadsworth Ctr, Albany, NY 12201 USA NewYork State Dept Hlth Albany NY USA 12201 lbany, NY 12201 USA
Citazione:
J.S. Carp et al., "Motor unit properties after operant conditioning of rat H-reflex", EXP BRAIN R, 140(3), 2001, pp. 382-386

Abstract

Operant conditioning of the H-reflex produces plasticity at several sites in the spinal cord, including the motoneuron. This study assessed whether this spinal,es in motor unit cord plasticity is accompanied by chang contractile properties. Thirty-one adult male Sprague-Dawley rats implanted for chronic recording of triceps surae electromyographic activity and H-reflex elicitation were exposed for at least 40 days to HRup or HRdown training, in which reward occurred when the H-reflex was greater than (12 HRup rats) or less than (12 HRdown rats) a criterion value,, or continued under the control mode in which the H-reflex was simply measured (7 HRcon rats). At the end of H-reflex data collection, rats were anesthetized and the contractile properties of 797 single triceps surae motor units activated by intraaxonal (or intramyelin) current injection were determined. Motor units were classified as S, FR, Fint, or FF on the basis of sag and fatigue properties. Maximum tetanic force and twitch contraction time were also measured. HRdown rats exhibited a significant increase in the fatigue index of fast-twitch motor units. This resulted in a significant decrease in the percentage of Fintmotor units and a significant increase in that of FR motor units. HRup conditioning had no effect on fatigue index. Neither HRup nor HRdown conditioning affected maximum tetanic force or twitch contraction time. These data are consistent with the hypothesis that conditioning mode-specific change inmotoneuron firing patterns causes activity-dependent change in muscle properties.

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Documento generato il 29/03/20 alle ore 08:48:30