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Titolo:
Organization of recurrent inhibition and facilitation in motoneuron pools innervating dorsiflexors of the cat hindlimb
Autore:
Trank, TV; Turkin, VV; Hamm, TM;
Indirizzi:
St5013ephs Hosp & Med Ctr, Barrow Neurol Inst, Div Neurobiol, Phoenix, AZ 8 St Josephs Hosp & Med Ctr Phoenix AZ USA 85013 v Neurobiol, Phoenix, AZ 8
Titolo Testata:
EXPERIMENTAL BRAIN RESEARCH
fascicolo: 3, volume: 125, anno: 1999,
pagine: 344 - 352
SICI:
0014-4819(199904)125:3<344:OORIAF>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
BACKWARD QUADRUPEDAL WALKING; HUMAN UPPER-LIMB; AXON COLLATERALS; MOTOR PATTERNS; ANKLE MUSCLES; RECIPROCAL INHIBITION; ALPHA-MOTONEURONS; SPINAL MECHANISMS; FLEXOR-DIGITORUM; ADAPTIVE-CONTROL;
Keywords:
recurrent inhibition; locomotion; digit function; Renshaw cells; recurrent collaterals;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
55
Recensione:
Indirizzi per estratti:
Indirizzo: Hamm, TM StRd,sephs Hosp & Med Ctr, Barrow Neurol Inst, Div Neurobiol, 350W Thomas St Josephs Hosp & Med Ctr 350 W Thomas Rd Phoenix AZ USA 85013 as
Citazione:
T.V. Trank et al., "Organization of recurrent inhibition and facilitation in motoneuron pools innervating dorsiflexors of the cat hindlimb", EXP BRAIN R, 125(3), 1999, pp. 344-352

Abstract

The incidence of recurrent inhibition and facilitation in motor nuclei innervating the dorsiflexors of the ankle and digits was examined in spinalized, decerebrate cats. Motoneurons innervating the anterior and posterior portions of the tibialis anterior (TAa and TAp, respectively) received strong recurrent inhibition following stimulation of either of the homonymous muscle nerves. Both motoneuron species received substantial recurrent inhibition from the semitendinosus (St), but stimulation of the nerve to the extensor digitorum longus (EDL), an ankle flexor synergist, evoked smaller recurrent IPSPs. TA motoneurons received mainly facilitation from hindlimb extensors of the hip and ankle. Motoneurons of the EDL and extensor digitorum brevis (EDB), synergists which share mechanical action at the metatarsophalangeal joint and the digits, received little recurrent inhibition in response to stimulation of the nerve to either muscle. Overall, stimulation of heteronymous flexor nerves (including TAa, TAp, and St) failed to evoke responsesin most of the EDB and EDL neurons tested (50-83%), and the amplitude of recurrent inhibitory responses was small. Recurrent facilitation from the extensors was more common in these motor nuclei. Most responses recorded in EDB motoneurons following either flexor or extensor nerve stimulation were recurrent facilitations. The sensitivity of this facilitation in EDB motoneurons to injection of polarizing current and its central latency indicate that it is mediated by a disinhibitory, trisynaptic pathway. Stimulation of the nerve to EDB produced recurrent IPSPs in some flexor motoneurons, but these potentials were infrequent and their amplitude was usually small. Basedon a comparison of the distribution of recurrent inhibition to published reports of the activities of TAa, TAp, EDL, and EDB during different forms of locomotion, we conclude that recurrent inhibition is large for motor nuclei that exhibit stereotypical activity, while motor nuclei that are activated independently receive and produce little recurrent inhibition. Despite the absence of recurrent inhibition in some motor nuclei, recurrent circuitsmay still participate in their control through disinhibitory, facilitatorymechanisms.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/11/20 alle ore 21:36:22