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Titolo:
Stretch and H reflexes in triceps surae are similar during tonic and rhythmic contractions in high decerebrate cats
Autore:
Misiaszek, JE; De Serres, SJ; Stein, RB; Jiang, W; Pearson, KG;
Indirizzi:
Univ Alberta, Dept Physiol, Edmonton, AB T6G 2H7, Canada Univ Alberta Edmonton AB Canada T6G 2H7 iol, Edmonton, AB T6G 2H7, Canada Univ Alberta, Div Neurosci, Edmonton, AB T6G 2H7, Canada Univ Alberta Edmonton AB Canada T6G 2H7 sci, Edmonton, AB T6G 2H7, Canada
Titolo Testata:
JOURNAL OF NEUROPHYSIOLOGY
fascicolo: 4, volume: 83, anno: 2000,
pagine: 1941 - 1950
SICI:
0022-3077(200004)83:4<1941:SAHRIT>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
FICTIVE LOCOMOTION; PRESYNAPTIC INHIBITION; MESENCEPHALIC CAT; MUSCLE-SPINDLE; SPINAL CATS; GROUP-IA; AFFERENTS; WALKING; MODULATION; EXCITABILITY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
27
Recensione:
Indirizzi per estratti:
Indirizzo: Misiaszek, JE Univ Alberta, Dept Occupat Therapy, 2-64 Corbett Hall, Edmonton, AB T6G 2G4, Canada Univ Alberta 2-64 Corbett Hall Edmonton AB Canada T6G 2G4 da
Citazione:
J.E. Misiaszek et al., "Stretch and H reflexes in triceps surae are similar during tonic and rhythmic contractions in high decerebrate cats", J NEUROPHYS, 83(4), 2000, pp. 1941-1950

Abstract

During locomotion in decerebrate and spinal cats the group Ia afferents from hind leg muscles are depolarized rhythmically. An earlier study concluded that this locomotor-related primary afferent depolarization (PAD) does not contribute to modulation of monosynaptic reflex pathways during locomotion. This finding indicated that the neural network generating the locomotor rhythm the central pattern generator (CPG), does not presynaptically inhibit monosynaptic reflexes. In this investigation we tested this prediction indecerebrate cats by measuring the magnitude of reflexes evoked in ankle extensor muscles during periods of tonic contractions and during sequences ofrhythmic contractions. The latter occurred when the animal was induced to walk on a treadmill. At the similar levels of activity in the soleus musclethere was no significant difference in the magnitude of the soleus H reflex in these two behavioral situations. Similar results were: obtained for reflexes evoked by brief stretches of the soleus muscle. We also examined thereflexes evoked by ramp-and-hold stretches during periods of rhythmic and tonic activity of the isolated medial gastrocnemius (MG) muscle. At similarlevels of background activity, the reflexes evoked in the MG muscle were the same during rhythmic and tonic contractions. Our failure to observe a reduction in the magnitude of H reflexes and stretch reflexes during rhythmiccontractions, compared with reflexes evoked at the same level of background activity during tonic contractions, is consistent with the notion that the CPG for stepping does not presynaptically inhibit monosynaptic reflexes during the extension phase of locomotor activity. Our results indicate that presynaptic inhibition of the monosynaptic reflex associated with normal locomotion in cats or humans arises from sources other than the extensor burst generating system of the central pattern generator.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 22/02/20 alle ore 10:30:35