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Titolo:
CONVERGENCE OF SKIN REFLEX AND CORTICOSPINAL EFFECTS IN SEGMENTAL ANDPROPRIOSPINAL PATHWAYS TO FORELIMB MOTONEURONS IN THE CAT
Autore:
SASAKI M; KITAZAWA S; OHKI Y; HONGO T;
Indirizzi:
TOKYO METROPOLITAN INST NEUROSCI,2-6 MUSASHIDAI FUCHU TOKYO 183 JAPAN TOKYO METROPOLITAN INST NEUROSCI FUCHU TOKYO 183 JAPAN TOKYO MED COLL,DEPT PHYSIOL,SHINJUKU KU TOKYO 160 JAPAN ELECTROTECH LAB,NEUROSCI SECT TSUKUBA IBARAKI 305 JAPAN KYORIN UNIV,DEPT PHYSIOL MITAKA TOKYO 181 JAPAN
Titolo Testata:
Experimental Brain Research
fascicolo: 3, volume: 107, anno: 1996,
pagine: 422 - 434
SICI:
0014-4819(1996)107:3<422:COSRAC>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
CONJUGATED HORSERADISH-PEROXIDASE; II MUSCLE AFFERENTS; SPINODELTOIDEUS MOTONEURONS; TRANSNEURONAL TRANSPORT; INHIBITORY PATHWAYS; INTERNEURONAL RELAY; SPINAL-CORD; NEURONS; INTEGRATION; EXCITATION;
Keywords:
FORELIMB MOTONEURONS; CUTANEOUS REFLEX; PYRAMIDAL TRACT; SPINAL CORD; CAT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
36
Recensione:
Indirizzi per estratti:
Citazione:
M. Sasaki et al., "CONVERGENCE OF SKIN REFLEX AND CORTICOSPINAL EFFECTS IN SEGMENTAL ANDPROPRIOSPINAL PATHWAYS TO FORELIMB MOTONEURONS IN THE CAT", Experimental Brain Research, 107(3), 1996, pp. 422-434

Abstract

The organization of facilitatory convergence from cutaneous afferents(Skin) and the corticospinal tract (pyramidal tract, Pyr) in pathwaysto forelimb motoneurones of mainly distal muscles was studied in anaesthetized cats by analysing postsynaptic potentials (PSPs), which werespatially facilitated by combinations of stimuli to the two sources at different time intervals, Conditioning Pyr volleys facilitated Skin-evoked PSPs of fixed (1.2-3.6 ms) central latencies (Skin PSPs), suggesting that disynaptic and polysynaptic skin reflex pathways are facilitated from the pyramidal tract. The shortest latencies (1.2-1.7 ms) ofpyramidal facilitation suggested direct connection of pyramidal fibres with last order neurones of skin reflex pathways. Conditioning Skin volleys facilitated Pyr-evoked PSPs of fixed, mostly disynaptic latencies (1.0-2.5 ms; Pyr PSPs), suggesting that pyramido-motoneuronal pathways are facilitated from Skin at a premotoneuronal level. The shortest pathway from skin afferents to the premotor neurones appeared to be monosynaptic. Although Pyr and Skin volleys were mutually facilitating, the facilitation curve of Pyr PSPs and that of Skin PSPs were discontinuous to each other, with the peak facilitation at different Skin-Pyr volley intervals. Transection of the dorsal column (DC) at the C5/C6border had little effect on the latencies or amplitudes evoked by maximal stimulation and the pyramidal facilitation of Skin PSPs. In contrast, the facilitation of Pyr PSPs by Skin stimulation was greatly decreased after the DC transection, and the facilitation curve of Pyr PSPswas continuous to that of Skin PSPs, with no separate peak. Latenciesof Pyr PSPs ranged similarly to those in DC intact preparations. Morerostral DC transection (C4/C5 border) reduced Skin-facilitated Pyr excitatory PSPs (EPSPs) less than C5/C6 lesions, suggesting that the C5 segment also contains neurones mediating Skin-facilitated Pyr EPSPs. The results show that convergence from skin afferents and the corticospinal tract occurs at premotor pathways of different cervical segments. We suggest that corticospinal facilitation of skin reflex occurs mostly in the brachial segments and Skin facilitation of cortico-motoneuronal effects takes place largely in the rostral cervical segments and partly in the brachial segments.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/11/20 alle ore 10:37:20