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Titolo:
FIELD POTENTIAL MAPPING OF NEURONS IN THE LUMBAR SPINAL-CORD ACTIVATED FOLLOWING STIMULATION OF THE MESENCEPHALIC LOCOMOTOR REGION
Autore:
NOGA BR; FORTIER PA; KRIELLAARS DJ; DAI X; DETILLIEUX GR; JORDAN LM;
Indirizzi:
UNIV MANITOBA,FAC MED,DEPT PHYSIOL WINNIPEG MB R3E 0W3 CANADA UNIV MANITOBA,FAC MED,DEPT PHYSIOL WINNIPEG MB R3E 0W3 CANADA
Titolo Testata:
The Journal of neuroscience
fascicolo: 3, volume: 15, anno: 1995,
parte:, 2
pagine: 2203 - 2217
SICI:
0270-6474(1995)15:3<2203:FPMONI>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
FORELIMB FICTIVE LOCOMOTION; INTERNEURONS CONTROLLING ACTIVITY; II MUSCLE AFFERENTS; HORSERADISH-PEROXIDASE; BRAIN-STEM; PROPRIOSPINAL NEURONS; TREADMILL LOCOMOTION; AXON COLLATERALS; REFLEX PATHWAYS; RENSHAW CELLS;
Keywords:
FIELD POTENTIALS; INTERNEURONS; SPINAL CORD; FICTIVE LOCOMOTION; MESENCEPHALIC LOCOMOTOR REGION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Science Citation Index Expanded
Citazioni:
82
Recensione:
Indirizzi per estratti:
Citazione:
B.R. Noga et al., "FIELD POTENTIAL MAPPING OF NEURONS IN THE LUMBAR SPINAL-CORD ACTIVATED FOLLOWING STIMULATION OF THE MESENCEPHALIC LOCOMOTOR REGION", The Journal of neuroscience, 15(3), 1995, pp. 2203-2217

Abstract

The spinal neurons involved in the control of locomotion in mammals have not been identified, and a major step that is necessary for this purpose is to determine where these cells are likely to be located. Theprincipal objective of this study was to localize lumbar spinal interneurons activated by stimulation of the mesencephalic locomotor region(MLR) of the cat. For this purpose, extracellular recordings of MLR-evoked cord dorsum and intraspinal field potentials were obtained from the lumbosacral enlargement during fictive locomotion in the precollicular-postmammillary decerebrate cat preparation. Potentials recorded from the dorsal surface of the cord between the third lumbar (L3) and first sacral (S1) segments typically showed four short-latency positivewaves (P1-P4). These P-waves were largest between the L4-L6 segments. The amplitude of the P2-4 waves increased with the appearance of locomotion and displayed rhythmic modulation during the locomotor step cycle. Microelectrode recordings from the L4-L7 spinal segments during fictive locomotion revealed the presence of both positive and negative short-latency MLR-evoked intraspinal field potentials, and were used toconstruct isopotential maps of the evoked potentials. Positive field potentials were observed throughout the dorsal horn of the L4-L7 spinal segments with the largest amplitude potentials occurring in laminae III-VI. Negative field potentials were found in laminae VI-X of the lumbar cord. The shortest latency negative field potentials were observed in lamina VII and at the border between laminae VI and VII and were considered to be evoked monosynaptically from the arrival of the descending volley. Short-latency mono- and disynaptic negative field potentials were also observed in lamina VIII, Longer latency, tri- and polysynaptic field potentials were observed in laminae VII and VIII. Many of the longer latency negative waves observed in laminae VII and VIII followed shorter latency negative potentials recorded from the same location. Laminae VII and VIII negative field potentials were largest in the L5-6 and L4-5 spinal segments, respectively. Negative field potentials were also evoked in the motor nuclei of the L4-7 spinal segments. The segmental latencies for these potentials indicate that they were evoked di- and trisynaptically, Di- and trisynaptic negative field potentials were also observed near the central canal (in lamina X and theadjacent medial lamina VII) of the L5 and L6 segments. The MLR-evokednegative field potentials were modulated during fictive locomotion. These results suggest that stimulation of the MLR produces a descendingvolley that activates interneurons in the intermediate zone and ventral horn throughout the lumbosacral segments of the spinal cord, but predominantly between L4 and L6. We propose that the neurons giving riseto MLR-evoked cord dorsum and negative field potentials form part of the spinal circuitry responsible for the initiation and/or maintenanceof locomotion.

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Documento generato il 27/11/20 alle ore 22:25:04