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Titolo:
Intracortical inhibition and facilitation in different representations of the human motor cortex
Autore:
Chen, R; Tam, A; Butefisch, C; Corwell, B; Ziemann, U; Rothwell, JC; Cohen, LG;
Indirizzi:
NINDS, Human Cort Physiol Sect, NIH, Bethesda, MD 20982 USA NINDS Bethesda MD USA 20982 ort Physiol Sect, NIH, Bethesda, MD 20982 USA Inst Neurol, MRC, Human Movement & Balance Unit, London WC1N 3BG, England Inst Neurol London England WC1N 3BG lance Unit, London WC1N 3BG, England
Titolo Testata:
JOURNAL OF NEUROPHYSIOLOGY
fascicolo: 6, volume: 80, anno: 1998,
pagine: 2870 - 2881
SICI:
0022-3077(199812)80:6<2870:IIAFID>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
TRANSCRANIAL MAGNETIC STIMULATION; CORTICOSPINAL PROJECTIONS; CORTICOCORTICAL INHIBITION; CORTICAL EXCITABILITY; INTRINSIC CONNECTIONS; LIMB MOTONEURONS; UNIT RESPONSES; SURFACE EMG; MONKEY; RECOVERY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
47
Recensione:
Indirizzi per estratti:
Indirizzo: Cohen, LG NINDS, Human Cort Physiol Sect, NIH, Bldg 10,Room 5N234,10 Ctr Dr,MSC-1430, NINDS Bldg 10,Room 5N234,10 Ctr Dr,MSC-1430 Bethesda MD USA 20982
Citazione:
R. Chen et al., "Intracortical inhibition and facilitation in different representations of the human motor cortex", J NEUROPHYS, 80(6), 1998, pp. 2870-2881

Abstract

Intracortical inhibition (ICI) and intracortical facilitation (ICF) of thehuman motor cortex can be studied with paired transcranial magnetic stimulation (TMS). Plastic changes and some neurological disorders in humans are associated with changes in ICI and ICF. Although well characterized in the hand representation, it is not known if ICI and ICF vary across different body part representations. Therefore we studied ICI and ICF in different motor representations of the human motor cortex. The target muscles were rectus abdominus (RA), biceps brachii (BB), abductor pollicis brevis (APB), quadriceps femoris (QF), and abductor hallucis (AH). For each muscle, we measured the rest and active motor thresholds (MTs), the motor-evoked potential (MEP) stimulus-response curve (MEP recruitment), ICI, and ICF. The effects of different interstimulus intervals (ISIs) were studied with a conditioningstimulus (CS) intensity of 80% active MT. The effects of different CS intensities were studied at ISI of 2 ms for ICI and ISI of 15 ms for ICF. MT was lowest for APE, followed by BE, AH, and QF, and was highest for RA. Except for BE, MEP recruitment was generally steeper for muscles with lower MT. ICI and ICF were present in all the motor representations tested. The stimulus intensity necessary to elicit ICI was consistently lower than that required to elicit ICF, suggesting that they are mediated by separate mechanisms. Despite wide differences in MT and MEP recruitment, the absolute CS intensities (expressed as percentage of the stimulator's output) required to elicit ICI and ICF appear unrelated to MT and MEP recruitment in the different muscles tested. These findings suggest that the intracortical mechanisms for inhibition and facilitation in different motor representations are not related to the strength of corticospinal projections.

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Documento generato il 10/04/20 alle ore 15:35:42