Short-interval intracortical inhibition to the biceps brachii is present during arm cycling but is not different than a position- and intensity-matched tonic contraction.
Exp Brain Res
; 237(9): 2145-2154, 2019 Sep.
Article
em En
| MEDLINE
| ID: mdl-31203402
ABSTRACT
We have previously shown that supraspinal excitability is higher during arm cycling than a position- and intensity-matched tonic contraction. The present study sought to determine if short-interval intracortical inhibition (SICI) was present during arm cycling and if so, if the amount of SICI was different from an intensity-matched tonic contraction. SICI was assessed using conditioning stimuli (CS) of 70 and 90% of active motor threshold (AMT) and a test stimulus (TS) of 120% AMT at an interstimulus interval (ISI) of 2.5 ms. SICI was elicited in all participants; on average (i.e., cycling and tonic contraction grouped) test MEP amplitudes were reduced by 64.2% (p < 0.001) and 62.8% (p = 0.001) following conditioning stimuli of 70% and 90% AMT, respectively. There was no significant difference in extent of SICI between tasks (p = 0.360). These data represent the novel finding that SICI is present during arm cycling, a motor output partially mediated by spinal interneuronal networks. The amount of SICI, however, was not different from that during a position- and intensity-matched tonic contraction, suggesting that SICI is not likely a cortical mechanism contributing to higher supraspinal excitability during arm cycling compared to tonic contraction.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Braço
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Córtex Cerebral
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Músculo Esquelético
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Potencial Evocado Motor
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Atividade Motora
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Contração Muscular
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Inibição Neural
Limite:
Adult
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Female
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Humans
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Male
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article