The severity of acute hypoxaemia determines distinct changes in intracortical and spinal neural circuits

Autor: Daniel J. McKeown, Glenn M. Stewart, Justin J. Kavanagh
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Experimental Physiology, Vol 108, Iss 9, Pp 1203-1214 (2023)
Druh dokumentu: article
ISSN: 1469-445X
0958-0670
DOI: 10.1113/EP091224
Popis: Abstract The purpose of this study was to examine how two common methods of continuous hypoxaemia impact the activity of intracortical circuits responsible for inhibition and facilitation of motor output, and spinal excitability. Ten participants were exposed to 2 h of hypoxaemia at 0.13 fraction of inspired oxygen (FIO2 clamping protocol) and 80% of peripheral capillary oxygen saturation (SpO2 clamping protocol) using a simulating altitude device on two visits separated by a week. Using transcranial magnetic and peripheral nerve stimulation, unconditioned motor evoked potential (MEP) area, short‐interval intracortical inhibition (SICI) and intracortical facilitation (ICF), and F‐wave persistence and area were assessed in the first dorsal interosseous (FDI) muscle before titration, after 1 and 2 h of hypoxic exposure, and at reoxygenation. The clamping protocols resulted in differing reductions in SpO2 by 2 h (SpO2 clamping protocol: 81.9 ± 1.3%, FIO2 clamping protocol: 90.6 ± 2.5%). Although unconditioned MEP peak to peak amplitude and area did not differ between the protocols, SICI during FIO2 clamping was significantly lower at 2 h compared to SpO2 clamping (P = 0.011) and baseline (P
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