a Laboratory for Brain Recovery and Function, Dalhousie University, Halifax, NS B3H 4R1, Canada.
b School of Physiotherapy, Dalhousie University, Halifax, NS B3H 4R2, Canada.
Appl Physiol Nutr Metab. 2019 Aug;44(8):869-878. doi: 10.1139/apnm-2018-0643. Epub 2019 Jan 16.
Aerobic exercise (AE) modulates cortical excitability. It can alter both corticospinal excitability and intra-cortical networks, which has implications for its use as a tool to facilitate processes such as motor learning, where increased levels of excitability are conducive to the induction of neural plasticity. Little is known about how different intensities of AE modulate cortical excitability or how individual-level characteristics impact on it. Therefore, we investigated whether AE intensities, lower than those previously employed, would be effective in increasing cortical excitability. We also examined whether the aerobic fitness of individual participants was related to the magnitude of change in AE-induced cortical excitability. In both experiments we employed transcranial magnetic stimulation to probe corticospinal excitability before and after AE. We show that 20 min of continuous moderate- (40% and 50% of heart rate reserve, HRR), but not low- (30% HRR) intensity AE was effective at increasing corticospinal excitability. We also found that while we observed increased corticospinal excitability following 20 min of continuous moderate-intensity (50% HRR) AE, aerobic fitness was not related to the magnitude of change. Our results suggest that there is a lower bound intensity of AE that is effective at driving changes in cortical excitability, and that while individual-level characteristics are important predictors of response to AE, aerobic fitness is not. Overall these findings have implication for the way that AE is used to facilitate processes such as motor learning, where increased levels of cortical excitability and plasticity are favourable.
有氧运动（AE）可调节皮质兴奋性。它可以改变皮质脊髓兴奋性和皮质内网络，这对其作为促进运动学习等过程的工具具有重要意义，因为兴奋性水平的提高有利于诱导神经可塑性。对于不同强度的 AE 如何调节皮质兴奋性，以及个体水平特征如何影响皮质兴奋性，人们知之甚少。因此，我们研究了低于以前使用的强度的 AE 是否会有效增加皮质兴奋性。我们还检查了个体参与者的有氧健身水平是否与 AE 诱导的皮质兴奋性变化幅度有关。在这两个实验中，我们都使用经颅磁刺激在 AE 前后探测皮质脊髓兴奋性。我们表明，20 分钟的连续中等强度（40%和 50%心率储备，HRR），而不是低强度（30% HRR）AE 有效增加皮质脊髓兴奋性。我们还发现，虽然我们观察到 20 分钟连续中等强度（50% HRR）AE 后皮质脊髓兴奋性增加，但有氧健身水平与变化幅度无关。我们的结果表明，AE 有效驱动皮质兴奋性变化的下限强度，而个体水平特征是对 AE 反应的重要预测因素，但有氧健身水平不是。总的来说，这些发现对 AE 用于促进运动学习等过程的方式具有重要意义，因为皮质兴奋性和可塑性的提高是有利的。
