Discipline of Physiology, School of Medicine, The University of Adelaide, Adelaide, Australia.
Robinson Research Institute, School of Medicine, The University of Adelaide, Adelaide, Australia.
Brain Stimul. 2017 Mar-Apr;10(2):298-304. doi: 10.1016/j.brs.2017.01.003. Epub 2017 Jan 4.
Primary motor cortex neuroplasticity is reduced in old adults, which may contribute to the motor deficits commonly observed in the elderly. Previous research in young subjects suggests that the neuroplastic response can be enhanced using non-invasive brain stimulation (NIBS), with a larger plastic response observed following priming with both long-term potentiation (LTP) and depression (LTD)-like protocols. However, it is not known if priming stimulation can also modulate plasticity in older adults.
To investigate if priming NIBS can be used to modulate motor cortical plasticity in old subjects.
In 16 young (22.3 ± 1.0 years) and 16 old (70.2 ± 1.7 years) subjects, we investigated the response to intermittent theta burst stimulation (iTBS; LTP-like) when applied 10 min after sham stimulation, continuous TBS (cTBS; LTD-like) or an identical block of iTBS. Corticospinal plasticity was assessed by recording changes in motor evoked potential (MEP) amplitude.
In young subjects, priming with cTBS (cTBS + iTBS) resulted in larger MEPs than priming with either iTBS (iTBS + iTBS; P = 0.001) or sham (sham + iTBS; P < 0.0001), while larger MEPs were seen following iTBS + iTBS than sham + iTBS (P < 0.0001). In old subjects, the response to iTBS + iTBS was not different to sham + iTBS (P > 0.9), whereas the response to cTBS + iTBS was reduced relative to iTBS + iTBS (P = 0.02) and sham + iTBS (P = 0.04).
Priming TBS is ineffective for modifying M1 plasticity in older adults, which may limit the therapeutic use of priming stimulation in neurological conditions common in the elderly.
初级运动皮层的神经可塑性在老年人中降低，这可能导致老年人常见的运动缺陷。以前在年轻受试者中的研究表明，使用非侵入性脑刺激 (NIBS) 可以增强神经可塑性反应，并且在使用长时程增强 (LTP) 和抑郁 (LTD) 样方案进行预处理后观察到更大的可塑性反应。然而，尚不清楚预处理刺激是否也可以调节老年人的可塑性。
研究预处理 NIBS 是否可用于调节老年受试者的运动皮层可塑性。
在 16 名年轻（22.3±1.0 岁）和 16 名老年（70.2±1.7 岁）受试者中，我们研究了在假刺激后 10 分钟应用间歇性 theta 爆发刺激 (iTBS；LTP 样)、连续 TBS (cTBS；LTD 样) 或相同的 iTBS 块时对运动诱发电位 (MEP) 幅度的反应。皮质脊髓可塑性通过记录运动诱发电位 (MEP) 幅度的变化来评估。
在年轻受试者中，与 iTBS（iTBS+iTBS）预处理相比，cTBS（cTBS+iTBS）预处理导致更大的 MEP（P=0.001），与 sham（sham+iTBS）预处理相比，导致更大的 MEP（P<0.0001），而 iTBS+iTBS 预处理后观察到更大的 MEP 比 sham+iTBS（P<0.0001）。在老年受试者中，iTBS+iTBS 预处理后的反应与 sham+iTBS 无差异（P>0.9），而 cTBS+iTBS 预处理后的反应与 iTBS+iTBS（P=0.02）和 sham+iTBS（P=0.04）相比降低。
TBS 预处理对调节老年人 M1 可塑性无效，这可能限制了预处理刺激在老年人常见神经疾病中的治疗应用。
