Neurosignals Group, Hospital Nacional de Parapléjicos, SESCAM, Finca La Peraleda s/n, 45071 Toledo, Spain.
Neuroimage. 2010 Feb 1;49(3):2304-10. doi: 10.1016/j.neuroimage.2009.10.044. Epub 2009 Oct 21.
Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that has been investigated for the treatment of many neurological or neuropsychiatric disorders. Its main effect is to modulate the cortical excitability depending on the polarity of the current applied. However, understanding the mechanisms by which these modulations are induced and persist is still an open question. A possible marker indicating a change in cortical activity is the subsequent variation in regional blood flow and metabolism. These variations can be effectively monitored using functional near-infrared spectroscopy (fNIRS), which offers a noninvasive and portable measure of regional blood oxygenation state in cortical tissue. We studied healthy volunteers at rest and evaluated the changes in cortical oxygenation related to tDCS using fNIRS. Subjects were tested after active stimulation (12 subjects) and sham stimulation (10 subjects). Electrodes were applied at two prefrontal locations; stimulation lasted 10 min and fNIRS data were then collected for 20 min. The anodal stimulation induced a significant increase in oxyhemoglobin (HbO(2)) concentration compared to sham stimulation. Additionally, the effect of active 10-min tDCS was localized in time and lasted up to 8-10 min after the end of the stimulation. The cathodal stimulation manifested instead a negligible effect. The changes induced by tDCS on HbO(2), as captured by fNIRS, agreed with the results of previous studies. Taken together, these results help clarify the mechanisms underlying the regional alterations induced by tDCS and validate the use of fNIRS as a possible noninvasive method to monitor the neuromodulation effect of tDCS.
经颅直流电刺激（tDCS）是一种非侵入性的脑刺激技术，已被用于治疗许多神经或神经精神疾病。其主要作用是根据所施加电流的极性来调节皮质兴奋性。然而，理解这些调制是如何诱导和持续的机制仍然是一个悬而未决的问题。表明皮质活动发生变化的一个可能标记是区域血流和代谢的后续变化。这些变化可以使用功能近红外光谱（fNIRS）有效地监测，fNIRS 提供了皮质组织中区域血氧状态的非侵入性和便携式测量方法。我们在休息时研究了健康志愿者，并使用 fNIRS 评估了与 tDCS 相关的皮质氧合变化。对主动刺激（12 名受试者）和假刺激（10 名受试者）后的受试者进行了测试。电极施加在前额两个位置；刺激持续 10 分钟，然后收集 20 分钟的 fNIRS 数据。与假刺激相比，阳极刺激可显著增加氧合血红蛋白（HbO（2））浓度。此外，主动 10 分钟 tDCS 的作用在时间上是局部的，并且在刺激结束后 8-10 分钟内持续。相反，阴极刺激表现出可以忽略不计的效果。fNIRS 捕获的 tDCS 对 HbO（2）的诱导变化与之前的研究结果一致。总的来说，这些结果有助于阐明 tDCS 诱导的区域改变的机制，并验证了使用 fNIRS 作为监测 tDCS 的神经调节效应的一种可能的非侵入性方法。
