Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada.
Feinstein Institute for Medical Research, Manhasset, NY 11030, USA.
Curr Biol. 2017 Oct 23;27(20):3086-3096.e3. doi: 10.1016/j.cub.2017.09.020. Epub 2017 Oct 12.
There has been growing interest in transcranial direct current stimulation (tDCS), a non-invasive technique purported to modulate neural activity via weak, externally applied electric fields. Although some promising preliminary data have been reported for applications ranging from stroke rehabilitation to cognitive enhancement, little is known about how tDCS affects the human brain, and some studies have concluded that it may have no effect at all. Here, we describe a macaque model of tDCS that allows us to simultaneously examine the effects of tDCS on brain activity and behavior. We find that applying tDCS to right prefrontal cortex improves monkeys' performance on an associative learning task. While firing rates do not change within the targeted area, tDCS does induce large low-frequency oscillations in the underlying tissue. These oscillations alter functional connectivity, both locally and between distant brain areas, and these long-range changes correlate with tDCS's effects on behavior. Together, these results are consistent with the idea that tDCS leads to widespread changes in brain activity and suggest that it may be a valuable method for cheaply and non-invasively altering functional connectivity in humans.
经颅直流电刺激（tDCS）作为一种非侵入性技术，通过施加微弱的外部电场来调节神经活动，引起了越来越多的关注。尽管已经有一些很有前景的初步数据报道了其在从中风康复到认知增强等方面的应用，但对于 tDCS 如何影响人类大脑，我们知之甚少，一些研究甚至得出结论，认为它可能根本没有效果。在这里，我们描述了一种猕猴 tDCS 模型，使我们能够同时检查 tDCS 对大脑活动和行为的影响。我们发现，对右前额叶皮层施加 tDCS 可以提高猴子在联想学习任务中的表现。虽然目标区域内的发射率没有变化，但 tDCS 确实会在下面的组织中引起大的低频振荡。这些振荡改变了局部和远距离脑区之间的功能连接，这些远程变化与 tDCS 对行为的影响相关。总之，这些结果与 tDCS 导致大脑活动广泛变化的观点一致，并表明它可能是一种廉价且非侵入性地改变人类功能连接的有效方法。
