Department of Biology, University of Oregon, Eugene, OR 97403.
Institute of Neuroscience, University of Oregon, Eugene, OR 97403.
Proc Natl Acad Sci U S A. 2018 Jul 3;115(27):E6339-E6346. doi: 10.1073/pnas.1802160115. Epub 2018 Jun 18.
Recent reports have begun to elucidate mechanisms by which learning and experience produce white matter changes in the brain. We previously reported changes in white matter surrounding the anterior cingulate cortex in humans after 2-4 weeks of meditation training. We further found that low-frequency optogenetic stimulation of the anterior cingulate in mice increased time spent in the light in a light/dark box paradigm, suggesting decreased anxiety similar to what is observed following meditation training. Here, we investigated the impact of this stimulation at the cellular level. We found that laser stimulation in the range of 1-8 Hz results in changes to subcortical white matter projection fibers in the corpus callosum. Specifically, stimulation resulted in increased oligodendrocyte proliferation, accompanied by a decrease in the g-ratio within the corpus callosum underlying the anterior cingulate cortex. These results suggest that low-frequency stimulation can result in activity-dependent remodeling of myelin, giving rise to enhanced connectivity and altered behavior.
最近的报告开始阐明学习和经验是如何在大脑中产生白质变化的机制。我们之前报道过，在冥想训练 2-4 周后，人类前扣带皮层周围的白质会发生变化。我们进一步发现，对小鼠前扣带皮层进行低频光遗传学刺激会增加它们在明暗箱范式中待在亮处的时间，这表明焦虑程度降低，类似于冥想训练后的情况。在这里，我们研究了这种刺激在细胞水平上的影响。我们发现，在 1-8 Hz 的范围内进行激光刺激会导致胼胝体下的皮质下白质投射纤维发生变化。具体来说，刺激导致少突胶质细胞增殖增加，同时在前扣带皮层下的胼胝体中 g 比值降低。这些结果表明，低频刺激可导致髓鞘的活性依赖性重塑，从而增强连接性并改变行为。
