Murphy Sean C, Palmer Lucy M, Nyffeler Thomas, Müri René M, Larkum Matthew E
Neurocure Cluster of Excellence, Humboldt University, Berlin, Germany.
Physiologisches Institut, Universität Bern, Bern, Switzerland.
Elife. 2016 Mar 18;5:e13598. doi: 10.7554/eLife.13598.
One of the leading approaches to non-invasively treat a variety of brain disorders is transcranial magnetic stimulation (TMS). However, despite its clinical prevalence, very little is known about the action of TMS at the cellular level let alone what effect it might have at the subcellular level (e.g. dendrites). Here, we examine the effect of single-pulse TMS on dendritic activity in layer 5 pyramidal neurons of the somatosensory cortex using an optical fiber imaging approach. We find that TMS causes GABAB-mediated inhibition of sensory-evoked dendritic Ca(2+) activity. We conclude that TMS directly activates fibers within the upper cortical layers that leads to the activation of dendrite-targeting inhibitory neurons which in turn suppress dendritic Ca(2+) activity. This result implies a specificity of TMS at the dendritic level that could in principle be exploited for investigating these structures non-invasively.
非侵入性治疗多种脑部疾病的主要方法之一是经颅磁刺激（TMS）。然而，尽管其在临床上很常见，但对于TMS在细胞水平的作用知之甚少，更不用说它在亚细胞水平（如树突）可能产生的影响了。在这里，我们使用光纤成像方法研究单脉冲TMS对体感皮层第5层锥体神经元树突活动的影响。我们发现TMS会导致GABAB介导的对感觉诱发的树突Ca(2+)活性的抑制。我们得出结论，TMS直接激活皮层上层内的纤维，导致靶向树突的抑制性神经元激活，进而抑制树突Ca(2+)活性。这一结果意味着TMS在树突水平具有特异性，原则上可用于无创研究这些结构。
