Transcranial Direct Current Stimulation Modulates Neurogenesis and Microglia Activation in the Mouse Brain

Figure 2

Multisession transcranial direct current stimulation (tDCS) at a high charge density causes cortical lesions. (a) After multisession tDCS with 198 kC/m², several animals presented with a disruption of neuronal integrity on NeuN neuronal staining. The lower image depicts the magnified region from the upper image. The scale bars represent 1 mm (upper image) and 200 µm (lower image), respectively. (b) In focal cortical lesions identified by NeuN-staining, an accumulation of Iba1-positive activated microglia indicated local inflammation. Again, the lower image depicts the magnified region from the upper image; scale bars represent 1 mm (upper image) and 200 µm (lower image), respectively. (c) Quantification confirmed that in focal cortical lesions induced by tDCS of high charge density, loss of NeuN-positive neurons was accompanied by upregulation of Iba1-positive microglia (, ). (d) Left: Fluoro-Jade staining depicts intact cortical tissue following tDCS with 99 kC/m². Right: small cortical lesion with Fluoro-Jade-positive degenerating neurons; scale bar represents 100 µm.

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