BACKGROUND Transcranial magnetic stimulation (TMS) is an emerging neuromodulation tool. However, preclinical models of TMS are limited. OBJECTIVE To develop a method for performing TMS in awake rats and to characterize neuronal response to TMS by mapping glucose uptake following TMS administration. METHODS A headpost was implanted into rat skull serving as a refence to guide TMS target. Motor threshold measurement was used as the metric to assess the consistency in TMS delivery across animals and across sessions. Using a fluorescent glucose analogue (2-NBDG) as a marker of neuronal activity, we mapped glucose uptake in response to TMS of the rat motor cortex. RESULTS The average motor threshold (n = 41) was 34.6 ± 6.3 % of maximum stimulator output (MSO). The variability of motor threshold across animals was similar to what has been reported in human studies. Furthermore, there was no significant difference in motor threshold measured across 3 separate days. Enhancement in fluorescent signals were TMS dose (power)-dependent, which centered around the motor cortex, covering an area medial-laterally 2 mm, rostral-caudally 4 mm at 55 % MSO, and 3 mm at 35 % MSO. The count of total cells with significant fluorescent signal was: 107 ± 23 (55 % MSO), 73 ± 11 (35 % MSO) and 42 ± 11 (sham, 5% MSO). CONCLUSIONS Our method allows for consistent motor threshold assessment for longitudinal studies. Notably, cells with fluorescent signal enhancement were consistently aggregated in deep cortical layers, with minimal enhancement in superficial layers COMPARISONS WITH EXISTING METHOD(S): To our knowledge, this is the first study of focal TMS in awake rodents.

中文翻译：

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清醒大鼠的局灶性经颅磁刺激：深层皮质层的葡萄糖摄取增强。

背景技术经颅磁刺激（TMS）是一种新兴的神经调节工具。然而，TMS 的临床前模型是有限的。目的：开发一种在清醒大鼠中进行 TMS 的方法，并通过绘制 TMS 给药后的葡萄糖摄取图来表征神经元对 TMS 的反应。方法将头柱植入大鼠颅骨内，作为参考，引导TMS靶点。运动阈值测量被用作评估 TMS 跨动物和跨会话传递的一致性的指标。我们使用荧光葡萄糖类似物 (2-NBDG) 作为神经元活动的标记，绘制了响应大鼠运动皮层 TMS 的葡萄糖摄取图。结果 平均运动阈值 (n = 41) 为最大刺激器输出 (MSO) 的 34.6 ± 6.3 %。动物间运动阈值的变异性与人类研究中报道的相似。此外，连续 3 天测量的运动阈值没有显着差异。荧光信号的增强是 TMS 剂量（功率）依赖性的，它以运动皮层为中心，在 55% MSO 时覆盖内侧 - 外侧 2 mm、头端 - 尾侧 4 mm 和 3 mm 在 35% MSO 时的区域。具有显着荧光信号的总细胞计数为：107 ± 23 (55% MSO)、73 ± 11 (35% MSO) 和 42 ± 11 (假, 5% MSO)。结论 我们的方法允许对纵向研究进行一致的运动阈值评估。值得注意的是，具有荧光信号增强的细胞始终聚集在深层皮质层中，表层增强最小。与现有方法的比较：据我们所知，