Effect of transcranial magnetic stimulation on single-unit activity in the cat primary visual cortex
Effect of transcranial magnetic stimulation on single-unit activity in the cat primary visual cortex
复制标题
DOI：
10.1113/jphysiol.2003.050153
复制
发表时间：
2003-12-01
影响因子：
5.5
通讯作者：
Funke, K
中科院分区：
文献类型：
--
作者：
Moliadze, V;Zhao, YQ;Funke, K
经颅磁刺激（TMS）已经成为测试和调节人类大脑区域神经元兴奋性的一种成熟的方法，但对这种相当粗糙的刺激诱导的细胞过程知之甚少。在第一次尝试中，我们在麻醉和瘫痪的猫的初级视觉皮层（17区）进行了细胞外单单元记录，刺激磁场集中在记录部位（2 x 70 mm 8字形线圈）。单双相TMS脉冲，在右半球枕极内诱导侧向内侧电流，对自发活动和视觉诱发活动进行了测试。对于猫的视觉皮层，我们发现一个单一的TMS脉冲会引起不同的增强和抑制活动的发作：一般来说，在前500毫秒发现活动的促进，随后是持续几秒钟的活动抑制。超过最大刺激输出50%的强刺激也可能导致前100-200毫秒的早期活动抑制，随后是更强的（反弹）促进。活动的早期抑制和促进可能与抑制性和兴奋性中间神经元或多或少的直接刺激有关，可能具有不同的阈值。晚期、持久的抑制更可能与代谢或代谢过程有关，甚至与血管反应有关。促进/抑制的时间过程可能为反复应用经颅磁刺激的作用提供线索。
Transcranial magnetic stimulation (TMS) has become a well established procedure for testing and modulating the neuronal excitability of human brain areas, but relatively little is known about the cellular processes induced by this rather coarse stimulus. In a first attempt, we performed extracellular single-unit recordings in the primary visual cortex (area 17) of the anaesthetised and paralysed cat, with the stimulating magnetic field centred at the recording site (2 x 70 mm figure-of-eight coil). The effect of single biphasic TMS pulses, which induce a lateral-to-medial electric current within the occipital pole of the right hemisphere, was tested for spontaneous as well as visually evoked activity. For cat visual cortex we found that a single TMS pulse elicited distinct episodes of enhanced and suppressed activity: in general, a facilitation of activity was found during the first 500 ms, followed thereafter by a suppression of activity lasting up to a few seconds. Strong stimuli exceeding 50% of maximal stimulator output could also lead to an early suppression of activity during the first 100-200 ms, followed by stronger (rebound) facilitation. Early suppression and facilitation of activity may be related to a more or less direct stimulation of inhibitory and excitatory interneurons, probably with different thresholds. The late, long-lasting suppression is more likely to be related to metabotropic or metabolic processes, or even vascular responses. The time course of facilitation/inhibition may provide clues regarding the action of repetitive TMS application.