The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, 52900, Israel.
Sci Rep. 2018 Sep 17;8(1):13913. doi: 10.1038/s41598-018-32148-0.
Intra-cortical microstimulation (ICMS) is a widely used technique to artificially stimulate cortical tissue. This method revealed functional maps and provided causal links between neuronal activity and cognitive, sensory or motor functions. The effects of ICMS on neural activity depend on stimulation parameters. Past studies investigated the effects of stimulation frequency mainly at the behavioral or motor level. Therefore the direct effect of frequency stimulation on the evoked spatio-temporal patterns of cortical activity is largely unknown. To study this question we used voltage-sensitive dye imaging to measure the population response in the barrel cortex of anesthetized rats evoked by high frequency stimulation (HFS), a lower frequency stimulation (LFS) of the same duration or a single pulse stimulation. We found that single pulse and short trains of ICMS induced cortical activity extending over few mm. HFS evoked a lower population response during the sustained response and showed a smaller activation across time and space compared with LFS. Finally the evoked population response started near the electrode site and spread horizontally at a propagation velocity in accordance with horizontal connections. In summary, HFS was less effective in cortical activation compared to LFS although HFS had 5 fold more energy than LFS.
皮层内微刺激（ICMS）是一种广泛用于人工刺激皮质组织的技术。这种方法揭示了功能图谱，并提供了神经元活动与认知、感觉或运动功能之间的因果联系。ICMS 对神经活动的影响取决于刺激参数。过去的研究主要在行为或运动水平上研究了刺激频率的影响。因此，高频刺激（HFS）对皮质活动诱发的时空模式的直接影响在很大程度上是未知的。为了研究这个问题，我们使用电压敏感染料成像来测量麻醉大鼠皮层的群体反应，这些反应是由高频刺激（HFS）、相同持续时间的低频刺激（LFS）或单个脉冲刺激引起的。我们发现，单个脉冲和短串的 ICMS 诱导的皮质活动延伸到几个毫米。与 LFS 相比，HFS 在持续反应期间引起的群体反应较低，并且在时间和空间上的激活较小。最后，诱发的群体反应从电极部位附近开始，并以与水平连接一致的传播速度水平传播。总之，与 LFS 相比，HFS 在皮质激活方面的效果较差，尽管 HFS 的能量是 LFS 的 5 倍。
