The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel.
Sci Rep. 2023 Aug 4;13(1):12689. doi: 10.1038/s41598-023-39808-w.
Optostimulation and electrical microstimulation are well-established techniques that enable to artificially stimulate the brain. While the activation patterns evoked by microstimulation in cortical network are well characterized, much less is known for optostimulation. Specifically, the activation maps of neuronal population at the membrane potential level and direct measurements of these maps were barely reported. In addition, only a few studies compared the activation patterns evoked by microstimulation and optostimulation. In this study we addressed these issues by applying optostimulation in the barrel cortex of anesthetized rats after a short (Short) or a long (Long) opsin expression time and compared it to microstimulation. We measured the membrane potential of neuronal populations at high spatial (meso-scale) and temporal resolution using voltage-sensitive dye imaging. Longer optostimulation pulses evoked higher neural responses spreading over larger region relative to short pulses. Interestingly, similar optostimulation pulses evoked stronger and more prolonged population response in the Long vs. the Short condition. Finally, the spatial activation patterns evoked in the Long condition showed an intermediate state, with higher resemblance to the microstimulation at the stimulation site. Therefore, short microstimulation and optostimulation can induce wide spread activation, however the effects of optostimulation depend on the opsin expression time.
光刺激和电微刺激是两种成熟的技术，可以人为地刺激大脑。虽然微刺激在皮质网络中引起的激活模式已得到很好的描述，但对于光刺激的了解却少得多。具体来说，在膜电位水平上的神经元群体的激活图以及这些图的直接测量几乎没有被报道。此外，只有少数研究比较了微刺激和光刺激引起的激活模式。在这项研究中，我们通过在麻醉大鼠的桶状皮层中施加短（Short）或长（Long）视蛋白表达时间后的光刺激来解决这些问题，并将其与微刺激进行了比较。我们使用电压敏感染料成像以高空间（中尺度）和时间分辨率测量神经元群体的膜电位。与短脉冲相比，较长的光刺激脉冲会引起更高的神经反应，并且扩散到更大的区域。有趣的是，在 Long 条件下，相似的光刺激脉冲会引起更强且更持久的群体反应。最后，在 Long 条件下引起的空间激活模式显示出中间状态，与刺激部位的微刺激更相似。因此，短时间的微刺激和光刺激可以引起广泛的激活，但是光刺激的效果取决于视蛋白的表达时间。
