Focal activation of neuronal circuits induced by microstimulation in the visual cortex
Focal activation of neuronal circuits induced by microstimulation in the visual cortex
复制标题
DOI：
10.1088/1741-2552/ab0b80
复制
发表时间：
2019-03
影响因子：
4
通讯作者：
Yuta Tanaka;Tomohiro Nomoto;Takuya Shiki;Y. Sakata;Yoshinori Shimada;Y. Hayashida;T. Yagi
中科院分区：
文献类型：
--
作者：
Yuta Tanaka;Tomohiro Nomoto;Takuya Shiki;Y. Sakata;Yoshinori Shimada;Y. Hayashida;T. Yagi
客观的。使用穿透电极对皮层组织进行微刺激，产生的电流在电极尖端周围同心传播，并且已知会引起焦点视觉感觉，即光幻视。然而，迄今为止，没有直接证据描述微刺激后立即诱导的神经元活动的时空特性以及这种活动如何驱动随后的局部皮质回路。方法。在本研究中，我们在小鼠初级视觉皮层切片中使用电压敏感染料（VSD）和钙敏感染料（CaSD）对微刺激直接诱导的动作电位（AP）的时空分布以及随后的跨突触信号传播进行成像。主要结果。直接感应的AP被限制在电极尖端附近，激发的有效距离与电流强度的平方根成正比。 IV 层电极尖端周围的激发主要传播到 II/III 层，进一步诱导下游局部皮质回路中的后续焦点激活。下游回路的激活程度受到兴奋性信号和抑制性信号之间的竞争性相互作用的限制。也就是说，兴奋沿 II/III 层向横向相邻神经元的传播受到延迟抑制的限制，延迟抑制也以更快的速度横向传播。意义。这些观察结果表明，兴奋性和抑制性信号之间的动态相互作用在响应皮质内微刺激的皮质回路的局部激活中发挥着关键作用，因此在唤起局部光幻视方面发挥着关键作用。
Objective. Microstimulation to the cortical tissue applied with penetrating electrodes delivers current that spreads concentrically around the electrode tip and is known to evoke focal visual sensations, i.e. phosphenes. However, to date, there is no direct evidence depicting the spatiotemporal properties of neuronal activity induced immediately after microstimulation and how such activity drives the subsequent local cortical circuits. Approach. In the present study, we imaged the spatiotemporal distribution of action potentials (APs) directly induced by microstimulation and the subsequent trans-synaptic signal propagation using a voltage-sensitive dye (VSD) and a calcium-sensitive dye (CaSD) in slice preparations of the mouse primary visual cortex. Main results. The directly induced APs were confined to the close vicinity of the electrode tip, and the effective distance of excitation was proportional to the square root of the current intensity. The excitation around the electrode tip in layer IV mainly propagated to layer II/III to further induce the subsequent focal activation in downstream local cortical circuits. The extent of activation in the downstream circuits was restrained by competitive interactions between excitatory and inhibitory signals. Namely, the spread of the excitation to lateral neighbor neurons along the layer II/III was confined by the delayed inhibition that also spread laterally at a faster rate. Significance. These observations indicate that dynamic interactions between excitatory and inhibitory signals play a critical role in the focal activation of a cortical circuit in response to intracortical microstimulation and, therefore, in evoking a localized phosphene.