Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland.
Neuron. 2013 Apr 24;78(2):325-38. doi: 10.1016/j.neuron.2013.02.014. Epub 2013 Mar 28.
Gradual changes in the sensory environment can lead to abrupt changes in brain computations and perception. However, mechanistic understanding of the mediating microcircuits is missing. By sliding through light levels from starlight to daylight, we identify retinal ganglion cell types in the mouse that abruptly and reversibly switch the weighting of center and surround interactions in their receptive field around cone threshold. Two-photon-targeted recordings and genetic and viral tracing experiments revealed that the circuit element responsible for the switch is a large inhibitory neuron that provides direct inhibition to ganglion cells. Our experiments suggest that weak excitatory input via electrical synapses together with the spiking threshold in inhibitory cells act as a switch. We also reveal a switch-like component in the spatial integration properties of human vision at cone threshold. This work demonstrates that circuits in the retina can quickly and reversibly switch between two distinct states, implementing distinct perceptual regimes at different light levels.
感觉环境的逐渐变化会导致大脑计算和感知的突然变化。然而，介导的微电路的机制理解却缺失了。通过从星光到日光的光水平滑动，我们在小鼠中鉴定出视网膜神经节细胞类型，它们在锥体阈值周围的感受野中突然且可逆地切换中心和周围相互作用的权重。双光子靶向记录和遗传及病毒追踪实验表明，负责开关的电路元件是一种大的抑制性神经元，它对神经节细胞提供直接抑制。我们的实验表明，通过电突触的弱兴奋性输入以及抑制性细胞中的尖峰阈值充当开关。我们还在锥体阈值的人类视觉空间整合特性中揭示了一个类似开关的组件。这项工作表明，视网膜中的电路可以在两种不同状态之间快速且可逆地切换，在不同的光水平下实现不同的感知状态。
