Optical and electrical population recording from two stages of the retinal code

描述(申请人提供)：神经回路是大脑的处理单元，由数千或数百万个神经细胞组成的网络转换信息。视网膜是中枢神经系统(CNS)中唯一可以完整移除的神经回路，其整个自然输入可以毫秒级的精度传递给数十万个细胞。它也是中枢神经系统中唯一有可能在疾病情况下被电子假体取代的神经回路。实现这一治疗目标的一个重要障碍是详细了解视网膜的内部信息处理--神经编码。为了理解视网膜电路中两个连续的处理层，我们将采取分而治之的方法来理解神经编码，方法是使用一种新的技术组合在电路中的两个不同水平同时记录。视觉场景从视频监视器投射到孤立的完整的火蜥蜴或老鼠视网膜的光感受器层上。红外双光子激光扫描显微镜与电压敏感染料结合使用，记录~100个中间神经元的活动。为此，我们将使用二次谐波成像，这是一种使用最小药理效应的染料选择性地成像神经细胞膜电位的技术。同时，一个由60个电极组成的阵列被用来记录组成视神经的视网膜输出细胞的动作电位。我们将使用测量的视网膜两层的视觉反应来分别模拟视网膜的外部和内部处理。我们还将使用来自神经元和神经节细胞群的同时记录来测试内部视网膜是否通过减少其突触输入中包含的冗余来压缩视觉场景。这些结果将立即适用于新兴的视网膜假体领域。视网膜假体系统的目标是通过用高分辨率电子电路取代受损视网膜的功能来治疗诸如老年性黄斑变性和视网膜色素变性等常见疾病。对视网膜神经编码的测量将直接用于合并到视网膜下和视网膜前假体系统中。

DESCRIPTION (provided by applicant): Neural circuits are the processing units of the brain, formed by networks of thousands or millions of nerve cells that transform information. The retina is the only neural circuit in the central nervous system (CNS) that can be removed intact and its entire natural input delivered to hundreds of thousands of cells with millisecond precision. It is also the only neural circuit of the CNS that can potentially be replaced by an electronic prosthesis in cases of disease. A substantial barrier to this therapeutic goal is a detailed understanding of the internal processing of information in the retina - the neural code. To understand the two sequential layers of processing in the retinal circuit, we will take a divide-and- conquer approach to understanding the neural code by simultaneously recording at two different levels in the circuit using a novel combination of techniques. Visual scenes are projected from a video monitor onto the photoreceptor layer of an isolated, intact salamander or mouse retina. An infrared two-photon laser-scanning microscope is used in conjunction with a voltage-sensitive dye to record the activity of ~ 100 interneurons. To do this, we will use second harmonic generation imaging, a technique that selectively images the membrane potential of neurons using dyes with minimal pharmacological effects. Simultaneously, an array of sixty electrodes is used to record action potentials in the output cells of the retina that comprise the optic nerve. We will use measured visual responses at two layers of the retina to separately model outer and inner retinal processing. We will also use simultaneous recordings from interneuron and ganglion cell populations to test whether the inner retina compresses the visual scene by reducing redundancy contained in its synaptic input. These results will have immediate applicability to the emerging field of retinal prostheses. The objective of a retinal prosthesis system is to treat prevalent diseases such as age-related macular degeneration and retinitis pigmentosa by replacing the function of the damaged retina with a high resolution electronic circuit. Measurements of the retinal neural code will be directly useful for incorporation into subretinal and epiretinal prostheses systems.