Understanding the Benefits of Infrared Nerve Stimulators for Neural Interfaces

描述（由申请人提供）：神经假体的目标是将神经功能恢复到具有健康系统保真度的状态。然而，当代的神经假体，包括人工耳蜗，无法实现这一目标。这些设备使用电流来刺激神经元，电流在组织中传播，因此不允许刺激集中的神经元群体。因此，高保真刺激是不可能的。在我们的模型系统，耳蜗，它已被认为，耳蜗植入用户的性能可以显着增加，如果位于沿着电极的神经元的更离散的位置可以被同时刺激。使用聚焦光辐射刺激神经元的设备可能会实现这一点。今天，我们知道红外神经刺激（INS）是可能的，可以实现的刺激率，允许编码的声学信息，耳蜗的空间选择性比电刺激的选择性高约五倍，在慢性实验中，单通道刺激显示至少六周内耳蜗没有功能损伤。这里提出的五年计划是我们以前实验的一个合乎逻辑的进展。目的包括验证INS的选择性将产生更多的独立通道，证明三通道器械可以在数周内安全刺激植入的耳蜗，并表明多通道INS的每个通道可以独立编码听觉系统感知的信息。在项目期结束时，我们打算提出一个原型的多通道神经接口的人，这里的人工耳蜗。为了确定独立刺激的最小通道间隔，我们将在聋猫中植入一个三通道装置。下丘的记录将用于构建空间调谐曲线（STC）。非重叠STC指示信道的分离。刺激源之间的距离将系统地改变，直到在相邻刺激源处获得独立刺激。通过改变刺激参数，如重复率，脉冲形状和相邻通道之间的延迟，实验还将提供有关光学刺激的时间特性的信息。将三通道装置长期植入猫耳蜗后的长期刺激将决定其安全性。将测量诱发听觉反应，并提供耳蜗功能和安全性信息。将通过组织学确认结果。使用温度敏感油墨的测量将提供有关刺激期间热负荷的重要信息。在该项目结束时，将根据物理和光学要求构建一个原型人类光学人工耳蜗。

DESCRIPTION (provided by applicant): The goal for neuroprostheses is to restore neural function to a condition having the fidelity of a healthy system. However, contemporary neural prostheses, including cochlear implants, are not able to achieve this goal. The devices use electrical current to stimulate the neurons, which spreads in the tissue and consequently does not allow stimulation of focused populations of neurons. Therefore, high fidelity stimulation is no possible. In our model system, the cochlea, it has been argued that the performance of cochlear implant users could be increased significantly if more discrete locations of neurons situated along the electrode could be stimulated simultaneously. This might be possible with devices that use focal optical radiation to stimulate neurons. Today we know that infrared neural stimulation (INS) is possible, that stimulation rates can be achieved that allow encoding of acoustic information, that the spatial selectivity in the cochlea is about five times more selective than electrical stimulation, and that single channel stimulation in chronic experiments shows no functional damage of the cochlea over at least six weeks. The five-year project proposed here is a logical progression of our previous experiments. The aims include validating that the selectivity of INS will result in a larger number of independent channels, demonstrating that a three-channel device can safely stimulate an implanted cochlea over several weeks, and showing that each channel of multichannel INS can independently encode information to be perceived by the auditory system. At the conclusion of the project period we intend to present a prototype for a multi-channel neural interface for the human, here a cochlear implant. To determine the minimum channel separation for independent stimulation, we will implant a three-channel device in deaf cats. Recordings from the inferior colliculus will be used to construct spatial tuning curves (STCs). Non-overlapping STCs indicate separation of the channels. The distance between the stimulation sources will be altered systematically until independent stimulation at neighboring stimulation sources is obtained. By varying stimulus parameters such as the repetition rate, the pulse shape, and the delay between neighboring channels, the experiments will also provide information on the temporal properties of optical stimulation. Long-term stimulation after chronic implantation of a three-channel device into a cat cochlea will determine the safety. Evoked auditory responses will be measured and will provide information on cochlear function and safety. Results will be confirmed through histology. Measurements with temperature sensitive ink will provide important information on the heat load during stimulation. At the conclusion of this project, a prototype human optical cochlear implant will be constructed based on the physical and the optical requirements.