Rennaker R L, Street S, Ruyle A M, Sloan A M
Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
J Neurosci Methods. 2005 Mar 30;142(2):169-76. doi: 10.1016/j.jneumeth.2004.08.009.
High-density multi-channel intra-cortical electrode arrays allow researchers to record simultaneously from populations of neurons for the purpose of understanding neural coding and plasticity. These devices have tens to hundreds of electrodes spaced within a few square millimeters. During insertion, the high-density probes can compress the cortex several millimeters prior to breaking through the pia. Compression of cortical tissue has been demonstrated to result in traumatic brain injury (TBI) which may be a major contributor to low electrode yield and decreased recording longevity. Two insertion techniques for chronically implanting multi-wire electrode arrays in layer IV of primary auditory cortex were compared. A mechanical insertion device, capable of rapidly inserting the electrode array without visible compression of the brain, was constructed. The neural responses to broadband clicks and pure tones recorded from the arrays inserted with the mechanical device were compared to the results from a manual insertion method using a micromanipulator. Both techniques result in a similar number of active channels directly following surgery with a mean signal-to-noise ratio of approximately 4.5. Over 60% of the animals implanted with the mechanical insertion device had driven activity at week 6 whereas none of the animals with manually inserted arrays exhibited functional responses after 3 weeks. This report provides initial evidence that mechanical insertion devices, which prevent cortical compression, increase electrode recording longevity.
高密度多通道皮层内电极阵列使研究人员能够同时记录神经元群体的活动，以了解神经编码和可塑性。这些设备有数十到数百个电极，分布在几平方毫米的范围内。在插入过程中，高密度探针在穿透软脑膜之前可将皮层压缩几毫米。皮层组织的压缩已被证明会导致创伤性脑损伤（TBI），这可能是电极产量低和记录寿命缩短的主要原因。比较了两种在初级听觉皮层IV层长期植入多线电极阵列的插入技术。构建了一种能够快速插入电极阵列而不会对大脑造成明显压缩的机械插入装置。将使用该机械装置插入的阵列记录的对宽带点击声和纯音的神经反应与使用微操纵器的手动插入方法的结果进行了比较。两种技术在手术后直接产生的活跃通道数量相似，平均信噪比约为4.5。超过60%植入机械插入装置的动物在第6周时有驱动活动，而手动插入阵列的动物在3周后均未表现出功能反应。本报告提供了初步证据，表明可防止皮层压缩的机械插入装置可延长电极记录寿命。
