NeuraPlex - High-density fully-immersible subcortical neural data digitizer based on time-division multiplexing

NeuraPlex - 基于时分复用的高密度完全浸入式皮层下神经数据数字化仪

• 批准号: 457287847
• 负责人: Professor Dr.-Ing. Yiannos Manoli
• 金额: --
• 依托单位: Institut für Mikrosystemtechnik (IMTEK)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/457287847?language=en
• 关键词: NeuraPlex; density; fully; immersible; subcortical

The objective of this research project is to develop and implement the first high-density fully-immersible CMOS neural probe with a spatial resolution lower than 50 µm. The state of the art is limited on one hand by conventional active neural-probes with a small electrode pitch but encompassing a large base and a high number of connecting wires. On the other hand, it offers a fully immersible CMOS neural probe featuring a minimal base and requiring fewer connections at the cost of a large electrode pitch. The new probe advances the state of the art by implementing an optimized signal processing chain tailored to this application. Hence, neither a bulky connector is required nor elaborate circuits need to be integrated into the base, which in turn yields a slim probe with a small electrode pitch and a uniform width from tip to base. Thus, substantial silicon area and costs can be saved. In addition, the probe can be fully immersed into the brain tissue whereby subcortical recording of single-neuron signals with a high signal-to-noise ratio, a large bandwidth and an appropriate spatial resolution becomes feasible.The objective will be met by integrating a “digital” multi-electrode-array into the shank. However, since the available area per channel on the shank is limited, multiple electrodes will need to share one analog-to-digital converter (ADC). Time-division multiplexing as performed up to now requires preamplifiers and an explicit anti-aliasing filter to be implemented on the base leading to a large area. To achieve the same on the limited area of the shank and still avoid excessive power consumption and temperature increase of the tissue, a dedicated ADC architecture needs to be developed. This ADC must meet, amongst others, the specifications of smallest-area, minimal-power consumption, and ultra-low-noise as defined by the high-density fully immersible CMOS neural probe. Fundamental research will thus be performed on architectures for continuous-time, incremental Delta-Sigma ADCs. Their intrinsic anti-aliasing filter as well as their applicability in multiplexed sensor systems make them the perfect candidate for neural recording systems.The resulting high-density neural probe with its capability to simultaneously monitor the single activity of hundreds of neurons will provide neuroscientists with new opportunities for performing research on brain activity in deeper regions and for gaining understanding of neural networks. Moreover, combined with a neural stimulator, it can be used to implement a closed-loop system and thus contribute to the pursuit of relieving the symptoms of neurological and psychological diseases.Due to the ever-increasing demand for ultra-low-power, high-resolution, multi-channel ADCs, the outcome of the fundamental research on architectures for continuous-time incremental Delta-Sigma ADCs are of high impact for other applications such as instrumentation and measurement or the Internet of Things.

本研究项目的目标是开发和实现第一个空间分辨率低于50微米的高密度全浸入式CMOS神经探头。一方面，传统的有源神经探头电极间距小，但基座大，连接线数量多，限制了该技术的发展。另一方面，它提供了一种完全可浸入式的CMOS神经探头，具有最小的基座和较少的连接，但成本较大的电极间距。新的探头通过实施为该应用量身定做的优化信号处理链来推进最先进的技术。因此，既不需要笨重的连接器，也不需要将复杂的电路集成到基座中，这反过来又产生了一个细长的探头，具有小电极间距和从尖端到基座的均匀宽度。因此，可以节省大量的硅面积和成本。此外，该探头可以完全浸入脑组织，从而能够以高信噪比、大带宽和适当的空间分辨率对单个神经元信号进行皮质下记录。这一目标将通过在小腿上集成“数字”多电极阵列来实现。然而，由于支架上每个通道的可用面积有限，多个电极将需要共享一个模数转换器(ADC)。到目前为止，时分复用需要在基座上实现前置放大器和显式抗混叠滤波，从而产生较大的面积。为了在小腿的有限面积上实现同样的效果，同时仍然避免组织的过度功耗和温度升高，需要开发一种专用的ADC架构。该ADC必须满足高密度全浸没式CMOS神经探头所定义的最小面积、最低功耗和超低噪声的规格。因此，将对连续时间、增量Delta-Sigma ADC的体系结构进行基础研究。其固有的抗混叠滤波以及在多路传感器系统中的适用性使其成为神经记录系统的完美候选者。由此产生的高密度神经探针能够同时监测数百个神经元的单个活动，将为神经科学家提供新的机会，以进行更深层次的大脑活动研究和了解神经网络。由于对超低功耗、高分辨率、多通道ADC的需求不断增加，连续时间增量式Delta-Sigma ADC结构的基础研究成果对仪器仪表和测量或物联网等其他应用具有很高的影响。