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Neural recording and stimulation using wireless networks of microimplants

Nature Electronics volume 4, pages 604–614 (2021)Cite this article

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Abstract

Multichannel electrophysiological sensors and stimulators—particularly those used to study the nervous system—are usually based on monolithic microelectrode arrays. However, the architecture of such arrays limits flexibility in electrode placement and scaling to a large number of nodes, especially across non-contiguous locations. Here we report wirelessly networked and powered electronic microchips that can autonomously perform neural sensing and electrical microstimulation. The microchips, which we term neurograins, have an ~1 GHz electromagnetic transcutaneous link to an external telecom hub, providing bidirectional communication and control at the individual device level. To illustrate the potential of the approach, we show that 48 neurograins can be individually addressed on a rat cortical surface and used for the acute recording of neural activity. Theoretical calculations and experimental measurements show that the link configuration could potentially be scaled to 770 neurograins using a customized time-division multiple access protocol.

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Fig. 1: Wireless neurograin system for distributed autonomous networking.
Fig. 2: Design of neurograin chip and wireless power and data link.
Fig. 3: Data communication demonstration on the benchtop with 8 mm separation between the Tx and relay coil in air.
Fig. 4: Neurograin recording and stimulation in saline and in vivo acute rat model.
Fig. 5: Wireless efficiency characterization.

Data availability

The dataset that supports the plots within this paper and other findings of this study are available in the Supplementary Information and from the corresponding author upon reasonable request.

Code availability

Custom-developed MATLAB codes for demodulation are available in the Supplementary Information and from the corresponding author upon reasonable request.

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Acknowledgements

We thank Y.-K. Song for insights into microfabrication and ASIC design, J. Jeong for his expertise with neurograin hermetic sealing and materials processing, and R. Rao for guidance on wireless networking design. We also thank C. Kilfoyle, E. Mok, S. Sigurdsson, and the Animal Care facility at Brown University for their contributions. We also acknowledge S. Li, S. Yu, L. Cui, S. Alluri and M. Lokhandwala at UCSD for their work on ASIC design and benchtop test. We have greatly benefited from the insight of our colleagues across multiple fields from microelectronics to brain sciences and clinical neurology: J. Donoghue, B. Dutta, J. Groe, L. Hochberg, T. Sejnowsky, K. Shenoy and S. Cash, among others. This research was initially supported by Defense Advanced Research Projects Agency N66001-17-C-4013, with subsequent support from private gifts. The post-processing work benefited from the equipment funded by MRI award no. DMR-1827453.

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Authors and Affiliations

  1. School of Engineering, Brown University, Providence, RI, USA

    Jihun Lee, Ah-Hyoung Lee, Lawrence Larson, Farah Laiwalla & Arto Nurmikko

  2. Electrical and Computer Engineering, Baylor University, Waco, TX, USA

    Vincent Leung

  3. Graduate School of Convergence Science and Technology, Seoul National University, Seoul, South Korea

    Ah-Hyoung Lee

  4. Electrical and Computer Engineering, University of California San Diego, San Diego, CA, USA

    Jiannan Huang, Peter Asbeck & Patrick P. Mercier

  5. Qualcomm Inc., San Diego, CA, USA

    Stephen Shellhammer

  6. Carney Institute for Brain Science, Brown University, Providence, RI, USA

    Arto Nurmikko

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Contributions

A.N. conceived the project with P.A., P.P.M. and L.L. J.L. and A.N. designed the neural experiment concept. J.L. designed the RF wireless powering and data communication method, performed system characterization and in vivo experiments, and analysed the results. V.L., P.A., S.S. and L.L. designed the RF data communication protocol. V.L., J.H., F.L. and P.P.M. designed the neurograin ASICs. A.-H.L. performed microfabrication and packaging. J.L., V.L., F.L. and A.N. wrote the paper. All the authors commented on the paper.

Corresponding author

Correspondence to Arto Nurmikko.

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The authors declare no competing interests.

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Peer review information Nature Electronics thanks Nitish Thakor, Samantha Santacruz and Jonathan Viventi for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–16 and Tables 1 and 2.

Reporting Summary

Supplementary Data 1

MATLAB codes for the neurograin BPSK dataset and demodulation.

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Lee, J., Leung, V., Lee, AH. et al. Neural recording and stimulation using wireless networks of microimplants. Nat Electron 4, 604–614 (2021). https://doi.org/10.1038/s41928-021-00631-8

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