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Culaclii S, Wang PM, Taccola G, Yang W, Bailey B, Chen YP, Lo YK, Liu W. A Biomimetic, SoC-Based Neural Stimulator for Novel Arbitrary-Waveform Stimulation Protocols. Front Neurosci 2021; 15:697731. [PMID: 34393710 PMCID: PMC8358079 DOI: 10.3389/fnins.2021.697731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 07/07/2021] [Indexed: 11/15/2022] Open
Abstract
Novel neural stimulation protocols mimicking biological signals and patterns have demonstrated significant advantages as compared to traditional protocols based on uniform periodic square pulses. At the same time, the treatments for neural disorders which employ such protocols require the stimulator to be integrated into miniaturized wearable devices or implantable neural prostheses. Unfortunately, most miniaturized stimulator designs show none or very limited ability to deliver biomimetic protocols due to the architecture of their control logic, which generates the waveform. Most such designs are integrated into a single System-on-Chip (SoC) for the size reduction and the option to implement them as neural implants. But their on-chip stimulation controllers are fixed and limited in memory and computing power, preventing them from accommodating the amplitude and timing variances, and the waveform data parameters necessary to output biomimetic stimulation. To that end, a new stimulator architecture is proposed, which distributes the control logic over three component tiers – software, microcontroller firmware and digital circuits of the SoC, which is compatible with existing and future biomimetic protocols and with integration into implantable neural prosthetics. A portable prototype with the proposed architecture is designed and demonstrated in a bench-top test with various known biomimetic output waveforms. The prototype is also tested in vivo to deliver a complex, continuous biomimetic stimulation to a rat model of a spinal-cord injury. By delivering this unique biomimetic stimulation, the device is shown to successfully reestablish the connectivity of the spinal cord post-injury and thus restore motor outputs in the rat model.
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Affiliation(s)
- Stanislav Culaclii
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States.,Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
| | - Po-Min Wang
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States
| | - Giuliano Taccola
- Neuroscience Department, International School for Advanced Studies, Trieste, Italy.,Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States
| | - William Yang
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States
| | - Brett Bailey
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States
| | - Yan-Peng Chen
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, CA, United States
| | - Yi-Kai Lo
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States.,Niche Biomedical Inc., Los Angeles, CA, United States
| | - Wentai Liu
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, CA, United States.,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, United States.,Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
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Mottaghi S, Afshari N, Buchholz O, Liebana S, Hofmann UG. Modular Current Stimulation System for Pre-clinical Studies. Front Neurosci 2020; 14:408. [PMID: 32425752 PMCID: PMC7203490 DOI: 10.3389/fnins.2020.00408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/03/2020] [Indexed: 11/13/2022] Open
Abstract
Electric stimulators with precise and reliable outputs are an indispensable part of electrophysiological research. From single cells to deep brain or neuromuscular tissue, there are diverse targets for electrical stimulation. Even though commercial systems are available, we state the need for a low-cost, high precision, functional, and modular (hardware, firmware, and software) current stimulation system with the capacity to generate stable and complex waveforms for pre-clinical research. The system presented in this study is a USB controlled 4-channel modular current stimulator that can be expanded and generate biphasic arbitrary waveforms with 16-bit resolution, high temporal precision (μs), and passive charge balancing: the NES STiM (Neuro Electronic Systems Stimulator). We present a detailed description of the system’s structural design, the controlling software, reliability test, and the pre-clinical studies [deep brain stimulation (DBS) in hemi-PD rat model] in which it was utilized. The NES STiM has been tested with MacOS and Windows operating systems. Interfaces to MATLAB source codes are provided. The system is inexpensive, relatively easy to build and can be assembled quickly. We hope that the NES STiM will be used in a wide variety of neurological applications such as Functional Electrical Stimulation (FES), DBS and closed loop neurophysiological research.
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Affiliation(s)
- Soheil Mottaghi
- Section for Neuroelectronic Systems, Department of Neurosurgery, Medical Center University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Technical Faculty, University of Freiburg, Freiburg, Germany
| | - Niloofar Afshari
- Section for Neuroelectronic Systems, Department of Neurosurgery, Medical Center University of Freiburg, Freiburg, Germany
| | - Oliver Buchholz
- Section for Neuroelectronic Systems, Department of Neurosurgery, Medical Center University of Freiburg, Freiburg, Germany
| | - Samuel Liebana
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Ulrich G Hofmann
- Section for Neuroelectronic Systems, Department of Neurosurgery, Medical Center University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Technical Faculty, University of Freiburg, Freiburg, Germany
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