1
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Park J, Kumar A, Zhou Y, Oh S, Kim JH, Shi Y, Jain S, Hota G, Qiu E, Nagle AL, Schuller IK, Schuman CD, Cauwenberghs G, Kuzum D. Multi-level, forming and filament free, bulk switching trilayer RRAM for neuromorphic computing at the edge. Nat Commun 2024; 15:3492. [PMID: 38664381 PMCID: PMC11045755 DOI: 10.1038/s41467-024-46682-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 03/06/2024] [Indexed: 04/28/2024] Open
Abstract
CMOS-RRAM integration holds great promise for low energy and high throughput neuromorphic computing. However, most RRAM technologies relying on filamentary switching suffer from variations and noise, leading to computational accuracy loss, increased energy consumption, and overhead by expensive program and verify schemes. We developed a filament-free, bulk switching RRAM technology to address these challenges. We systematically engineered a trilayer metal-oxide stack and investigated the switching characteristics of RRAM with varying thicknesses and oxygen vacancy distributions to achieve reliable bulk switching without any filament formation. We demonstrated bulk switching at megaohm regime with high current nonlinearity, up to 100 levels without compliance current. We developed a neuromorphic compute-in-memory platform and showcased edge computing by implementing a spiking neural network for an autonomous navigation/racing task. Our work addresses challenges posed by existing RRAM technologies and paves the way for neuromorphic computing at the edge under strict size, weight, and power constraints.
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Affiliation(s)
- Jaeseoung Park
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Ashwani Kumar
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Yucheng Zhou
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Sangheon Oh
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Jeong-Hoon Kim
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Yuhan Shi
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Soumil Jain
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
| | - Gopabandhu Hota
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Erbin Qiu
- Department of Physics, University of California San Diego, La Jolla, CA, USA
| | - Amelie L Nagle
- Department of Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ivan K Schuller
- Department of Physics, University of California San Diego, La Jolla, CA, USA
| | - Catherine D Schuman
- Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, TN, USA
| | - Gert Cauwenberghs
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
| | - Duygu Kuzum
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA.
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2
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Ramezani M, Kim JH, Liu X, Ren C, Alothman A, De-Eknamkul C, Wilson MN, Cubukcu E, Gilja V, Komiyama T, Kuzum D. High-density transparent graphene arrays for predicting cellular calcium activity at depth from surface potential recordings. Nat Nanotechnol 2024; 19:504-513. [PMID: 38212523 DOI: 10.1038/s41565-023-01576-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 11/16/2023] [Indexed: 01/13/2024]
Abstract
Optically transparent neural microelectrodes have facilitated simultaneous electrophysiological recordings from the brain surface with the optical imaging and stimulation of neural activity. A remaining challenge is to scale down the electrode dimensions to the single-cell size and increase the density to record neural activity with high spatial resolution across large areas to capture nonlinear neural dynamics. Here we developed transparent graphene microelectrodes with ultrasmall openings and a large, transparent recording area without any gold extensions in the field of view with high-density microelectrode arrays up to 256 channels. We used platinum nanoparticles to overcome the quantum capacitance limit of graphene and to scale down the microelectrode diameter to 20 µm. An interlayer-doped double-layer graphene was introduced to prevent open-circuit failures. We conducted multimodal experiments, combining the recordings of cortical potentials of microelectrode arrays with two-photon calcium imaging of the mouse visual cortex. Our results revealed that visually evoked responses are spatially localized for high-frequency bands, particularly for the multiunit activity band. The multiunit activity power was found to be correlated with cellular calcium activity. Leveraging this, we employed dimensionality reduction techniques and neural networks to demonstrate that single-cell and average calcium activities can be decoded from surface potentials recorded by high-density transparent graphene arrays.
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Affiliation(s)
- Mehrdad Ramezani
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Jeong-Hoon Kim
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Xin Liu
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Chi Ren
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Abdullah Alothman
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Chawina De-Eknamkul
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Madison N Wilson
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Ertugrul Cubukcu
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Vikash Gilja
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Takaki Komiyama
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Duygu Kuzum
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA.
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3
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Bisht RS, Park J, Yu H, Wu C, Tilak N, Rangan S, Park TJ, Yuan Y, Das S, Goteti U, Yi HT, Hijazi H, Al-Mahboob A, Sadowski JT, Zhou H, Oh S, Andrei EY, Allen MT, Kuzum D, Frano A, Dynes RC, Ramanathan S. Spatial Interactions in Hydrogenated Perovskite Nickelate Synaptic Networks. Nano Lett 2023; 23:7166-7173. [PMID: 37506183 DOI: 10.1021/acs.nanolett.3c02076] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
A key aspect of how the brain learns and enables decision-making processes is through synaptic interactions. Electrical transmission and communication in a network of synapses are modulated by extracellular fields generated by ionic chemical gradients. Emulating such spatial interactions in synthetic networks can be of potential use for neuromorphic learning and the hardware implementation of artificial intelligence. Here, we demonstrate that in a network of hydrogen-doped perovskite nickelate devices, electric bias across a single junction can tune the coupling strength between the neighboring cells. Electrical transport measurements and spatially resolved diffraction and nanoprobe X-ray and scanning microwave impedance spectroscopic studies suggest that graded proton distribution in the inhomogeneous medium of hydrogen-doped nickelate film enables this behavior. We further demonstrate signal integration through the coupling of various junctions.
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Affiliation(s)
- Ravindra Singh Bisht
- Department of Electrical and Computer Engineering, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Jaeseoung Park
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Haoming Yu
- School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Chen Wu
- Department of Physics, University of California, San Diego, La Jolla, California 92093, United States
| | - Nikhil Tilak
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Sylvie Rangan
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Tae J Park
- School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Yifan Yuan
- Department of Electrical and Computer Engineering, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Sarmistha Das
- Department of Physics, University of California, San Diego, La Jolla, California 92093, United States
| | - Uday Goteti
- Department of Physics, University of California, San Diego, La Jolla, California 92093, United States
| | - Hee Taek Yi
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Hussein Hijazi
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Abdullah Al-Mahboob
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Jerzy T Sadowski
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Hua Zhou
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Seongshik Oh
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Eva Y Andrei
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Monica T Allen
- Department of Physics, University of California, San Diego, La Jolla, California 92093, United States
| | - Duygu Kuzum
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Alex Frano
- Department of Physics, University of California, San Diego, La Jolla, California 92093, United States
| | - Robert C Dynes
- Department of Physics, University of California, San Diego, La Jolla, California 92093, United States
| | - Shriram Ramanathan
- Department of Electrical and Computer Engineering, Rutgers University, Piscataway, New Jersey 08854, United States
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4
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Wilson MN, Thunemann M, Liu X, Lu Y, Puppo F, Adams JW, Kim JH, Ramezani M, Pizzo DP, Djurovic S, Andreassen OA, Mansour AA, Gage FH, Muotri AR, Devor A, Kuzum D. Multimodal monitoring of human cortical organoids implanted in mice reveal functional connection with visual cortex. Nat Commun 2022; 13:7945. [PMID: 36572698 PMCID: PMC9792589 DOI: 10.1038/s41467-022-35536-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Accepted: 12/09/2022] [Indexed: 12/27/2022] Open
Abstract
Human cortical organoids, three-dimensional neuronal cultures, are emerging as powerful tools to study brain development and dysfunction. However, whether organoids can functionally connect to a sensory network in vivo has yet to be demonstrated. Here, we combine transparent microelectrode arrays and two-photon imaging for longitudinal, multimodal monitoring of human cortical organoids transplanted into the retrosplenial cortex of adult mice. Two-photon imaging shows vascularization of the transplanted organoid. Visual stimuli evoke electrophysiological responses in the organoid, matching the responses from the surrounding cortex. Increases in multi-unit activity (MUA) and gamma power and phase locking of stimulus-evoked MUA with slow oscillations indicate functional integration between the organoid and the host brain. Immunostaining confirms the presence of human-mouse synapses. Implantation of transparent microelectrodes with organoids serves as a versatile in vivo platform for comprehensive evaluation of the development, maturation, and functional integration of human neuronal networks within the mouse brain.
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Affiliation(s)
- Madison N Wilson
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Martin Thunemann
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Xin Liu
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Yichen Lu
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Francesca Puppo
- Department of Pediatrics, University of California San Diego, School of Medicine, La Jolla, CA, USA
| | - Jason W Adams
- Department of Pediatrics, University of California San Diego, School of Medicine, La Jolla, CA, USA
- Department of Cellular and Molecular Medicine, University of California San Diego, School of Medicine, La Jolla, CA, USA
| | - Jeong-Hoon Kim
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Mehrdad Ramezani
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Donald P Pizzo
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Srdjan Djurovic
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
- NORMENT Center, Oslo, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
- K. G. Jebsen Center for Neurodevelopmental Disorders, University of Oslo, Oslo, Norway
| | - Ole A Andreassen
- NORMENT Center, Oslo, Norway
- K. G. Jebsen Center for Neurodevelopmental Disorders, University of Oslo, Oslo, Norway
- Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Abed AlFatah Mansour
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA, USA
- Department of Medical Neurobiology, The Hebrew University of Jerusalem, Ein Kerem-Jerusalem, Israel
| | - Fred H Gage
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Alysson R Muotri
- Department of Pediatrics, University of California San Diego, School of Medicine, La Jolla, CA, USA
- Department of Cellular and Molecular Medicine, University of California San Diego, School of Medicine, La Jolla, CA, USA
- Center for Academic Research and Training in Anthropogeny, University of California San Diego, La Jolla, CA, USA
- Archealization Center, University of California San Diego, La Jolla, CA, USA
- Kavli Institute for Brain and Mind, University of California San Diego, La Jolla, CA, USA
| | - Anna Devor
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Charlestown, MA, USA.
| | - Duygu Kuzum
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA.
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5
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Liu X, Terada S, Ramezani M, Kim JH, Lu Y, Grosmark A, Losonczy A, Kuzum D. E-Cannula reveals anatomical diversity in sharp-wave ripples as a driver for the recruitment of distinct hippocampal assemblies. Cell Rep 2022; 41:111453. [PMID: 36198271 PMCID: PMC9640218 DOI: 10.1016/j.celrep.2022.111453] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 07/07/2022] [Accepted: 09/14/2022] [Indexed: 11/17/2022] Open
Abstract
The hippocampus plays a critical role in spatial navigation and episodic memory. However, research on in vivo hippocampal activity dynamics mostly relies on single modalities, such as electrical recordings or optical imaging, with respectively limited spatial and temporal resolution. Here, we develop the E-Cannula, integrating fully transparent graphene microelectrodes with imaging cannula, which enables simultaneous electrical recording and two-photon calcium imaging from the exact same neural populations across an anatomically extended region of the mouse hippocampal CA1 stably across several days. The large-scale multimodal recordings show that sharp wave ripples (SWRs) exhibit spatiotemporal wave patterns along multiple axes in two-dimensional (2D) space with different spatial extents and temporal propagation modes. Notably, distinct SWR wave patterns are associated with the selective recruitment of orthogonal CA1 cell assemblies. These results demonstrate the utility of the E-Cannula as a versatile neurotechnology with the potential for future integration with other optical components.
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Affiliation(s)
- Xin Liu
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, USA
| | - Satoshi Terada
- Department of Neuroscience, Columbia University, New York, NY, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Mehrdad Ramezani
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, USA
| | - Jeong-Hoon Kim
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, USA
| | - Yichen Lu
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, USA
| | - Andres Grosmark
- Department of Neuroscience, Columbia University, New York, NY, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA; The Kavli Institute for Brain Science, Columbia University, New York, NY, USA
| | - Attila Losonczy
- Department of Neuroscience, Columbia University, New York, NY, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA; The Kavli Institute for Brain Science, Columbia University, New York, NY, USA.
| | - Duygu Kuzum
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, USA; Halıcıoğlu Data Science Institute, University of California, San Diego, La Jolla, CA, USA.
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6
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Shi Y, Ananthakrishnan A, Oh S, Liu X, Hota G, Cauwenberghs G, Kuzum D. A Neuromorphic Brain Interface based on RRAM Crossbar Arrays for High Throughput Real-time Spike Sorting. IEEE Trans Electron Devices 2022; 69:2137-2144. [PMID: 37168652 PMCID: PMC10168101 DOI: 10.1109/ted.2021.3131116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Real-time spike sorting and processing are crucial for closed-loop brain-machine interfaces and neural prosthetics. Recent developments in high-density multi-electrode arrays with hundreds of electrodes have enabled simultaneous recordings of spikes from a large number of neurons. However, the high channel count imposes stringent demands on real-time spike sorting hardware regarding data transmission bandwidth and computation complexity. Thus, it is necessary to develop a specialized real-time hardware that can sort neural spikes on the fly with high throughputs while consuming minimal power. Here, we present a real-time, low latency spike sorting processor that utilizes high-density CuOx resistive crossbars to implement in-memory spike sorting in a massively parallel manner. We developed a fabrication process which is compatible with CMOS BEOL integration. We extensively characterized switching characteristics and statistical variations of the CuOx memory devices. In order to implement spike sorting with crossbar arrays, we developed a template matching-based spike sorting algorithm that can be directly mapped onto RRAM crossbars. By using synthetic and in vivo recordings of extracellular spikes, we experimentally demonstrated energy efficient spike sorting with high accuracy. Our neuromorphic interface offers substantial improvements in area (~1000× less area), power (~200× less power), and latency (4.8μs latency for sorting 100 channels) for real-time spike sorting compared to other hardware implementations based on FPGAs and microcontrollers.
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Affiliation(s)
- Yuhan Shi
- Electrical and Computer Engineering Department. G. Cauwenberghs is with Bioengineering Department, University of California at San Diego, San Diego, CA 92093, USA
| | - Akshay Ananthakrishnan
- Electrical and Computer Engineering Department. G. Cauwenberghs is with Bioengineering Department, University of California at San Diego, San Diego, CA 92093, USA
| | - Sangheon Oh
- Electrical and Computer Engineering Department. G. Cauwenberghs is with Bioengineering Department, University of California at San Diego, San Diego, CA 92093, USA
| | - Xin Liu
- Electrical and Computer Engineering Department. G. Cauwenberghs is with Bioengineering Department, University of California at San Diego, San Diego, CA 92093, USA
| | - Gopabandhu Hota
- Electrical and Computer Engineering Department. G. Cauwenberghs is with Bioengineering Department, University of California at San Diego, San Diego, CA 92093, USA
| | - Gert Cauwenberghs
- Electrical and Computer Engineering Department. G. Cauwenberghs is with Bioengineering Department, University of California at San Diego, San Diego, CA 92093, USA
| | - Duygu Kuzum
- Electrical and Computer Engineering Department. G. Cauwenberghs is with Bioengineering Department, University of California at San Diego, San Diego, CA 92093, USA
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7
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Liu X, Ren C, Huang Z, Wilson M, Kim JH, Lu Y, Ramezani M, Komiyama T, Kuzum D. Decoding of cortex-wide brain activity from local recordings of neural potentials. J Neural Eng 2021; 18. [PMID: 34706356 DOI: 10.1088/1741-2552/ac33e7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 10/27/2021] [Indexed: 11/11/2022]
Abstract
Objective. Electrical recordings of neural activity from brain surface have been widely employed in basic neuroscience research and clinical practice for investigations of neural circuit functions, brain-computer interfaces, and treatments for neurological disorders. Traditionally, these surface potentials have been believed to mainly reflect local neural activity. It is not known how informative the locally recorded surface potentials are for the neural activities across multiple cortical regions.Approach. To investigate that, we perform simultaneous local electrical recording and wide-field calcium imaging in awake head-fixed mice. Using a recurrent neural network model, we try to decode the calcium fluorescence activity of multiple cortical regions from local electrical recordings.Main results. The mean activity of different cortical regions could be decoded from locally recorded surface potentials. Also, each frequency band of surface potentials differentially encodes activities from multiple cortical regions so that including all the frequency bands in the decoding model gives the highest decoding performance. Despite the close spacing between recording channels, surface potentials from different channels provide complementary information about the large-scale cortical activity and the decoding performance continues to improve as more channels are included. Finally, we demonstrate the successful decoding of whole dorsal cortex activity at pixel-level using locally recorded surface potentials.Significance. These results show that the locally recorded surface potentials indeed contain rich information of the large-scale neural activities, which could be further demixed to recover the neural activity across individual cortical regions. In the future, our cross-modality inference approach could be adapted to virtually reconstruct cortex-wide brain activity, greatly expanding the spatial reach of surface electrical recordings without increasing invasiveness. Furthermore, it could be used to facilitate imaging neural activity across the whole cortex in freely moving animals, without requirement of head-fixed microscopy configurations.
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Affiliation(s)
- Xin Liu
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, United States of America
| | - Chi Ren
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America.,Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA, United States of America.,Department of Neurosciences, University of California San Diego, La Jolla, CA, United States of America
| | - Zhisheng Huang
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, United States of America
| | - Madison Wilson
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, United States of America
| | - Jeong-Hoon Kim
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, United States of America
| | - Yichen Lu
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, United States of America
| | - Mehrdad Ramezani
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, United States of America
| | - Takaki Komiyama
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America.,Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA, United States of America.,Department of Neurosciences, University of California San Diego, La Jolla, CA, United States of America.,Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla, CA, United States of America
| | - Duygu Kuzum
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, United States of America.,Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla, CA, United States of America
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8
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Liu X, Ren C, Lu Y, Liu Y, Kim JH, Leutgeb S, Komiyama T, Kuzum D. Multimodal neural recordings with Neuro-FITM uncover diverse patterns of cortical-hippocampal interactions. Nat Neurosci 2021; 24:886-896. [PMID: 33875893 PMCID: PMC8627685 DOI: 10.1038/s41593-021-00841-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 03/15/2021] [Indexed: 12/19/2022]
Abstract
Many cognitive processes require communication between the neocortex and the hippocampus. However, coordination between large-scale cortical dynamics and hippocampal activity is not well understood, partially due to the difficulty in simultaneously recording from those regions. In the present study, we developed a flexible, insertable and transparent microelectrode array (Neuro-FITM) that enables investigation of cortical-hippocampal coordinations during hippocampal sharp-wave ripples (SWRs). Flexibility and transparency of Neuro-FITM allow simultaneous recordings of local field potentials and neural spiking from the hippocampus during wide-field calcium imaging. These experiments revealed that diverse cortical activity patterns accompanied SWRs and, in most cases, cortical activation preceded hippocampal SWRs. We demonstrated that, during SWRs, different hippocampal neural population activity was associated with distinct cortical activity patterns. These results suggest that hippocampus and large-scale cortical activity interact in a selective and diverse manner during SWRs underlying various cognitive functions. Our technology can be broadly applied to comprehensive investigations of interactions between the cortex and other subcortical structures.
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Affiliation(s)
- Xin Liu
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Chi Ren
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
- Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA, USA
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Yichen Lu
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Yixiu Liu
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Jeong-Hoon Kim
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Stefan Leutgeb
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
- Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA, USA
- Kavli Institute for Brain and Mind, University of California San Diego, La Jolla, CA, USA
| | - Takaki Komiyama
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA.
- Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA, USA.
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA.
- Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla, CA, USA.
| | - Duygu Kuzum
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA.
- Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla, CA, USA.
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9
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Oh S, Shi Y, Del Valle J, Salev P, Lu Y, Huang Z, Kalcheim Y, Schuller IK, Kuzum D. Energy-efficient Mott activation neuron for full-hardware implementation of neural networks. Nat Nanotechnol 2021; 16:680-687. [PMID: 33737724 PMCID: PMC8627686 DOI: 10.1038/s41565-021-00874-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 02/02/2021] [Indexed: 05/09/2023]
Abstract
To circumvent the von Neumann bottleneck, substantial progress has been made towards in-memory computing with synaptic devices. However, compact nanodevices implementing non-linear activation functions are required for efficient full-hardware implementation of deep neural networks. Here, we present an energy-efficient and compact Mott activation neuron based on vanadium dioxide and its successful integration with a conductive bridge random access memory (CBRAM) crossbar array in hardware. The Mott activation neuron implements the rectified linear unit function in the analogue domain. The neuron devices consume substantially less energy and occupy two orders of magnitude smaller area than those of analogue complementary metal-oxide semiconductor implementations. The LeNet-5 network with Mott activation neurons achieves 98.38% accuracy on the MNIST dataset, close to the ideal software accuracy. We perform large-scale image edge detection using the Mott activation neurons integrated with a CBRAM crossbar array. Our findings provide a solution towards large-scale, highly parallel and energy-efficient in-memory computing systems for neural networks.
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Affiliation(s)
- Sangheon Oh
- Electrical and Computer Engineering Department, University of California San Diego, La Jolla, CA, USA
| | - Yuhan Shi
- Electrical and Computer Engineering Department, University of California San Diego, La Jolla, CA, USA
| | - Javier Del Valle
- Department of Physics, University of California San Diego, La Jolla, CA, USA
| | - Pavel Salev
- Department of Physics, University of California San Diego, La Jolla, CA, USA
| | - Yichen Lu
- Electrical and Computer Engineering Department, University of California San Diego, La Jolla, CA, USA
| | - Zhisheng Huang
- Electrical and Computer Engineering Department, University of California San Diego, La Jolla, CA, USA
| | - Yoav Kalcheim
- Department of Physics, University of California San Diego, La Jolla, CA, USA
| | - Ivan K Schuller
- Department of Physics, University of California San Diego, La Jolla, CA, USA
| | - Duygu Kuzum
- Electrical and Computer Engineering Department, University of California San Diego, La Jolla, CA, USA.
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10
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Ding D, Lu Y, Zhao R, Liu X, De-Eknamkul C, Ren C, Mehrsa A, Komiyama T, Kuzum D. Evaluation of Durability of Transparent Graphene Electrodes Fabricated on Different Flexible Substrates for Chronic In Vivo Experiments. IEEE Trans Biomed Eng 2020; 67:3203-3210. [PMID: 32191878 PMCID: PMC8560430 DOI: 10.1109/tbme.2020.2979475] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To investigate chronic durability of transparent graphene electrodes fabricated on polyethylene terephthalate (PET) and SU-8 substrates for chronic in vivo studies. METHODS We perform systematic accelerated aging tests to understand the chronic reliability and failure modes of transparent graphene microelectrode arrays built on PET and SU-8 substrates. We employ graphene microelectrodes fabricated on PET substrate in chronic in vivo experiments with transgenic mice. RESULTS Our results show that graphene microelectrodes fabricated on PET substrate work reliably after 30 days accelerated aging test performed at 87 °C, equivalent to 960 days in vivo lifetime. We demonstrate stable chronic recordings of cortical potentials in multimodal imaging/recording experiments using transparent graphene microelectrodes fabricated on PET substrate. On the other hand, graphene microelectrode arrays built on SU-8 substrate exhibit extensive crack formation across microelectrode sites and wires after one to two weeks, resulting in total failure of recording capability for chronic studies. CONCLUSION PET shows superior reliability as a substrate for graphene microelectrode arrays for chronic in vivo experiments. SIGNIFICANCE Graphene is a unique neural interface material enabling cross-talk free integration of electrical and optical recording and stimulation techniques in the same experiment. To date, graphene-based microelectrode arrays have been demonstrated in various multi-modal acute experiments involving electrophysiological sensing or stimulation, optical imaging and optogenetics stimulation. Understanding chronic reliability of graphene-based transparent interfaces is very important to expand the use of this technology for long-term behavioral studies with animal models.
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11
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Liu X, Kuzum D. Hippocampal-Cortical Memory Trace Transfer and Reactivation Through Cell-Specific Stimulus and Spontaneous Background Noise. Front Comput Neurosci 2019; 13:67. [PMID: 31680922 PMCID: PMC6798041 DOI: 10.3389/fncom.2019.00067] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [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: 04/29/2019] [Accepted: 09/10/2019] [Indexed: 01/07/2023] Open
Abstract
The hippocampus plays important roles in memory formation and retrieval through sharp-wave-ripples. Recent studies have shown that certain neuron populations in the prefrontal cortex (PFC) exhibit coordinated reactivations during awake ripple events. These experimental findings suggest that the awake ripple is an important biomarker, through which the hippocampus interacts with the neocortex to assist memory formation and retrieval. However, the computational mechanisms of this ripple based hippocampal-cortical coordination are still not clear due to the lack of unified models that include both the hippocampal and cortical networks. In this work, using a coupled biophysical model of both CA1 and PFC, we investigate possible mechanisms of hippocampal-cortical memory trace transfer and the conditions that assist reactivation of the transferred memory traces in the PFC. To validate our model, we first show that the local field potentials generated in the hippocampus and PFC exhibit ripple range activities that are consistent with the recent experimental studies. Then we demonstrate that during ripples, sequence replays can successfully transfer the information stored in the hippocampus to the PFC recurrent networks. We investigate possible mechanisms of memory retrieval in PFC networks. Our results suggest that the stored memory traces in the PFC network can be retrieved through two different mechanisms, namely the cell-specific input representing external stimuli and non-specific spontaneous background noise representing spontaneous memory recall events. Importantly, in both cases, the memory reactivation quality is robust to network connection loss. Finally, we find out that the quality of sequence reactivations is enhanced by both increased number of SWRs and an optimal background noise intensity, which tunes the excitability of neurons to a proper level. Our study presents a mechanistic explanation for the memory trace transfer from the hippocampus to neocortex through ripple coupling in awake states and reports two different mechanisms by which the stored memory traces can be successfully retrieved.
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Affiliation(s)
- Xin Liu
- Department of Electrical and Computer Engineering, University of California, San Diego, San Diego, CA, United States
| | - Duygu Kuzum
- Department of Electrical and Computer Engineering, University of California, San Diego, San Diego, CA, United States
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12
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Shi Y, Nguyen L, Oh S, Liu X, Kuzum D. A Soft-Pruning Method Applied During Training of Spiking Neural Networks for In-memory Computing Applications. Front Neurosci 2019; 13:405. [PMID: 31080402 PMCID: PMC6497807 DOI: 10.3389/fnins.2019.00405] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [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: 11/23/2018] [Accepted: 04/09/2019] [Indexed: 11/13/2022] Open
Abstract
Inspired from the computational efficiency of the biological brain, spiking neural networks (SNNs) emulate biological neural networks, neural codes, dynamics, and circuitry. SNNs show great potential for the implementation of unsupervised learning using in-memory computing. Here, we report an algorithmic optimization that improves energy efficiency of online learning with SNNs on emerging non-volatile memory (eNVM) devices. We develop a pruning method for SNNs by exploiting the output firing characteristics of neurons. Our pruning method can be applied during network training, which is different from previous approaches in the literature that employ pruning on already-trained networks. This approach prevents unnecessary updates of network parameters during training. This algorithmic optimization can complement the energy efficiency of eNVM technology, which offers a unique in-memory computing platform for the parallelization of neural network operations. Our SNN maintains ~90% classification accuracy on the MNIST dataset with up to ~75% pruning, significantly reducing the number of weight updates. The SNN and pruning scheme developed in this work can pave the way toward applications of eNVM based neuro-inspired systems for energy efficient online learning in low power applications.
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Affiliation(s)
- Yuhan Shi
- Electrical and Computer Engineering Department, University of California, San Diego, San Diego, CA, United States
| | - Leon Nguyen
- Electrical and Computer Engineering Department, University of California, San Diego, San Diego, CA, United States
| | - Sangheon Oh
- Electrical and Computer Engineering Department, University of California, San Diego, San Diego, CA, United States
| | - Xin Liu
- Electrical and Computer Engineering Department, University of California, San Diego, San Diego, CA, United States
| | - Duygu Kuzum
- Electrical and Computer Engineering Department, University of California, San Diego, San Diego, CA, United States
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13
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Liu X, Lu Y, Kuzum D. Investigation of Propagating Cortical Waves and Spirals Recorded by High Density Porous Graphene Arrays. Annu Int Conf IEEE Eng Med Biol Soc 2018; 2018:995-998. [PMID: 30440558 DOI: 10.1109/embc.2018.8512428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Propagating waves along the cortical surface have recently attracted significant attention by the neuroscience community. However, whether these propagating waves imply network connectivity changes for the neural circuits is not known. In this work, we employ a high density porous graphene microelectrode array and perform in vivo experiments with rodents to investigate network connectivity during cortical propagating waves. The spatial-temporal analysis of the cortical recordings reveals various types of propagating waves across the recording area. Network analysis results show that these propagating waves are consistent with the functional connectivity changes in the neural circuits, suggesting that the underlying network states are reflected by the cortical potential propagation patterns.
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14
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15
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Lu Y, Liu X, Hattori R, Ren C, Zhang X, Komiyama T, Kuzum D. Ultra-low Impedance Graphene Microelectrodes with High Optical Transparency for Simultaneous Deep 2-photon Imaging in Transgenic Mice. Adv Funct Mater 2018; 28:1800002. [PMID: 34084100 PMCID: PMC8172040 DOI: 10.1002/adfm.201800002] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Indexed: 05/27/2023]
Abstract
The last decades have witnessed substantial progress in optical technologies revolutionizing our ability to record and manipulate neural activity in genetically modified animal models. Meanwhile, human studies mostly rely on electrophysiological recordings of cortical potentials, which cannot be inferred from optical recordings, leading to a gap between our understanding of dynamics of microscale populations and brain-scale neural activity. By enabling concurrent integration of electrical and optical modalities, transparent graphene microelectrodes can close this gap. However, the high impedance of graphene constitutes a big challenge towards the widespread use of this technology. Here, we experimentally demonstrate that this high impedance of graphene microelectrodes is fundamentally limited by quantum capacitance. We overcome this quantum capacitance limit by creating a parallel conduction path using platinum nanoparticles. We achieve a 100 times reduction in graphene electrode impedance, while maintaining the high optical transparency crucial for deep 2-photon microscopy. Using a transgenic mouse model, we demonstrate simultaneous electrical recording of cortical activity with high fidelity while imaging calcium signals at various cortical depths right beneath the transparent microelectrodes. Multimodal analysis of Ca2+ spikes and cortical surface potentials offers unique opportunities to bridge our understanding of cellular dynamics and brain-scale neural activity.
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Affiliation(s)
- Yichen Lu
- 9500 Gilman Drive, Electrical and Computer Engineering Department, Jacobs School of Engineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Xin Liu
- 9500 Gilman Drive, Electrical and Computer Engineering Department, Jacobs School of Engineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Ryoma Hattori
- 9500 Gilman Drive, Neurobiology Section, Center for Neural Circuits and Behavior, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Chi Ren
- 9500 Gilman Drive, Neurobiology Section, Center for Neural Circuits and Behavior, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Xingwang Zhang
- 9500 Gilman Drive, Nanoengineering Department, Jacobs School of Engineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Takaki Komiyama
- 9500 Gilman Drive, Neurobiology Section, Center for Neural Circuits and Behavior, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Duygu Kuzum
- 9500 Gilman Drive, Electrical and Computer Engineering Department, Jacobs School of Engineering, University of California, San Diego, La Jolla, California 92093, USA
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16
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17
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Liu X, Lu Y, Iseri E, Shi Y, Kuzum D. A Compact Closed-Loop Optogenetics System Based on Artifact-Free Transparent Graphene Electrodes. Front Neurosci 2018; 12:132. [PMID: 29559885 PMCID: PMC5845553 DOI: 10.3389/fnins.2018.00132] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [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: 10/27/2017] [Accepted: 02/19/2018] [Indexed: 11/13/2022] Open
Abstract
Electrophysiology is a decades-old technique widely used for monitoring activity of individual neurons and local field potentials. Optogenetics has revolutionized neuroscience studies by offering selective and fast control of targeted neurons and neuron populations. The combination of these two techniques is crucial for causal investigation of neural circuits and understanding their functional connectivity. However, electrical artifacts generated by light stimulation interfere with neural recordings and hinder the development of compact closed-loop systems for precise control of neural activity. Here, we demonstrate that transparent graphene micro-electrodes fabricated on a clear polyethylene terephthalate film eliminate the light-induced artifact problem and allow development of a compact battery-powered closed-loop optogenetics system. We extensively investigate light-induced artifacts for graphene electrodes in comparison to metal control electrodes. We then design optical stimulation module using micro-LED chips coupled to optical fibers to deliver light to intended depth for optogenetic stimulation. For artifact-free integration of graphene micro-electrode recordings with optogenetic stimulation, we design and develop a compact closed-loop system and validate it for different frequencies of interest for neural recordings. This compact closed-loop optogenetics system can be used for various applications involving optogenetic stimulation and electrophysiological recordings.
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Affiliation(s)
- Xin Liu
- Neuroelectronics Group, Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, United States
| | - Yichen Lu
- Neuroelectronics Group, Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, United States
| | - Ege Iseri
- Neuroelectronics Group, Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, United States
| | - Yuhan Shi
- Neuroelectronics Group, Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, United States
| | - Duygu Kuzum
- Neuroelectronics Group, Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, United States
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18
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Bink H, Sedigh-Sarvestani M, Fernandez-Lamo I, Kini L, Ung H, Kuzum D, Vitale F, Litt B, Contreras D. Spatiotemporal evolution of focal epileptiform activity from surface and laminar field recordings in cat neocortex. J Neurophysiol 2018; 119:2068-2081. [PMID: 29488838 DOI: 10.1152/jn.00764.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
New devices that use targeted electrical stimulation to treat refractory localization-related epilepsy have shown great promise, although it is not well known which targets most effectively prevent the initiation and spread of seizures. To better understand how the brain transitions from healthy to seizing on a local scale, we induced focal epileptiform activity in the visual cortex of five anesthetized cats with local application of the GABAA blocker picrotoxin while simultaneously recording local field potentials on a high-resolution electrocorticography array and laminar depth probes. Epileptiform activity appeared in the form of isolated events, revealing a consistent temporal pattern of ictogenesis across animals with interictal events consistently preceding the appearance of seizures. Based on the number of spikes per event, there was a natural separation between seizures and shorter interictal events. Two distinct spatial regions were seen: an epileptic focus that grew in size as activity progressed, and an inhibitory surround that exhibited a distinct relationship with the focus both on the surface and in the depth of the cortex. Epileptiform activity in the cortical laminae was seen concomitant with activity on the surface. Focus spikes appeared earlier on electrodes deeper in the cortex, suggesting that deep cortical layers may be integral to recruiting healthy tissue into the epileptic network and could be a promising target for interventional devices. Our study may inform more effective therapies to prevent seizure generation and spread in localization-related epilepsies. NEW & NOTEWORTHY We induced local epileptiform activity and recorded continuous, high-resolution local field potentials from the surface and depth of the visual cortex in anesthetized cats. Our results reveal a consistent pattern of ictogenesis, characterize the spatial spread of the epileptic focus and its relationship with the inhibitory surround, and show that focus activity within events appears earliest in deeper cortical layers. These findings have potential implications for the monitoring and treatment of refractory epilepsy.
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Affiliation(s)
- Hank Bink
- Department of Bioengineering, University of Pennsylvania , Philadelphia, Pennsylvania.,Center for Neuroengineering and Therapeutics, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Madineh Sedigh-Sarvestani
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Ivan Fernandez-Lamo
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Lohith Kini
- Department of Bioengineering, University of Pennsylvania , Philadelphia, Pennsylvania.,Center for Neuroengineering and Therapeutics, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Hoameng Ung
- Department of Bioengineering, University of Pennsylvania , Philadelphia, Pennsylvania.,Center for Neuroengineering and Therapeutics, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Duygu Kuzum
- Department of Electrical and Computer Engineering, University of California San Diego , La Jolla, California
| | - Flavia Vitale
- Center for Neuroengineering and Therapeutics, University of Pennsylvania , Philadelphia, Pennsylvania.,Department of Neurology, Hospital of the University of Pennsylvania , Philadelphia, Pennsylvania.,Department of Physical Medicine and Rehabilitation, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Brian Litt
- Department of Bioengineering, University of Pennsylvania , Philadelphia, Pennsylvania.,Center for Neuroengineering and Therapeutics, University of Pennsylvania , Philadelphia, Pennsylvania.,Department of Neurology, Hospital of the University of Pennsylvania , Philadelphia, Pennsylvania
| | - Diego Contreras
- Center for Neuroengineering and Therapeutics, University of Pennsylvania , Philadelphia, Pennsylvania.,Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
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19
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Canakci S, Toy MF, Inci AF, Liu X, Kuzum D. Computational analysis of network activity and spatial reach of sharp wave-ripples. PLoS One 2017; 12:e0184542. [PMID: 28915251 PMCID: PMC5600383 DOI: 10.1371/journal.pone.0184542] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 08/25/2017] [Indexed: 11/19/2022] Open
Abstract
Network oscillations of different frequencies, durations and amplitudes are hypothesized to coordinate information processing and transfer across brain areas. Among these oscillations, hippocampal sharp wave-ripple complexes (SPW-Rs) are one of the most prominent. SPW-Rs occurring in the hippocampus are suggested to play essential roles in memory consolidation as well as information transfer to the neocortex. To-date, most of the knowledge about SPW-Rs comes from experimental studies averaging responses from neuronal populations monitored by conventional microelectrodes. In this work, we investigate spatiotemporal characteristics of SPW-Rs and how microelectrode size and distance influence SPW-R recordings using a biophysical model of hippocampus. We also explore contributions from neuronal spikes and synaptic potentials to SPW-Rs based on two different types of network activity. Our study suggests that neuronal spikes from pyramidal cells contribute significantly to ripples while high amplitude sharp waves mainly arise from synaptic activity. Our simulations on spatial reach of SPW-Rs show that the amplitudes of sharp waves and ripples exhibit a steep decrease with distance from the network and this effect is more prominent for smaller area electrodes. Furthermore, the amplitude of the signal decreases strongly with increasing electrode surface area as a result of averaging. The relative decrease is more pronounced when the recording electrode is closer to the source of the activity. Through simulations of field potentials across a high-density microelectrode array, we demonstrate the importance of finding the ideal spatial resolution for capturing SPW-Rs with great sensitivity. Our work provides insights on contributions from spikes and synaptic potentials to SPW-Rs and describes the effect of measurement configuration on LFPs to guide experimental studies towards improved SPW-R recordings.
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Affiliation(s)
- Sadullah Canakci
- Electrical and Computer Engineering Department, Boston University, Boston, Massachusetts, United States of America
| | - Muhammed Faruk Toy
- Electrical and Computer Engineering Department, University of California San Diego, La Jolla, California, United States of America
- Electrical and Electronics Engineering, Middle East Technical University, Ankara, Turkey
| | - Ahmet Fatih Inci
- Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul, Turkey
| | - Xin Liu
- Electrical and Computer Engineering Department, University of California San Diego, La Jolla, California, United States of America
| | - Duygu Kuzum
- Electrical and Computer Engineering Department, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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20
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Makino H, Ren C, Liu H, Kim AN, Kondapaneni N, Liu X, Kuzum D, Komiyama T. Transformation of Cortex-wide Emergent Properties during Motor Learning. Neuron 2017; 94:880-890.e8. [PMID: 28521138 DOI: 10.1016/j.neuron.2017.04.015] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 02/14/2017] [Accepted: 04/11/2017] [Indexed: 12/25/2022]
Abstract
Learning involves a transformation of brain-wide operation dynamics. However, our understanding of learning-related changes in macroscopic dynamics is limited. Here, we monitored cortex-wide activity of the mouse brain using wide-field calcium imaging while the mouse learned a motor task over weeks. Over learning, the sequential activity across cortical modules became temporally more compressed, and its trial-by-trial variability decreased. Moreover, a new flow of activity emerged during learning, originating from premotor cortex (M2), and M2 became predictive of the activity of many other modules. Inactivation experiments showed that M2 is critical for the post-learning dynamics in the cortex-wide activity. Furthermore, two-photon calcium imaging revealed that M2 ensemble activity also showed earlier activity onset and reduced variability with learning, which was accompanied by changes in the activity-movement relationship. These results reveal newly emergent properties of macroscopic cortical dynamics during motor learning and highlight the importance of M2 in controlling learned movements.
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Affiliation(s)
- Hiroshi Makino
- Neurobiology Section, Center for Neural Circuits and Behavior, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore.
| | - Chi Ren
- Neurobiology Section, Center for Neural Circuits and Behavior, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Haixin Liu
- Neurobiology Section, Center for Neural Circuits and Behavior, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - An Na Kim
- Neurobiology Section, Center for Neural Circuits and Behavior, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Neehar Kondapaneni
- Neurobiology Section, Center for Neural Circuits and Behavior, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Xin Liu
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Duygu Kuzum
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Takaki Komiyama
- Neurobiology Section, Center for Neural Circuits and Behavior, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA; JST, PRESTO, University of California, San Diego, La Jolla, CA 92093, USA.
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Abstract
More than a decade has passed since optics and genetics came together and lead to the emerging technologies of optogenetics. The advent of light-sensitive opsins made it possible to optically trigger the neurons into activation or inhibition by using visible light. The importance of spatiotemporally isolating a segment of a neural network and controlling nervous signaling in a precise manner has driven neuroscience researchers and engineers to invest great efforts in designing high precision in vivo implantable devices. These efforts have focused on delivery of sufficient power to deep brain regions, while monitoring neural activity with high resolution and fidelity. In this review, we report the progress made in the field of hybrid optoelectronic neural interfaces that combine optical stimulation with electrophysiological recordings. Different approaches that incorporate optical or electrical components on implantable devices are discussed in detail. Advantages of various different designs as well as practical and fundamental limitations are summarized to illuminate the future of neurotechnology development.
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Affiliation(s)
- Ege Iseri
- Department of Electrical and Computer Engineering, University of California, San Diego, CA, United States of America
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22
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Rogers N, Gilja V, Kuzum D. Graphene neural interfaces for artifact free optogenetics. Annu Int Conf IEEE Eng Med Biol Soc 2016; 2016:4204-4207. [PMID: 28269210 DOI: 10.1109/embc.2016.7591654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Light-induced artifacts in metal-based microelectrodes significantly limit simultaneous use of electrophysiology with optogenetics or optical imaging. In this work, we systematically investigate light-induced artifacts in Au and transparent graphene electrodes fabricated in the same batch. We demonstrate that the Au electrodes show light artifacts resembling genuine local field potentials, while graphene electrodes are free of light-induced artifacts. With its other desirable properties including high mechanical strength, good conductivity, transparency, and biocompatibility, graphene electrodes show great promise for combining electrical and optical modalities in the same experiment.
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23
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Yu KJ, Kuzum D, Hwang SW, Kim BH, Juul H, Kim NH, Won SM, Chiang K, Trumpis M, Richardson AG, Cheng H, Fang H, Thomson M, Bink H, Talos D, Seo KJ, Lee HN, Kang SK, Kim JH, Lee JY, Huang Y, Jensen FE, Dichter MA, Lucas TH, Viventi J, Litt B, Rogers JA. Bioresorbable silicon electronics for transient spatiotemporal mapping of electrical activity from the cerebral cortex. Nat Mater 2016; 15:782-791. [PMID: 27088236 PMCID: PMC4919903 DOI: 10.1038/nmat4624] [Citation(s) in RCA: 214] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 03/14/2016] [Indexed: 05/18/2023]
Abstract
Bioresorbable silicon electronics technology offers unprecedented opportunities to deploy advanced implantable monitoring systems that eliminate risks, cost and discomfort associated with surgical extraction. Applications include postoperative monitoring and transient physiologic recording after percutaneous or minimally invasive placement of vascular, cardiac, orthopaedic, neural or other devices. We present an embodiment of these materials in both passive and actively addressed arrays of bioresorbable silicon electrodes with multiplexing capabilities, which record in vivo electrophysiological signals from the cortical surface and the subgaleal space. The devices detect normal physiologic and epileptiform activity, both in acute and chronic recordings. Comparative studies show sensor performance comparable to standard clinical systems and reduced tissue reactivity relative to conventional clinical electrocorticography (ECoG) electrodes. This technology offers general applicability in neural interfaces, with additional potential utility in treatment of disorders where transient monitoring and modulation of physiologic function, implant integrity and tissue recovery or regeneration are required.
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Affiliation(s)
- Ki Jun Yu
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Duygu Kuzum
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Electrical and Computer Engineering, University of California, San Diego, San Diego, CA 92093
| | - Suk-Won Hwang
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-701, Republic of Korea
| | - Bong Hoon Kim
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Halvor Juul
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nam Heon Kim
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Sang Min Won
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Ken Chiang
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Michael Trumpis
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Andrew G. Richardson
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Huanyu Cheng
- Department of Engineering Science and Mechanics, Penn State University, University Park, PA 16802, USA
| | - Hui Fang
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Marissa Thomson
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Chemical and Biomolecular Engineering University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Hank Bink
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Delia Talos
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kyung Jin Seo
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Hee Nam Lee
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana- Champaign, Urbana, IL 61801, USA
| | - Seung-Kyun Kang
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jae-Hwan Kim
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jung Yup Lee
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana- Champaign, Urbana, IL 61801, USA
| | - Younggang Huang
- Department of Mechanical Engineering and Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Frances E. Jensen
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Marc A. Dichter
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Timothy H. Lucas
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jonathan Viventi
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Brian Litt
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- To whom correspondence should be addressed. or
| | - John A. Rogers
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- To whom correspondence should be addressed. or
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Akinwande D, Tao L, Yu Q, Lou X, Peng P, Kuzum D. Large-Area Graphene Electrodes: Using CVD to facilitate applications in commercial touchscreens, flexible nanoelectronics, and neural interfaces. IEEE Nanotechnology Mag 2015. [DOI: 10.1109/mnano.2015.2441105] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Kuzum D, Takano H, Shim E, Reed JC, Juul H, Richardson AG, de Vries J, Bink H, Dichter MA, Lucas TH, Coulter DA, Cubukcu E, Litt B. Transparent and flexible low noise graphene electrodes for simultaneous electrophysiology and neuroimaging. Nat Commun 2014; 5:5259. [PMID: 25327632 DOI: 10.1038/ncomms6259] [Citation(s) in RCA: 259] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 09/12/2014] [Indexed: 12/24/2022] Open
Abstract
Calcium imaging is a versatile experimental approach capable of resolving single neurons with single-cell spatial resolution in the brain. Electrophysiological recordings provide high temporal, but limited spatial resolution, because of the geometrical inaccessibility of the brain. An approach that integrates the advantages of both techniques could provide new insights into functions of neural circuits. Here, we report a transparent, flexible neural electrode technology based on graphene, which enables simultaneous optical imaging and electrophysiological recording. We demonstrate that hippocampal slices can be imaged through transparent graphene electrodes by both confocal and two-photon microscopy without causing any light-induced artefacts in the electrical recordings. Graphene electrodes record high-frequency bursting activity and slow synaptic potentials that are hard to resolve by multicellular calcium imaging. This transparent electrode technology may pave the way for high spatio-temporal resolution electro-optic mapping of the dynamic neuronal activity.
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Affiliation(s)
- Duygu Kuzum
- 1] Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [2] Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Hajime Takano
- 1] Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [2] Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA [3] Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [4] Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Euijae Shim
- 1] Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [2] Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Jason C Reed
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Halvor Juul
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Andrew G Richardson
- 1] Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [2] Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Julius de Vries
- 1] Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [2] Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Hank Bink
- 1] Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [2] Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Marc A Dichter
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Timothy H Lucas
- 1] Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [2] Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Douglas A Coulter
- 1] Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [2] Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA [3] Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [4] Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Ertugrul Cubukcu
- 1] Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [2] Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [3] Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Brian Litt
- 1] Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [2] Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [3] Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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26
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Eryilmaz SB, Kuzum D, Jeyasingh R, Kim S, BrightSky M, Lam C, Wong HSP. Brain-like associative learning using a nanoscale non-volatile phase change synaptic device array. Front Neurosci 2014; 8:205. [PMID: 25100936 PMCID: PMC4106403 DOI: 10.3389/fnins.2014.00205] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [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: 05/01/2014] [Accepted: 06/30/2014] [Indexed: 11/13/2022] Open
Abstract
Recent advances in neuroscience together with nanoscale electronic device technology have resulted in huge interests in realizing brain-like computing hardwares using emerging nanoscale memory devices as synaptic elements. Although there has been experimental work that demonstrated the operation of nanoscale synaptic element at the single device level, network level studies have been limited to simulations. In this work, we demonstrate, using experiments, array level associative learning using phase change synaptic devices connected in a grid like configuration similar to the organization of the biological brain. Implementing Hebbian learning with phase change memory cells, the synaptic grid was able to store presented patterns and recall missing patterns in an associative brain-like fashion. We found that the system is robust to device variations, and large variations in cell resistance states can be accommodated by increasing the number of training epochs. We illustrated the tradeoff between variation tolerance of the network and the overall energy consumption, and found that energy consumption is decreased significantly for lower variation tolerance.
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Affiliation(s)
- Sukru B Eryilmaz
- Department of Electrical Engineering, Stanford University Stanford, CA, USA
| | - Duygu Kuzum
- Department of Bioengineering, University of Pennsylvania Philadelphia, PA, USA
| | - Rakesh Jeyasingh
- Department of Electrical Engineering, Stanford University Stanford, CA, USA
| | - SangBum Kim
- IBM Research, T. J. Watson Research Center Yorktown Heights, NY, USA
| | - Matthew BrightSky
- IBM Research, T. J. Watson Research Center Yorktown Heights, NY, USA
| | - Chung Lam
- IBM Research, T. J. Watson Research Center Yorktown Heights, NY, USA
| | - H-S Philip Wong
- Department of Electrical Engineering, Stanford University Stanford, CA, USA
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Abstract
In this paper, the recent progress of synaptic electronics is reviewed. The basics of biological synaptic plasticity and learning are described. The material properties and electrical switching characteristics of a variety of synaptic devices are discussed, with a focus on the use of synaptic devices for neuromorphic or brain-inspired computing. Performance metrics desirable for large-scale implementations of synaptic devices are illustrated. A review of recent work on targeted computing applications with synaptic devices is presented.
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Affiliation(s)
- Duygu Kuzum
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA.
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Kuzum D, Jeyasingh RGD, Lee B, Wong HSP. Nanoelectronic programmable synapses based on phase change materials for brain-inspired computing. Nano Lett 2012; 12:2179-86. [PMID: 21668029 DOI: 10.1021/nl201040y] [Citation(s) in RCA: 354] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Brain-inspired computing is an emerging field, which aims to extend the capabilities of information technology beyond digital logic. A compact nanoscale device, emulating biological synapses, is needed as the building block for brain-like computational systems. Here, we report a new nanoscale electronic synapse based on technologically mature phase change materials employed in optical data storage and nonvolatile memory applications. We utilize continuous resistance transitions in phase change materials to mimic the analog nature of biological synapses, enabling the implementation of a synaptic learning rule. We demonstrate different forms of spike-timing-dependent plasticity using the same nanoscale synapse with picojoule level energy consumption.
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Affiliation(s)
- Duygu Kuzum
- Center for Integrated Systems, Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA.
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Okyay AK, Pethe AJ, Kuzum D, Latif S, Miller DA, Saraswat KC. SiGe optoelectronic metal-oxide semiconductor field-effect transistor. Opt Lett 2007; 32:2022-4. [PMID: 17632630 DOI: 10.1364/ol.32.002022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We propose a novel semiconductor optoelectronic switch that is a fusion of a Ge optical detector and a Si metal-oxide semiconductor field-effect transistor (MOSFET). The device operation is investigated with simulations and experiments. The switch can be fabricated at the nanoscale with extremely low capacitance. This device operates in telecommunication standard wavelengths, hence providing the surrounding Si circuitry with noise immunity from signaling. The Ge gate absorbs light, and the gate photocurrent is amplified at the drain terminal. Experimental current gain of up to 1000x is demonstrated. The device exhibits increased responsivity (approximately 3.5x) and lower off-state current (approximately 4x) compared with traditional detector schemes.
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Affiliation(s)
- Ali K Okyay
- Center for Integrated Systems, Stanford University, Stanford, California 94305, USA.
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