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Suematsu N, Vazquez AL, Kozai TDY. Activation and depression of neural and hemodynamic responses induced by the intracortical microstimulation and visual stimulation in the mouse visual cortex. J Neural Eng 2024; 21:026033. [PMID: 38537268 PMCID: PMC11002944 DOI: 10.1088/1741-2552/ad3853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/28/2024] [Accepted: 03/27/2024] [Indexed: 04/09/2024]
Abstract
Objective. Intracortical microstimulation (ICMS) can be an effective method for restoring sensory perception in contemporary brain-machine interfaces. However, the mechanisms underlying better control of neuronal responses remain poorly understood, as well as the relationship between neuronal activity and other concomitant phenomena occurring around the stimulation site.Approach. Different microstimulation frequencies were investigatedin vivoon Thy1-GCaMP6s mice using widefield and two-photon imaging to evaluate the evoked excitatory neural responses across multiple spatial scales as well as the induced hemodynamic responses. Specifically, we quantified stimulation-induced neuronal activation and depression in the mouse visual cortex and measured hemodynamic oxyhemoglobin and deoxyhemoglobin signals using mesoscopic-scale widefield imaging.Main results. Our calcium imaging findings revealed a preference for lower-frequency stimulation in driving stronger neuronal activation. A depressive response following the neural activation preferred a slightly higher frequency stimulation compared to the activation. Hemodynamic signals exhibited a comparable spatial spread to neural calcium signals. Oxyhemoglobin concentration around the stimulation site remained elevated during the post-activation (depression) period. Somatic and neuropil calcium responses measured by two-photon microscopy showed similar dependence on stimulation parameters, although the magnitudes measured in soma was greater than in neuropil. Furthermore, higher-frequency stimulation induced a more pronounced activation in soma compared to neuropil, while depression was predominantly induced in soma irrespective of stimulation frequencies.Significance. These results suggest that the mechanism underlying depression differs from activation, requiring ample oxygen supply, and affecting neurons. Our findings provide a novel understanding of evoked excitatory neuronal activity induced by ICMS and offer insights into neuro-devices that utilize both activation and depression phenomena to achieve desired neural responses.
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Affiliation(s)
- Naofumi Suematsu
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Alberto L Vazquez
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, United States of America
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, United States of America
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States of America
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
- NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, United States of America
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2
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Cunha AB, Schuelke C, Mesri A, Ruud SK, Aizenshtadt A, Ferrari G, Heiskanen A, Asif A, Keller SS, Ramos-Moreno T, Kalvøy H, Martínez-Serrano A, Krauss S, Emnéus J, Sampietro M, Martinsen ØG. Development of a Smart Wireless Multisensor Platform for an Optogenetic Brain Implant. SENSORS (BASEL, SWITZERLAND) 2024; 24:575. [PMID: 38257668 PMCID: PMC11154348 DOI: 10.3390/s24020575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/09/2024] [Accepted: 01/12/2024] [Indexed: 01/24/2024]
Abstract
Implantable cell replacement therapies promise to completely restore the function of neural structures, possibly changing how we currently perceive the onset of neurodegenerative diseases. One of the major clinical hurdles for the routine implementation of stem cell therapies is poor cell retention and survival, demanding the need to better understand these mechanisms while providing precise and scalable approaches to monitor these cell-based therapies in both pre-clinical and clinical scenarios. This poses significant multidisciplinary challenges regarding planning, defining the methodology and requirements, prototyping and different stages of testing. Aiming toward an optogenetic neural stem cell implant controlled by a smart wireless electronic frontend, we show how an iterative development methodology coupled with a modular design philosophy can mitigate some of these challenges. In this study, we present a miniaturized, wireless-controlled, modular multisensor platform with fully interfaced electronics featuring three different modules: an impedance analyzer, a potentiostat and an optical stimulator. We show the application of the platform for electrical impedance spectroscopy-based cell monitoring, optical stimulation to induce dopamine release from optogenetically modified neurons and a potentiostat for cyclic voltammetry and amperometric detection of dopamine release. The multisensor platform is designed to be used as an opto-electric headstage for future in vivo animal experiments.
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Affiliation(s)
- André B. Cunha
- Department of Physics, University of Oslo, Sem Sælands vei 24, 0371 Oslo, Norway; (A.B.C.); (C.S.); (S.K.R.)
| | - Christin Schuelke
- Department of Physics, University of Oslo, Sem Sælands vei 24, 0371 Oslo, Norway; (A.B.C.); (C.S.); (S.K.R.)
- Hybrid Technology Hub—Centre of Excellence, Institute of Basic Medical Sciences, P.O. Box 1110 Blindern, 0317 Oslo, Norway; (A.A.); (S.K.)
| | - Alireza Mesri
- Department of Electronics Information and Bioengineering, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy; (A.M.); (G.F.); (M.S.)
| | - Simen K. Ruud
- Department of Physics, University of Oslo, Sem Sælands vei 24, 0371 Oslo, Norway; (A.B.C.); (C.S.); (S.K.R.)
| | - Aleksandra Aizenshtadt
- Hybrid Technology Hub—Centre of Excellence, Institute of Basic Medical Sciences, P.O. Box 1110 Blindern, 0317 Oslo, Norway; (A.A.); (S.K.)
| | - Giorgio Ferrari
- Department of Electronics Information and Bioengineering, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy; (A.M.); (G.F.); (M.S.)
| | - Arto Heiskanen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (A.H.); (A.A.); (J.E.)
| | - Afia Asif
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (A.H.); (A.A.); (J.E.)
| | - Stephan S. Keller
- National Centre for Nano Fabrication and Characterization, Technical University of Denmark, 2800 Kongens Lyngby, Denmark;
| | - Tania Ramos-Moreno
- Lund Stem Cell Center, Division of Neurosurgery, Department of Clinical Sciences, Faculty of Medicine, Lund University, 22184 Lund, Sweden;
| | - Håvard Kalvøy
- Department of Clinical and Biomedical Engineering, Oslo University Hospital, Sognsvannsveien 20, 0372 Oslo, Norway;
| | - Alberto Martínez-Serrano
- Department of Molecular Neurobiology, Center of Molecular Biology ‘Severo Ochoa’, Universidad Autónoma de Madrid, Calle Nicolás Cabrera 1, 28049 Madrid, Spain;
| | - Stefan Krauss
- Hybrid Technology Hub—Centre of Excellence, Institute of Basic Medical Sciences, P.O. Box 1110 Blindern, 0317 Oslo, Norway; (A.A.); (S.K.)
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, P.O. Box 4950, 0424 Oslo, Norway
| | - Jenny Emnéus
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (A.H.); (A.A.); (J.E.)
| | - Marco Sampietro
- Department of Electronics Information and Bioengineering, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy; (A.M.); (G.F.); (M.S.)
| | - Ørjan G. Martinsen
- Department of Physics, University of Oslo, Sem Sælands vei 24, 0371 Oslo, Norway; (A.B.C.); (C.S.); (S.K.R.)
- Department of Clinical and Biomedical Engineering, Oslo University Hospital, Sognsvannsveien 20, 0372 Oslo, Norway;
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3
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Suematsu N, Vazquez AL, Kozai TD. Activation and depression of neural and hemodynamic responses induced by the intracortical microstimulation and visual stimulation in the mouse visual cortex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.01.573814. [PMID: 38260671 PMCID: PMC10802282 DOI: 10.1101/2024.01.01.573814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Objective . Intracortical microstimulation can be an effective method for restoring sensory perception in contemporary brain-machine interfaces. However, the mechanisms underlying better control of neuronal responses remain poorly understood, as well as the relationship between neuronal activity and other concomitant phenomena occurring around the stimulation site. Approach . Different microstimulation frequencies were investigated in vivo on Thy1-GCaMP6s mice using widefield and two-photon imaging to evaluate the evoked excitatory neural responses across multiple spatial scales as well as the induced hemodynamic responses. Specifically, we quantified stimulation-induced neuronal activation and depression in the mouse visual cortex and measured hemodynamic oxyhemoglobin and deoxyhemoglobin signals using mesoscopic-scale widefield imaging. Main results . Our calcium imaging findings revealed a preference for lower-frequency stimulation in driving stronger neuronal activation. A depressive response following the neural activation preferred a slightly higher frequency stimulation compared to the activation. Hemodynamic signals exhibited a comparable spatial spread to neural calcium signals. Oxyhemoglobin concentration around the stimulation site remained elevated during the post-activation (depression) period. Somatic and neuropil calcium responses measured by two-photon microscopy showed similar dependence on stimulation parameters, although the magnitudes measured in soma was greater than in neuropil. Furthermore, higher-frequency stimulation induced a more pronounced activation in soma compared to neuropil, while depression was predominantly induced in soma irrespective of stimulation frequencies. Significance . These results suggest that the mechanism underlying depression differs from activation, requiring ample oxygen supply, and affecting neurons. Our findings provide a novel understanding of evoked excitatory neuronal activity induced by intracortical microstimulation and offer insights into neuro-devices that utilize both activation and depression phenomena to achieve desired neural responses.
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4
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In vivo neurovascular response to focused photoactivation of Channelrhodopsin-2. Neuroimage 2019; 192:135-144. [DOI: 10.1016/j.neuroimage.2019.01.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 12/31/2018] [Accepted: 01/14/2019] [Indexed: 01/03/2023] Open
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5
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In vivo imaging for neurovascular disease research. Arch Pharm Res 2019; 42:263-273. [PMID: 30756309 DOI: 10.1007/s12272-019-01128-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 01/29/2019] [Indexed: 01/10/2023]
Abstract
Connections between various cell types in the brain enable cognitive function. The neurovascular unit is a structure composed of different cell types that regulate neurovascular coupling, blood-brain barrier permeability, and other interactions with peripheral systems. The relationship among the components of the neurovascular unit is complex and difficult to study without the use of in vivo neurovascular disease imaging. In this review, we introduce principles and examples of various in vivo optical imaging techniques including laser Doppler flowmetry, laser speckle contrast imaging, intrinsic optical signal imaging, optical coherence tomography, and two-photon microscopy. Furthermore, we introduce recent advances of in vivo imaging and future directions for promoting neurovascular disease research.
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Masamoto K, Vazquez A. Optical imaging and modulation of neurovascular responses. J Cereb Blood Flow Metab 2018; 38:2057-2072. [PMID: 30334644 PMCID: PMC6282226 DOI: 10.1177/0271678x18803372] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 09/02/2018] [Indexed: 12/17/2022]
Abstract
The cerebral microvasculature consists of pial vascular networks, parenchymal descending arterioles, ascending venules and parenchymal capillaries. This vascular compartmentalization is vital to precisely deliver blood to balance continuously varying neural demands in multiple brain regions. Optical imaging techniques have facilitated the investigation of dynamic spatial and temporal properties of microvascular functions in real time. Their combination with transgenic animal models encoding specific genetic targets have further strengthened the importance of optical methods for neurovascular research by allowing for the modulation and monitoring of neuro vascular function. Image analysis methods with three-dimensional reconstruction are also helping to understand the complexity of microscopic observations. Here, we review the compartmentalized cerebral microvascular responses to global perturbations as well as regional changes in response to neural activity to highlight the differences in vascular action sites. In addition, microvascular responses elicited by optical modulation of different cell-type targets are summarized with emphasis on variable spatiotemporal dynamics of microvascular responses. Finally, long-term changes in microvascular compartmentalization are discussed to help understand potential relationships between CBF disturbances and the development of neurodegenerative diseases and cognitive decline.
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Affiliation(s)
- Kazuto Masamoto
- Faculty of Informatics and Engineering, University of Electro-Communications, Tokyo, Japan
- Brain Science Inspired Life Support Research Center, University of Electro-Communications, Tokyo, Japan
| | - Alberto Vazquez
- Departments of Radiology and Bioengineering, University of Pittsburgh, PA, USA
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7
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Atry F, Chen RCH, Pisaniello J, Brodnick S, Suminski AJ, Novello J, Ness J, Williams JC, Pashaie R. Optogenetic interrogation of neurovascular coupling in the cerebral cortex of transgenic mice. J Neural Eng 2018; 15:056033. [DOI: 10.1088/1741-2552/aad840] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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8
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Wen D, Li Y, Zhu X, Chen M, Lu J, Li P. Selective photoactivation of neural activity combined with laser speckle imaging of cerebral blood flow. OPTICS LETTERS 2018; 43:3798-3801. [PMID: 30067682 DOI: 10.1364/ol.43.003798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 07/09/2018] [Indexed: 06/08/2023]
Abstract
Neural activity leads to alterations in cerebral blood flow (CBF), i.e., neurovascular regulation, which is implicated in brain physiology and pathology. Here a method for simultaneous imaging of CBF and spatially selective photoactivation of neural activity is proposed. CBF was obtained by laser speckle contrast imaging, and a liquid-crystal spatial light modulator (LC-SLM) was used to generate photoactivation patterns targeting designated locations in the cortex. Animal experiments stimulating defined cortical regions of VGAT-ChR2 and wild-type mice were conducted, and experiments with low-intensity stimulation were performed to investigate the influence of background light produced by the LC-SLM.
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9
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Kim M, Hong J, Kim J, Shin HJ. Fiber bundle-based integrated platform for wide-field fluorescence imaging and patterned optical stimulation for modulation of vasoconstriction in the deep brain of a living animal. BIOMEDICAL OPTICS EXPRESS 2017; 8:2781-2795. [PMID: 28663906 PMCID: PMC5480429 DOI: 10.1364/boe.8.002781] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 04/12/2017] [Accepted: 04/25/2017] [Indexed: 05/26/2023]
Abstract
We report a fiber optics-based intravital fluorescence imaging platform that includes epi-fluorescence microscopy and laser patterned-light stimulation system. The platform can perform real-time fluorescence imaging with a lateral resolution of ~4.9 μm while directly inserted into the intact mouse brain, optically stimulate vasoconstriction during real-time imaging, and avoid vessel damage in the penetration path of imaging probe. Using 473-nm patterned-light stimulation, we successfully modulated the vasoconstriction of a single targeted 37-μm-diameter blood vessel located more than 4.7 mm below the brain surface of a live SM22-ChR2 mouse. This platform may permit the hemodynamic studies associated with deeper brain neurovascular disorders.
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Affiliation(s)
- Minkyung Kim
- Center for Bionics, Korea Institute of Science and Technology (KIST), Seoul, South Korea
- Biomedical Engineering, Korea University of Science and Technology, Daejeon, South Korea
| | - Jinki Hong
- Center for Bionics, Korea Institute of Science and Technology (KIST), Seoul, South Korea
- Biomedical Engineering, Korea University of Science and Technology, Daejeon, South Korea
| | - Jinsik Kim
- Department of Medical Biotechnology, College of Life Science and Biotechnology, Dongguk University, Seoul, South Korea
| | - Hyun-joon Shin
- Center for Bionics, Korea Institute of Science and Technology (KIST), Seoul, South Korea
- Biomedical Engineering, Korea University of Science and Technology, Daejeon, South Korea
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10
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Park DW, Brodnick SK, Ness JP, Atry F, Krugner-Higby L, Sandberg A, Mikael S, Richner TJ, Novello J, Kim H, Baek DH, Bong J, Frye ST, Thongpang S, Swanson KI, Lake W, Pashaie R, Williams JC, Ma Z. Fabrication and utility of a transparent graphene neural electrode array for electrophysiology, in vivo imaging, and optogenetics. Nat Protoc 2016; 11:2201-2222. [DOI: 10.1038/nprot.2016.127] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 05/19/2016] [Indexed: 11/09/2022]
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11
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Williams JC, Campagnola PJ. Wearable Second Harmonic Generation Imaging: The Sarcomeric Bridge to the Clinic. Neuron 2016; 88:1067-1069. [PMID: 26687213 DOI: 10.1016/j.neuron.2015.12.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Imaging of sarcomere dynamics in vivo in patients has significant clinical importance, as the structure and function is altered in numerous pathologies. In this issue of Neuron, Schnitzer and coworkers (Sanchez et al., 2015) demonstrate this capability through a miniature, wearable Second Harmonic Generation microscope.
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Affiliation(s)
- Justin C Williams
- Department of Biomedical Engineering, University of Wisconsin-Madison, 1550 Engineering Drive, Madison, WI 53706, USA
| | - Paul J Campagnola
- Department of Biomedical Engineering, University of Wisconsin-Madison, 1550 Engineering Drive, Madison, WI 53706, USA.
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12
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Insanally M, Trumpis M, Wang C, Chiang CH, Woods V, Palopoli-Trojani K, Bossi S, Froemke RC, Viventi J. A low-cost, multiplexed μECoG system for high-density recordings in freely moving rodents. J Neural Eng 2016; 13:026030-26030. [PMID: 26975462 DOI: 10.1088/1741-2560/13/2/026030] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Micro-electrocorticography (μECoG) offers a minimally invasive neural interface with high spatial resolution over large areas of cortex. However, electrode arrays with many contacts that are individually wired to external recording systems are cumbersome and make recordings in freely behaving rodents challenging. We report a novel high-density 60-electrode system for μECoG recording in freely moving rats. APPROACH Multiplexed headstages overcome the problem of wiring complexity by combining signals from many electrodes to a smaller number of connections. We have developed a low-cost, multiplexed recording system with 60 contacts at 406 μm spacing. We characterized the quality of the electrode signals using multiple metrics that tracked spatial variation, evoked-response detectability, and decoding value. Performance of the system was validated both in anesthetized animals and freely moving awake animals. MAIN RESULTS We recorded μECoG signals over the primary auditory cortex, measuring responses to acoustic stimuli across all channels. Single-trial responses had high signal-to-noise ratios (SNR) (up to 25 dB under anesthesia), and were used to rapidly measure network topography within ∼10 s by constructing all single-channel receptive fields in parallel. We characterized evoked potential amplitudes and spatial correlations across the array in the anesthetized and awake animals. Recording quality in awake animals was stable for at least 30 days. Finally, we used these responses to accurately decode auditory stimuli on single trials. SIGNIFICANCE This study introduces (1) a μECoG recording system based on practical hardware design and (2) a rigorous analytical method for characterizing the signal characteristics of μECoG electrode arrays. This methodology can be applied to evaluate the fidelity and lifetime of any μECoG electrode array. Our μECoG-based recording system is accessible and will be useful for studies of perception and decision-making in rodents, particularly over the entire time course of behavioral training and learning.
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Affiliation(s)
- Michele Insanally
- Skirball Institute for Biomolecular Medicine, Neuroscience Institute, Departments of Otolaryngology, Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA.,Center for Neural Science, New York University, New York, NY, USA
| | - Michael Trumpis
- Polytechnic Institute of New York University, Department of Electrical and Computer Engineering, New York, NY, USA.,Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Charles Wang
- Polytechnic Institute of New York University, Department of Electrical and Computer Engineering, New York, NY, USA.,Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Chia-Han Chiang
- Polytechnic Institute of New York University, Department of Electrical and Computer Engineering, New York, NY, USA.,Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Virginia Woods
- Polytechnic Institute of New York University, Department of Electrical and Computer Engineering, New York, NY, USA.,Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | | | - Silvia Bossi
- Department of Biomedical Engineering, Duke University, Durham, NC, USA.,Robotics Laboratory, C.R. Casaccia, ENEA, V. Anguillarese, 301, 00123 S. Maria di Galeria, Roma, Italy.,BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, 56025 Pontedera, Italy
| | - Robert C Froemke
- Skirball Institute for Biomolecular Medicine, Neuroscience Institute, Departments of Otolaryngology, Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA.,Center for Neural Science, New York University, New York, NY, USA
| | - Jonathan Viventi
- Polytechnic Institute of New York University, Department of Electrical and Computer Engineering, New York, NY, USA.,Department of Biomedical Engineering, Duke University, Durham, NC, USA
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Pashaie R, Baumgartner R, Richner TJ, Brodnick SK, Azimipour M, Eliceiri KW, Williams JC. Closed-Loop Optogenetic Brain Interface. IEEE Trans Biomed Eng 2015; 62:2327-37. [PMID: 26011877 DOI: 10.1109/tbme.2015.2436817] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This paper presents a new approach for implementation of closed-loop brain-machine interface algorithms by combining optogenetic neural stimulation with electrocorticography and fluorescence microscopy. We used a new generation of microfabricated electrocorticography (micro-ECoG) devices in which electrode arrays are embedded within an optically transparent biocompatible substrate that provides optical access to the brain tissue during electrophysiology recording. An optical setup was designed capable of projecting arbitrary patterns of light for optogenetic stimulation and performing fluorescence microscopy through the implant. For realization of a closed-loop system using this platform, the feedback can be taken from electrophysiology data or fluorescence imaging. In the closed-loop systems discussed in this paper, the feedback signal was taken from the micro-ECoG. In these algorithms, the electrophysiology data are continuously transferred to a computer and compared with some predefined spatial-temporal patterns of neural activity. The computer which processes the data also readjusts the duration and distribution of optogenetic stimulating pulses to minimize the difference between the recorded activity and the predefined set points so that after a limited period of transient response the recorded activity follows the set points. Details of the system design and implementation of typical closed-loop paradigms are discussed in this paper.
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14
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Azimipour M, Atry F, Pashaie R. Effect of blood vessels on light distribution in optogenetic stimulation of cortex. OPTICS LETTERS 2015; 40:2173-6. [PMID: 26393692 DOI: 10.1364/ol.40.002173] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
In this Letter, the impact of blood vessels on light distribution during photostimulation of cortical tissue in small rodents is investigated. Brain optical properties were extracted using a double-integrating sphere setup, and optical coherence tomography was used to image cortical vessels and capillaries to generate a three-dimensional angiogram of the cortex. By combining these two datasets, a complete volumetric structure of the cortical tissue was developed and linked to a Monte Carlo code which simulates light propagation in this inhomogeneous structure and illustrates the effect of blood vessels on the penetration depth and pattern preservation in optogenetic stimulation.
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