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Sander MY, Zhu X. Infrared neuromodulation-a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:066701. [PMID: 38701769 DOI: 10.1088/1361-6633/ad4729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 05/03/2024] [Indexed: 05/05/2024]
Abstract
Infrared (IR) neuromodulation (INM) is an emerging light-based neuromodulation approach that can reversibly control neuronal and muscular activities through the transient and localized deposition of pulsed IR light without requiring any chemical or genetic pre-treatment of the target cells. Though the efficacy and short-term safety of INM have been widely demonstrated in both peripheral and central nervous systems, the investigations of the detailed cellular and biological processes and the underlying biophysical mechanisms are still ongoing. In this review, we discuss the current research progress in the INM field with a focus on the more recently discovered IR nerve inhibition. Major biophysical mechanisms associated with IR nerve stimulation are summarized. As the INM effects are primarily attributed to the spatiotemporal thermal transients induced by water and tissue absorption of pulsed IR light, temperature monitoring techniques and simulation models adopted in INM studies are discussed. Potential translational applications, current limitations, and challenges of the field are elucidated to provide guidance for future INM research and advancement.
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Affiliation(s)
- Michelle Y Sander
- Department of Electrical and Computer Engineering, Boston University, 8 Saint Mary's Street, Boston, MA 02215, United States of America
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA 02215, United States of America
- Division of Materials Science and Engineering, Boston University, 15 Saint Mary's Street, Brookline, MA 02446, United States of America
- Photonics Center, Boston University, 8 Saint Mary's Street, Boston, MA 02215, United States of America
- Neurophotonics Center, Boston University, 24 Cummington Mall, Boston, MA 02215, United States of America
| | - Xuedong Zhu
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA 02215, United States of America
- Photonics Center, Boston University, 8 Saint Mary's Street, Boston, MA 02215, United States of America
- Neurophotonics Center, Boston University, 24 Cummington Mall, Boston, MA 02215, United States of America
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Soto E, Pliego A, Vega R. Vestibular prosthesis: from basic research to clinics. Front Integr Neurosci 2023; 17:1161860. [PMID: 37265514 PMCID: PMC10230114 DOI: 10.3389/fnint.2023.1161860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 04/26/2023] [Indexed: 06/03/2023] Open
Abstract
Balance disorders are highly prevalent worldwide, causing substantial disability with high personal and socioeconomic impact. The prognosis in many of these patients is poor, and rehabilitation programs provide little help in many cases. This medical problem can be addressed using microelectronics by combining the highly successful cochlear implant experience to produce a vestibular prosthesis, using the technical advances in micro gyroscopes and micro accelerometers, which are the electronic equivalents of the semicircular canals (SCC) and the otolithic organs. Reaching this technological milestone fostered the possibility of using these electronic devices to substitute the vestibular function, mainly for visual stability and posture, in case of damage to the vestibular endorgans. The development of implantable and non-implantable devices showed diverse outcomes when considering the integrity of the vestibular pathways, the device parameters (current intensity, impedance, and waveform), and the targeted physiological function (balance and gaze). In this review, we will examine the development and testing of various prototypes of the vestibular implant (VI). The insight raised by examining the state-of-the-art vestibular prosthesis will facilitate the development of new device-development strategies and discuss the feasibility of complex combinations of implantable devices for disorders that directly affect balance and motor performance.
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Affiliation(s)
- Enrique Soto
- Benemérita Universidad Autónoma de Puebla, Instituto de Fisiología, Puebla, Mexico
| | - Adriana Pliego
- Benemérita Universidad Autónoma de Puebla, Instituto de Fisiología, Puebla, Mexico
- Universidad Autónoma del Estado de México (UAEMéx), Facultad de Medicina, Toluca, Mexico
| | - Rosario Vega
- Benemérita Universidad Autónoma de Puebla, Instituto de Fisiología, Puebla, Mexico
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3
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Barrett JN, Barrett EF, Rajguru SM. Mitochondrial responses to intracellular Ca 2+ release following infrared stimulation. J Neurophysiol 2023; 129:700-716. [PMID: 36752512 PMCID: PMC10026987 DOI: 10.1152/jn.00293.2022] [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: 07/11/2022] [Revised: 01/31/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
Many studies of Ca2+ effects on mitochondrial respiration in intact cells have used electrical and/or chemical stimulation to elevate intracellular [Ca2+], and have reported increases in [NADH] and increased ADP/ATP ratios as dominant controllers of respiration. This study tested a different form of stimulation: brief temperature increases produced by pulses of infrared light (IR, 1,863 nm, 8-10°C for ∼5 s). Fluorescence imaging techniques applied to single PC-12 cells in low µM extracellular [Ca2+] revealed IR stimulation-induced increases in both cytosolic (fluo5F) and mitochondrial (rhod2) [Ca2+]. IR stimulation increased O2 consumption (porphyrin fluorescence), and produced an alkaline shift in mitochondrial matrix pH (Snarf1), indicating activation of the electron transport chain (ETC). The increase in O2 consumption persisted in oligomycin, and began during a decrease in NADH, suggesting that the initial increase in ETC activity was not driven by increased ATP synthase activity or an increased fuel supply to ETC complex I. Imaging with two potentiometric dyes [tetramethyl rhodamine methyl ester (TMRM) and R123] indicated a depolarizing shift in ΔΨm that persisted in high [K+] medium. High-resolution fluorescence imaging disclosed large, reversible mitochondrial depolarizations that were inhibited by cyclosporin A (CSA), consistent with the opening of transient mitochondrial permeability transition pores. IR stimulation also produced a Ca2+-dependent increase in superoxide production (MitoSox) that was not inhibited by CSA, indicating that the increase in superoxide did not require transition pore opening. Thus, the intracellular Ca2+ release that follows pulses of infrared light offers new insights into Ca2+-dependent processes controlling respiration and reactive oxygen species in intact cells.NEW & NOTEWORTHY Pulses of infrared light (IR) provide a novel method for rapidly transferring Ca2+ from the endoplasmic reticulum to mitochondria in intact cells. In PC12 cells the resulting ETC activation was not driven by increased ATP synthase activity or NADH. IR stimulation produced a Ca2+-dependent, reversible depolarization of ΔΨm that was partially blocked by cyclosporin A, and a Ca2+-dependent increase in superoxide that did not require transition pore opening.
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Affiliation(s)
- John N Barrett
- Department of Physiology and Biophysics, University of Miami, Florida, United States
- Neuroscience Program, University of Miami, Florida, United States
| | - Ellen F Barrett
- Department of Physiology and Biophysics, University of Miami, Florida, United States
- Neuroscience Program, University of Miami, Florida, United States
| | - Suhrud M Rajguru
- Department of Biomedical Engineering, University of Miami, Florida, United States
- Department of Otolaryngology, University of Miami, Florida, United States
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4
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Kim T, Kadji H, Whalen AJ, Ashourvan A, Freeman E, Fried SI, Tadigadapa S, Schiff SJ. Thermal effects on neurons during stimulation of the brain. J Neural Eng 2022; 19:056029. [PMID: 36126646 PMCID: PMC9855718 DOI: 10.1088/1741-2552/ac9339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 09/13/2022] [Accepted: 09/20/2022] [Indexed: 01/25/2023]
Abstract
All electric and magnetic stimulation of the brain deposits thermal energy in the brain. This occurs through either Joule heating of the conductors carrying current through electrodes and magnetic coils, or through dissipation of energy in the conductive brain.Objective.Although electrical interaction with brain tissue is inseparable from thermal effects when electrodes are used, magnetic induction enables us to separate Joule heating from induction effects by contrasting AC and DC driving of magnetic coils using the same energy deposition within the conductors. Since mammalian cortical neurons have no known sensitivity to static magnetic fields, and if there is no evidence of effect on spike timing to oscillating magnetic fields, we can presume that the induced electrical currents within the brain are below the molecular shot noise where any interaction with tissue is purely thermal.Approach.In this study, we examined a range of frequencies produced from micromagnetic coils operating below the molecular shot noise threshold for electrical interaction with single neurons.Main results.We found that small temperature increases and decreases of 1∘C caused consistent transient suppression and excitation of neurons during temperature change. Numerical modeling of the biophysics demonstrated that the Na-K pump, and to a lesser extent the Nernst potential, could account for these transient effects. Such effects are dependent upon compartmental ion fluxes and the rate of temperature change.Significance.A new bifurcation is described in the model dynamics that accounts for the transient suppression and excitation; in addition, we note the remarkable similarity of this bifurcation's rate dependency with other thermal rate-dependent tipping points in planetary warming dynamics. These experimental and theoretical findings demonstrate that stimulation of the brain must take into account small thermal effects that are ubiquitously present in electrical and magnetic stimulation. More sophisticated models of electrical current interaction with neurons combined with thermal effects will lead to more accurate modulation of neuronal activity.
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Affiliation(s)
- TaeKen Kim
- Department of Physics, The Pennsylvania State University, University Park, PA, United States of America
| | - Herve Kadji
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States of America
- Department of Radiation Oncology, Hackensack Meridian Health Mountainside Medical Center, Montclair, NJ, United States of America
| | - Andrew J Whalen
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, PA, United States of America
- Department of Neurosurgery, Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States of America
| | - Arian Ashourvan
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States of America
| | - Eugene Freeman
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, United States of America
- Honeywell International Aerospace Advanced Technology, Plymouth, MN, United States of America
| | - Shelley I Fried
- Department of Neurosurgery, Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States of America
- Boston VA Healthcare System, Boston 02130, United States of America
| | - Srinivas Tadigadapa
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, United States of America
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, United States of America
| | - Steven J Schiff
- Department of Physics, The Pennsylvania State University, University Park, PA, United States of America
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States of America
- Department of Neurosurgery, Penn State College of Medicine, Hershey, PA 17033, United States of America
- Department of Neurosurgery, Yale University, 333 Cedar Street, TMP 410, New Haven, CT 06510, United States of America
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Zhu X, Lin JW, Sander MY. Bidirectional modulation of evoked synaptic transmission by pulsed infrared light. Sci Rep 2022; 12:14196. [PMID: 35987765 PMCID: PMC9392733 DOI: 10.1038/s41598-022-18139-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/05/2022] [Indexed: 12/05/2022] Open
Abstract
Infrared (IR) neuromodulation (INM) has been demonstrated as a novel modulation modality of neuronal excitability. However, the effects of pulsed IR light on synaptic transmission have not been investigated systematically. In this report, the IR light (2 μm) is used to directly modulate evoked synaptic transmission at the crayfish opener neuromuscular junction. The extracellularly recorded terminal action potentials (tAPs) and evoked excitatory postsynaptic currents (EPSCs) modulated by localized IR light illumination (500 ms, 3–13 mW) aimed at the synapses are analyzed. The impact of a single IR light pulse on the presynaptic Ca2+ influx is monitored with Ca2+ indicators. The EPSC amplitude is enhanced, and its rising phase is accelerated under relatively low IR light power levels and localized temperature rises. Increasing the IR light power reversibly suppresses and eventually blocks the EPSCs. Meanwhile, the synaptic delay, tAP amplitude, and presynaptic Ca2+ influx decrease monotonously with higher IR light power. It is demonstrated for the first time that IR light illumination has bidirectional effects on evoked synaptic transmission. These results highlight the efficacy and flexibility of using pulsed IR light to directly control synaptic transmission and advance our understanding of INM of neural networks.
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Wei J, Li L, Song H, Du Z, Yang J, Zhang M, Liu X. Response of a neuronal network computational model to infrared neural stimulation. Front Comput Neurosci 2022; 16:933818. [PMID: 36045903 PMCID: PMC9423709 DOI: 10.3389/fncom.2022.933818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
Infrared neural stimulation (INS), as a novel form of neuromodulation, allows modulating the activity of nerve cells through thermally induced capacitive currents and thermal sensitivity ion channels. However, fundamental questions remain about the exact mechanism of INS and how the photothermal effect influences the neural response. Computational neural modeling can provide a powerful methodology for understanding the law of action of INS. We developed a temperature-dependent model of ion channels and membrane capacitance based on the photothermal effect to quantify the effect of INS on the direct response of individual neurons and neuronal networks. The neurons were connected through excitatory and inhibitory synapses and constituted a complex neuronal network model. Our results showed that a slight increase in temperature promoted the neuronal spikes and enhanced network activity, whereas the ultra-temperature inhibited neuronal activity. This biophysically based simulation illustrated the optical dose-dependent biphasic cell response with capacitive current as the core change condition. The computational model provided a new sight to elucidate mechanisms and inform parameter selection of INS.
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Affiliation(s)
- Jinzhao Wei
- Key Laboratory of Digital Medical Engineering of Hebei, Hebei University, Baoding, China
- College of Electronic and Information Engineering, Hebei University, Baoding, China
| | - Licong Li
- Key Laboratory of Digital Medical Engineering of Hebei, Hebei University, Baoding, China
- College of Electronic and Information Engineering, Hebei University, Baoding, China
- Licong Li
| | - Hao Song
- Key Laboratory of Digital Medical Engineering of Hebei, Hebei University, Baoding, China
- College of Electronic and Information Engineering, Hebei University, Baoding, China
| | - Zhaoning Du
- Key Laboratory of Digital Medical Engineering of Hebei, Hebei University, Baoding, China
- College of Electronic and Information Engineering, Hebei University, Baoding, China
| | - Jianli Yang
- Key Laboratory of Digital Medical Engineering of Hebei, Hebei University, Baoding, China
- College of Electronic and Information Engineering, Hebei University, Baoding, China
| | - Mingsha Zhang
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
- IDG/McGovern Institute for Brain Research at BNU, Beijing Normal University, Beijing, China
- Division of Psychology, Beijing Normal University, Beijing, China
| | - Xiuling Liu
- Key Laboratory of Digital Medical Engineering of Hebei, Hebei University, Baoding, China
- College of Electronic and Information Engineering, Hebei University, Baoding, China
- *Correspondence: Xiuling Liu
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Huang J, Tang X, Xu Y, Zhang C, Chen T, Yu Y, Mustain W, Allison J, Iversen MM, Rabbitt RD, Zhou W, Zhu H. Differential Activation of Canal and Otolith Afferents by Acoustic Tone Bursts in Rats. J Assoc Res Otolaryngol 2022; 23:435-453. [DOI: 10.1007/s10162-022-00839-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 01/31/2022] [Indexed: 01/08/2023] Open
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8
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Jiang W, Wang Z, Xiao S, Zeng D, Wu Z, Peng C, Chen F. Pulsed infrared stimulation evoked electrical potential in mouse vestibular system. Neurosci Lett 2022; 775:136510. [DOI: 10.1016/j.neulet.2022.136510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 01/17/2022] [Accepted: 02/01/2022] [Indexed: 10/19/2022]
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Nonthermal and reversible control of neuronal signaling and behavior by midinfrared stimulation. Proc Natl Acad Sci U S A 2021; 118:2015685118. [PMID: 33649213 PMCID: PMC7958416 DOI: 10.1073/pnas.2015685118] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Various neuromodulation approaches have been employed to alter neuronal spiking activity and thus regulate brain functions and alleviate neurological disorders. Infrared neural stimulation (INS) could be a potential approach for neuromodulation because it requires no tissue contact and possesses a high spatial resolution. However, the risk of overheating and an unclear mechanism hamper its application. Here we show that midinfrared stimulation (MIRS) with a specific wavelength exerts nonthermal, long-distance, and reversible modulatory effects on ion channel activity, neuronal signaling, and sensorimotor behavior. Patch-clamp recording from mouse neocortical pyramidal cells revealed that MIRS readily provides gain control over spiking activities, inhibiting spiking responses to weak inputs but enhancing those to strong inputs. MIRS also shortens action potential (AP) waveforms by accelerating its repolarization, through an increase in voltage-gated K+ (but not Na+) currents. Molecular dynamics simulations further revealed that MIRS-induced resonance vibration of -C=O bonds at the K+ channel ion selectivity filter contributes to the K+ current increase. Importantly, these effects are readily reversible and independent of temperature increase. At the behavioral level in larval zebrafish, MIRS modulates startle responses by sharply increasing the slope of the sensorimotor input-output curve. Therefore, MIRS represents a promising neuromodulation approach suitable for clinical application.
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10
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Rice D, Martinelli GP, Jiang W, Holstein GR, Rajguru SM. Pulsed Infrared Stimulation of Vertical Semicircular Canals Evokes Cardiovascular Changes in the Rat. Front Neurol 2021; 12:680044. [PMID: 34122320 PMCID: PMC8193737 DOI: 10.3389/fneur.2021.680044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 04/20/2021] [Indexed: 11/28/2022] Open
Abstract
A variety of stimuli activating vestibular end organs, including sinusoidal galvanic vestibular stimulation, whole body rotation and tilt, and head flexion have been shown to evoke significant changes in blood pressure (BP) and heart rate (HR). While a role for the vertical semicircular canals in altering autonomic activity has been hypothesized, studies to-date attribute the evoked BP and HR responses to the otolith organs. The present study determined whether unilateral activation of the posterior (PC) or anterior (AC) semicircular canal is sufficient to elicit changes in BP and/or HR. The study employed frequency-modulated pulsed infrared radiation (IR: 1,863 nm) directed via optical fibers to PC or AC of adult male Long-Evans rats. BP and HR changes were detected using a small-animal single pressure telemetry device implanted in the femoral artery. Eye movements evoked during IR of the vestibular endorgans were used to confirm the stimulation site. We found that sinusoidal IR delivered to either PC or AC elicited a rapid decrease in BP and HR followed by a stimulation frequency-matched modulation. The magnitude of the initial decrements in HR and BP did not correlate with the energy of the suprathreshold stimulus. This response pattern was consistent across multiple trials within an experimental session, replicable, and in most animals showed no evidence of habituation or an additive effect. Frequency modulated electrical current delivered to the PC and IR stimulation of the AC, caused decrements in HR and BP that resembled those evoked by IR of the PC. Frequency domain heart rate variability assessment revealed that, in most subjects, IR stimulation increased the low frequency (LF) component and decreased the high frequency (HF) component, resulting in an increase in the LF/HF ratio. This ratio estimates the relative contributions of sympathetic nervous system (SNS) and parasympathetic nervous system (PNS) activities. An injection of atropine, a muscarinic cholinergic receptor antagonist, diminished the IR evoked changes in HR, while the non-selective beta blocker propranolol eliminated changes in both HR and BP. This study provides direct evidence that activation of a single vertical semicircular canal is sufficient to activate and modulate central pathways that control HR and BP.
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Affiliation(s)
- Darrian Rice
- Department of Biomedical Engineering, University of Miami, Miami, FL, United States
| | - Giorgio P Martinelli
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Weitao Jiang
- Department of Biomedical Engineering, University of Miami, Miami, FL, United States
| | - Gay R Holstein
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Suhrud M Rajguru
- Department of Biomedical Engineering, University of Miami, Miami, FL, United States.,Department of Otolaryngology, University of Miami, Miami, FL, United States
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11
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Kaszas A, Szalay G, Slézia A, Bojdán A, Vanzetta I, Hangya B, Rózsa B, O'Connor R, Moreau D. Two-photon GCaMP6f imaging of infrared neural stimulation evoked calcium signals in mouse cortical neurons in vivo. Sci Rep 2021; 11:9775. [PMID: 33963220 PMCID: PMC8105372 DOI: 10.1038/s41598-021-89163-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 04/22/2021] [Indexed: 02/07/2023] Open
Abstract
Infrared neural stimulation is a promising tool for stimulating the brain because it can be used to excite with high spatial precision without the need of delivering or inserting any exogenous agent into the tissue. Very few studies have explored its use in the brain, as most investigations have focused on sensory or motor nerve stimulation. Using intravital calcium imaging with the genetically encoded calcium indicator GCaMP6f, here we show that the application of infrared neural stimulation induces intracellular calcium signals in Layer 2/3 neurons in mouse cortex in vivo. The number of neurons exhibiting infrared-induced calcium response as well as the amplitude of those signals are shown to be both increasing with the energy density applied. By studying as well the spatial extent of the stimulation, we show that reproducibility of the stimulation is achieved mainly in the central part of the infrared beam path. Stimulating in vivo at such a degree of precision and without any exogenous chromophores enables multiple applications, from mapping the brain's connectome to applications in systems neuroscience and the development of new therapeutic tools for investigating the pathological brain.
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Affiliation(s)
- Attila Kaszas
- Mines Saint-Etienne, Centre CMP, Département BEL, F - 13541, Gardanne, France
- Institut de Neurosciences de la Timone, CNRS UMR 7289 & Aix-Marseille Université, 13005, Marseille, France
| | - Gergely Szalay
- Laboratory of 3D Functional Network and Dendritic Imaging, Institute of Experimental Medicine, Budapest, 1083, Hungary
| | - Andrea Slézia
- Mines Saint-Etienne, Centre CMP, Département BEL, F - 13541, Gardanne, France
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, 1083, Hungary
| | - Alexandra Bojdán
- Laboratory of 3D Functional Network and Dendritic Imaging, Institute of Experimental Medicine, Budapest, 1083, Hungary
| | - Ivo Vanzetta
- Institut de Neurosciences de la Timone, CNRS UMR 7289 & Aix-Marseille Université, 13005, Marseille, France
| | - Balázs Hangya
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, 1083, Hungary
| | - Balázs Rózsa
- Laboratory of 3D Functional Network and Dendritic Imaging, Institute of Experimental Medicine, Budapest, 1083, Hungary
- Two-Photon Laboratory, Faculty of Information Technology, Pázmány Péter Catholic University, Budapest, 1083, Hungary
| | - Rodney O'Connor
- Mines Saint-Etienne, Centre CMP, Département BEL, F - 13541, Gardanne, France
- Institut de Neurosciences de la Timone, CNRS UMR 7289 & Aix-Marseille Université, 13005, Marseille, France
| | - David Moreau
- Mines Saint-Etienne, Centre CMP, Département BEL, F - 13541, Gardanne, France.
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12
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Littlefield PD, Richter C. Near-infrared stimulation of the auditory nerve: A decade of progress toward an optical cochlear implant. Laryngoscope Investig Otolaryngol 2021; 6:310-319. [PMID: 33869763 PMCID: PMC8035937 DOI: 10.1002/lio2.541] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 12/14/2020] [Accepted: 02/12/2021] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVES We provide an appraisal of recent research on stimulation of the auditory system with light. In particular, we discuss direct infrared stimulation and ongoing controversies regarding the feasibility of this modality. We also discuss advancements and barriers to the development of an optical cochlear implant. METHODS This is a review article that covers relevant animal studies. RESULTS The auditory system has been stimulated with infrared light, and in a much more spatially selective manner than with electrical stimulation. However, there are experiments from other labs that have not been able to reproduce these results. This has resulted in an ongoing controversy regarding the feasibility of infrared stimulation, and the reasons for these experimental differences still require explanation. The neural response characteristics also appear to be much different than with electrical stimulation. The electrical stimulation paradigms used for modern cochlear implants do not apply well to optical stimulation and new coding strategies are under development. Stimulation with infrared light brings the risk of heat accumulation in the tissue at high pulse repetition rates, so optimal pulse shapes and combined optical/electrical stimulation are being investigated to mitigate this. Optogenetics is another promising technique, which makes neurons more sensitive to light stimulation by inserting light sensitive ion channels via viral vectors. Challenges of optogenetics include the expression of light sensitive channels in sufficient density in the target neurons, and the risk of damaging neurons by the expression of a foreign protein. CONCLUSION Optical stimulation of the nervous system is a promising new field, and there has been progress toward the development of a cochlear implant that takes advantage of the benefits of optical stimulation. There are barriers, and controversies, but so far none that seem intractable. LEVEL OF EVIDENCE NA (animal studies and basic research).
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Affiliation(s)
| | - Claus‐Peter Richter
- Department of OtolaryngologyNorthwestern UniversityChicagoIllinoisUSA
- Department of Communication Sciences and DisordersNorthwestern UniversityEvanstonIllinoisUSA
- Department of Biomedical EngineeringNorthwestern UniversityEvanstonIllinoisUSA
- The Hugh Knowles Center, Department of Communication Sciences and DisordersNorthwestern UniversityEvanstonIllinoisUSA
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Brown WGA, Needham K, Begeng JM, Thompson AC, Nayagam BA, Kameneva T, Stoddart PR. Response of primary auditory neurons to stimulation with infrared light in vitro. J Neural Eng 2021; 18:046003. [PMID: 33724234 DOI: 10.1088/1741-2552/abe7b8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Infrared light can be used to modulate the activity of neuronal cells through thermally-evoked capacitive currents and thermosensitive ion channel modulation. The infrared power threshold for action potentials has previously been found to be far lower in the in vivo cochlea when compared with other neuronal targets, implicating spiral ganglion neurons (SGNs) as a potential target for infrared auditory prostheses. However, conflicting experimental evidence suggests that this low threshold may arise from an intermediary mechanism other than direct SGN stimulation, potentially involving residual hair cell activity. APPROACH Patch-clamp recordings from cultured SGNs were used to explicitly quantify the capacitive and ion channel currents in an environment devoid of hair cells. Neurons were irradiated by a 1870 nm laser with pulse durations of 0.2-5.0 ms and powers up to 1.5 W. A Hodgkin-Huxley-type model was established by first characterising the voltage dependent currents, and then incorporating laser-evoked currents separated into temperature-dependent and temperature-gradient-dependent components. This model was found to accurately simulate neuronal responses and allowed the results to be extrapolated to stimulation parameter spaces not accessible during this study. MAIN RESULTS The previously-reported low in vivo SGN stimulation threshold was not observed, and only subthreshold depolarisation was achieved, even at high light exposures. Extrapolating these results with our Hodgkin-Huxley-type model predicts an action potential threshold which does not deviate significantly from other neuronal types. SIGNIFICANCE This suggests that the low-threshold response that is commonly reported in vivo may arise from an alternative mechanism, and calls into question the potential usefulness of the effect for auditory prostheses. The step-wise approach to modelling optically-evoked currents described here may prove useful for analysing a wider range of cell types where capacitive currents and conductance modulation are dominant.
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Affiliation(s)
- William G A Brown
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn VIC 3122, Australia
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Xu Y, Magnuson M, Agarwal A, Tan X, Richter CP. Infrared neural stimulation at different wavelengths and pulse shapes. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 162:89-100. [PMID: 33359901 DOI: 10.1016/j.pbiomolbio.2020.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 11/26/2020] [Accepted: 12/18/2020] [Indexed: 11/30/2022]
Abstract
Neural stimulation with infrared radiation has been explored for brain tissue, peripheral nerves, and cranial nerves including the auditory nerve. Initial experiments were conducted at wavelengths between λ = 1850 and λ = 2140 nm and the radiant energy was delivered with square pulses. Water absorption of the infrared radiation at λ = 1860 nm is similar to absorption at wavelengths between λ = 1310 and λ = 1600 nm, which are in the radiation wavelength range used for the communication industry. Technology for those wavelengths has already been developed and miniaturized and is readily available. The possibility of the infrared light to evoke compound action potentials (CAP) in the cochlea at λ = 1,375, λ = 1,460, and λ = 1550 nm was explored and compared to that of λ = 1860 nm in guinea pigs. Furthermore, rise and fall times of the 100 μs long pulses were changed and four basic pulse shapes (square, triangular, ramp-up, and ramp-down) were explored in their ability to evoke a CAP. In animals with pure tone threshold averages (PTAs) above 70 dB SPL, the results show that the favorable wavelength is λ = 1460 nm to reach threshold for stimulation and λ = 1375 nm or λ = 1460 nm for obtaining maximum amplitude. The most favorable pulse shape is either ramp-up or triangular.
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Affiliation(s)
- Yingyue Xu
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave, Searle 12-561, Chicago, IL, 60611, USA; Department of Communication Sciences and Disorders, Northwestern University, Frances Searle Building, 2240 Campus Drive, Evanston, IL, 60208, USA
| | - Mario Magnuson
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave, Searle 12-561, Chicago, IL, 60611, USA
| | - Aditi Agarwal
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave, Searle 12-561, Chicago, IL, 60611, USA
| | - Xiaodong Tan
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave, Searle 12-561, Chicago, IL, 60611, USA
| | - Claus-Peter Richter
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave, Searle 12-561, Chicago, IL, 60611, USA; Department of Communication Sciences and Disorders, Northwestern University, Frances Searle Building, 2240 Campus Drive, Evanston, IL, 60208, USA; Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Tech E310, Evanston, IL, 60208, USA; The Hugh Knowles Center, Northwestern University, Frances Searle Building, 2240 Campus Drive, Evanston, IL, 60208, USA.
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15
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Damnjanovic R, Bazard P, Frisina RD, Bhethanabotla VR. Hybrid Electro-Plasmonic Neural Stimulation with Visible-Light-Sensitive Gold Nanoparticles. ACS NANO 2020; 14:10917-10928. [PMID: 32603090 DOI: 10.1021/acsnano.0c00722] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Biomedical prosthetics utilizing electrical stimulation have limited, effective spatial resolution due to spread of electrical currents to surrounding tissue, causing nonselective stimulation. So, precise spatial resolution is not possible for traditional neural prosthetic devices, such as cochlear implants. More recently, alternative methods utilize optical stimulation, mainly infrared, sometimes paired with nanotechnology for stimulating action potentials. Infrared stimulation has its own drawbacks, as it may cause collateral heating of surrounding tissue. In previous work, we employed a plasmonic method for stimulation of an electrically excitable neuroblastoma cell line, which had limited success. Here, we report the development of a hybrid electro-plasmonic stimulation platform for spatially and temporally precise neural excitation to address the above deficiencies. Primary trigeminal neurons were costimulated in vitro in a whole-cell patch-clamp configuration with subthreshold-level short-duration (1-5 ms) electrical and visible light pulses (1-5 ms). The visible light pulses were aimed at a gold-nanoparticle-coated nanoelectrode placed alongside the neuron, within 2 μm distance. Membrane action potentials were recorded with a 3-fold higher success rate and 5-fold better poststimulation cell recovery rate than with pure optical stimulation alone. Also, electrical stimulus current input was being reduced by up to 40%. The subthreshold levels of electrical stimuli in conjunction with visible light (532 nm) reliably triggered trains of action potentials. This single-cell hybrid activation was reliable and repeatable, without any damage as observed with pure optical stimulation. This work represents an empirical cellular study of the membrane action potential response produced by the cultured primary sensory trigeminal neurons when costimulated with plasmonic and electrical (hybrid) stimulation. Our hybrid neurostimulation method can be used toward development of high-acuity neural modulation prosthetic devices, tunable for individual needs, which would qualify as a preferred alternative over traditional electrical stimulation technologies.
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Zhu A, Qureshi AA, Kozin ED, Lee DJ. Concepts in Neural Stimulation: Electrical and Optical Modulation of the Auditory Pathways. Otolaryngol Clin North Am 2019; 53:31-43. [PMID: 31685241 DOI: 10.1016/j.otc.2019.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Understanding the mechanisms of neural stimulation is necessary to improve the management of sensory disorders. Neurons can be artificially stimulated using electrical current, or with newer stimulation modalities, including optogenetics. Electrical stimulation forms the basis for all neuroprosthetic devices that are used clinically. Off-target stimulation and poor implant performance remain concerns for patients with electrically based neuroprosthetic devices. Optogenetic techniques may improve cranial nerve stimulation strategies used by various neuroprostheses and result in better patient outcomes. This article reviews the fundamentals of neural stimulation and provides an overview of recent major advancements in light-based neuromodulation."
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Affiliation(s)
- Angela Zhu
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, USA
| | - Ahad A Qureshi
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, USA
| | - Elliott D Kozin
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, USA
| | - Daniel J Lee
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, USA.
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17
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Efferent Inputs Are Required for Normal Function of Vestibular Nerve Afferents. J Neurosci 2019; 39:6922-6935. [PMID: 31285300 DOI: 10.1523/jneurosci.0237-19.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/28/2019] [Accepted: 07/01/2019] [Indexed: 01/09/2023] Open
Abstract
A group of vestibular afferent nerve fibers with irregular-firing resting discharges are thought to play a prominent role in responses to fast head movements and vestibular plasticity. We show that, in C57BL/6 mice (either sex, 4-5 weeks old), normal activity in the efferent vestibular pathway is required for function of these irregular afferents. Thermal inhibition of efferent fibers results in a profound inhibition of irregular afferents' resting discharges, rendering them inadequate for signaling head movements. In this way, efferent inputs adjust the contribution of the peripheral irregular afferent pathway that plays a critical role in peripheral vestibular signaling and plasticity.SIGNIFICANCE STATEMENT Vestibular end organs in the inner ear receive efferent inputs from the brainstem. Previously, electrical stimulation of efferents was linked to an increase in resting discharges of afferents and a decrease in their sensitivities. Here, we show that localized thermal inhibition of unmyelinated efferents results in a significant decrease in the activity of afferent nerve fibers, particularly those with irregular resting discharges implicated in responses to fast head movements and vestibular compensation. Thus, by upregulating and downregulating of afferent firing, particularly irregular afferents, efferents adjust neural activity sensitive to rapid head movements. These findings support the notion that peripheral vestibular end organs are not passive transducers of head movements and their sensory signal transmission is modulated by efferent inputs.
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18
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Rabbitt RD. Semicircular canal biomechanics in health and disease. J Neurophysiol 2019; 121:732-755. [PMID: 30565972 PMCID: PMC6520623 DOI: 10.1152/jn.00708.2018] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 12/11/2018] [Accepted: 12/11/2018] [Indexed: 12/12/2022] Open
Abstract
The semicircular canals are responsible for sensing angular head motion in three-dimensional space and for providing neural inputs to the central nervous system (CNS) essential for agile mobility, stable vision, and autonomic control of the cardiovascular and other gravity-sensitive systems. Sensation relies on fluid mechanics within the labyrinth to selectively convert angular head acceleration into sensory hair bundle displacements in each of three inner ear sensory organs. Canal afferent neurons encode the direction and time course of head movements over a broad range of movement frequencies and amplitudes. Disorders altering canal mechanics result in pathological inputs to the CNS, often leading to debilitating symptoms. Vestibular disorders and conditions with mechanical substrates include benign paroxysmal positional nystagmus, direction-changing positional nystagmus, alcohol positional nystagmus, caloric nystagmus, Tullio phenomena, and others. Here, the mechanics of angular motion transduction and how it contributes to neural encoding by the semicircular canals is reviewed in both health and disease.
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Affiliation(s)
- R. D. Rabbitt
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah
- Otolaryngology-Head Neck Surgery, University of Utah, Salt Lake City, Utah
- Neuroscience Program, University of Utah, Salt Lake City, Utah
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19
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Xu Y, Xia N, Lim M, Tan X, Tran MH, Boulger E, Peng F, Young H, Rau C, Rack A, Richter CP. Multichannel optrodes for photonic stimulation. NEUROPHOTONICS 2018; 5:045002. [PMID: 30397630 PMCID: PMC6197865 DOI: 10.1117/1.nph.5.4.045002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 09/24/2018] [Indexed: 05/27/2023]
Abstract
An emerging method in the field of neural stimulation is the use of photons to activate neurons. The possible advantage of optical stimulation over electrical is attributable to its spatially selective activation of small neuron populations, which is promising in generating superior spatial resolution in neural interfaces. Two principal methods are explored for cochlear prostheses: direct stimulation of nerves with infrared light and optogenetics. This paper discusses basic requirements for developing a light delivery system (LDS) for the cochlea and provides examples for building such devices. The proposed device relies on small optical sources, which are assembled in an array to be inserted into the cochlea. The mechanical properties, the biocompatibility, and the efficacy of optrodes have been tested in animal models. The force required to insert optrodes into a model of the human scala tympani was comparable to insertion forces obtained for contemporary cochlear implant electrodes. Side-emitting diodes are powerful enough to evoke auditory responses in guinea pigs. Chronic implantation of the LDS did not elevate auditory brainstem responses over 26 weeks.
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Affiliation(s)
- Yingyue Xu
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
- Northwestern University, Department of Communication Sciences and Disorders, Evanston, Illinois, United States
| | - Nan Xia
- Qingdao University, Institute for Digital Medicine and Computer-assisted Surgery, Qingdao, China
| | - Michelle Lim
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
| | - Xiaodong Tan
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
| | - Minh Ha Tran
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
| | - Erin Boulger
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
| | - Fei Peng
- Chongqing University, Bioengineering College, Chongqing, China
| | - Hunter Young
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
| | - Christoph Rau
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, United Kingdom
| | - Alexander Rack
- Structure of Materials Group-ID19, European Synchrotron Radiation Facility, Cedex 9, France
| | - Claus-Peter Richter
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
- Northwestern University, Department of Communication Sciences and Disorders, Evanston, Illinois, United States
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
- Northwestern University, Hugh Knowles Center for Clinical and Basic Sciences in Hearing, Evanston, Illinois, United States
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20
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Jiang W, Rajguru SM. Eye Movements Evoked by Pulsed Infrared Radiation of the Rat Vestibular System. Ann Biomed Eng 2018; 46:1406-1418. [PMID: 29845411 PMCID: PMC6095805 DOI: 10.1007/s10439-018-2059-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 05/24/2018] [Indexed: 10/16/2022]
Abstract
Light at infrared wavelengths has been demonstrated to modulate the pattern of neural signals transmitted from the angular motion sensing semicircular canals of the vestibular system to the brain. In the present study, we have characterized physiological eye movements evoked by focused, pulsed infrared radiation (IR) stimuli directed at an individual semicircular canal in a mammalian model. Pulsed IR (1863 nm) trains were directed at the posterior semicircular canal in a rat using 200-400 µm optical fibers. Evoked bilateral eye movements were measured using a custom-modified video-oculography system. The activation of vestibulo-ocular motor pathways by frequency modulated pulsed IR directed at single posterior semicircular canals evoked significant, characteristic bilateral eye movements. In this case, the resulting eye movements were disconjugate with ipsilateral eye moving upwards with a rotation towards the stimulated ear and the contralateral eye moving downwards. The eye movements were stable through several hours of repeated stimulation and could be maintained with 30 + minutes of continuous, frequency-modulated IR stimulation. Following the measurements, the distance of the fiber from target structures and orientation of the beam relative to vestibular structures were determined using micro-computed tomography. Results highlight the spatial selectivity of optical stimulation. Our results demonstrate a novel strategy for direct optical stimulation of the vestibular pathway in rodents and lays the groundwork for future applications of optical neural stimulation in inner ear research and therapeutic applications.
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Affiliation(s)
- Weitao Jiang
- Department of Biomedical Engineering, University of Miami, 1251 Memorial Drive, MEA 204, Coral Gables, FL, 33146, USA
| | - Suhrud M Rajguru
- Department of Biomedical Engineering, University of Miami, 1251 Memorial Drive, MEA 204, Coral Gables, FL, 33146, USA.
- Department of Otolaryngology, University of Miami, 1600 NW 10th Ave, RMSB 3160, Miami, FL, 33136, USA.
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21
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Barrett JN, Rincon S, Singh J, Matthewman C, Pasos J, Barrett EF, Rajguru SM. Pulsed infrared releases Ca 2+ from the endoplasmic reticulum of cultured spiral ganglion neurons. J Neurophysiol 2018; 120:509-524. [PMID: 29668377 DOI: 10.1152/jn.00740.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Inner ear spiral ganglion neurons were cultured from day 4 postnatal mice and loaded with a fluorescent Ca2+ indicator (fluo-4, -5F, or -5N). Pulses of infrared radiation (IR; 1,863 nm, 200 µs, 200-250 Hz for 2-5 s, delivered via an optical fiber) produced a rapid, transient temperature increase of 6-12°C (above a baseline of 24-30°C). These IR pulse trains evoked transient increases in both nuclear and cytosolic Ca2+ concentration ([Ca2+]) of 0.20-1.4 µM, with a simultaneous reduction of [Ca2+] in regions containing endoplasmic reticulum (ER). IR-induced increases in cytosolic [Ca2+] continued in medium containing no added Ca2+ (±Ca2+ buffers) and low [Na+], indicating that the [Ca2+] increase was mediated by release from intracellular stores. Consistent with this hypothesis, the IR-induced [Ca2+] response was prolonged and eventually blocked by inhibition of ER Ca2+-ATPase with cyclopiazonic acid, and was also inhibited by a high concentration of ryanodine and by inhibitors of inositol (1,4,5)-trisphosphate (IP3)-mediated Ca2+ release (xestospongin C and 2-aminoethoxydiphenyl borate). The thermal sensitivity of the response suggested involvement of warmth-sensitive transient receptor potential (TRP) channels. The IR-induced [Ca2+] increase was inhibited by TRPV4 inhibitors (HC-067047 and GSK-2193874), and immunostaining of spiral ganglion cultures demonstrated the presence of TRPV4 and TRPM2 that colocalized with ER marker GRP78. These results suggest that the temperature sensitivity of IR-induced [Ca2+] elevations is conferred by TRP channels on ER membranes, which facilitate Ca2+ efflux into the cytosol and thereby contribute to Ca2+-induced Ca2+-release via IP3 and ryanodine receptors. NEW & NOTEWORTHY Infrared radiation-induced photothermal effects release Ca2+ from the endoplasmic reticulum of primary spiral ganglion neurons. This Ca2+ release is mediated by activation of transient receptor potential (TRPV4) channels and involves amplification by Ca2+-induced Ca2+-release. The neurons immunostained for warmth-sensitive channels, TRPV4 and TRPM2, which colocalize with endoplasmic reticulum. Pulsed infrared radiation provides a novel experimental tool for releasing intracellular Ca2+, studying Ca2+ regulatory mechanisms, and influencing neuronal excitability.
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Affiliation(s)
- John N Barrett
- Department of Physiology and Biophysics, University of Miami , Miami, Florida.,Neuroscience Program, University of Miami , Miami, Florida
| | - Samantha Rincon
- Department of Biomedical Engineering, University of Miami , Miami, Florida
| | - Jayanti Singh
- Department of Otolaryngology, University of Miami , Miami, Florida
| | | | - Julio Pasos
- Department of Otolaryngology, University of Miami , Miami, Florida
| | - Ellen F Barrett
- Department of Physiology and Biophysics, University of Miami , Miami, Florida.,Neuroscience Program, University of Miami , Miami, Florida
| | - Suhrud M Rajguru
- Department of Biomedical Engineering, University of Miami , Miami, Florida.,Department of Otolaryngology, University of Miami , Miami, Florida
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22
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Azimzadeh JB, Fabella BA, Kastan NR, Hudspeth AJ. Thermal Excitation of the Mechanotransduction Apparatus of Hair Cells. Neuron 2018; 97:586-595.e4. [PMID: 29395911 PMCID: PMC5805653 DOI: 10.1016/j.neuron.2018.01.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 12/13/2017] [Accepted: 01/03/2018] [Indexed: 12/21/2022]
Abstract
Although a hair bundle is normally deflected by mechanical stimuli, we found that irradiation of a hair cell from the bullfrog's sacculus with ultraviolet light causes rapid motion of the hair bundle toward its tall edge. This movement is associated with opening of mechanotransduction channels and disappears when tip links are disrupted. We localized the absorptive element responsible for the motion to the region directly below the hair bundle and measured an action spectrum similar to the absorption spectra of mitochondrial constituents. Temperature measurements revealed heating around the site of absorption; direct heating of the hair bundle confirmed that the response to light is mediated through heat. Although mechanical offsets of the hair bundle revealed that heat softens gating springs, it also acts directly to open transduction channels. This study identifies an unconventional method of hair-cell stimulation and clarifies the previously unexplained sensitivity of auditory organs to thermal stimulation.
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Affiliation(s)
- Julien B Azimzadeh
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Laboratory of Sensory Neuroscience, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Brian A Fabella
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Laboratory of Sensory Neuroscience, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Nathaniel R Kastan
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Laboratory of Sensory Neuroscience, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - A J Hudspeth
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Laboratory of Sensory Neuroscience, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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23
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Tan X, Jahan I, Xu Y, Stock S, Kwan CC, Soriano C, Xiao X, García-Añoveros J, Fritzsch B, Richter CP. Auditory Neural Activity in Congenitally Deaf Mice Induced by Infrared Neural Stimulation. Sci Rep 2018; 8:388. [PMID: 29321651 PMCID: PMC5762820 DOI: 10.1038/s41598-017-18814-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/11/2017] [Indexed: 11/16/2022] Open
Abstract
To determine whether responses during infrared neural stimulation (INS) result from the direct interaction with spiral ganglion neurons (SGNs), we tested three genetically modified deaf mouse models: Atoh1-cre; Atoh1f/f (Atoh1 conditional knockout, CKO), Atoh1-cre; Atoh1f/kiNeurog1 (Neurog1 knockin, KI), and the Vglut3 knockout (Vglut3−/−) mice. All animals were exposed to tone bursts and clicks up to 107 dB (re 20 µPa) and to INS, delivered with a 200 µm optical fiber. The wavelength (λ) was 1860 nm, the radiant energy (Q) 0-800 µJ/pulse, and the pulse width (PW) 100–500 µs. No auditory responses to acoustic stimuli could be evoked in any of these animals. INS could not evoke auditory brainstem responses in Atoh1 CKO mice but could in Neurog1 KI and Vglut3−/− mice. X-ray micro-computed tomography of the cochleae showed that responses correlated with the presence of SGNs and hair cells. Results in Neurog1 KI mice do not support a mechanical stimulation through the vibration of the basilar membrane, but cannot rule out the direct activation of the inner hair cells. Results in Vglut3−/− mice, which have no synaptic transmission between inner hair cells and SGNs, suggested that hair cells are not required.
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Affiliation(s)
- Xiaodong Tan
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA
| | - Israt Jahan
- Department of Biology, University of Iowa, 129 E. Jefferson Street, Iowa City, IA, 52242, USA
| | - Yingyue Xu
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA
| | - Stuart Stock
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Avenue, Chicago, IL, 60611, USA
| | - Changyow Claire Kwan
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA
| | - Carmen Soriano
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA
| | - Xianghui Xiao
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA
| | - Jaime García-Añoveros
- Departments of Anesthesiology, Physiology, and Neurology, Northwestern University Institute for Neuroscience, Ward 10-070, 303 East Chicago Avenue, Chicago, IL, 60611, USA
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, 129 E. Jefferson Street, Iowa City, IA, 52242, USA
| | - Claus-Peter Richter
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA. .,Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Tech E310, Evanston, IL, 60208, USA. .,The Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, Frances Searle Building, 2240 Campus Drive, Evanston, IL, 60208, USA.
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24
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Favre-Bulle IA, Stilgoe AB, Rubinsztein-Dunlop H, Scott EK. Optical trapping of otoliths drives vestibular behaviours in larval zebrafish. Nat Commun 2017; 8:630. [PMID: 28931814 PMCID: PMC5606998 DOI: 10.1038/s41467-017-00713-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 07/18/2017] [Indexed: 11/22/2022] Open
Abstract
The vestibular system, which detects gravity and motion, is crucial to survival, but the neural circuits processing vestibular information remain incompletely characterised. In part, this is because the movement needed to stimulate the vestibular system hampers traditional neuroscientific methods. Optical trapping uses focussed light to apply forces to targeted objects, typically ranging from nanometres to a few microns across. In principle, optical trapping of the otoliths (ear stones) could produce fictive vestibular stimuli in a stationary animal. Here we use optical trapping in vivo to manipulate 55-micron otoliths in larval zebrafish. Medial and lateral forces on the otoliths result in complementary corrective tail movements, and lateral forces on either otolith are sufficient to cause a rolling correction in both eyes. This confirms that optical trapping is sufficiently powerful and precise to move large objects in vivo, and sets the stage for the functional mapping of the resulting vestibular processing.The neural circuits of the vestibular system, which detects gravity and motion, remain incompletely characterised. Here the authors use an optical trap to manipulate otoliths (ear stones) in zebrafish larvae, and elicit corrective tail movements and eye rolling, thus establishing a method for mapping vestibular processing.
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Affiliation(s)
- Itia A Favre-Bulle
- School of Mathematics and Physics, The University of Queensland, St. Lucia, QLD, 4072, Australia
- School of Biomedical Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Alexander B Stilgoe
- School of Mathematics and Physics, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | | | - Ethan K Scott
- School of Biomedical Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia.
- Queensland Brain Institute, The University of Queensland, St. Lucia, QLD, 4072, Australia.
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25
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Weissler Y, Farah N, Shoham S. Simulation of morphologically structured photo-thermal neural stimulation. J Neural Eng 2017; 14:055001. [PMID: 28820744 DOI: 10.1088/1741-2552/aa7805] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Rational design of next-generation techniques for photo-thermal excitation requires the development of tools capable of modeling the effects of spatially- and temporally-dependent temperature distribution on cellular neuronal structures. APPROACH We present a new computer simulation tool for predicting the effects of arbitrary spatiotemporally-structured photo-thermal stimulation on 3D, morphologically realistic neurons. The new simulation tool is based on interfacing two generic platforms, NEURON and MATLAB and is therefore suited for capturing different kinds of stimuli and neural models. MAIN RESULTS Simulation results are validated using photo-absorber induced neuro-thermal stimulation (PAINTS) empirical results, and advanced features are explored. SIGNIFICANCE The new simulation tool could have an important role in understanding and investigating complex optical stimulation at the single-cell and network levels.
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Affiliation(s)
- Y Weissler
- The Faculty of Biomedical Engineering and Russel-Berrie Nanoscience and Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa, Israel
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26
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Iversen MM, Christensen DA, Parker DL, Holman HA, Chen J, Frerck MJ, Rabbitt RD. Low-intensity ultrasound activates vestibular otolith organs through acoustic radiation force. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 141:4209. [PMID: 28618821 PMCID: PMC5552392 DOI: 10.1121/1.4984287] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 05/11/2017] [Accepted: 05/15/2017] [Indexed: 06/03/2023]
Abstract
The present study examined the efficacy of 5 MHz low-intensity focused ultrasound (LiFU) as a stimulus to remotely activate inner ear vestibular otolith organs. The otolith organs are the primary sensory apparati responsible for detecting orientation of the head relative to gravity and linear acceleration in three-dimensional space. These organs also respond to loud sounds and vibration of the temporal bone. The oyster toadfish, Opsanus tau, was used to facilitate unobstructed acoustic access to the otolith organs in vivo. Single-unit responses to amplitude-modulated LiFU were recorded in afferent neurons identified as innervating the utricle or the saccule. Neural responses were equivalent to direct mechanical stimulation, and arose from the nonlinear acoustic radiation force acting on the otolithic mass. The magnitude of the acoustic radiation force acting on the otolith was measured ex vivo. Results demonstrate that LiFU stimuli can be tuned to mimic directional forces occurring naturally during physiological movements of the head, loud air conducted sound, or bone conducted vibration.
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Affiliation(s)
- M M Iversen
- Department of Bioengineering, University of Utah, 36 South Wasatch Drive, Salt Lake City, Utah 84112, USA
| | - D A Christensen
- Department of Bioengineering, University of Utah, 36 South Wasatch Drive, Salt Lake City, Utah 84112, USA
| | - D L Parker
- Department of Radiology, University of Utah, 30 North 1900 East, Salt Lake City, Utah 84132, USA
| | - H A Holman
- Department of Bioengineering, University of Utah, 36 South Wasatch Drive, Salt Lake City, Utah 84112, USA
| | - J Chen
- Communication Sciences and Disorders, University of Utah, 390 South 1530 East, Salt Lake City, Utah 84112, USA
| | - M J Frerck
- Department of Bioengineering, University of Utah, 36 South Wasatch Drive, Salt Lake City, Utah 84112, USA
| | - R D Rabbitt
- Department of Bioengineering, University of Utah, 36 South Wasatch Drive, Salt Lake City, Utah 84112, USA
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Tsai SR, Hamblin MR. Biological effects and medical applications of infrared radiation. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2017; 170:197-207. [PMID: 28441605 PMCID: PMC5505738 DOI: 10.1016/j.jphotobiol.2017.04.014] [Citation(s) in RCA: 179] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 04/11/2017] [Accepted: 04/12/2017] [Indexed: 02/07/2023]
Abstract
Infrared (IR) radiation is electromagnetic radiation with wavelengths between 760nm and 100,000nm. Low-level light therapy (LLLT) or photobiomodulation (PBM) therapy generally employs light at red and near-infrared wavelengths (600-100nm) to modulate biological activity. Many factors, conditions, and parameters influence the therapeutic effects of IR, including fluence, irradiance, treatment timing and repetition, pulsing, and wavelength. Increasing evidence suggests that IR can carry out photostimulation and photobiomodulation effects particularly benefiting neural stimulation, wound healing, and cancer treatment. Nerve cells respond particularly well to IR, which has been proposed for a range of neurostimulation and neuromodulation applications, and recent progress in neural stimulation and regeneration are discussed in this review. The applications of IR therapy have moved on rapidly in recent years. For example, IR therapy has been developed that does not actually require an external power source, such as IR-emitting materials, and garments that can be powered by body heat alone. Another area of interest is the possible involvement of solar IR radiation in photoaging or photorejuvenation as opposites sides of the coin, and whether sunscreens should protect against solar IR? A better understanding of new developments and biological implications of IR could help us to improve therapeutic effectiveness or develop new methods of PBM using IR wavelengths.
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Affiliation(s)
- Shang-Ru Tsai
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan; Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Michael R Hamblin
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Dermatology, Harvard Medical School, Boston, MA 02115, USA; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA.
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Richardson RT, Thompson AC, Wise AK, Needham K. Challenges for the application of optical stimulation in the cochlea for the study and treatment of hearing loss. Expert Opin Biol Ther 2016; 17:213-223. [PMID: 27960585 DOI: 10.1080/14712598.2017.1271870] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
INTRODUCTION Electrical stimulation has long been the most effective strategy for evoking neural activity from bionic devices and has been used with great success in the cochlear implant to allow deaf people to hear speech and sound. Despite its success, the spread of electrical current stimulates a broad region of neural tissue meaning that contemporary devices have limited precision. Optical stimulation as an alternative has attracted much recent interest for its capacity to provide highly focused stimuli, and therefore, potentially improved sensory perception. Given its specificity of activation, optical stimulation may also provide a useful tool in the study of fundamental neuroanatomy and neurophysiological processes. Areas covered: This review examines the advances in optical stimulation - infrared, nanoparticle-enhanced, and optogenetic-based - and its application in the inner ear for the restoration of auditory function following hearing loss. Expert opinion: Initial outcomes suggest that optogenetic-based approaches hold the greatest potential and viability amongst optical techniques for application in the cochlea. The future success of this approach will be governed by advances in the targeted delivery of opsins to auditory neurons, improvements in channel kinetics, development of optical arrays, and innovation of opsins that activate within the optimal near-infrared therapeutic window.
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Affiliation(s)
- Rachael T Richardson
- a Bionics Institute , East Melbourne , Australia.,b Department of Medical Bionics , University of Melbourne , East Melbourne , Australia
| | | | - Andrew K Wise
- a Bionics Institute , East Melbourne , Australia.,b Department of Medical Bionics , University of Melbourne , East Melbourne , Australia
| | - Karina Needham
- d Department of Surgery (Otolaryngology) , University of Melbourne, Royal Victorian Eye & Ear Hospital , East Melbourne , Australia
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Effect of shorter pulse duration in cochlear neural activation with an 810-nm near-infrared laser. Lasers Med Sci 2016; 32:389-396. [PMID: 27995385 DOI: 10.1007/s10103-016-2129-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 12/08/2016] [Indexed: 10/20/2022]
Abstract
Optical neural stimulation in the cochlea has been presented as an alternative technique to the electrical stimulation due to its potential in spatially selectivity enhancement. So far, few studies have selected the near-infrared (NIR) laser in cochlear neural stimulation and limited optical parameter space has been examined. This paper focused on investigating the optical parameter effect on NIR stimulation of auditory neurons, especially under shorter pulse durations. The spiral ganglion neurons in the cochlea of deafened guinea pigs were stimulated with a pulsed 810-nm NIR laser in vivo. The laser radiation was delivered by an optical fiber and irradiated towards the modiolus. Optically evoked auditory brainstem responses (OABRs) with various optical parameters were recorded and investigated. The OABRs could be elicited with the cochlear deafened animals by using the 810-nm laser in a wide pulse duration ranged from 20 to 1000 μs. Results showed that the OABR intensity increased along with the increasing laser radiant exposure of limited range at each specific pulse duration. In addition, for the pulse durations from 20 to 300 μs, the OABR intensity increased monotonically along with the pulse duration broadening. While for pulse durations above 300 μs, the OABR intensity basically kept stable with the increasing pulse duration. The 810-nm NIR laser could be an effective stimulus in evoking the cochlear neuron response. Our experimental data provided evidence to optimize the pulse duration range, and the results suggested that the pulse durations from 20 to 300 μs could be the optimized range in cochlear neural activation with the 810-nm-wavelength laser.
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Xia N, Tan X, Xu Y, Hou W, Mao T, Richter CP. Pressure in the Cochlea During Infrared Irradiation. IEEE Trans Biomed Eng 2016; 65:1575-1584. [PMID: 27959792 DOI: 10.1109/tbme.2016.2636149] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE The purpose of the study is to demonstrate laser-evoked pressure waves in small confined volumes such as the cochlea. METHODS Custom-fabricated pressure probes were used to determine the pressure in front of the optical fiber in a small dish and patch pipettes to measure temperature changes. Pressure probes were inserted into scala tympani (ST) or vestibuli during laser stimulation. With a sensitive microphone the pressure was measured in the outer ear canal. RESULTS Heating was spatially confined. The heat relaxation time was 35 ms. During laser stimulation in the cochlea at 17 μJ/pulse, the pressure in the outer ear canal (EC) was 43.5 dB (re 20 μPa). The corresponding intracochlear pressure was calculated to be about 78.5 dB (re 20 μPa) using the middle ear reverse transfer function of -35 dB. At 164 μJ/pulse, the pressure in the EC was on average 63 dB (re 20 μPa) and the intracochlear pressure was estimated to be 98 dB (re 20 μPa), which is similar to the value obtained with the pressure probe, 100 dB (re 20 μPa). Side-emitting optical fibers were used to steer the beam path. The pressure values were independent of the orientation of the beam path. Evoked compound action potentials of the auditory nerve were maximum when spiral ganglion neurons were in the beam path. CONCLUSION Pressure waves are generated during infrared laser stimulation. The intracochlear pressure was independent from the orientation of the beam path. SIGNIFICANCE Neural responses required the spiral ganglion neurons to be directly irradiated.
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BODIPY-Conjugated Xyloside Primes Fluorescent Glycosaminoglycans in the Inner Ear of Opsanus tau. J Assoc Res Otolaryngol 2016; 17:525-540. [PMID: 27619213 DOI: 10.1007/s10162-016-0585-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 08/23/2016] [Indexed: 12/22/2022] Open
Abstract
We report on a new xyloside conjugated to BODIPY, BX and its utility to prime fluorescent glycosaminoglycans (BX-GAGs) within the inner ear in vivo. When BX is administered directly into the endolymphatic space of the oyster toadfish (Opsanus tau) inner ear, fluorescent BX-GAGs are primed and become visible in the sensory epithelia of the semicircular canals, utricle, and saccule. Confocal and 2-photon microscopy of vestibular organs fixed 4 h following BX treatment, reveal BX-GAGs constituting glycocalyces that envelop hair cell kinocilium, nerve fibers, and capillaries. In the presence of GAG-specific enzymes, the BX-GAG signals are diminished, suggesting that chondroitin sulfates are the primary GAGs primed by BX. Results are consistent with similar click-xylosides in CHO cell lines, where the xyloside enters the Golgi and preferentially initiates chondroitin sulfate B production. Introduction of BX produces a temporary block of hair cell mechanoelectrical transduction (MET) currents in the crista, reduction in background discharge rate of afferent neurons, and a reduction in sensitivity to physiological stimulation. A six-degree-of-freedom pharmacokinetic mathematical model has been applied to interpret the time course and spatial distribution of BX and BX-GAGs. Results demonstrate a new optical approach to study GAG biology in the inner ear, for tracking synthesis and localization in real time.
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Liljemalm R, Nyberg T. Damage criteria for cerebral cortex cells subjected to hyperthermia. Int J Hyperthermia 2016; 32:704-12. [PMID: 27269303 DOI: 10.1080/02656736.2016.1181275] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Temperatures above the normal physiological threshold may cause damage to cells and tissue. In this study, the response of a culture of dissociated cerebral cortex cells exposed to laser-induced temperature gradients was examined. The cellular response was evaluated using a fluorescent dye indicating metabolic activity. Furthermore, by using a finite element model of the heating during the pulsed laser application, threshold temperatures could be extracted for the cellular response at different laser pulse lengths. These threshold temperatures were used in an Arrhenius model to extract the kinetic parameters, i.e. the activation energy (Ea), and the frequency factor (Ac), for the system. A damage signal ratio was defined and calculated to 5% for the cells to increase their metabolism as a response to the heat. Furthermore, efficient stimulation with 20-ms long laser pulses did not evoke changes in metabolism. Thus, 20 ms could be a potential pulse length for functional stimulation of neural cells.
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Affiliation(s)
- Rickard Liljemalm
- a Royal Institute of Technology , School of Technology and Health , Huddinge , Sweden
| | - Tobias Nyberg
- a Royal Institute of Technology , School of Technology and Health , Huddinge , Sweden
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Wang YT, Rollins AM, Jenkins MW. Infrared inhibition of embryonic hearts. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:60505. [PMID: 27367249 PMCID: PMC5994995 DOI: 10.1117/1.jbo.21.6.060505] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 06/13/2016] [Indexed: 05/18/2023]
Abstract
Infrared control is a new technique that uses pulsed infrared lasers to thermally alter electrical activity. Originally developed for nerves, we have applied this technology to embryonic hearts using a quail model, previously demonstrating infrared stimulation and, here, infrared inhibition. Infrared inhibition enables repeatable and reversible block, stopping cardiac contractions for several seconds. Normal beating resumes after the laser is turned off. The block can be spatially specific, affecting propagation on the ventricle or initiation on the atrium. Optical mapping showed that the block affects action potentials and not just calcium or contraction. Increased resting intracellular calcium was observed after a 30-s exposure to the inhibition laser, which likely resulted in reduced mechanical function. Further optimization of the laser illumination should reduce potential damage. Stopping cardiac contractions by disrupting electrical activity with infrared inhibition has the potential to be a powerful tool for studying the developing heart.
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Affiliation(s)
- Yves T. Wang
- Case Western Reserve University, Department of Pediatrics, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
- Case Western Reserve University, Department of Biomedical Engineering, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Andrew M. Rollins
- Case Western Reserve University, Department of Biomedical Engineering, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Michael W. Jenkins
- Case Western Reserve University, Department of Pediatrics, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
- Case Western Reserve University, Department of Biomedical Engineering, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
- Address all correspondence to: Michael W. Jenkins, E-mail:
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Rabbitt RD, Brichta AM, Tabatabaee H, Boutros PJ, Ahn J, Della Santina CC, Poppi LA, Lim R. Heat pulse excitability of vestibular hair cells and afferent neurons. J Neurophysiol 2016; 116:825-43. [PMID: 27226448 DOI: 10.1152/jn.00110.2016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/24/2016] [Indexed: 11/22/2022] Open
Abstract
In the present study we combined electrophysiology with optical heat pulse stimuli to examine thermodynamics of membrane electrical excitability in mammalian vestibular hair cells and afferent neurons. We recorded whole cell currents in mammalian type II vestibular hair cells using an excised preparation (mouse) and action potentials (APs) in afferent neurons in vivo (chinchilla) in response to optical heat pulses applied to the crista (ΔT ≈ 0.25°C per pulse). Afferent spike trains evoked by heat pulse stimuli were diverse and included asynchronous inhibition, asynchronous excitation, and/or phase-locked APs synchronized to each infrared heat pulse. Thermal responses of membrane currents responsible for APs in ganglion neurons were strictly excitatory, with Q10 ≈ 2. In contrast, hair cells responded with a mix of excitatory and inhibitory currents. Excitatory hair cell membrane currents included a thermoelectric capacitive current proportional to the rate of temperature rise (dT/dt) and an inward conduction current driven by ΔT An iberiotoxin-sensitive inhibitory conduction current was also evoked by ΔT, rising in <3 ms and decaying with a time constant of ∼24 ms. The inhibitory component dominated whole cell currents in 50% of hair cells at -68 mV and in 67% of hair cells at -60 mV. Responses were quantified and described on the basis of first principles of thermodynamics. Results identify key molecular targets underlying heat pulse excitability in vestibular sensory organs and provide quantitative methods for rational application of optical heat pulses to examine protein biophysics and manipulate cellular excitability.
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Affiliation(s)
- Richard D Rabbitt
- Departments of Bioengineering and Otolaryngology, University of Utah, Salt Lake City, Utah;
| | - Alan M Brichta
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
| | - Hessam Tabatabaee
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
| | - Peter J Boutros
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - JoongHo Ahn
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Charles C Della Santina
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Lauren A Poppi
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
| | - Rebecca Lim
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
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Antognazza MR, Martino N, Ghezzi D, Feyen P, Colombo E, Endeman D, Benfenati F, Lanzani G. Shedding Light on Living Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:7662-7669. [PMID: 25469452 DOI: 10.1002/adma.201403513] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 10/01/2014] [Indexed: 06/04/2023]
Abstract
An overview of the optical methods available to modulate the cellular activity in cell cultures and biological tissues is presented, with a focus on the use of exogenous functional materials that absorb electromagnetic radiation and transduce it into a secondary stimulus for cell excitation, with high temporal and spatial resolution. Both organic and inorganic materials are critically evaluated, for in vitro and in vivo applications. Finally, as a direct practical application of optical-stimulation techniques, the most recent results in the realization of artificial visual implants are discussed.
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Affiliation(s)
- Maria Rosa Antognazza
- Center for Nano Science and Technology, @PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, Milano, 20133, Italy
| | - Nicola Martino
- Center for Nano Science and Technology, @PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, Milano, 20133, Italy
- Politecnico di Milano, Dipartimento di Fisica, Piazza L. da Vinci 32, Milano, 20133, Italy
| | - Diego Ghezzi
- Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies Department, Via Morego 30, Genova, 16163, Italy
| | - Paul Feyen
- Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies Department, Via Morego 30, Genova, 16163, Italy
| | - Elisabetta Colombo
- Center for Nano Science and Technology, @PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, Milano, 20133, Italy
- Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies Department, Via Morego 30, Genova, 16163, Italy
| | - Duco Endeman
- Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies Department, Via Morego 30, Genova, 16163, Italy
| | - Fabio Benfenati
- Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies Department, Via Morego 30, Genova, 16163, Italy
| | - Guglielmo Lanzani
- Center for Nano Science and Technology, @PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, Milano, 20133, Italy
- Politecnico di Milano, Dipartimento di Fisica, Piazza L. da Vinci 32, Milano, 20133, Italy
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Tan X, Young H, Matic AI, Zirkle W, Rajguru S, Richter CP. Temporal properties of inferior colliculus neurons to photonic stimulation in the cochlea. Physiol Rep 2015; 3:3/8/e12491. [PMID: 26311831 PMCID: PMC4562577 DOI: 10.14814/phy2.12491] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Infrared neural stimulation (INS) may be beneficial in auditory prostheses because of its spatially selective activation of spiral ganglion neurons. However, the response properties of single auditory neurons to INS and the possible contributions of its optoacoustic effects are yet to be examined. In this study, the temporal properties of auditory neurons in the central nucleus of the inferior colliculus (ICC) of guinea pigs in response to INS were characterized. Spatial selectivity of INS was observed along the tonotopically organized ICC. Trains of laser pulses and trains of acoustic clicks were used to evoke single unit responses in ICC of normal hearing animals. In response to INS, ICC neurons showed lower limiting rates, longer latencies, and lower firing efficiencies. In deaf animals, ICC neurons could still be stimulated by INS while unresponsive to acoustic stimulation. The site and spatial selectivity of INS both likely shaped the temporal properties of ICC neurons.
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Affiliation(s)
- Xiaodong Tan
- Department of Otolaryngology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Hunter Young
- Department of Otolaryngology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Agnella Izzo Matic
- Department of Otolaryngology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Whitney Zirkle
- Department of Otolaryngology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Suhrud Rajguru
- Department of Biomedical Engineering, University of Miami, Miami, Florida, USA Department of Otolaryngology, University of Miami, Miami, Florida, USA
| | - Claus-Peter Richter
- Department of Otolaryngology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA The Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, Evanston, Illinois, USA
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Radiant energy required for infrared neural stimulation. Sci Rep 2015; 5:13273. [PMID: 26305106 PMCID: PMC4548241 DOI: 10.1038/srep13273] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 07/06/2015] [Indexed: 12/15/2022] Open
Abstract
Infrared neural stimulation (INS) has been proposed as an alternative method to electrical stimulation because of its spatial selective stimulation. Independent of the mechanism for INS, to translate the method into a device it is important to determine the energy for stimulation required at the target structure. Custom-designed, flat and angle polished fibers, were used to deliver the photons. By rotating the angle polished fibers, the orientation of the radiation beam in the cochlea could be changed. INS-evoked compound action potentials and single unit responses in the central nucleus of the inferior colliculus (ICC) were recorded. X-ray computed tomography was used to determine the orientation of the optical fiber. Maximum responses were observed when the radiation beam was directed towards the spiral ganglion neurons (SGNs), whereas little responses were seen when the beam was directed towards the basilar membrane. The radiant exposure required at the SGNs to evoke compound action potentials (CAPs) or ICC responses was on average 18.9 ± 12.2 or 10.3 ± 4.9 mJ/cm(2), respectively. For cochlear INS it has been debated whether the radiation directly stimulates the SGNs or evokes a photoacoustic effect. The results support the view that a direct interaction between neurons and radiation dominates the response to INS.
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Xie B, Dai C, Li H. Attenuated infrared neuron stimulation response in cochlea of deaf animals may associate with the degeneration of spiral ganglion neurons. BIOMEDICAL OPTICS EXPRESS 2015; 6:1990-2005. [PMID: 26114024 PMCID: PMC4473739 DOI: 10.1364/boe.6.001990] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 04/23/2015] [Accepted: 04/24/2015] [Indexed: 05/13/2023]
Abstract
HYPOTHESIS We hypothesize that degenerated spiral ganglion neurons (SGNs) in guinea pigs reduces auditory brainstem responses evoked by pulsed infrared stimulation. BACKGROUND Pulsed infrared laser excitation can directly evoke physiological responses in neuronal and other excitable cells in vivo and in vitro. Laser pulses could benefit patients with cochlear implants to stimulate the auditory system. METHODS Pulsed infrared lasers were used to study evoked optical auditory brainstem responses (oABRs) in normal hearing and deafened animals. Aslo, the morphology and anatomy of SGNs in normal hearing and deafened guinea pigs were compared. RESULTS By recording oABRs evoked by varying infrared laser pulse durations, it is suggested that degeneration of SGNs in deafened guinea pigs was associated with an elevated oABR threshold and with lower amplitudes. Moreover, oABR threshold decreased while amplitudes increased in both normal hearing and deafened animals as the pulse duration prolonged. Electron microscopy revealed that SGNs in deafened guinea pigs had swollen and vacuolar mitochondria, as well as demyelinated soma and axons. CONCLUSION Infrared laser pulses can stimulate SGNs to evoke oABRs in guinea pigs. Deafened guinea pigs have elevated thresholds and smaller amplitude responses, likely a result of degenerated SGNs. Short pulse durations are more suitable to evoke responses in both normal hearing and deafened animals.
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Affiliation(s)
- Bingbin Xie
- Department of Otology and Skull Base Surgery, Hearing Research Key Lab of Health Ministry of China, Eye and ENT Hospital, Fudan University, Shanghai, 200031, China
| | - Chunfu Dai
- Department of Otology and Skull Base Surgery, Hearing Research Key Lab of Health Ministry of China, Eye and ENT Hospital, Fudan University, Shanghai, 200031, China ;
| | - Huawei Li
- Department of Otology and Skull Base Surgery, Hearing Research Key Lab of Health Ministry of China, Eye and ENT Hospital, Fudan University, Shanghai, 200031, China ;
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Young HK, Tan X, Xia N, Richter CP. Target structures for cochlear infrared neural stimulation. NEUROPHOTONICS 2015; 2:025002. [PMID: 26158006 PMCID: PMC4478722 DOI: 10.1117/1.nph.2.2.025002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 04/21/2015] [Indexed: 05/13/2023]
Abstract
Infrared neural stimulation (INS) is a method to depolarize neurons with infrared light. While consensus exists that heating of the target structure is essential, subsequent steps that result in the generation of an action potential are controversially discussed in the literature. The question of whether cochlear INS is an acoustic event has not been clarified. Results have been published that could be explained solely by an acoustic event. However, data exist that do not support an acoustical stimulus as the dominant factor in cochlear INS. We review the different findings that have been suggested for the mechanism of INS. Furthermore, we present the data that clarify the role of an acoustical event in cochlear INS. Masking experiments have been performed in hearing, hearing impaired, and severely hearing impaired animals. In normal hearing animals, the laser response could be masked by the acoustic stimulus. Once thresholds to acoustic stimuli were elevated, the ability to acoustically mask the INS response gradually disappeared. Thresholds for acoustic stimuli were significantly elevated in animals with compromised cochlear function, while the thresholds for optical stimulation remained largely unchanged. The results suggest that the direct interaction between the radiation and the target structure dominates cochlear INS.
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Affiliation(s)
- Hunter K. Young
- Northwestern University, Department of Otolaryngology, 303 East Chicago Avenue, Searle 12-561, Chicago, Illinois 60611, United States
| | - Xiaodong Tan
- Northwestern University, Department of Otolaryngology, 303 East Chicago Avenue, Searle 12-561, Chicago, Illinois 60611, United States
| | - Nan Xia
- Northwestern University, Department of Otolaryngology, 303 East Chicago Avenue, Searle 12-561, Chicago, Illinois 60611, United States
- Chongqing University, Key Laboratory of Biorheological Science and Technology, Ministry of Education, 174 Shazheng Street, Chongqing 400044, China
| | - Claus-Peter Richter
- Northwestern University, Department of Otolaryngology, 303 East Chicago Avenue, Searle 12-561, Chicago, Illinois 60611, United States
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Tech E310, Evanston, Illinois 60208, United States
- Northwestern University, The Hugh Knowles Center, Department of Communication Sciences and Disorders, 2240 Campus Drive, Evanston, Illinois 60208, United States
- Address all correspondence to: Claus-Peter Richter, E-mail:
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40
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Infrared neural stimulation fails to evoke neural activity in the deaf guinea pig cochlea. Hear Res 2015; 324:46-53. [PMID: 25796297 DOI: 10.1016/j.heares.2015.03.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 03/02/2015] [Accepted: 03/09/2015] [Indexed: 11/23/2022]
Abstract
At present there is some debate as to the processes by which infrared neural stimulation (INS) activates neurons in the cochlea, as the lasers used for INS can potentially generate a range of secondary stimuli e.g. an acoustic stimulus is produced when the light is absorbed by water. To clarify whether INS in the cochlea requires functioning hair cells and to explore the potential relevance to cochlear implants, experiments using INS were performed in the cochleae of both normal hearing and profoundly deaf guinea pigs. A response to laser stimulation was readily evoked in normal hearing cochlea. However, no response was evoked in any profoundly deaf cochleae, for either acute or chronic deafening, contrary to previous work where a response was observed after acute deafening with ototoxic drugs. A neural response to electrical stimulation was readily evoked in all cochleae after deafening. The absence of a response from optical stimuli in profoundly deaf cochleae suggests that the response from INS in the cochlea is hair cell mediated.
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41
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Zhang L, Tung VWK, Mathews M, Camp AJ. Near infrared (NIr) light increases expression of a marker of mitochondrial function in the mouse vestibular sensory epithelium. J Vis Exp 2015:52265. [PMID: 25868009 PMCID: PMC4401252 DOI: 10.3791/52265] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Strategies for attenuating decline in balance function with increasing age are predominantly focused on physical therapies including balance tasks and exercise. However, these approaches do not address the underlying causes of balance decline. Using mice, the impact of near infrared light (NIr) on the metabolism of cells in the vestibular sensory epithelium was assessed. Data collected shows that this simple and safe intervention may protect these vulnerable cells from the deleterious effects of natural aging. mRNA was extracted from the isolated peripheral vestibular sensory epithelium (crista ampullaris and utricular macula) and subsequently transcribed into a cDNA library. This library was then probed for the expression of ubiquitous antioxidant (SOD-1). Antioxidant gene expression was then used to quantify cellular metabolism. Using transcranial delivery of NIr in young (4 weeks) and older (8-9 months) mice, and a brief treatment regime (90 sec/day for 5 days), this work suggests NIr alone may be sufficient to improve mitochondrial function in the vestibular sensory epithelium. Since there are currently no available, affordable, non-invasive methods of therapy to improve vestibular hair cell function, the application of external NIr radiation provides a potential strategy to counteract the impact of aging on cellular metabolism inthe vestibular sensory epithelium.
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Affiliation(s)
- Lucy Zhang
- Discipline of Physiology, University of Sydney
| | | | | | - Aaron J Camp
- Discipline of Biomedical Science, University of Sydney;
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42
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Thompson AC, Stoddart PR, Jansen ED. Optical Stimulation of Neurons. ACTA ACUST UNITED AC 2015; 3:162-177. [PMID: 26322269 PMCID: PMC4541079 DOI: 10.2174/2211555203666141117220611] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/26/2014] [Accepted: 10/20/2014] [Indexed: 01/01/2023]
Abstract
Our capacity to interface with the nervous system remains overwhelmingly reliant on electrical stimulation devices, such as electrode arrays and cuff electrodes that can stimulate both central and peripheral nervous systems. However, electrical stimulation has to deal with multiple challenges, including selectivity, spatial resolution, mechanical stability, implant-induced injury and the subsequent inflammatory response. Optical stimulation techniques may avoid some of these challenges by providing more selective stimulation, higher spatial resolution and reduced invasiveness of the device, while also avoiding the electrical artefacts that complicate recordings of electrically stimulated neuronal activity. This review explores the current status of optical stimulation techniques, including optogenetic methods, photoactive molecule approaches and infrared neural stimulation, together with emerging techniques such as hybrid optical-electrical stimulation, nanoparticle enhanced stimulation and optoelectric methods. Infrared neural stimulation is particularly emphasised, due to the potential for direct activation of neural tissue by infrared light, as opposed to techniques that rely on the introduction of exogenous light responsive materials. However, infrared neural stimulation remains imperfectly understood, and techniques for accurately delivering light are still under development. While the various techniques reviewed here confirm the overall feasibility of optical stimulation, a number of challenges remain to be overcome before they can deliver their full potential.
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Affiliation(s)
- Alexander C Thompson
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Australia
| | - Paul R Stoddart
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Australia
| | - E Duco Jansen
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
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43
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Cayce JM, Wells JD, Malphrus JD, Kao C, Thomsen S, Tulipan NB, Konrad PE, Jansen ED, Mahadevan-Jansen A. Infrared neural stimulation of human spinal nerve roots in vivo. NEUROPHOTONICS 2015; 2:015007. [PMID: 26157986 PMCID: PMC4478764 DOI: 10.1117/1.nph.2.1.015007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 01/12/2015] [Indexed: 05/13/2023]
Abstract
Infrared neural stimulation (INS) is a neurostimulation modality that uses pulsed infrared light to evoke artifact-free, spatially precise neural activity with a noncontact interface; however, the technique has not been demonstrated in humans. The objective of this study is to demonstrate the safety and efficacy of INS in humans in vivo. The feasibility of INS in humans was assessed in patients ([Formula: see text]) undergoing selective dorsal root rhizotomy, where hyperactive dorsal roots, identified for transection, were stimulated in vivo with INS on two to three sites per nerve with electromyogram recordings acquired throughout the stimulation. The stimulated dorsal root was removed and histology was performed to determine thermal damage thresholds of INS. Threshold activation of human dorsal rootlets occurred in 63% of nerves for radiant exposures between 0.53 and [Formula: see text]. In all cases, only one or two monitored muscle groups were activated from INS stimulation of a hyperactive spinal root identified by electrical stimulation. Thermal damage was first noted at [Formula: see text] and a [Formula: see text] safety ratio was identified. These findings demonstrate the success of INS as a fresh approach for activating human nerves in vivo and providing the necessary safety data needed to pursue clinically driven therapeutic and diagnostic applications of INS in humans.
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Affiliation(s)
- Jonathan M. Cayce
- Vanderbilt University, Department of Biomedical Engineering, 5824 Stevenson Center, Station B, Box 351631 Nashville, Tennessee 37235-1631, United States
| | - Jonathon D. Wells
- Lockheed Martin, 22121 20th Avenue SE, Bothell, Washington 98021, United States
| | - Jonathan D. Malphrus
- Vanderbilt University, Department of Biomedical Engineering, 5824 Stevenson Center, Station B, Box 351631 Nashville, Tennessee 37235-1631, United States
| | - Chris Kao
- Vanderbilt University, Department of Neurological Surgery, 1161 21st Avenue, Nashville, Tennessee 37232-2380, United States
| | - Sharon Thomsen
- University of Texas, Department of Biomedical Engineering, Austin, Texas, and 500 Discovery View Drive, Sequim, Washington 98382, United States
| | - Noel B. Tulipan
- Vanderbilt University, Department of Neurological Surgery, 1161 21st Avenue, Nashville, Tennessee 37232-2380, United States
| | - Peter E. Konrad
- Vanderbilt University, Department of Biomedical Engineering, 5824 Stevenson Center, Station B, Box 351631 Nashville, Tennessee 37235-1631, United States
- Vanderbilt University, Department of Neurological Surgery, 1161 21st Avenue, Nashville, Tennessee 37232-2380, United States
| | - E. Duco Jansen
- Vanderbilt University, Department of Biomedical Engineering, 5824 Stevenson Center, Station B, Box 351631 Nashville, Tennessee 37235-1631, United States
- Vanderbilt University, Department of Neurological Surgery, 1161 21st Avenue, Nashville, Tennessee 37232-2380, United States
| | - Anita Mahadevan-Jansen
- Vanderbilt University, Department of Biomedical Engineering, 5824 Stevenson Center, Station B, Box 351631 Nashville, Tennessee 37235-1631, United States
- Vanderbilt University, Department of Neurological Surgery, 1161 21st Avenue, Nashville, Tennessee 37232-2380, United States
- Address all correspondence to: Anita Mahadevan-Jansen, E-mail:
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44
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Liu Q, Frerck MJ, Holman HA, Jorgensen EM, Rabbitt RD. Exciting cell membranes with a blustering heat shock. Biophys J 2014; 106:1570-7. [PMID: 24739156 DOI: 10.1016/j.bpj.2014.03.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 03/05/2014] [Accepted: 03/06/2014] [Indexed: 11/30/2022] Open
Abstract
Brief heat shocks delivered to cells by pulsed laser light can evoke action potentials in neurons and contraction in cardiomyocytes, but the primary biophysical mechanism has been elusive. In this report we show in the neuromuscular junction of Caenorhabditis elegans that application of a 500°C/s heat shock for 500 μs evoked ~35 pA of excitatory current and injected ~23 fC(femtocoulomb) of charge into the cell while raising the temperature only 0.25°C. The key variable driving the current was the rate of change of temperature (dT/dt heat shock), not temperature itself. The photothermal heat shock current was voltage-dependent and was from thermally driven displacement of ions near the plasma membrane. The charge movement was rapid during the heat shock and slow during thermal relaxation, thus leading to an asymmetrical capacitive current that briefly depolarized the cell. A simple quantitative model is introduced to describe modulation of the membrane potential and facilitate practical application of optical heat shock stimuli.
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Affiliation(s)
- Qiang Liu
- Department of Biology, University of Utah, Salt Lake City, Utah
| | - Micah J Frerck
- Department of Bioengineering, University of Utah, Salt Lake City, Utah
| | - Holly A Holman
- Department of Bioengineering, University of Utah, Salt Lake City, Utah
| | - Erik M Jorgensen
- Department of Biology, University of Utah, Salt Lake City, Utah; Howard Hughes Medical Institute, University of Utah, Salt Lake City, Utah
| | - Richard D Rabbitt
- Department of Bioengineering, University of Utah, Salt Lake City, Utah; Marine Biological Laboratory, Woods Hole, Massachusetts.
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Abstract
The success of conventional hearing aids and electrical auditory prostheses for hearing impaired patients is still limited in noisy environments and for sounds more complex than speech (e. g. music). This is partially due to the difficulty of frequency-specific activation of the auditory system using these devices. Stimulation of the auditory system using light pulses represents an alternative to mechanical and electrical stimulation. Light is a source of energy that can be very exactly focused and applied with little scattering, thus offering perspectives for optimal activation of the auditory system. Studies investigating light stimulation of sectors along the auditory pathway have shown stimulation of the auditory system is possible using light pulses. However, further studies and developments are needed before a new generation of light stimulation-based auditory prostheses can be made available for clinical application.
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46
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Lumbreras V, Bas E, Gupta C, Rajguru SM. Pulsed infrared radiation excites cultured neonatal spiral and vestibular ganglion neurons by modulating mitochondrial calcium cycling. J Neurophysiol 2014; 112:1246-55. [PMID: 24920028 DOI: 10.1152/jn.00253.2014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cochlear implants are currently the most effective solution for profound sensorineural hearing loss, and vestibular prostheses are under development to treat bilateral vestibulopathies. Electrical current spread in these neuroprostheses limits channel independence and, in some cases, may impair their performance. In comparison, optical stimuli that are spatially confined may result in a significant functional improvement. Pulsed infrared radiation (IR) has previously been shown to elicit responses in neurons. This study analyzes the response of neonatal rat spiral and vestibular ganglion neurons in vitro to IR (wavelength = 1,863 nm) using Ca(2+) imaging. Both types of neurons responded consistently with robust intracellular Ca(2+) ([Ca(2+)]i) transients that matched the low-frequency IR pulses applied (4 ms, 0.25-1 pps). Radiant exposures of ∼637 mJ/cm(2) resulted in continual neuronal activation. Temperature or [Ca(2+)] variations in the media did not alter the IR-evoked transients, ruling out extracellular Ca(2+) involvement or primary mediation by thermal effects on the plasma membrane. While blockage of Na(+), K(+), and Ca(2+) plasma membrane channels did not alter the IR-evoked response, blocking of mitochondrial Ca(2+) cycling with CGP-37157 or ruthenium red reversibly inhibited the IR-evoked [Ca(2+)]i transients. Additionally, the magnitude of the IR-evoked transients was dependent on ryanodine and cyclopiazonic acid-dependent Ca(2+) release. These results suggest that IR modulation of intracellular calcium cycling contributes to stimulation of spiral and vestibular ganglion neurons. As a whole, the results suggest selective excitation of neurons in the IR beam path and the potential of IR stimulation in future auditory and vestibular prostheses.
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Affiliation(s)
- Vicente Lumbreras
- Department of Biomedical Engineering, University of Miami, Miami, Florida; and
| | - Esperanza Bas
- Department of Otolaryngology, University of Miami, Miami, Florida
| | - Chhavi Gupta
- Department of Otolaryngology, University of Miami, Miami, Florida
| | - Suhrud M Rajguru
- Department of Biomedical Engineering, University of Miami, Miami, Florida; and Department of Otolaryngology, University of Miami, Miami, Florida
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Wang YT, Gu S, Ma P, Watanabe M, Rollins AM, Jenkins MW. Optical stimulation enables paced electrophysiological studies in embryonic hearts. BIOMEDICAL OPTICS EXPRESS 2014; 5:1000-13. [PMID: 24761284 PMCID: PMC3985989 DOI: 10.1364/boe.5.001000] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 02/13/2014] [Accepted: 02/21/2014] [Indexed: 05/11/2023]
Abstract
Cardiac electrophysiology plays a critical role in the development and function of the heart. Studies of early embryonic electrical activity have lacked a viable point stimulation technique to pace in vitro samples. Here, optical pacing by high-precision infrared stimulation is used to pace excised embryonic hearts, allowing electrophysiological parameters to be quantified during pacing at varying rates with optical mapping. Combined optical pacing and optical mapping enables electrophysiological studies in embryos under more physiological conditions and at varying heart rates, allowing detection of abnormal conduction and comparisons between normal and pathological electrical activity during development in various models.
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Affiliation(s)
- Yves T. Wang
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44120, USA
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, 44120, USA
| | - Shi Gu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44120, USA
| | - Pei Ma
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44120, USA
| | - Michiko Watanabe
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, 44120, USA
| | - Andrew M. Rollins
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44120, USA
| | - Michael W. Jenkins
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44120, USA
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, 44120, USA
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48
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Duke AR, Jenkins MW, Lu H, McManus JM, Chiel HJ, Jansen ED. Transient and selective suppression of neural activity with infrared light. Sci Rep 2014; 3:2600. [PMID: 24009039 PMCID: PMC3764437 DOI: 10.1038/srep02600] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 08/19/2013] [Indexed: 11/09/2022] Open
Abstract
Analysis and control of neural circuitry requires the ability to selectively activate or inhibit neurons. Previous work showed that infrared laser light selectively excited neural activity in endogenous unmyelinated and myelinated axons. However, inhibition of neuronal firing with infrared light was only observed in limited cases, is not well understood and was not precisely controlled. Using an experimentally tractable unmyelinated preparation for detailed investigation and a myelinated preparation for validation, we report that it is possible to selectively and transiently inhibit electrically-initiated axonal activation, as well as to both block or enhance the propagation of action potentials of specific motor neurons. Thus, in addition to previously shown excitation, we demonstrate an optical method of suppressing components of the nervous system with functional spatiotemporal precision. We believe this technique is well-suited for non-invasive investigations of diverse excitable tissues and may ultimately be applied for treating neurological disorders.
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Affiliation(s)
- Austin R Duke
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
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49
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Calcium imaging of infrared-stimulated activity in rodent brain. Cell Calcium 2014; 55:183-90. [PMID: 24674600 DOI: 10.1016/j.ceca.2014.01.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 01/16/2014] [Accepted: 01/21/2014] [Indexed: 11/20/2022]
Abstract
Infrared neural stimulation (INS) is a promising neurostimulation technique that can activate neural tissue with high spatial precision and without the need for exogenous agents. However, little is understood about how infrared light interacts with neural tissue on a cellular level, particularly within the living brain. In this study, we use calcium sensitive dye imaging on macroscopic and microscopic scales to explore the spatiotemporal effects of INS on cortical calcium dynamics. The INS-evoked calcium signal that was observed exhibited a fast and slow component suggesting activation of multiple cellular mechanisms. The slow component of the evoked signal exhibited wave-like properties suggesting network activation, and was verified to originate from astrocytes through pharmacology and 2-photon imaging. We also provide evidence that the fast calcium signal may have been evoked through modulation of glutamate transients. This study demonstrates that pulsed infrared light can induce intracellular calcium modulations in both astrocytes and neurons, providing new insights into the mechanisms of action of INS in the brain.
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50
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Abstract
Temperature is one of the key parameters that controlled the origin and evolution of life on earth and it continues to be a principal regulator of the functions of organisms. Some aspects of the response of simple and complex organisms to temperature variations are encoded in the physical properties of the cell components, with the all-important plasma membrane playing a principal role. Other responses to temperature are more specific and through evolution, specialized receptors with particular temperature sensitivities have appeared to mediate this signaling. While some of these receptors are ancient and can be found in very primitive organisms, it seems that the mechanisms used by prokaryotes and eukaryotes are very different, indicating that temperature sensitivity has evolved in more than one occasion during evolution.
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Affiliation(s)
- León D Islas
- Department of Physiology, School of Medicine, National Autonomous University of Mexico (UNAM), Mexico City, Mexico.
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