1
|
Yousefi T, Timonina K, Zoidl G, Kassiri H. An Implantable Optogenetic Neuro-Stimulator SoC With Extended Optical Pulse-Width Enabled by Supply-Variation-Immune Cycled Light-Toggling Stimulation. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2022; 16:557-569. [PMID: 35969561 DOI: 10.1109/tbcas.2022.3198911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The design, development, and experimental validation of an inductively-powered four-channel optical neuro-stimulator system on a chip (SoC) with on-chip neural recording, temperature monitoring, signal processing, and bidirectional wireless data communication are presented. A biologically-inspired optical stimulation approach is employed that extends the limitations on the stimulation pulse-width and frequency (i.e., enabling wirelessly-powered optical stimulation at very low frequencies (e.g., 10 Hz)) while significantly reducing the required on-device storage capacitor size. The biological efficacy of the proposed approach is validated and compared with conventional stimulation through in vitro experiments. The stimulator's energy efficiency is enhanced by employing a high-gain (850 A/A) current amplifier/driver in each channel that steers up to 10 mA into the optical source with an excellent linearity ( 0.5LSB), while 1) yielding the lowest-in-literature required voltage headroom, and 2) being insensitive to large (up to 12%) supply voltage drops, which is ideal for battery-less implantable devices. Additionally, to maximize the percentage of the generated optical power that reaches the targeted cells (thus, further energy efficiency enhancement), inkjet printing is utilized to fabricate custom-designed optical μlenses that are placed directly on top of the silicon SoC to enhance the generated light's directivity by > 30×. An electrophysiological recording channel for real-time monitoring of the stimulation efficacy and a high-precision (0.1 °C resolution) temperature readout circuit for shutting off stimulation upon detection of an unsafe temperature increase are also integrated on the chip. Additionally, the SoC hosts an ASK receiver and an LSK transmitter for downlink and uplink wireless data communication, respectively. The SoC is fabricated in a standard 130 nm CMOS process and occupies 6 mm 2. Measurement results for different sensory and communication blocks are presented, as well as in vitro experimental validation results showing simultaneous optical stimulation, electrical recording, and calcium imaging.
Collapse
|
2
|
Yousefi T, Taghadosi M, Dabbaghian A, Siu R, Grau G, Zoidl G, Kassiri H. An Energy-Efficient Optically-Enhanced Highly-Linear Implantable Wirelessly-Powered Bidirectional Optogenetic Neuro-Stimulator. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2020; 14:1274-1286. [PMID: 32976106 DOI: 10.1109/tbcas.2020.3026937] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This paper presents an energy-efficient mm-scale self-contained bidirectional optogenetic neuro-stimulator, which employs a novel highly-linear μLED driving circuit architecture as well as inkjet-printed custom-designed optical μlenses for light directivity enhancement. The proposed current-mode μLED driver performs linear control of optical stimulation for the entire target range ( 10 mA) while requiring the smallest reported headroom, yielding a significant boost in the energy conversion efficiency. A 30.46× improvement in the power delivery efficiency to the target tissue is achieved by employing a pair of printed optical μlenses. The fabricated SoC also integrates two recording channels for LFP recording and digitization, as well as power management blocks. A micro-coil is also embedded on the chip to receive inductive power and our experimental results show a PTE of 2.24 % for the wireless link. The self-contained system including the μLEDs, μlenses and the capacitors required by the power management blocks is sized 6 mm 3 and weighs 12.5 mg. Full experimental measurement results for electrical and optical circuitry as well as in vitro measurement results are reported.
Collapse
|
3
|
Kim J, Augustine GJ. Molecular Layer Interneurons: Key Elements of Cerebellar Network Computation and Behavior. Neuroscience 2020; 462:22-35. [PMID: 33075461 DOI: 10.1016/j.neuroscience.2020.10.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/02/2020] [Accepted: 10/05/2020] [Indexed: 02/05/2023]
Abstract
Molecular layer interneurons (MLIs) play an important role in cerebellar information processing by controlling Purkinje cell (PC) activity via inhibitory synaptic transmission. A local MLI network, constructed from both chemical and electrical synapses, is organized into spatially structured clusters that amplify feedforward and lateral inhibition to shape the temporal and spatial patterns of PC activity. Several recent in vivo studies indicate that such MLI circuits contribute not only to sensorimotor information processing, but also to precise motor coordination and cognitive processes. Here, we review current understanding of the organization of MLI circuits and their roles in the function of the mammalian cerebellum.
Collapse
Affiliation(s)
- Jinsook Kim
- Lee Kong Chian School of Medicine Nanyang Technological University Singapore 308238, Singapore
| | - George J Augustine
- Lee Kong Chian School of Medicine Nanyang Technological University Singapore 308238, Singapore.
| |
Collapse
|
4
|
Stahlberg MA, Ramakrishnan C, Willig KI, Boyden ES, Deisseroth K, Dean C. Investigating the feasibility of channelrhodopsin variants for nanoscale optogenetics. NEUROPHOTONICS 2019; 6:015007. [PMID: 30854405 PMCID: PMC6393647 DOI: 10.1117/1.nph.6.1.015007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 02/05/2019] [Indexed: 06/09/2023]
Abstract
Optogenetics has revolutionized the study of circuit function in the brain, by allowing activation of specific ensembles of neurons by light. However, this technique has not yet been exploited extensively at the subcellular level. Here, we test the feasibility of a focal stimulation approach using stimulated emission depletion/reversible saturable optical fluorescence transitions-like illumination, whereby switchable light-gated channels are focally activated by a laser beam of one wavelength and deactivated by an overlapping donut-shaped beam of a different wavelength, confining activation to a center focal region. This method requires that activated channelrhodopsins are inactivated by overlapping illumination of a distinct wavelength and that photocurrents are large enough to be detected at the nanoscale. In tests of current optogenetic tools, we found that ChR2 C128A/H134R/T159C and CoChR C108S and C108S/D136A-activated with 405-nm light and inactivated by coillumination with 594-nm light-and C1V1 E122T/C167S-activated by 561-nm light and inactivated by 405-nm light-were most promising in terms of highest photocurrents and efficient inactivation with coillumination. Although further engineering of step-function channelrhodopsin variants with higher photoconductances will be required to employ this approach at the nanoscale, our findings provide a framework to guide future development of this technique.
Collapse
Affiliation(s)
- Markus A. Stahlberg
- European Neuroscience Institute, Trans-Synaptic Signaling Group, Goettingen, Germany
| | - Charu Ramakrishnan
- Stanford University, Howard Hughes Medical Institute, Department of Bioengineering, Department of Psychiatry, CNC Program, Stanford, California, United States
| | - Katrin I. Willig
- University Medical Center, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Goettingen, Germany
| | - Edward S. Boyden
- MIT Media Lab and McGovern Institute, Departments of Brain and Cognitive Science and Biological Engineering, Cambridge, Massachusetts, United States
| | - Karl Deisseroth
- Stanford University, Howard Hughes Medical Institute, Department of Bioengineering, Department of Psychiatry, CNC Program, Stanford, California, United States
| | - Camin Dean
- European Neuroscience Institute, Trans-Synaptic Signaling Group, Goettingen, Germany
| |
Collapse
|
5
|
Gobbo F, Marchetti L, Jacob A, Pinto B, Binini N, Pecoraro Bisogni F, Alia C, Luin S, Caleo M, Fellin T, Cancedda L, Cattaneo A. Activity-dependent expression of Channelrhodopsin at neuronal synapses. Nat Commun 2017; 8:1629. [PMID: 29158498 PMCID: PMC5696361 DOI: 10.1038/s41467-017-01699-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 10/06/2017] [Indexed: 12/14/2022] Open
Abstract
Increasing evidence points to the importance of dendritic spines in the formation and allocation of memories, and alterations of spine number and physiology are associated to memory and cognitive disorders. Modifications of the activity of subsets of synapses are believed to be crucial for memory establishment. However, the development of a method to directly test this hypothesis, by selectively controlling the activity of potentiated spines, is currently lagging. Here we introduce a hybrid RNA/protein approach to regulate the expression of a light-sensitive membrane channel at activated synapses, enabling selective tagging of potentiated spines following the encoding of a novel context in the hippocampus. This approach can be used to map potentiated synapses in the brain and will make it possible to re-activate the neuron only at previously activated synapses, extending current neuron-tagging technologies in the investigation of memory processes.
Collapse
Affiliation(s)
- Francesco Gobbo
- Bio@SNS, Scuola Normale Superiore, piazza dei Cavalieri 7, 56126, Pisa, Italy.,NEST, Scuola Normale Superiore, piazza San Silvestro 12, 56127, Pisa, Italy
| | - Laura Marchetti
- Bio@SNS, Scuola Normale Superiore, piazza dei Cavalieri 7, 56126, Pisa, Italy.,NEST, Scuola Normale Superiore, piazza San Silvestro 12, 56127, Pisa, Italy.,Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, piazza San Silvestro 12, 56127, Pisa, Italy
| | - Ajesh Jacob
- Bio@SNS, Scuola Normale Superiore, piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - Bruno Pinto
- Bio@SNS, Scuola Normale Superiore, piazza dei Cavalieri 7, 56126, Pisa, Italy.,Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy
| | - Noemi Binini
- Optical Approaches to Brain Function Laboratory, Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genova, Italy
| | - Federico Pecoraro Bisogni
- Optical Approaches to Brain Function Laboratory, Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genova, Italy
| | - Claudia Alia
- Bio@SNS, Scuola Normale Superiore, piazza dei Cavalieri 7, 56126, Pisa, Italy.,Istituto di Neuroscienze, Consiglio Nazionale delle Ricerche, via Moruzzi 1, 56124, Pisa, Italy
| | - Stefano Luin
- NEST, Scuola Normale Superiore, piazza San Silvestro 12, 56127, Pisa, Italy
| | - Matteo Caleo
- Istituto di Neuroscienze, Consiglio Nazionale delle Ricerche, via Moruzzi 1, 56124, Pisa, Italy
| | - Tommaso Fellin
- Optical Approaches to Brain Function Laboratory, Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genova, Italy
| | - Laura Cancedda
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy.,Dulbecco Telethon Institute, via Varese 16b, 00185, Rome, Italy
| | - Antonino Cattaneo
- Bio@SNS, Scuola Normale Superiore, piazza dei Cavalieri 7, 56126, Pisa, Italy.
| |
Collapse
|
6
|
Parvalbumin-expressing interneurons can act solo while somatostatin-expressing interneurons act in chorus in most cases on cortical pyramidal cells. Sci Rep 2017; 7:12764. [PMID: 28986578 PMCID: PMC5630625 DOI: 10.1038/s41598-017-12958-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 09/13/2017] [Indexed: 11/24/2022] Open
Abstract
Neural circuits in the cerebral cortex consist primarily of excitatory pyramidal (Pyr) cells and inhibitory interneurons. Interneurons are divided into several subtypes, in which the two major groups are those expressing parvalbumin (PV) or somatostatin (SOM). These subtypes of interneurons are reported to play distinct roles in tuning and/or gain of visual response of pyramidal cells in the visual cortex. It remains unclear whether there is any quantitative and functional difference between the PV → Pyr and SOM → Pyr connections. We compared unitary inhibitory postsynaptic currents (uIPSCs) evoked by electrophysiological activation of single presynaptic interneurons with population IPSCs evoked by photo-activation of a mass of interneurons in vivo and in vitro in transgenic mice in which PV or SOM neurons expressed channelrhodopsin-2, and found that at least about 14 PV neurons made strong connections with a postsynaptic Pyr cell while a much larger number of SOM neurons made weak connections. Activation or suppression of single PV neurons modified visual responses of postsynaptic Pyr cells in 6 of 7 pairs whereas that of single SOM neurons showed no significant modification in 8 of 11 pairs, suggesting that PV neurons can act solo whereas most of SOM neurons may act in chorus on Pyr cells.
Collapse
|
7
|
Weiss RS, Voss A, Hemmert W. Optogenetic stimulation of the cochlea-A review of mechanisms, measurements, and first models. NETWORK (BRISTOL, ENGLAND) 2016; 27:212-236. [PMID: 27644125 DOI: 10.1080/0954898x.2016.1224944] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This review evaluates the potential of optogenetic methods for the stimulation of the auditory nerve and assesses the feasability of optogenetic cochlear implants (CIs). It provides an overview of all critical steps like opsin targeting strategies, how opsins work, how their function can be modeled and included in neuronal models and the properties of light sources available for optical stimulation. From these foundations, quantitative estimates for the number of independent stimulation channels and the temporal precision of optogenetic stimulation of the auditory nerve are derived and compared with state-of-the-art electrical CIs. We conclude that optogenetic CIs have the potential to increase the number of independent stimulation channels by up to one order of magnitude to about 100, but only if light sources are able to deliver confined illumination patterns independently and parallelly. Already now, opsin variants like ChETA and Chronos enable driving of the auditory nerve up to rates of 200 spikes/s, close to the physiological value of their maximum sustained firing rate. Apart from requiring 10 times more energy than electrical stimulation, optical CIs still face major hurdles concerning the safety of gene transfection and optrode array implantation, for example, before becoming an option to replace electrical CIs.
Collapse
Affiliation(s)
- Robin S Weiss
- a Bio-Inspired Information Processing, Faculty of Electrical and Computer Engineering , Technical University of Munich , Garching , Germany
| | - Andrej Voss
- a Bio-Inspired Information Processing, Faculty of Electrical and Computer Engineering , Technical University of Munich , Garching , Germany
| | - Werner Hemmert
- a Bio-Inspired Information Processing, Faculty of Electrical and Computer Engineering , Technical University of Munich , Garching , Germany
| |
Collapse
|
8
|
Uhlirova H, Kılıç K, Tian P, Thunemann M, Desjardins M, Saisan PA, Sakadžić S, Ness TV, Mateo C, Cheng Q, Weldy KL, Razoux F, Vandenberghe M, Cremonesi JA, Ferri CG, Nizar K, Sridhar VB, Steed TC, Abashin M, Fainman Y, Masliah E, Djurovic S, Andreassen OA, Silva GA, Boas DA, Kleinfeld D, Buxton RB, Einevoll GT, Dale AM, Devor A. Cell type specificity of neurovascular coupling in cerebral cortex. eLife 2016; 5. [PMID: 27244241 PMCID: PMC4933561 DOI: 10.7554/elife.14315] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Accepted: 05/30/2016] [Indexed: 12/16/2022] Open
Abstract
Identification of the cellular players and molecular messengers that communicate neuronal activity to the vasculature driving cerebral hemodynamics is important for (1) the basic understanding of cerebrovascular regulation and (2) interpretation of functional Magnetic Resonance Imaging (fMRI) signals. Using a combination of optogenetic stimulation and 2-photon imaging in mice, we demonstrate that selective activation of cortical excitation and inhibition elicits distinct vascular responses and identify the vasoconstrictive mechanism as Neuropeptide Y (NPY) acting on Y1 receptors. The latter implies that task-related negative Blood Oxygenation Level Dependent (BOLD) fMRI signals in the cerebral cortex under normal physiological conditions may be mainly driven by the NPY-positive inhibitory neurons. Further, the NPY-Y1 pathway may offer a potential therapeutic target in cerebrovascular disease.
Collapse
Affiliation(s)
- Hana Uhlirova
- Department of Radiology, University of California, San Diego, La Jolla, United States
| | - Kıvılcım Kılıç
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Peifang Tian
- Department of Neurosciences, University of California, San Diego, La Jolla, United States.,Department of Physics, John Carroll University, University Heights, United States
| | - Martin Thunemann
- Department of Radiology, University of California, San Diego, La Jolla, United States
| | - Michèle Desjardins
- Department of Radiology, University of California, San Diego, La Jolla, United States
| | - Payam A Saisan
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Sava Sakadžić
- Martinos Center for Biomedical Imaging, Harvard Medical School, Charlestown, United States
| | - Torbjørn V Ness
- Department of Mathematical Sciences and Technology, Norwegian University of Life Sciences, Ås, Norway
| | - Celine Mateo
- Department of Physics, University of California, San Diego, La Jolla, United States
| | - Qun Cheng
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Kimberly L Weldy
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Florence Razoux
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Matthieu Vandenberghe
- Department of Radiology, University of California, San Diego, La Jolla, United States.,NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, University of Oslo, Oslo, Norway
| | - Jonathan A Cremonesi
- Biology Undergraduate Program, University of California, San Diego, La Jolla, United States
| | - Christopher Gl Ferri
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Krystal Nizar
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, United States
| | - Vishnu B Sridhar
- Department of Bioengineering, University of California, San Diego, La Jolla, United States
| | - Tyler C Steed
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, United States
| | - Maxim Abashin
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, United States
| | - Yeshaiahu Fainman
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, United States
| | - Eliezer Masliah
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Srdjan Djurovic
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway.,NORMENT, KG Jebsen Centre for Psychosis Research, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Ole A Andreassen
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, University of Oslo, Oslo, Norway
| | - Gabriel A Silva
- Department of Bioengineering, University of California, San Diego, La Jolla, United States.,Department of Ophthalmology, University of California, San Diego, La Jolla, United States
| | - David A Boas
- Martinos Center for Biomedical Imaging, Harvard Medical School, Charlestown, United States
| | - David Kleinfeld
- Department of Physics, University of California, San Diego, La Jolla, United States.,Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, United States.,Section of Neurobiology, University of California, San Diego, La Jolla, United States
| | - Richard B Buxton
- Department of Radiology, University of California, San Diego, La Jolla, United States
| | - Gaute T Einevoll
- Department of Mathematical Sciences and Technology, Norwegian University of Life Sciences, Ås, Norway.,Department of Physics, University of Oslo, Oslo, Norway
| | - Anders M Dale
- Department of Radiology, University of California, San Diego, La Jolla, United States.,Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Anna Devor
- Department of Radiology, University of California, San Diego, La Jolla, United States.,Department of Neurosciences, University of California, San Diego, La Jolla, United States.,Martinos Center for Biomedical Imaging, Harvard Medical School, Charlestown, United States
| |
Collapse
|
9
|
Pulizzi R, Musumeci G, Van den Haute C, Van De Vijver S, Baekelandt V, Giugliano M. Brief wide-field photostimuli evoke and modulate oscillatory reverberating activity in cortical networks. Sci Rep 2016; 6:24701. [PMID: 27099182 PMCID: PMC4838830 DOI: 10.1038/srep24701] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 04/04/2016] [Indexed: 01/18/2023] Open
Abstract
Cell assemblies manipulation by optogenetics is pivotal to advance neuroscience and neuroengineering. In in vivo applications, photostimulation often broadly addresses a population of cells simultaneously, leading to feed-forward and to reverberating responses in recurrent microcircuits. The former arise from direct activation of targets downstream, and are straightforward to interpret. The latter are consequence of feedback connectivity and may reflect a variety of time-scales and complex dynamical properties. We investigated wide-field photostimulation in cortical networks in vitro, employing substrate-integrated microelectrode arrays and long-term cultured neuronal networks. We characterized the effect of brief light pulses, while restricting the expression of channelrhodopsin to principal neurons. We evoked robust reverberating responses, oscillating in the physiological gamma frequency range, and found that such a frequency could be reliably manipulated varying the light pulse duration, not its intensity. By pharmacology, mathematical modelling, and intracellular recordings, we conclude that gamma oscillations likely emerge as in vivo from the excitatory-inhibitory interplay and that, unexpectedly, the light stimuli transiently facilitate excitatory synaptic transmission. Of relevance for in vitro models of (dys)functional cortical microcircuitry and in vivo manipulations of cell assemblies, we give for the first time evidence of network-level consequences of the alteration of synaptic physiology by optogenetics.
Collapse
Affiliation(s)
- Rocco Pulizzi
- Theoretical Neurobiology &Neuroengineering, University of Antwerp, Antwerp, Belgium
| | - Gabriele Musumeci
- Theoretical Neurobiology &Neuroengineering, University of Antwerp, Antwerp, Belgium
| | - Chris Van den Haute
- Laboratory of Neurobiology and Gene Therapy, Katholieke Universiteit Leuven, Leuven, Belgium.,Leuven Viral Vector Core, Katholieke Universiteit Leuven, Leuven, Belgium
| | | | - Veerle Baekelandt
- Laboratory of Neurobiology and Gene Therapy, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Michele Giugliano
- Theoretical Neurobiology &Neuroengineering, University of Antwerp, Antwerp, Belgium.,Department of Computer Science, University of Sheffield, S1 4DP Sheffield, UK.,Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, CH-1015 Lausanne, Switzerland
| |
Collapse
|
10
|
Transparent intracortical microprobe array for simultaneous spatiotemporal optical stimulation and multichannel electrical recording. Nat Methods 2015; 12:1157-62. [DOI: 10.1038/nmeth.3620] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 09/08/2015] [Indexed: 12/22/2022]
|
11
|
Advantages and limitations of the use of optogenetic approach in studying fast-scale spike encoding. PLoS One 2015; 10:e0122286. [PMID: 25850004 PMCID: PMC4388689 DOI: 10.1371/journal.pone.0122286] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 02/15/2015] [Indexed: 12/04/2022] Open
Abstract
Understanding single-neuron computations and encoding performed by spike-generation mechanisms of cortical neurons is one of the central challenges for cell electrophysiology and computational neuroscience. An established paradigm to study spike encoding in controlled conditions in vitro uses intracellular injection of a mixture of signals with fluctuating currents that mimic in vivo-like background activity. However this technique has two serious limitations: it uses current injection, while synaptic activation leads to changes of conductance, and current injection is technically most feasible in the soma, while the vast majority of synaptic inputs are located on the dendrites. Recent progress in optogenetics provides an opportunity to circumvent these limitations. Transgenic expression of light-activated ionic channels, such as Channelrhodopsin2 (ChR2), allows induction of controlled conductance changes even in thin distant dendrites. Here we show that photostimulation provides a useful extension of the tools to study neuronal encoding, but it has its own limitations. Optically induced fluctuating currents have a low cutoff (~70Hz), thus limiting the dynamic range of frequency response of cortical neurons. This leads to severe underestimation of the ability of neurons to phase-lock their firing to high frequency components of the input. This limitation could be worked around by using short (2 ms) light stimuli which produce membrane potential responses resembling EPSPs by their fast onset and prolonged decay kinetics. We show that combining application of short light stimuli to different parts of dendritic tree for mimicking distant EPSCs with somatic injection of fluctuating current that mimics fluctuations of membrane potential in vivo, allowed us to study fast encoding of artificial EPSPs photoinduced at different distances from the soma. We conclude that dendritic photostimulation of ChR2 with short light pulses provides a powerful tool to investigate population encoding of simulated synaptic potentials generated in dendrites at different distances from the soma.
Collapse
|
12
|
Jeschke M, Moser T. Considering optogenetic stimulation for cochlear implants. Hear Res 2015; 322:224-34. [PMID: 25601298 DOI: 10.1016/j.heares.2015.01.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 12/09/2014] [Accepted: 01/08/2015] [Indexed: 02/04/2023]
Abstract
Electrical cochlear implants are by far the most successful neuroprostheses and have been implanted in over 300,000 people worldwide. Cochlear implants enable open speech comprehension in most patients but are limited in providing music appreciation and speech understanding in noisy environments. This is generally considered to be due to low frequency resolution as a consequence of wide current spread from stimulation contacts. Accordingly, the number of independently usable stimulation channels is limited to less than a dozen. As light can be conveniently focused, optical stimulation might provide an alternative approach to cochlear implants with increased number of independent stimulation channels. Here, we focus on summarizing recent work on optogenetic stimulation as one way to develop optical cochlear implants. We conclude that proof of principle has been presented for optogenetic stimulation of the cochlea and central auditory neurons in rodents as well as for the technical realization of flexible μLED-based multichannel cochlear implants. Still, much remains to be done in order to advance the technique for auditory research and even more for eventual clinical translation. This article is part of a Special Issue entitled <Lasker Award>.
Collapse
Affiliation(s)
- Marcus Jeschke
- Institute for Auditory Neuroscience, University Medical Center Goettingen, Goettingen, Germany; Auditory Neuroscience Group, German Primate Center, Goettingen, Germany.
| | - Tobias Moser
- Institute for Auditory Neuroscience, University Medical Center Goettingen, Goettingen, Germany; Auditory Neuroscience Group, German Primate Center, Goettingen, Germany; Bernstein Focus for Neurotechnology, University of Göttingen, Goettingen, Germany; Collaborative Research Center 889, University of Goettingen Medical Center, Goettingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University of Goettingen, Goettingen, Germany.
| |
Collapse
|
13
|
Hochbaum DR, Zhao Y, Farhi SL, Klapoetke N, Werley CA, Kapoor V, Zou P, Kralj JM, Maclaurin D, Smedemark-Margulies N, Saulnier JL, Boulting GL, Straub C, Cho YK, Melkonian M, Wong GKS, Harrison DJ, Murthy VN, Sabatini BL, Boyden ES, Campbell RE, Cohen AE. All-optical electrophysiology in mammalian neurons using engineered microbial rhodopsins. Nat Methods 2014; 11:825-33. [PMID: 24952910 PMCID: PMC4117813 DOI: 10.1038/nmeth.3000] [Citation(s) in RCA: 508] [Impact Index Per Article: 50.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 05/17/2014] [Indexed: 01/27/2023]
Abstract
All-optical electrophysiology-spatially resolved simultaneous optical perturbation and measurement of membrane voltage-would open new vistas in neuroscience research. We evolved two archaerhodopsin-based voltage indicators, QuasAr1 and QuasAr2, which show improved brightness and voltage sensitivity, have microsecond response times and produce no photocurrent. We engineered a channelrhodopsin actuator, CheRiff, which shows high light sensitivity and rapid kinetics and is spectrally orthogonal to the QuasArs. A coexpression vector, Optopatch, enabled cross-talk-free genetically targeted all-optical electrophysiology. In cultured rat neurons, we combined Optopatch with patterned optical excitation to probe back-propagating action potentials (APs) in dendritic spines, synaptic transmission, subcellular microsecond-timescale details of AP propagation, and simultaneous firing of many neurons in a network. Optopatch measurements revealed homeostatic tuning of intrinsic excitability in human stem cell-derived neurons. In rat brain slices, Optopatch induced and reported APs and subthreshold events with high signal-to-noise ratios. The Optopatch platform enables high-throughput, spatially resolved electrophysiology without the use of conventional electrodes.
Collapse
Affiliation(s)
- Daniel R Hochbaum
- 1] Applied Physics Program, School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts, USA. [2]
| | - Yongxin Zhao
- 1] Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada. [2]
| | - Samouil L Farhi
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Nathan Klapoetke
- 1] The MIT Media Laboratory, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA. [2] Department of Biological Engineering, MIT, Cambridge, Massachusetts, USA. [3] Department of Brain and Cognitive Sciences, MIT, Cambridge, Massachusetts, USA. [4] McGovern Institute for Brain Research, MIT, Cambridge, Massachusetts, USA
| | - Christopher A Werley
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Vikrant Kapoor
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Peng Zou
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Joel M Kralj
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Dougal Maclaurin
- Department of Physics, Harvard University, Cambridge, Massachusetts, USA
| | | | - Jessica L Saulnier
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | | | - Christoph Straub
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Yong Ku Cho
- 1] The MIT Media Laboratory, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA. [2] Department of Biological Engineering, MIT, Cambridge, Massachusetts, USA. [3] Department of Brain and Cognitive Sciences, MIT, Cambridge, Massachusetts, USA. [4] McGovern Institute for Brain Research, MIT, Cambridge, Massachusetts, USA
| | - Michael Melkonian
- Institute of Botany, Cologne Biocenter, University of Cologne, Cologne, Germany
| | - Gane Ka-Shu Wong
- 1] Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada. [2] Department of Medicine, University of Alberta, Edmonton, Alberta, Canada. [3] Beijing Genomics Institute-Shenzhen, Shenzhen, China
| | - D Jed Harrison
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Venkatesh N Murthy
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Bernardo L Sabatini
- 1] Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA. [2] Howard Hughes Medical Institute, Harvard University, Cambridge, Massachusetts, USA
| | - Edward S Boyden
- 1] The MIT Media Laboratory, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA. [2] Department of Biological Engineering, MIT, Cambridge, Massachusetts, USA. [3] Department of Brain and Cognitive Sciences, MIT, Cambridge, Massachusetts, USA. [4] McGovern Institute for Brain Research, MIT, Cambridge, Massachusetts, USA. [5]
| | - Robert E Campbell
- 1] Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada. [2]
| | - Adam E Cohen
- 1] Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA. [2] Department of Physics, Harvard University, Cambridge, Massachusetts, USA. [3] Howard Hughes Medical Institute, Harvard University, Cambridge, Massachusetts, USA
| |
Collapse
|
14
|
Kim J, Lee S, Tsuda S, Zhang X, Asrican B, Gloss B, Feng G, Augustine GJ. Optogenetic mapping of cerebellar inhibitory circuitry reveals spatially biased coordination of interneurons via electrical synapses. Cell Rep 2014; 7:1601-1613. [PMID: 24857665 DOI: 10.1016/j.celrep.2014.04.047] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 02/10/2014] [Accepted: 04/21/2014] [Indexed: 11/26/2022] Open
Abstract
We used high-speed optogenetic mapping technology to examine the spatial organization of local inhibitory circuits formed by cerebellar interneurons. Transgenic mice expressing channelrhodopsin-2 exclusively in molecular layer interneurons allowed us to focally photostimulate these neurons, while measuring resulting responses in postsynaptic Purkinje cells. This approach revealed that interneurons converge upon Purkinje cells over a broad area and that at least seven interneurons form functional synapses with a single Purkinje cell. The number of converging interneurons was reduced by treatment with gap junction blockers, revealing that electrical synapses between interneurons contribute substantially to the spatial convergence. Remarkably, gap junction blockers affected convergence in sagittal slices, but not in coronal slices, indicating a sagittal bias in electrical coupling between interneurons. We conclude that electrical synapse networks spatially coordinate interneurons in the cerebellum and may also serve this function in other brain regions.
Collapse
Affiliation(s)
- Jinsook Kim
- Lee Kong Chian School of Medicine, Nanyang Technological University, 50 Nanyang Drive, Research Techno Plaza, Singapore 637553, Singapore; Laboratory of Synaptic Circuitry, Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, 8 College Road, Singapore 169857, Singapore; A(∗)STAR/Duke-NUS Neuroscience Research Partnership, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore; Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore; Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Soojung Lee
- Laboratory of Synaptic Circuitry, Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, 8 College Road, Singapore 169857, Singapore; A(∗)STAR/Duke-NUS Neuroscience Research Partnership, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore; Center for Functional Connectomics, Korea Institute of Science and Technology, 39-1 Hawolgokdong, Seongbukgu, Seoul 136-791, Republic of Korea; Department of Maxillofacial Tissue Regeneration, School of Dentistry, Kyung Hee University, Seoul 130-050, Republic of Korea
| | - Sachiko Tsuda
- Lee Kong Chian School of Medicine, Nanyang Technological University, 50 Nanyang Drive, Research Techno Plaza, Singapore 637553, Singapore; Laboratory of Synaptic Circuitry, Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, 8 College Road, Singapore 169857, Singapore; A(∗)STAR/Duke-NUS Neuroscience Research Partnership, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore; Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore; Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Xuying Zhang
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Brent Asrican
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Bernd Gloss
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Guoping Feng
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - George J Augustine
- Lee Kong Chian School of Medicine, Nanyang Technological University, 50 Nanyang Drive, Research Techno Plaza, Singapore 637553, Singapore; Laboratory of Synaptic Circuitry, Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, 8 College Road, Singapore 169857, Singapore; A(∗)STAR/Duke-NUS Neuroscience Research Partnership, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore; Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore; Marine Biological Laboratory, Woods Hole, MA 02543, USA; Center for Functional Connectomics, Korea Institute of Science and Technology, 39-1 Hawolgokdong, Seongbukgu, Seoul 136-791, Republic of Korea; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117599, Singapore.
| |
Collapse
|
15
|
Asrican B, Augustine GJ, Berglund K, Chen S, Chow N, Deisseroth K, Feng G, Gloss B, Hira R, Hoffmann C, Kasai H, Katarya M, Kim J, Kudolo J, Lee LM, Lo SQ, Mancuso J, Matsuzaki M, Nakajima R, Qiu L, Tan G, Tang Y, Ting JT, Tsuda S, Wen L, Zhang X, Zhao S. Next-generation transgenic mice for optogenetic analysis of neural circuits. Front Neural Circuits 2013; 7:160. [PMID: 24324405 PMCID: PMC3840435 DOI: 10.3389/fncir.2013.00160] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 09/19/2013] [Indexed: 12/31/2022] Open
Abstract
Here we characterize several new lines of transgenic mice useful for optogenetic analysis of brain circuit function. These mice express optogenetic probes, such as enhanced halorhodopsin or several different versions of channelrhodopsins, behind various neuron-specific promoters. These mice permit photoinhibition or photostimulation both in vitro and in vivo. Our results also reveal the important influence of fluorescent tags on optogenetic probe expression and function in transgenic mice.
Collapse
Affiliation(s)
- Brent Asrican
- Department of Neurobiology, Duke University Medical Center Durham, NC, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Witt A, Palmigiano A, Neef A, El Hady A, Wolf F, Battaglia D. Controlling the oscillation phase through precisely timed closed-loop optogenetic stimulation: a computational study. Front Neural Circuits 2013; 7:49. [PMID: 23616748 PMCID: PMC3627980 DOI: 10.3389/fncir.2013.00049] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 03/07/2013] [Indexed: 11/24/2022] Open
Abstract
Dynamic oscillatory coherence is believed to play a central role in flexible communication between brain circuits. To test this communication-through-coherence hypothesis, experimental protocols that allow a reliable control of phase-relations between neuronal populations are needed. In this modeling study, we explore the potential of closed-loop optogenetic stimulation for the control of functional interactions mediated by oscillatory coherence. The theory of non-linear oscillators predicts that the efficacy of local stimulation will depend not only on the stimulation intensity but also on its timing relative to the ongoing oscillation in the target area. Induced phase-shifts are expected to be stronger when the stimulation is applied within specific narrow phase intervals. Conversely, stimulations with the same or even stronger intensity are less effective when timed randomly. Stimulation should thus be properly phased with respect to ongoing oscillations (in order to optimally perturb them) and the timing of the stimulation onset must be determined by a real-time phase analysis of simultaneously recorded local field potentials (LFPs). Here, we introduce an electrophysiologically calibrated model of Channelrhodopsin 2 (ChR2)-induced photocurrents, based on fits holding over two decades of light intensity. Through simulations of a neural population which undergoes coherent gamma oscillations—either spontaneously or as an effect of continuous optogenetic driving—we show that precisely-timed photostimulation pulses can be used to shift the phase of oscillation, even at transduction rates smaller than 25%. We consider then a canonic circuit with two inter-connected neural populations oscillating with gamma frequency in a phase-locked manner. We demonstrate that photostimulation pulses applied locally to a single population can induce, if precisely phased, a lasting reorganization of the phase-locking pattern and hence modify functional interactions between the two populations.
Collapse
Affiliation(s)
- Annette Witt
- Cognitive Neuroscience Department, German Primate Center, Bernstein Center for Computational Neuroscience, Max Planck Institute for Dynamics and Self-Organization Göttingen, Germany
| | | | | | | | | | | |
Collapse
|
17
|
Foutz TJ, Arlow RL, McIntyre CC. Theoretical principles underlying optical stimulation of a channelrhodopsin-2 positive pyramidal neuron. J Neurophysiol 2012; 107:3235-45. [PMID: 22442566 DOI: 10.1152/jn.00501.2011] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Optogenetics is an emerging field of neuromodulation that permits scaled, millisecond temporal control of the membrane dynamics of genetically targeted cells using light. Optogenetic technology has revolutionized neuroscience research; however, numerous biophysical questions remain on the optical and neuronal factors impacting the modulation of neural activity with photon-sensitive ion channels. To begin to address such questions, we developed a computational tool to explore the underlying principles of optogenetic neural stimulation. This "light-neuron" model consists of theoretical representations of the light dynamics generated by a fiber optic in brain tissue, coupled to a multicompartment cable model of a cortical pyramidal neuron embedded with channelrhodopsin-2 (ChR2) membrane dynamics. Simulations revealed that the large energies required to generate an action potential are primarily due to the limited conductivity of ChR2, and that the major determinants of stimulation threshold are the surface area of illuminated cell membrane and proximity to the light source. Our results predict that the activation threshold is sensitive to many of the properties of ChR2 (density, conductivity, and kinetics), tissue medium (scattering and absorbance), and the fiber-optic light source (diameter and numerical aperture). We also illustrate the impact of redistributing the ChR2 expression density (uniform vs. nonuniform) on the activation threshold. The model system developed in this study represents a scientific instrument to characterize the effects of optogenetic neuromodulation, as well as an engineering design tool to help guide future development of optogenetic technology.
Collapse
Affiliation(s)
- Thomas J Foutz
- Cleveland Clinic Foundation, Dept. of Biomedical Engineering, Cleveland, OH 44195, USA.
| | | | | |
Collapse
|
18
|
Stirman JN, Crane MM, Husson SJ, Gottschalk A, Lu H. A multispectral optical illumination system with precise spatiotemporal control for the manipulation of optogenetic reagents. Nat Protoc 2012; 7:207-20. [PMID: 22240583 DOI: 10.1038/nprot.2011.433] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Optogenetics is an excellent tool for noninvasive activation and silencing of neurons and muscles. Although they have been widely adopted, illumination techniques for optogenetic tools remain limited and relatively nonstandardized. We present a protocol for constructing an illumination system capable of dynamic multispectral optical targeting of micrometer-sized structures in both stationary and moving objects. The initial steps of the protocol describe how to modify an off-the-shelf video projector by insertion of optical filters and modification of projector optics. Subsequent steps involve altering the microscope's epifluorescence optical train as well as alignment and characterization of the system. When fully assembled, the illumination system is capable of dynamically projecting multispectral patterns with a resolution better than 10 μm at medium magnifications. Compared with other custom-assembled systems and commercially available products, this protocol allows a researcher to assemble the illumination system for a fraction of the cost and can be completed within a few days.
Collapse
Affiliation(s)
- Jeffrey N Stirman
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | | | | | | | | |
Collapse
|
19
|
Astrocytes display complex and localized calcium responses to single-neuron stimulation in the hippocampus. J Neurosci 2011; 31:8905-19. [PMID: 21677174 DOI: 10.1523/jneurosci.6341-10.2011] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Astrocytes show a complex structural and physiological interplay with neurons and respond to neuronal activation in vitro and in vivo with intracellular calcium elevations. These calcium changes enable astrocytes to modulate synaptic transmission and plasticity through various mechanisms. However, the response pattern of astrocytes to single neuronal depolarization events still remains unresolved. This information is critical for fully understanding the coordinated network of neuron-glial signaling in the brain. To address this, we developed a system to map astrocyte calcium responses along apical dendrites of CA1 pyramidal neurons in hippocampal slices using single-neuron stimulation with channelrhodopsin-2. This technique allowed selective neuronal depolarization without invasive manipulations known to alter calcium levels in astrocytes. Light-evoked neuronal depolarization was elicited and calcium events in surrounding astrocytes were monitored using the calcium-sensitive dye Calcium Orange. Stimulation of single neurons caused calcium responses in populations of astrocytes along the apical axis of CA1 cell dendrites. Calcium responses included single events that were synchronized with neuronal stimulation and poststimulus changes in calcium event frequency, both of which were modulated by glutamatergic and purinergic signaling. Individual astrocytes near CA1 cells showed low ability to respond to repeated neuronal depolarization events. However, the response of the surrounding astrocyte population was remarkably accurate. Interestingly, the reliability of responses was graded with respect to astrocyte location along the CA1 cell dendrite, with astrocytes residing in the primary dendrite subregion being most responsive. This study provides a new perspective on the dynamic response property of astrocyte ensembles to neuronal activity.
Collapse
|
20
|
Abstract
A significant challenge for neuroscientists is to determine how both electrical and chemical signals affect the activity of cells and circuits and how the nervous system subsequently translates that activity into behavior. Remote, bidirectional manipulation of those signals with high spatiotemporal precision is an ideal approach to addressing that challenge. Neuroscientists have recently developed a diverse set of tools that permit such experimental manipulation with varying degrees of spatial, temporal, and directional control. These tools use light, peptides, and small molecules to primarily activate ion channels and G protein-coupled receptors (GPCRs) that in turn activate or inhibit neuronal firing. By monitoring the electrophysiological, biochemical, and behavioral effects of such activation/inhibition, researchers can better understand the links between brain activity and behavior. Here, we review the tools that are available for this type of experimentation. We describe the development of the tools and highlight exciting in vivo data. We focus primarily on designer GPCRs (receptors activated solely by synthetic ligands, designer receptors exclusively activated by designer drugs) and microbial opsins (e.g., channelrhodopsin-2, halorhodopsin, Volvox carteri channelrhodopsin) but also describe other novel techniques that use orthogonal receptors, caged ligands, allosteric modulators, and other approaches. These tools differ in the direction of their effect (activation/inhibition, hyperpolarization/depolarization), their onset and offset kinetics (milliseconds/minutes/hours), the degree of spatial resolution they afford, and their invasiveness. Although none of these tools is perfect, each has advantages and disadvantages, which we describe, and they are all still works in progress. We conclude with suggestions for improving upon the existing tools.
Collapse
Affiliation(s)
- Sarah C Rogan
- University of North Carolina School of Medicine, Department of Pharmacology, 120 Mason Farm Rd, Chapel Hill, NC 27514, USA
| | | |
Collapse
|
21
|
Ebeling W, Natoli RC, Hemmi JM. Diversity of color vision: not all Australian marsupials are trichromatic. PLoS One 2010; 5:e14231. [PMID: 21151905 PMCID: PMC2997786 DOI: 10.1371/journal.pone.0014231] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Accepted: 11/01/2010] [Indexed: 11/25/2022] Open
Abstract
Color vision in marsupials has recently emerged as a particularly interesting case among mammals. It appears that there are both dichromats and trichromats among closely related species. In contrast to primates, marsupials seem to have evolved a different type of trichromacy that is not linked to the X-chromosome. Based on microspectrophotometry and retinal whole-mount immunohistochemistry, four trichromatic marsupial species have been described: quokka, quenda, honey possum, and fat-tailed dunnart. It has, however, been impossible to identify the photopigment of the third cone type, and genetically, all evidence so far suggests that all marsupials are dichromatic. The tammar wallaby is the only Australian marsupial to date for which there is no evidence of a third cone type. To clarify whether the wallaby is indeed a dichromat or trichromatic like other Australian marsupials, we analyzed the number of cone types in the “dichromatic” wallaby and the “trichromatic” dunnart. Employing identical immunohistochemical protocols, we confirmed that the wallaby has only two cone types, whereas 20–25% of cones remained unlabeled by S- and LM-opsin antibodies in the dunnart retina. In addition, we found no evidence to support the hypothesis that the rod photopigment (rod opsin) is expressed in cones which would have explained the absence of a third cone opsin gene. Our study is the first comprehensive and quantitative account of color vision in Australian marsupials where we now know that an unexpected diversity of different color vision systems appears to have evolved.
Collapse
Affiliation(s)
- Wiebke Ebeling
- ARC Centre of Excellence in Vision Science, Research School of Biology, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, Australia.
| | | | | |
Collapse
|
22
|
Bamann C, Nagel G, Bamberg E. Microbial rhodopsins in the spotlight. Curr Opin Neurobiol 2010; 20:610-6. [PMID: 20691581 DOI: 10.1016/j.conb.2010.07.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Accepted: 07/07/2010] [Indexed: 10/19/2022]
Abstract
The discovery of the light-gated cation channel Channelrhodopsin-2 (ChR2) and the use of the rediscovered light-driven Cl-pump halorhodopsin (HR) as optogenetic tools--genetically encoded switches that enable neurons to be turned on or off with bursts of light--refines the functional study of neurons in larger networks. Cell-specific expression allows a fast optical scanning approach to determine neuronal crosstalk following plasticity at the single synapse level or long-range projections in locomotion and somatosensory networks. Both rhodopsins proved to work functionally and could evoke behavioral responses in lower model organisms, reinstall rudimentary visual perception in blind mice and were set in a biomedical context with the investigation of neurodegenerative diseases.
Collapse
Affiliation(s)
- Christian Bamann
- Max-Planck-Institut für Biophysik, Max-von-Laue Strasse 3, 60438 Frankfurt, Germany
| | | | | |
Collapse
|
23
|
Schoenenberger P, Schärer YPZ, Oertner TG. Channelrhodopsin as a tool to investigate synaptic transmission and plasticity. Exp Physiol 2010; 96:34-9. [PMID: 20562296 DOI: 10.1113/expphysiol.2009.051219] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The light-gated cation channel channelrhodopsin-2 (ChR2) has been used in a variety of model systems to investigate the function of complex neuronal networks by stimulation of genetically targeted neurons. In slice physiology, ChR2 opens the door to novel types of experiments and greatly extends the technical possibilities offered by traditional electrophysiology. In this short review, we first consider several technical aspects concerning the use of ChR2 in slice physiology, providing examples from our own work. More specifically, we discuss differences between light-evoked action potentials and spontaneous or electrically induced action potentials. Our work implies that light-evoked action potentials are associated with increased calcium influx and a very high probability of neurotransmitter release. Furthermore, we point out the factors limiting the spatial resolution of ChR2 activation. Secondly, we discuss how synaptic transmission and plasticity can be studied using ChR2. Postsynaptic depolarization induced by ChR2 can be combined with two-photon glutamate uncaging to potentiate visually identified dendritic spines. ChR2-mediated stimulation of presynaptic axons induces neurotransmitter release and reliably activates postsynaptic spines. In conclusion, ChR2 is a powerful tool to investigate activity-dependent changes in structure and function of synapses.
Collapse
Affiliation(s)
- Philipp Schoenenberger
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland.
| | | | | |
Collapse
|
24
|
Two-photon single-cell optogenetic control of neuronal activity by sculpted light. Proc Natl Acad Sci U S A 2010; 107:11981-6. [PMID: 20543137 DOI: 10.1073/pnas.1006620107] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recent advances in optogenetic techniques have generated new tools for controlling neuronal activity, with a wide range of neuroscience applications. The most commonly used approach has been the optical activation of the light-gated ion channel channelrhodopsin-2 (ChR2). However, targeted single-cell-level optogenetic activation with temporal precessions comparable to the spike timing remained challenging. Here we report fast (< or = 1 ms), selective, and targeted control of neuronal activity with single-cell resolution in hippocampal slices. Using temporally focused laser pulses (TEFO) for which the axial beam profile can be controlled independently of its lateral distribution, large numbers of channels on individual neurons can be excited simultaneously, leading to strong (up to 15 mV) and fast (< or = 1 ms) depolarizations. Furthermore, we demonstrated selective activation of cellular compartments, such as dendrites and large presynaptic terminals, at depths up to 150 microm. The demonstrated spatiotemporal resolution and the selectivity provided by TEFO allow manipulation of neuronal activity, with a large number of applications in studies of neuronal microcircuit function in vitro and in vivo.
Collapse
|
25
|
Grossman N, Poher V, Grubb MS, Kennedy GT, Nikolic K, McGovern B, Berlinguer Palmini R, Gong Z, Drakakis EM, Neil MAA, Dawson MD, Burrone J, Degenaar P. Multi-site optical excitation using ChR2 and micro-LED array. J Neural Eng 2010; 7:16004. [PMID: 20075504 DOI: 10.1088/1741-2560/7/1/016004] [Citation(s) in RCA: 190] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Studying neuronal processes such as synaptic summation, dendritic physiology and neural network dynamics requires complex spatiotemporal control over neuronal activities. The recent development of neural photosensitization tools, such as channelrhodopsin-2 (ChR2), offers new opportunities for non-invasive, flexible and cell-specific neuronal stimulation. Previously, complex spatiotemporal control of photosensitized neurons has been limited by the lack of appropriate optical devices which can provide 2D stimulation with sufficient irradiance. Here we present a simple and powerful solution that is based on an array of high-power micro light-emitting diodes (micro-LEDs) that can generate arbitrary optical excitation patterns on a neuronal sample with micrometre and millisecond resolution. We first describe the design and fabrication of the system and characterize its capabilities. We then demonstrate its capacity to elicit precise electrophysiological responses in cultured and slice neurons expressing ChR2.
Collapse
Affiliation(s)
- Nir Grossman
- Institute of Biomedical Engineering, Imperial College, London, UK. Devision of Neuroscience, Imperial College, London, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Zhu P, Narita Y, Bundschuh ST, Fajardo O, Schärer YPZ, Chattopadhyaya B, Bouldoires EA, Stepien AE, Deisseroth K, Arber S, Sprengel R, Rijli FM, Friedrich RW. Optogenetic Dissection of Neuronal Circuits in Zebrafish using Viral Gene Transfer and the Tet System. Front Neural Circuits 2009; 3:21. [PMID: 20126518 PMCID: PMC2805431 DOI: 10.3389/neuro.04.021.2009] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 11/27/2009] [Indexed: 01/07/2023] Open
Abstract
The conditional expression of transgenes at high levels in sparse and specific populations of neurons is important for high-resolution optogenetic analyses of neuronal circuits. We explored two complementary methods, viral gene delivery and the iTet-Off system, to express transgenes in the brain of zebrafish. High-level gene expression in neurons was achieved by Sindbis and Rabies viruses. The Tet system produced strong and specific gene expression that could be modulated conveniently by doxycycline. Moreover, transgenic lines showed expression in distinct, sparse and stable populations of neurons that appeared to be subsets of the neurons targeted by the promoter driving the Tet-activator. The Tet system therefore provides the opportunity to generate libraries of diverse expression patterns similar to gene trap approaches or the thy-1 promoter in mice, but with the additional possibility to pre-select cell types of interest. In transgenic lines expressing channelrhodopsin-2, action potential firing could be precisely controlled by two-photon stimulation at low laser power, presumably because the expression levels of the Tet-controlled genes were high even in adults. In channelrhodopsin-2-expressing larvae, optical stimulation with a single blue LED evoked distinct swimming behaviors including backward swimming. These approaches provide new opportunities for the optogenetic dissection of neuronal circuit structure and function.
Collapse
Affiliation(s)
- Peixin Zhu
- Friedrich Miescher Institute for Biomedical Research, Novartis Research Foundation Basel, Switzerland
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Schoenenberger P, Gerosa D, Oertner TG. Temporal control of immediate early gene induction by light. PLoS One 2009; 4:e8185. [PMID: 19997631 PMCID: PMC2780714 DOI: 10.1371/journal.pone.0008185] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 11/12/2009] [Indexed: 01/05/2023] Open
Abstract
Background The light-gated cation channel channelrhodopsin-2 (ChR2) is a powerful tool for the optical induction of action potentials in neurons. Mutations of the cysteine 128 (C128) residue have been shown to greatly extend the lifetime of the conducting state of ChR2. However, until now, only subthreshold depolarizations have been reported from C128 mutants. Methods and Findings Here we report the induction of long high-frequency spike trains by brief light pulses in ChR2(C128A)-transfected pyramidal cells in hippocampal slice culture. ChR2(C128A)-mediated spike bursts triggered expression of the immediate early gene c-fos in pyramidal neurons. Robust and cell-specific expression of c-Fos protein was detected after a single blue light pulse and depended on action potential firing, but not on synaptic activity. However, photocurrents diminished upon repeated stimulation and limited the number of action potential bursts that could be elicited. Conclusions We conclude that the C128A mutant is not suitable for chronic stimulation of neurons, but very useful for light-controlled induction of immediate early genes. This property of ChR2(C128A) could be harnessed to control the expression of proteins under control of the c-fos promoter with precise timing and single cell specificity.
Collapse
Affiliation(s)
| | - Daniela Gerosa
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Thomas G. Oertner
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- * E-mail:
| |
Collapse
|
28
|
Abstract
We demonstrate that channelrhodopsin-2 (CR), a light-gated ion channel that is conventionally activated by using visible-light excitation, can also be activated by using IR two-photon excitation (TPE). An empirical estimate of CR's two-photon absorption cross-section at lambda = 920 nm is presented, with a value (260 +/- 20 GM) indicating that TPE stimulation of CR photocurrents is not typically limited by intrinsic molecular excitability [1 GM = 10(-50)(cm4 s)/photon]. By using direct physiological measurements of CR photocurrents and a model of ground-state depletion, we evaluate how saturation of CR's current-conducting state influences the spatial resolution of focused TPE photostimulation, and how photocurrents stimulated by using low-power scanning TPE temporally summate. We show that TPE, like visible-light excitation, can be used to stimulate action potentials in cultured CR-expressing neurons.
Collapse
|
29
|
Wang J, Hasan MT, Seung HS. Laser-evoked synaptic transmission in cultured hippocampal neurons expressing channelrhodopsin-2 delivered by adeno-associated virus. J Neurosci Methods 2009; 183:165-75. [PMID: 19560489 PMCID: PMC2762116 DOI: 10.1016/j.jneumeth.2009.06.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 06/17/2009] [Accepted: 06/18/2009] [Indexed: 11/15/2022]
Abstract
We present a method for studying synaptic transmission in mass cultures of dissociated hippocampal neurons based on patch clamp recording combined with laser stimulation of neurons expressing channelrhodopsin-2 (ChR2). Our goal was to use the high spatial resolution of laser illumination to come as close as possible to the ideal of identifying monosynaptically coupled pairs of neurons, which is conventionally done using microisland rather than mass cultures. Using recombinant adeno-associated virus (rAAV) to deliver the ChR2 gene, we focused on the time period between 14 and 20 days in vitro, during which expression levels are high, and spontaneous bursting activity has not yet started. Stimulation by wide-field illumination is sufficient to make the majority of ChR2-expressing neurons spike. Stimulation with a laser spot at least 10 microm in diameter also produces action potentials, but in a reduced fraction of neurons. We studied synaptic transmission by voltage-clamping a neuron with low expression of ChR2 and scanning a 40 microm laser spot at surrounding locations. Responses were observed to stimulation at a subset of locations in the culture, indicating spatial localization of stimulation. Pharmacological means were used to identify responses that were synaptic. Many responses were of smaller amplitude than those typically found in microisland cultures. We were unable to find an entirely reliable criterion for distinguishing between monosynaptic and polysynaptic responses. However, we propose that postsynaptic currents with small amplitudes, simple shapes, and latencies not much greater than 8 ms are reasonable candidates for monosynaptic interactions.
Collapse
Affiliation(s)
- Jennifer Wang
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue 46-5065, Cambridge, MA 02139, USA.
| | | | | |
Collapse
|