Optogenetics in Neural Systems

Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.
Neuron (Impact Factor: 15.98). 07/2011; 71(1):9-34. DOI: 10.1016/j.neuron.2011.06.004
Source: PubMed

ABSTRACT Both observational and perturbational technologies are essential for advancing the understanding of brain function and dysfunction. But while observational techniques have greatly advanced in the last century, techniques for perturbation that are matched to the speed and heterogeneity of neural systems have lagged behind. The technology of optogenetics represents a step toward addressing this disparity. Reliable and targetable single-component tools (which encompass both light sensation and effector function within a single protein) have enabled versatile new classes of investigation in the study of neural systems. Here we provide a primer on the application of optogenetics in neuroscience, focusing on the single-component tools and highlighting important problems, challenges, and technical considerations.


Available from: Ofer Yizhar, Jun 04, 2015
  • [Show abstract] [Hide abstract]
    ABSTRACT: As a consequence of conditioning visual cues with delayed reward, cue-evoked neural activity that predicts the time of expected future reward emerges in the primary visual cortex (V1). We hypothesized that this reward-timing activity is engendered by a reinforcement signal conveying reward acquisition to V1. In lieu of behavioral conditioning, we assessed in vivo whether selective activation of either basal forebrain (BF) or cholinergic innervation is sufficient to condition cued interval-timing activity. Substituting for actual reward, optogenetic activation of BF or cholinergic input within V1 at fixed delays following visual stimulation entrains neural responses that mimic behaviorally conditioned reward-timing activity. Optogenetically conditioned neural responses express cue-evoked temporal intervals that correspond to the conditioning intervals, are bidirectionally modifiable, display experience-dependent refinement, and exhibit a scale invariance to the encoded delay. Our results demonstrate that the activation of BF or cholinergic input within V1 is sufficient to encode cued interval-timing activity and indicate that V1 itself is a substrate for associative learning that may inform the timing of visually cued behaviors. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Current biology: CB 05/2015; DOI:10.1016/j.cub.2015.04.028 · 9.92 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper we report the combination of microfluidics, optogenetics and calcium imaging as a cheap and convenient platform to study synaptic communication between neuronal populations in vitro. We first show that Calcium Orange indicator is compatible in vitro with a commonly used Channelrhodopsine-2 (ChR2) variant, as standard calcium imaging conditions did not alter significantly the activity of transduced cultures of rodent primary neurons. A fast, robust and scalable process for micro-chip fabrication was developed in parallel to build micro-compartmented cultures. Coupling optical fibers to each micro-compartment allowed for the independent control of ChR2 activation in the different populations without crosstalk. By analyzing the post-stimuli activity across the different populations, we finally show how this platform can be used to evaluate quantitatively the effective connectivity between connected neuronal populations.
    PLoS ONE 04/2015; 10(4). DOI:10.1371/journal.pone.0120680 · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Due to the limited regenerative ability of neural tissue, a diverse set of biochemical and biophysical cues for increasing nerve growth has been investigated, including neurotrophic factors, topography, and electrical stimulation. In this report, we explore optogenetic control of neurite growth as a cell-specific alternative to electrical stimulation. By investigating a broad range of optical stimulation parameters on dorsal root ganglia (DRGs) expressing channelrhodopsin 2 (ChR2), we identified conditions that enhance neurite outgrowth by threefold as compared to unstimulated or wild-type (WT) controls. Furthermore, optogenetic stimulation of ChR2 expressing DRGs induces directional outgrowth in WT DRGs co-cultured within a 10 mm vicinity of the optically sensitive ganglia. This observed enhancement and polarization of neurite growth was accompanied by an increased expression of neural growth and brain derived neurotrophic factors (NGF, BDNF). This work highlights the potential for implementing optogenetics to drive nerve growth in specific cell populations. F ollowing traumatic injury, functional recovery of the peripheral nervous system (PNS) is impeded by cellular debris, scarring, and tardy axonal growth 1,2 , and injury gaps exceeding 4 cm often require surgical intervention 3,4. The 'gold-standard' for nerve repair, autografts, as well as FDA-approved synthetic nerve guidance channels yield limited success for larger injury gaps, leaving patients with long-term disabilities 5,6. Thus, a clinical need exists for new strategies to promote axonal regeneration and re-myelination. To overcome the regenerative barriers such as inhibitory myelin and scarring, and to increase the rate of axonal growth, numerous strategies have been investigated. Presentation of neurotrophic factors 7,8 , geometric constraints 9,10 , supportive cell grafts (Schwann cells 11 or stem cells 12
    Scientific Reports 05/2015; 5:9669. DOI:10.1038/srep09669 · 5.08 Impact Factor