Cellular resolution circuit mapping in mouse brain with temporal-focused excitation of soma-targeted channelrhodopsin

  1. Christopher A Baker  Is a corresponding author
  2. Yishai M Elyada
  3. Andres Parra-Martin
  4. McLean Bolton  Is a corresponding author
  1. Max Planck Florida Institute for Neuroscience, United States
  2. Max Planck Institute for Neuroscience, United States

Abstract

We describe refinements in optogenetic methods for circuit mapping that enable measurements of functional synaptic connectivity with single neuron resolution. By expanding a two-photon beam in the imaging plane using the temporal focusing method and restricting channelrhodopsin to the soma and proximal dendrites, we are able to reliably evoke action potentials in individual neurons, verify spike generation with GCaMP6s, and determine the presence or absence of synaptic connections with patch-clamp electrophysiological recording.

Article and author information

Author details

  1. Christopher A Baker

    Disorders of Neural Circuit Function, Max Planck Florida Institute for Neuroscience, Jupiter, United States
    For correspondence
    christopher.baker@mpfi.org
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-0604-8449
  2. Yishai M Elyada

    Functional Architecture of the Cerebral Cortex, Max Planck Florida Institute for Neuroscience, Jupiter, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Andres Parra-Martin

    Functional Architecture of the Cerebral Cortex, Max Planck Institute for Neuroscience, Jupiter, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. McLean Bolton

    Disorders of Neural Circuit Function, Max Planck Florida Institute for Neuroscience, Jupiter, United States
    For correspondence
    mclean.bolton@mpfi.org
    Competing interests
    The authors declare that no competing interests exist.

Funding

Max Planck Florida Institute

  • Christopher A Baker
  • Yishai M Elyada
  • Andres Parra-Martin
  • McLean Bolton

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Ethics

Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health, and all animals were handled according to protocols approved by the Institutional Animal Care and Use Committee of the Max Planck Florida Institute for Neuroscience.

Copyright

© 2016, Baker et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 8,659
    views
  • 1,825
    downloads
  • 141
    citations

Views, downloads and citations are aggregated across all versions of this paper published by eLife.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Christopher A Baker
  2. Yishai M Elyada
  3. Andres Parra-Martin
  4. McLean Bolton
(2016)
Cellular resolution circuit mapping in mouse brain with temporal-focused excitation of soma-targeted channelrhodopsin
eLife 5:e14193.
https://doi.org/10.7554/eLife.14193

Share this article

https://doi.org/10.7554/eLife.14193

Further reading

    1. Neuroscience
    2. Physics of Living Systems
    Moritz Schloetter, Georg U Maret, Christoph J Kleineidam
    Research Article

    Neurons generate and propagate electrical pulses called action potentials which annihilate on arrival at the axon terminal. We measure the extracellular electric field generated by propagating and annihilating action potentials and find that on annihilation, action potentials expel a local discharge. The discharge at the axon terminal generates an inhomogeneous electric field that immediately influences target neurons and thus provokes ephaptic coupling. Our measurements are quantitatively verified by a powerful analytical model which reveals excitation and inhibition in target neurons, depending on position and morphology of the source-target arrangement. Our model is in full agreement with experimental findings on ephaptic coupling at the well-studied Basket cell-Purkinje cell synapse. It is able to predict ephaptic coupling for any other synaptic geometry as illustrated by a few examples.

    1. Neuroscience
    Ulrike Pech, Jasper Janssens ... Patrik Verstreken
    Research Article

    The classical diagnosis of Parkinsonism is based on motor symptoms that are the consequence of nigrostriatal pathway dysfunction and reduced dopaminergic output. However, a decade prior to the emergence of motor issues, patients frequently experience non-motor symptoms, such as a reduced sense of smell (hyposmia). The cellular and molecular bases for these early defects remain enigmatic. To explore this, we developed a new collection of five fruit fly models of familial Parkinsonism and conducted single-cell RNA sequencing on young brains of these models. Interestingly, cholinergic projection neurons are the most vulnerable cells, and genes associated with presynaptic function are the most deregulated. Additional single nucleus sequencing of three specific brain regions of Parkinson’s disease patients confirms these findings. Indeed, the disturbances lead to early synaptic dysfunction, notably affecting cholinergic olfactory projection neurons crucial for olfactory function in flies. Correcting these defects specifically in olfactory cholinergic interneurons in flies or inducing cholinergic signaling in Parkinson mutant human induced dopaminergic neurons in vitro using nicotine, both rescue age-dependent dopaminergic neuron decline. Hence, our research uncovers that one of the earliest indicators of disease in five different models of familial Parkinsonism is synaptic dysfunction in higher-order cholinergic projection neurons and this contributes to the development of hyposmia. Furthermore, the shared pathways of synaptic failure in these cholinergic neurons ultimately contribute to dopaminergic dysfunction later in life.