title: Imaging neural activity in worms, flies and mice with improved GCaMP calcium indicators.
abstract: Genetically encoded calcium indicators (GECIs) can be used to image activity in defined neuronal populations. However, current GECIs produce inferior signals compared to synthetic indicators and recording electrodes, precluding detection of low firing rates. We developed a single-wavelength GCaMP2-based GECI (GCaMP3), with increased baseline fluorescence (3-fold), increased dynamic range (3-fold) and higher affinity for calcium (1.3-fold). We detected GCaMP3 fluorescence changes triggered by single action potentials in pyramidal cell dendrites, with signal-to-noise ratio and photostability substantially better than those of GCaMP2, D3cpVenus and TN-XXL. In Caenorhabditis elegans chemosensory neurons and the Drosophila melanogaster antennal lobe, sensory stimulation-evoked fluorescence responses were significantly enhanced with GCaMP3 (4-6-fold). In somatosensory and motor cortical neurons in the intact mouse, GCaMP3 detected calcium transients with amplitudes linearly dependent on action potential number. Long-term imaging in the motor cortex of behaving mice revealed large fluorescence changes in imaged neurons over months.
authors.affiliation: Howard Hughes Medical Institute, Ashburn, Virginia, USA.
authors.forename: Lin
authors.initials: L
authors.lastname: Tian
authors.forename: S Andrew
authors.initials: SA
authors.lastname: Hires
authors.forename: Tianyi
authors.initials: T
authors.lastname: Mao
authors.forename: Daniel
authors.initials: D
authors.lastname: Huber
authors.forename: M Eugenia
authors.initials: ME
authors.lastname: Chiappe
authors.forename: Sreekanth H
authors.initials: SH
authors.lastname: Chalasani
authors.forename: Leopoldo
authors.initials: L
authors.lastname: Petreanu
authors.forename: Jasper
authors.initials: J
authors.lastname: Akerboom
authors.forename: Sean A
authors.initials: SA
authors.lastname: McKinney
authors.forename: Eric R
authors.initials: ER
authors.lastname: Schreiter
authors.forename: Cornelia I
authors.initials: CI
authors.lastname: Bargmann
authors.forename: Vivek
authors.initials: V
authors.lastname: Jayaraman
authors.forename: Karel
authors.initials: K
authors.lastname: Svoboda
authors.forename: Loren L
authors.initials: LL
authors.lastname: Looger
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D017173:Caenorhabditis elegans / Q000166:cytology* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D004331:Drosophila melanogaster / Q000166:cytology* / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D051379:Mice; D009474:Neurons / Q000378:metabolism*
chemical_list: D002118:Calcium