Article abstract

Nature Methods 6, 875 - 881 (2009)
Published online: 8 November 2009 | doi:10.1038/nmeth.1398

Imaging neural activity in worms, flies and mice with improved GCaMP calcium indicators

Lin Tian1, S Andrew Hires1, Tianyi Mao1, Daniel Huber1, M Eugenia Chiappe1, Sreekanth H Chalasani2, Leopoldo Petreanu1, Jasper Akerboom1, Sean A McKinney1,4, Eric R Schreiter3, Cornelia I Bargmann2, Vivek Jayaraman1, Karel Svoboda1 & Loren L Looger1

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.

  1. Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, Virginia, USA.
  2. Howard Hughes Medical Institute, Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, New York, USA.
  3. Department of Chemistry, University of Puerto Rico, Río Piedras, San Juan, Puerto Rico.
  4. Present address: The Stowers Institute, Kansas City, Missouri, USA.

Correspondence to: Loren L Looger1 e-mail:


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