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Updated: Jun 24, 2026
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Functional Calcium Imaging in Developing Cortical Networks
Published on: October 22, 2011
A sensitive orange fluorescent calcium ion indicator for imaging neural activity
Abhi Aggarwal1,2,3, Heather A Baker4,5, Céline D Dürst6
1Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
Nature Communications
|June 22, 2026
Summary
Researchers developed OCaMP, a new orange fluorescent genetically encoded calcium indicator (GECI). This advanced GECI enhances neural imaging by offering improved performance and compatibility with specific laser wavelengths.
Area of Science:
- Neuroscience
- Biophysics
- Molecular Biology
Background:
- Genetically encoded calcium indicators (GECIs) are essential for visualizing neuronal activity.
- Current GECIs primarily emit green or red fluorescence, limiting multiplexing and excitation with 1030 nm femtosecond lasers.
Purpose of the Study:
- To develop a novel orange fluorescent GECI to overcome limitations of existing GECIs.
- To engineer a GECI with improved calcium affinity and photophysical properties for enhanced neural imaging.
Main Methods:
- Engineered OCaMP from O-GECO1 via targeted substitutions.
- Assessed OCaMP's photophysical properties, including two-photon cross-section, responsiveness, photostability, and calcium affinity.
- Evaluated OCaMP performance in cultured neurons, zebrafish, and mouse cortex.
Main Results:
- OCaMP demonstrated superior two-photon cross-section, responsiveness, photostability, and calcium affinity compared to O-GECO1.
- OCaMP outperformed red GECIs (jRCaMP1a, jRGECO1a) in sensitivity, photostability, and signal-to-noise ratio in neural imaging.
- OCaMP is optimized for excitation wavelengths above 1000 nm.
Conclusions:
- OCaMP is a robust orange fluorescent GECI for high-fidelity neural imaging.
- OCaMP fills the spectral gap between green and red GECIs, expanding multiplexing possibilities.
- OCaMP offers a practical solution for neural activity visualization using 1030 nm lasers.
