TABLE 2.
Commonly used GCaMP reporters.
| Class | Indicator | Emission wavelength (nm) | Description | References |
| GFP | GCaMP1.3/1.6 | 510 | Slow kinetics for calcium binding; unable to resolve single APs. | Nakai et al., 2001; Ohkura et al., 2005; Reiff et al., 2005; Hendel et al., 2008 |
| GCaMP2 | 511 | Slow kinetics for calcium binding; unable to resolve single APs. | Tallini et al., 2006; Hendel et al., 2008 | |
| GCaMP3 | 513 | Adequate fluorescence at basal cell [Ca2+]. Unable to resolve single action potentials (APs) in vivo. | Tian et al., 2009; Akerboom et al., 2013; Redolfi et al., 2021 | |
| GCaMP5A/D/G/K/L | 510 | Improved dynamic range (increased threefold from GCaMP3). Variants can be chosen according to their properties to fit particular experimental requirements. | Akerboom et al., 2012; Redolfi et al., 2021 | |
| GCaMP6f/m/s | 510 | Able to detect single APs. 6f has shortest half-decay time. Variants can be chosen according to their properties to fit experimental requirements. Adequate for imaging experiments over multiple weeks. Adequate fluorescence at basal cell [Ca2+]. |
Chen et al., 2013; Rose et al., 2014; Redolfi et al., 2021 | |
| jGCaMP7 | 515 | Enhanced signal-to-noise ratio allows detection of individual spikes over wide fields of view (jGCaMP7s,f). Used for imaging of small processes thanks to the enhanced brightness (jGCaMP7b). | Dana et al., 2019; Redolfi et al., 2021 | |
| jGCaMP8 | ∼510 | Enhanced signal intensity, similar kinetics to GCaMP6. Well suited for bulk population recordings. | Ohkura et al., 2012b; Redolfi et al., 2021 | |
| RFP | RCaMP1a | 630 | Brighter than RGECO, but lower calcium binding affinity and dynamic range. Not activated by blue light, making it suitable for use with optogenetics. | Akerboom et al., 2013; Dana et al., 2016 |
| RCaMP1.07 | 584 | Higher fluorescence than RGECO. Well suited for use with optogenetics. | Ohkura et al., 2012a | |
| RCaMP2 | 583 | Strong single AP responses, very fast kinetics, suited for dual color calcium imaging with green fluorescent indicators. | Inoue et al., 2015 | |
| Multiple color variants | XCaMP | blue, green, yellow, red | Improved signal linearity. Adequate fluorescence at basal cell [Ca2+] (XCaMP-G). Enables measurement of fast-spike trains in individual neurons. | Inoue et al., 2019; Redolfi et al., 2021 |