Fiber Photometry Solutions

Fiber photometry is a technique of monitoring the neuronal activity of neurons labeled with a fluorescent reporter(s) in behaving lab animals that uses chronically implanted optical fiber to deliver excitation light and collects induced fluorescence from the targeted brain region.

 

 

  • Advantages:
    • Record neural activity of a specific neuron population
    • Compatible with deep brain fiber-optic cannula
    • Low impact on an animal in freely behaving experiment
    • Allows for multiple sites recordings
    • High temporal resolution
    • High sensitivity, low optical power required
  • Disadvantages:
    • Spatial resolution limited to the optical fiber core diameter
    • Limited sampling depth, due to tissue scattering (1-photon)
    • Invasive chronic implant

Solutions

Doric Lenses offers several complete solutions for fiber photometry going from data acquisition and analysis software, light sources, detectors, optical filter cubes, patch cords, and rotary-joints to fiber-optic cannulas and related accessories. 

While each offered solution has its own advantages, they all share the same data acquisition console controlled by Doric Neuroscience Studio which takes care of data recording, real-time lock-in amplifier, or interleaves demodulation with a user-intuitive interface requiring no programming skills. The console enables synchronization of the fiber photometry recordings with behavior recordings, optogenetics light stimulation control, and/or electrophysiology recordings.

In addition to the data acquisition console, Basic setup for fiber photometry consists of the LED light source(s) that can provide microWatts (µW) of fluorescence excitation light and a photo-detector(s) sensitive to picoWatts (pW) of fluorescence emission, all packaged within compact Fluorescence Mini Cube (FMC) with appropriate spectral filtering of excitation and emission light and connectorized to a low auto-fluorescence fiber-optic patch cord and fiber-optic rotary joint followed with a chronically implanted fiber-optic cannula.

Different FMC configurations are available to work with 1, 2, or 3 fluorophores and for optogenetics stimulation. The original connectorized FMC cubes are of modular design where an optical fiber is connected to each port to light sources and photodetectors. Newly developed Generation 2 of FMC cubes gets away with optical fibers and some electrical cables wherever possible and integrates LED light sources, photodetectors, and their amplifiers into a compact unit with improved sensitivity.

For those experiments where the transmission artifacts from optical rotary-joint rotation are not acceptable, we recommend the Rotary-Fluorescence Mini Cube fiber photometry system. It uses the same equipment as a basic system, except the fluorescence mini cube that integrates LED and detectors and is redesigned to be attached on the rotor of an assisted electrical rotary-joint; removing the transmission variation in a rotation of an optical rotary-joint.

When simultaneous fiber photometry recordings are required for several animals in separate locations or several sites on the same animal, the simplest and most cost-effective solution is the Bundle imaging Fluorescence Mini-Cube fiber-photometry system that can record fluorescence signals from multiple optical fibers in parallel. Optical fibers are bundled together at the end facing the CMOS detector while the other end is branching out to individual fibers. When used for freely behaving recordings on several animals in a separate location, each fiber end has to be equipped with a fiber-optic rotary joint. If recordings are for several sites on the same animals then the animal has to be restrained from turning around.

A solution to overcome this limitation is to merge the Rotary FMC and Bundle imaging FMC approaches to allow fiber photometry recording of multiple sites in an animal for a long-term freely-moving experiment. This solution has been developed and should be released later this year.

All our fiber photometry solutions can be combined with other techniques as optogenetics, electrophysiology, and miniaturized fluorescence microscopy.

Comparison Table for Fiber Photometry systems
System Type Basic FMC Rotary FMC Bundle imaging FMC Bundle imaging Rotary FMC
Number of sites
(total)
up to 4 up to 4 up to 100 up to 100
Number of sites
(per animal, freely-moving)
2 2 2 up to 100
Sensitivity (SNR) high high good good
Fluorescent markers up to 3 up to 2 up to 2 up to 2
Different configurations for each site yes yes no no
Combine with Optogenetics
yes yes yes no
Reference Baseline Correction lock-in /
interleaved
lock-in /
interleaved
interleaved interleaved
Availability now now now fall 2021


External References

1. Tecuapetla F et al. Balanced activity in basal ganglia projection pathways is critical for contraversive movements.
   Nat. Commun. 5, 4315 (2014).
2. Lerner TN et al. Intact-Brain Analyses Reveal Distinct Information Carried by SNc Dopamine Subcircuits.
   Cell 30, 635-47 (2015).
3. Kim CK, et al. Simultaneous fast measurement of circuit dynamics at multiple sites across the mammalian brain.
   Nat Methods 13, 325-8 (2016) 
4. Deisseroth lab Clarity Ressource Center 
5. Fiber Photometry forum