Amuza and Teleopto launch the first commercial wireless fiber photometry system at Neuroscience 2019
Our wireless optogenetic users have frequently asked us if we could provide wireless photometry – we are happy to announce that now we can!
TeleFipho wireless headstages allow your freely behaving animals to move with true freedom, enabling novel experimental approaches with fiber photometry. The 3 gram headstages are optimized for GCaMP and other GFP based indicators.
What is Fiber Photometry?
Fiber Photometry is a powerful technique for measuring rapid changes in neuromodulators in vivo via fluorescence. It is most commonly used to measure fast (subsecond) changes in concentrations of calcium in freely behaving animals, but it is now also capable of being used to monitor neurotransmitters and other molecules.To use fiber photometry, genetically encoded fluorescent indicators are first expressed at the location of interest. When excited by light of the right wavelength, these proteins fluoresce – but only while they are bound to their target analyte. As local concentrations of the analyte rise and fall, the fluorescence intensity rises and falls in response. Genetically encoded calcium indicators (GECIs), such as GcAMP have been the mainstay of fiber photometry and also for calcium imaging, a closely related technique. Recently dopamine indicators (Dlight1, GRABDA) and norepinephrine indicators (GRABNE) have been introduced, and more neurochemical sensors are in development.
To capture this signal in vivo, an optical fiber is implanted at the target region in the animal. The other end of the fiber is attached to the photometry hardware. First an LED or laser light source passes light through the fiber to excite the indicator proteins in the target region. The resulting fluorescent light then travels back through the fiber to a photodetector, creating a record of the changing concentrations of the analyte. Careful filtering and splitting of the light traveling through the fiber optic is required to separate the light used for excitation from the fluorescence being sent to the photodetector.
Why use Fiber Photometry?
The most frequent use is to measure changes in calcium levels at synapses as a proxy for changes in neural activity, helping researchers discern the links between behavior states and the firing patterns of neurons. But the same technique is also used to monitor the activity of GPCRs and ion channel drug targets.
When used with freely moving animals, fiber optic tethers can be problematic. The cable can prevent animals from using exercise wheels or shelters or get tangled in complicated environments, limiting behavioral testing. Cables can also cause artifacts when used with video tracking software. For example, the cable often continues to sway after the animal has stopped moving, making it difficult to recognize freezing behavior during fear conditioning studies. Placing all of the necessary components for fiber photometry in a small lightweight headstage ends these problems.
Shrinking the components for fiber photometry has an added bonus: it also allows us to shrink the price. Telefipho starts at roughly half of the cost of other commercial fiber photometry systems.
Please stop by our booth during SfN 2019 to ask for a demonstration and visit our product page for more information.