Recording Neural Activity in Freely Moving Mice Using Fiber Photometry
Transcript
Start with a freely moving mouse with an implanted optic fiber cannula.
Connect one end of a fiber-optic patch cord to the cannula and the other end to an excitation light source.
The mouse expresses a green fluorophore-tagged genetically encoded calcium indicator, or GECI, in the lateral hypothalamic area, or LHA neurons.
The implanted optic fiber contacts the lateral habenula, or LHb, region, where the LHA axons terminate.
Excite the GECI at its optimal excitation wavelength and record the baseline signal.
Now, apply repeated air puffs to the mouse to evoke an aversive stress response.
This stimulus triggers action potentials in LHA axon terminals, opening voltage-gated calcium channels and allowing calcium influx.
Intracellular calcium ions bind to the GECI, inducing a conformational change that increases green fluorescence emission.
Visualize the optical signal.
Increased fluorescence in response to air puffs in the mouse confirms the role of the LHA-LHb pathway in transmitting aversive signals.
