Recently, Alexxai Kravitz’s lab (Washington University in St. Louis) published a preprint in BioRxiv using Mightex’s OASIS Implant for single-cell resolution calcium imaging. In this paper, they tested whether fiber photometry signals reflect changes in population activity or subthreshold changes. Using the OASIS Implant, they were able to record GCaMP activity from both somatic and non-somatic sources in the striatum through an implanted GRIN lens. By correlating the somatic and non-somatic changes with the fiber photometry signal, they could
determine the source of the fiber photometry signal. They found that the fiber photometry signal was strongly correlated with the non-somatic changes and weakly correlated with the somatic changes, suggesting that the fiber photometry signal may reflect changes in non-somatic sources.
You can read the full paper on BioRxiv.
Legaria AA, Licholai JA, Kravitz AV. (2021). Fiber photometry does not reflect spiking activity in the striatum. BioRxiv.