Zebra finch birds have a fascinating ability to navigate and find direction using the Earth’s magnetic field. Scientists have proposed that this remarkable skill is made possible by photoinduced radical pairs mechanisms in cryptochrome proteins of retinal ganglion cells (RGC’s), which act as a magnetic compass for these birds. By sensing the Earth’s polarity and angular inclination, zebra finches are able to orient themselves and travel long distances with precision. This natural navigation system allows them to migrate, find food, and locate their nests with remarkable accuracy.

However, radiofrequency (RF) emissions have the potential to interfere with this process by affecting the cryptochrome protein, which is essential for magnetoreception in animals. This disruption could hinder an animals’ ability to navigate using the Earth’s magnetic field.

The primary goal of the study was to find out which wavelengths of light stimulate cryptochrome RGC activity by minimizing RF interference. Zebra finch photoreceptor samples were placed in a helmholtz coil magnetic field bolted within an ETS-Lindgren 5240 Tabletop RF-shielded copper faraday box. This setup was used to reduce the impact of RF background noise and earth’s magnetic field on the samples.

RGC’s were exposed to flashes of LED light ranging from 400 nm to 800 nm for a period of 10 seconds. However, LED stimulation was found to be responsible for generating a considerable level of RF interference, which in turn impacted the cryptochrome activity within our cell samples. RGC’s did not react to the LED light probes during testing. In order to resolve this issue, a shielded LED apparatus was constructed and attached to a shielded optic cable.

LED’s were then inserted into the apparatus with the optic cable spanning through the ceiling of the copper faraday box directly onto the cell samples. The optic cable successfully transmitted LED light from outside the Faraday cage towards RGC’s within the helmholtz coil magnetic field, as evidenced by an increased level of RGC-mediated magnetoreception activity beginning at the 450 nm wavelength. This suggests that blue-light between 450 and 495 nm triggers radical pair mechanisms in cryptochrome activity in zebra finch birds.