Bird brain? What's goes on in it? Pigeons are interesting, as it turns out. Researchers have discovered the part of pigeon's brain that can process magnetic signals they detect, and it's enough to direct them travelling across the globe.
But how do you figure out what's going on in their brains? Researchers at Baylor College of Medicine created a dark room with a three dimensional coil system that allowed them to cancel the Earth's natural magnetic field and create a customized one on demand. They recorded the neuronal activity in the birds while changing the magnetic field. Researchers discovered how the brain decodes magnetic fields.
They found 53 vestibular brainstem neurons that react to the magnetic field and encode the direction, intensity, and polarity of a magnetic field. With that, the birds could navigate:
We suggest that MR cells encode a geomagnetic vector that could be used by the neural population to computationally derive the bird's position and directional heading. The geomagnetic vector elevation component could provide the bird's latitude, the vector azimuth component could be used as a magnetic compass to provide heading direction, and the vector magnitude could provide spatial position cues through local variations in intensity relative to a learned internal model of geomagnetic space.