Neurons In Bird Brains Encode Earth's Magnetic Field

Working with seven awake pigeons, the researchers used a Tesla coil to cancel out the effects of Earth’s magnetic field and induce an artificial one. They put the pigeons in a completely dark room to cancel out any light-polarization effects, which have also been suggested as a mechanism for animals’ magnetic navigation capabilities. They also stabilized the birds’ heads so they couldn’t rely on inner-ear cues to determine their directions.

Then Wu and Dickman turned up the magnetic field, adjusting its magnitude, elevation and other variables. They used a gene marker to identify when neurons were activated, focusing on neural areas that were already good candidates for this type of information processing. Ultimately, they pinpointed 53 neurons in the birds’ brain stems that had greatly enhanced activity. What’s more, those cells were most sensitive to the magnetic field ranges that correspond to Earth’s real ones — 20 micro-Tesla (μT) at the magnetic equator to more than 60 μT at the magnetic poles.

The poles shift over time, however, so the researchers note that these neurons must be somewhat adaptable, either through evolution or brain plasticity.

http://m.popsci.com/technology/arti...ic-field-giving-pigeons-reliable-internal-gps

 

What is new is the actual neurons mapping to solidify previous theories.