Washington, Sept 26 : Ornithologists from Oldenburg in Germany have found that the cryptochrome-containing neurons in the eye and a forebrain region (Cluster N), of migratory birds become active when processing magnetic compass information during flights.

Cryptochromes, which fulfil the molecular requirements for sensing the magnetic reference direction, has recently been found in retinal neurons of migratory birds.

In the current study, the researchers traced the neurons from the eye and from Cluster N and found a functional neuronal connection between the retinal neurons and Cluster N via the visual thalamus.

In other words, the only two parts of the central nervous system shown to be highly active during magnetic compass orientation are linked to each other by a well-known visual brain circuit, namely by parts of the so-called thalamofugal pathway, the scientists said.

“For the first time, clear neuroanatomical data suggest which specific brain pathway processes magnetic compass information in migratory birds. These findings strongly support the hypothesis that migratory birds use their visual system to perceive the reference compass direction of the geomagnetic field and that migratory birds are thus likely to “see” the geomagnetic field,” the researchers wrote in their study.

The research, “A Visual Pathway Links Brain Structures Active during Magnetic Compass Orientation in Migratory Birds” appears in the journal PLoS ONE. (With inputs from ANI)