Reading Pigeons’ Brains as They Fly
How homing pigeons find their way back to a starting point is not completely known. Studies have shown that the birds variously use the position of the Sun and the Earth’s magnetic field as a compass, and sense of smell and visual cues as navigation aids. But the use of visual cues has been difficult to study, because if a bird flies over a landmark and doesn’t change its course, it’s impossible to know whether the bird has not perceived the cue or is ignoring it.
The researchers developed tiny neurologgers, to record electrical activity in the pigeons’ brains as they flew. The birds also carried small global positioning system units to track position. By matching brain activity to location, the researchers could determine the effect of flying over a landmark.
The birds’ flights began over water, a relatively featureless environment, and then continued over land to a homing point. This enabled the researchers to determine brain activity as the birds reached the coastline and then flew over other landmarks.
They found that activity in both high- and mid-range frequencies occurred as the birds passed over a landmark. The researchers, who reported their findings in Current Biology, suggest that the mid-range frequencies are linked to the perception of visual information, while the high-frequency activity may be related to cognitive processing — perhaps the recognition of a landmark as something the bird has seen before…. (via NY Times)
