According to the study, a unique array of sensory receptors that cover the animals' wings give them constant feedback on changes in airflow. When the researchers stimulated the tiny hairs on their wings with puffs of air, they saw immediate responses in their sensory cortex.
Bats also have an unusual way of getting this sensory input from their wing hairs to the rest of their bodies. Because of the way that bat wings evolved, their nerve distribution is unlike that in any other mammalian forelimb. Neurons in the bat wings the researchers studied didn't just go to the top of the spinal cord, where they connect. Instead, they also carried signals down to the lower part of the spinal cord. In most mammals, only signals from the trunk move down that way.
This unusual nerve distribution, the researchers write in the study, has been "co-opted to enhance flight control." They believe they've shown that a sense of touch is much more important to bat flight precision than previously thought, right up there with more commonly studied hearing and smell. But now they'll need to figure out how bats take all this raw sensory data and turn it into a flight plan.
"Our next steps will be following the sensory circuits in the wings all the way from the skin to the brain. In this study, we have identified individual components of these circuits, but next we would like to see how they are connected in the central nervous system," co-senior study author Cynthia Moss of Johns Hopkins University said in a statement. "An even bigger goal will be to understand how the bat integrates sensory information from the many receptors in the wing to create smooth, nimble flight."
Moss and her colleagues hope that their findings can inform new aircraft designs, allowing engineers to develop similar sensors that react to turbulence and other disturbances.
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