Equipped with forelimbs that form webbed wings, bats are the only mammals naturally capable of true and sustained flight. Although most microbat species have evolved small and poorly developed eyes, their navigational capabilities are bolstered by echolocation and a unique array of sensory receptors embedded in the wings.
Indeed, a recent Cell Reports study suggests neurons in the bat brain respond to incoming airflow and touch signals, effectively triggering rapid adjustments in wing position to optimize flight control.
“This study provides evidence that the sense of touch plays a key role in the evolution of powered flight in mammals,” says co-senior study author Ellen Lumpkin, a Columbia University associate professor of dermatology and physiology and cellular biophysics.
“This research also lays the groundwork for understanding what sensory information bats use to perform such remarkable feats when flying through the air and catching insects. Humans cannot currently build aircrafts that match the agility of bats, so a better grasp of these processes could inspire new aircraft design and new sensors for monitoring airflow.”
According to first author Kara Marshall of Columbia University, bat wings have a distinct sensory circuitry in comparison to other mammalian forelimbs. More specifically, sensory neurons on the wing send projections to a broader and lower section of the spinal cord, including much of the thoracic region. This unusual circuitry, says Marshall, reflects the motley roots of the bat wing, which arises from the fusion of the forelimb, trunk and hindlimb during embryonic development.
In addition, researchers discovered neurons in the brain responded when the wing was either stimulated by air puffs or touched with a thin filament – suggesting airflow and tactile stimulation activated common neural pathways.
Commenting on the Cell Reports study, LSS co-inventor Dr. Patrick R. Gill told Rambus Press that the research findings illustrate how animals have evolved integrated sensing capability throughout their bodies.
“Tiny, simple sensory neurons sprinkled throughout the organism frequently report on local conditions more effectively than a few dedicated, but isolated, sense organs,” he explains.
Image Credit: Kara Marshall, Columbia University Medical Center
“Facilitating just the right amount of sensing where it’s needed is one of the objectives of our lensless smart sensors (LSS), as it enables our technology to be more ‘bat-like’ in its approach to navigating the world’s complexity.”
As the LSS co-inventor notes, flying insects also employ a wide range of sensory-motor responses to help them navigate the world and avoid potentially dangerous obstacles. For example, the work of Harald Esch demonstrates how bees use optic flow to measure how far they should travel in a certain direction.
“LSS is fully capable of measuring optic flow, even if the uber-mini tech is fitted in atypically small form factors,” he adds. “For applications like tiny flying robots, LSS technology could potentially enable sensing in one of the smallest form factors and power budgets available.”
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