Bran owls useful in navigating and locating direction

 

Innovative research led by team of Penn State Engineers concludes that barn owls are the key for navigation and location. According to experts, the brains of barn owl use sound in order to locate a prey, a template for electronic navigational devices.

The study is based on the Jeffress model, developed by Lloyd Jeffress in 1948. The model centers on the working of biological hearing systems, enabling it to analyze and register the arrival time of sound to the ears and can also locate the sound’s source.

According to Saptarshi Das, assistant professor of engineering science and mechanics, owls are capable of recognizing the direction of sound falling within one or two degrees. This ability of the owls lies in contrast to humans, who are not that precise with sound. The characteristic helps the owls with their hunting ability, especially during the night and makes up for their not so good eyesight.

Furthermore, the use of sound to locate depends upon the distance between the ears. Among owls that distance is quite small, however their brain’s circuitry is well adapted to understand the small differences. For instance, if the owl is facing the sound, both its ears receive the sound simultaneously. On the other hand, if the sound is to the right, the right ear can register the sound slightly before the left ear.

Since the speed of sound is faster than the owl’s nerves, owl’s brain converts the sound to an electrical pulse and the pulse is slowed down. Additionally, brain’s circuitry uses lattice of nerves, of varying lengths. These have inputs from two ends, which also determines where the two signals coincide or arrive simultaneously, in order to provide direction.

Saptarshi Das’s team has worked on to create an electric circuit which can slow down the input signals and can also determine the coincidence point, thus mimicking the actual working of the barn owl brain.

Moreover, the team created a series of split-gate molybdenum sulfide transistors which help to authenticate the coincidence nerve network in the owl’s brain. By means of the biomimetic circuitry the time-delay mechanism can also slow down the signal.

“Millions of years of evolution in the animal kingdom have ensured that only the most efficient materials and structures have survived,” quoted Sarbashis Das. “In effect, nature has done most of the work for us. All we have to do now is adapt these neurobiological architectures for our semiconductor devices.”

According to researchers, the proof-of-concept circuit has standard substrates and device types. By means of 2D materials the device becomes more accurate, in addition to becoming more efficient, as the split gate transistors increase, thus providing more precise coincidence times.

“While we are trying to make energy-efficient devices, mammalian computing backed by natural selection has necessitated extreme energy-efficiency, which we are trying to mimic in our devices,”according to Akhil Dodda. He is a graduate student in engineering science and mechanics.

Experts also suggest that only the direction does not provide location of the sound source. In order to actually navigate or locate, knowledge of height of the sound source is equally important.

Further research includes examining other animals for their sensory circuitry and will draw efforts towards replicating the super sensors of animals, by mimicking the intellectual capacity of human brain.