A researcher at the University at Buffalo in New York has found that mice discriminate partial sounds just as humans do with partial words. Micheal L. Dent, PhD, studies the ultrasonic vocalizations (USVs) of mice. These sounds are above the frequencies that are audible to the human ear, but they can be recorded and played back using specialized equipment that has allowed Dent and her research team to capture an impressive repertoire.
Studies suggest that mice use these vocalizations for acoustic communication, but it’s not conclusive whether USVs carry meaning. Though diverse, the mice USVs are not entirely understood, so Dent is first trying to learn if mice can tell the difference between the vocalizations.
When graphically represented, the mice USVs show a variety of sweeps, arcs, dips and curves. The tempo and intensity of these vocalizations change, as does their frequency bandwidth, and the amount of frequency and amplitude modulation.
“There is so much complexity in these USVs,” said Dent, an associate professor of psychology in the UB College of Arts and Sciences.
According to the study, which was published in the December 2014 edition of the Journal of the Acoustical Society of America, if these USVs are behaviorally relevant to the mice, then being able to perceive and identify them accurately in the environment, even when portions of the calls are perceptually masked, would be beneficial to an individual’s survival.
Mice are reportedly being used more as models because their inner ear structure and auditory system organization are similar to humans. Mice also progressively lose their hearing and are completely deaf at 18 months old. They also have what Dent says is an undeserved reputation as being uncooperative subjects for behavioral research.
“It has been said that mice can’t be trained,”said Dent. “We have found that’s not the case. We train them to detect sounds, discriminate between sounds, localize sounds, and categorize sounds using operant conditioning and positive reinforcement.”
Dent states in the announcement from UB that the study results don’t prove the mice vocalizations have meaning, but they do point toward communication purposes. She further stressed that, while the research is still in its infancy, she believes the work strengthens the utility of mice as good models for human communication. Her research is supported by a grant from the National Institute on Deafness and Other Communication Disorders.
Source: University at Buffalo