U.S. scientists have found primitive emotion-like behavior in fruit fly, Drosophila melanogaster.

According to researchers, their findings could provide new insights into the neurological basis of attention deficit hyperactivity disorder (ADHD).

Most of the genes found in the fruit fly, also referred to as the vinegar fly, are found in humans as well, including those neurons that produce brain chemicals like dopamine and serotonin.

During the study, researchers from California Institute of Technology (Caltech) found that a series of brief but brisk air puffs, delivered in rapid succession, caused flies to run around their test chamber in what they called a "frantic manner."

This behavior persisted for several minutes after the last of the puffs.

"Even after the flies had ’calmed down’ they remained hypersensitive to a single air puff," said David Anderson, Caltech’s Seymour Benzer Professor of Biology and a Howard Hughes Medical Institute investigator.

The team led by postdoctoral fellow Tim Lebestky developed an automated machine-vision-based system to track the movement of the flies, and derived a simple mathematical model to fit the movement data and to extract metrics that described various aspects of the flies’ responses under different conditions.

They found that flies with the dopamine-receptor mutation were hypersensitive to the air puffs, and took much longer to calm down than did "normal" flies without the mutation.

It is often assumed that because individuals with ADHD are hyperactive and easily distracted, they have difficulty learning.