Biologists at Cornell University highlight the possible origin of differences in human social behaviors

Male fruit flies usually don’t like each other. Socially, they reject their male mates and focus on females whom they recognize via chemical receptors – or so scientists thought.

New research by biologists at Cornell University suggests that the fruit fly’s visual system, not just chemoreceptors, has a major role in its social behaviors. This work highlights the potential origin of differences in human social behaviors, such as those seen in people with bipolar disorder and autism.

The paper was published with the title “Visual feedback neurons control courtship in Drosophila males via GABA-mediated inhibition.” Current biology On September 5th.

Many animal species use vision to regulate their social behavior, but the underlying mechanisms are largely unknown. Vision in fruit flies is thought to be used explicitly to detect and follow movement, not to regulate social behaviours, but researchers have found that this may not be the case.

In our study, we found that hyperactivation of the visual system overcame inhibition caused by chemical signals emitted by male flies to tell the other male, “Okay, you know, I’m another male, don’t mess with me.” Surprisingly, increased visual gain in the brain somehow overcomes chemical sensory inhibition, attracting male flies to other males.”

Nilay Yapisi, lead author, is an assistant professor of neuroscience and behavior

Researchers found that changing GABARAP/GABA_a Receptor signals in visual feedback neurons in the male brain influenced the flies’ social inhibitions. When GABARAP is destroyed in the visual system, males unexpectedly show increased courtship toward other males.

The researchers found that genes similar to those in the human brain control the fruit fly’s visual neurons. Reduced GABA signaling in the human brain has been linked to characteristics of social withdrawal in conditions such as autism and schizophrenia.

“Our results provide a promising way to study how these proteins regulate social behaviors in the mammalian brain and their potential contribution to human psychological states,” said lead author Yuta Mabuchi, MD, PhD. ’23.