Fruit Flies Take Time To Arrive at a Difficult Decision

A team of neuroscientist has found evidence that fruit flies when trapped in a difficult situation take time to arrive at a decision.

For the first time, scientists have come up with sound evidence that fruit flies indulge in a proper decision making process. Neuroscientists at the University of Oxford's Centre for Neural Circuits and Behavior found that when it comes to making difficult decisions the fruit flies don't act instinctively; they rather take time to consider all available options before taking action.

This ability to collect data before arriving at a decision is considered a sign of superior intelligence and is displayed by primates and humans.

"Freedom of action from automatic impulses is considered a hallmark of cognition or intelligence," says Professor Gero Miesenböck, in whose laboratory the new research was performed. "What our findings show is that fruit flies have a surprising mental capacity that has previously been unrecognized."

 The study revealed the presence of an active gene called FoxP that is placed inside a tiny set of 200 neurons.  According to the researchers, it is this gene FoxP that is involved in the crucial decision making process in the brain of the fruit fly.

 To test the hypothesis research was conducted on Drosophila fruit flies. The researchers noticed how the fruit flies made a choice between concentrations of two different odors. The orders were presented from the opposite ends of a narrow chamber. The fruit flies were already trained to avoid a particular concentration. When the flies were presented with the two different kinds of odor the flies made a quick decision and moved to the correct end of the chamber.

When the concentrations were placed too close together making it difficult to differentiate the odors, the researchers noticed that the flies took much longer to come to a decision.  They made a lot of mistakes. 

This find matched the mathematical models developed to describe the mechanism of decision making in both humans and primates.

The fruit flies that had a mutated FoxP gene tool a longer time than the normal flies to arrive at a decision when odors were tough to differentiate.

The activity of FoxP gene was tracked to a small cluster of just 200 neurons out of over 200,000 neurons present in the brain of the fly. 

Dr Shamik DasGupta, the lead author of the study, explains, "Before a decision is made, brain circuits collect information like a bucket collects water. Once the accumulated information has risen to a certain level, the decision is triggered. When FoxP is defective, either the flow of information into the bucket is reduced to a trickle, or the bucket has sprung a leak."

In humans there are four related FoxP gene but fruit flies have one of this gene.  FoxP1 and FoxP2 in humans is linked with language and cognitive development.

"We don't know why this gene pops up in such diverse mental processes as language, decision-making and motor learning,' says Professor Miesenböck. However, he speculates: 'One feature common to all of these processes is that they unfold over time. FoxP may be important for wiring the capacity to produce and process temporal sequences in the brain. FoxP is not a 'language gene,' a "decision-making gene,' even a 'temporal-processing' or 'intelligence gene'. Any such description would in all likelihood be wrong. What FoxP does give us is a tool to understand the brain circuits involved in these processes. It has already led us to a site in the brain that is important in decision-making."

The finding was documented in the journal Science. The study was funded by Wellcome Trust, the Gatsby Charitable Foundation, the U.S. National Institutes of Health and the Oxford Martin School.