Human benefit from fly's tiny brain

Think twice before swatting one of those pesky flies - they could provide insights into Parkinson's disease or depression.

Researchers have found that the study of Drosophila (a fruit fly) can help isolate and test key genes related to memory, and manipulate certain compounds linked with brain 'circuitry'.

'It could influence our understanding of the cognitive decline associated with Parkinson's disease and depression in humans,' said Troy Zars of the University of Missouri.

The idea that animals have a system that can match the quality of a memory with the significance of the memory is well established. If the event is significant, the memory and detail surrounding it is much stronger, lasts longer and is more easily recalled compared to more insignificant or common events.

The problem the new study addresses is the understanding of the mechanism by which that occurs.

Findings of the study have been published in the Proceedings of the National Academy of Sciences.

'We have developed a strategy to address how this matching occurs, so we can 'turn that crank' over and over again. It allows us to answer the questions like what gene is it, how does it function, how does it interact with other proteins. We can find brand-new, completely unexpected things,' Zars said.

A major goal of neuroscience is to discover and study memory-forming structures within a brain. Zars said he works with Drosophila because it is a well-established genetic model, has a relatively less complex brain than the mouse or human (250,000 neurons versus 100 billion neurons), and has a broad repertoire of behaviours.

Memory in the flies was tested using a specialised chamber in which single flies were allowed to wander freely. The chamber was outfitted with heating elements.

When the fly moved to a particular side, the whole chamber rapidly heated to an uncomfortable temperature. The flies eventually learned, or remembered, to avoid that half if brain 'circuitry' is functioning properly.

A mutation in certain flies, however, altered the levels of serotonin and dopamine, which resulted in lower memory scores.

'This research is important because by studying a simple brain it will help us ultimately understand complex neural systems,' Zars said.