While the wooly musk ox may like it cold, fruit flies definitely do not. They like it hot, or at least warm. In fact, their preferred optimum temperature is very similar to that of humans-76 degrees F.
Scientists have known that a type of brain cell circuit helps regulate a variety of innate and learned behavior in animals, including their temperature preferences. What has been a mystery is whether or not this behavior stems from a specific set of neurons (brain cells) or overlapping sets.
Now, a new study from The Scripps Research Institute (TSRI) shows that a complex set of overlapping neuronal circuits works in concert to drive temperature preferences in the fruit fly Drosophila by affecting a single target, a heavy bundle of neurons within the fly brain known as the mushroom body. These nerve bundles, which get their name from their bulbous shape, play critical roles in learning and memory.
The study, published in the January 30, 2013 edition of the Journal of Neuroscience, shows that dopaminergic circuits-brain cells that synthesize dopamine, a common neurotransmitter-within the mushroom body do not encode a single signal, but rather perform a more complex computation of environmental conditions.
"We found that dopamine neurons process multiple inputs to generate multiple outputs-the same set of nerves process sensory information and reward-avoidance learning," said TSRI Assistant Professor Seth Tomchik. "This discovery helps lay the groundwork to better understand how information is processed in the brain. A similar set of neurons is involved in behavior preferences in humans-from basic rewards to more complex learning and memory."