Fruit Flies and Musical Language
Some interesting research on Futurity this week, covering a couple of my favorite scientific topics: fruit flies and music. The first, out of Caltech, used the humble little Drosophila melanogaster (only about 2.5mm in size) to study a very complex human behavior mystery: ADHD. While it might seem impossible to model the attention deficits of schoolchildren in a fly, Drosophila proves again and again that its relatively simple brain (with only 200,000 neurons) and its well-understood genetics make it the ideal lab animal – easy to store too!
In this study, researchers found that one thing flies do not like is being puffed with air, as they respond by flying chaotically around their chamber for several minutes after the puff. Some flies respond even more dramatically and quickly to the puffs, and these were found to have a mutation the receptor for the neurotransmitter dopamine – a frequent focus of the blog thanks to its role in addiction and learning. Dopamine is also thought to play a role in human ADHD – children with the disorder are given Ritalin, a stimulant drug that increases dopamine – so the hyperactive flies with deficient dopamine matches up nicely with the human data. In a separate study, the authors found that flies with the same dopamine mutation also have issues learning to pair an odor with a shock, suggesting that the learning disabilities of many ADHD kids may also be down to dopamine.
The second Futurity study to catch my eye this week came from Duke, and took on the challenging question of why humans like music. As a human that likes music, I was naturally intrigued. The Duke theory: we listen to music because it mimics speech. A paper by Kamraan Gill and Dale Purves asked why we only generally use five- and seven-note scales (Harry Partch excepted) to produce music when there are literally billions of scales available. Gill and Purves argue that this is because human speech itself can be organized into pentatonic or heptatonic scales, a trick they demonstrate in this video. The idea fits snugly into current theories of why music evolved in the first place – as an early language, or, as Steven Pinker calls it, “auditory cheesecake”?
(Fun fact: Darwin’s theory on the origin of music was that “musical notes and rhythm were first acquired by the male or female progenitors of mankind for the sake of charming the opposite sex.” I think Mick Jagger would agree.)
Assorted Followups & Curiosities
– Project HM is still rolling along; as of Friday afternoon on the webcast, they were still cutting the brain of the famous amnesiac, though it appears to my amateur eye that they’re into the cerebellum at the back of the brain. I’m very excited to see the finished product.
– One of the themes of the Darwin/Chicago conference was how Darwin’s ideas of natural selection and evolution have infiltrated fields beyond biology. This week, the National Science Foundation put up a cool interactive exhibit elaborating on just that point, including an excellent essay by Darwin/Chicago participant Ronald Numbers about how a French astronomer’s “nebular hypothesis” influenced Darwin’s thinking.
– If you want to dig into some real old-timey science, the Royal Society has scanned in a whole bunch of fascinating scientific articles that date back to 1650. Wired’s Brandon Keim did a better job of finding the best entries, such as Benjamin Franklin’s lightning-attracting kite and creationist papers by Newton and Einstein.
– Want to name a newly discovered shrimp species? Get ready to bid on eBay.