Science, September 25
The week’s biggest news: there’s water, water everywhere in our solar system, or at least on our moon and on Mars. First, a trio of studies reported on the latest findings from the moon, where an Indian orbiter and two NASA probes detected the chemical signature of water all around the moon, not just in the permanently shadowed polar craters where scientists think ice might lurk. But researchers say the water isn’t sitting around in pools–it’s bound up with rocks and minerals in the top few millimeters of moon dust. In the Mars finding, researchers looked at five craters recently created by meteor impacts, and discovered that subterranean ice had been kicked up to the surface. The presence of ice on Mars wasn’t a surprise, but the quantity of it was–researchers say there may be ice sheets hundreds of miles across just beneath the surface.
Nature Neuroscience, October
Two papers in this journal upended expectations of who can learn, and what they can learn. In the first study, researchers found that coma patients in a completely unresponsive, vegetative state are nonetheless capable of the most basic kind of learning: Pavlovian conditioning. These patients learned to associate a noise with an unpleasant puff of air to their eye, and began blinking or twitching as soon as they heard the noise. The findings suggest that these patients may have a rudimentary level of consciousness that isn’t detected in other tests. In the second study, researchers trained paralyzed rats to walk again using a combination of treadmill exercise, drugs, and direct electrical stimulation of their nerves. Although the rats’ damaged spinal cords couldn’t convey a message from their brains to their legs, the spinal circuits could be coaxed into sending the messages to the legs, resulting in movement that was almost indistinguishable from normal walking.
Proceedings of the National Academy of Sciences, September 22
This was pretty clever. Researchers had been stymied in their attempts to determine whether drinking alcohol at a young age causes people to take more risks later in life; the evidence seemed to suggest it, but researchers couldn’t rule out the possibility that it was people’s risk-prone personalities that caused them to drink in the first place. So in this study, researchers took two groups of genetically identical adolescent rats, and fed one group alcoholic jello shots! Then they taught both groups of rats to gamble, with sugar pellets as the jackpots, and found that the rats that had boozy diets were more likely to take big risks. Like we said–pretty clever.
Nature, September 24
Nature‘s cover story didn’t get much attention, probably because population genetics isn’t as fun to read about as boozing rats. The study conducted the largest ever DNA survey of people living on the Indian subcontinent, and found that its population descends from two distinct genetic groups. One lineage, which has genetic similarities to people from the Middle East and Europe, while the second lineage was similar only to indigenous people in the remote Andaman Islands in the Bay of Bengal. Another report looked ahead instead of backward, and issued guidelines for what humans should do in order to keep our planet’s environment from crashing and burning, which would inevitably have serious implications for human life. In what they called a “user’s manual” for Earth, researchers listed nine limits that we should live within, including the amount of carbon dioxide in the air, the amount of nitrogen pollution in our waters, etc. One troubling aspect: We’ve already surpassed three of the limits.