This has been an extraordinarily good summer for nature documentaries. March of the Penguins covers a year in the life of the intrepid Emperor penguins who make a home and a life in one of the most inhospitable places on earth. The Wild Parrots of Telegraph Hill explores one man’s relationship to a flock of wild parrots on the streets of San Francisco. Grizzly Man is an unsettling look at the life and death of Timothy Treadwell, who lived among the grizzlies in Alaska for 13 summers before being eaten by one of them. I’ve had the good luck to see all three movies with companions whose insights added some depth to my experience of each film, and I wrote down my thoughts in a new TM essay. Hope you enjoy it.
Far more males than females are autistic. In investigating why autistic children have such a hard time relating to other people, researchers have looked at another thing that’s very different between the sexes: roughhousing or physically rough play. Boys do far more of this than girls do, and for a long time everyone thought testosterone was the cause. It turns out, however, that you can get female rats to roughhouse like the males if you give them, not testosterone, but estrogen. Dopamine also appears to have a similar effect on rough play. Further research into these kinds of social behaviors and the biochemical underpinnings may shed some light on what exactly is going on in autistic children and what might be done to help them have a normal life.
When you hear a sound, your brain processes the differences between the sound arriving at your right ear and the sound arriving at your left ear, and as a result you’re usually able to tell, with some degree of accuracy, where the sound is coming from. It turns out that your brain does something similar with incoming smells, processing input from each nostril in a different location in the olfactory cortex. Scientists at Berkeley discovered this by using a special face mask and a functional MRI scanner that identified which brain regions were active in test subjects. Their results show that humans possess the ability to tell where a smell is coming from. I don’t suppose we have as many occasions to use this ability now as we probably did in earlier times, but we do still possess it.
Furthermore, the fMRI showed that another brain region was active when people were localizing smells, and it’s an area (the superior temporal gyrus) that’s involved in processing stereo visual and audio input to come up with spatial information.
Thanks to Greg H. for telling me about this story.
I didn’t know this, but people who use heroin and other opiates are much more likely to have problems with anxiety. It turns out this is probably caused in part by the fact that the opiates themselves seem to leave animals more vulnerable to stress. Research on rats involved giving them either morphine or a saline solution regularly and then exposing them to a stressor well after they were no longer receiving the injections. Rats who had been given the morphine showed more symptoms of anxiety when stressed. The effect was more pronounced with longer exposure to the morphine and with higher doses of morphine.
Everyone knows about the placebo effect, in which people report feeling better after taking medicine that they believe will help them, even if the supposed medicine in fact has no active ingredients. It’s long been believed that this effect was purely psychological, but scientists have figured out that a placebo painkiller somehow triggers the release of endorphins, the body’s own painkillers. So people really do feel better after the placebo because of the physical effects of the endorphins. We don’t know yet how it works, though.
Here’s a story from the New Scientist about researchers at the University of Michigan who are investigating subtle behavioral differences that might reflect the different philosophical backgrounds of Western culture and East Asian culture. Westerners tend to be more analytical and individualistic, while those from East Asia are more attuned to seeing the whole in the interactions of the parts. The researchers looked at eye movement in Chinese and American students who looked at a picture with an obvious visual focus in the center and a realistic background. The Americans looked longer at the central image, and the Chinese moved their eyes over the whole picture more. They believe this difference is related to differing cultural values–goal-oriented focus versus harmony and holism. The article also mentions language differences that reflect the underlying cultural differences. The article closes with a quote from one of the researchers to the effect that understanding that we are different “should form the basis of respect”. I hope he’s right.
I’m listening to the radio, people singing music from the Renaissance. I can’t carry a tune, so I’m always impressed by people who can produce the correct musical pitch for each note. I can at least recognize when two notes are the same or different, though, and I can tell when an instrument is out of tune. Until recently, no one has known how the brain interprets musical pitch; scientists knew what part of the brain was active when we try to identify a pitch, but no one had observed individual brain cells responding to particular pitches. New work with marmoset monkeys has shown the location of individual neurons that fire when they hear a particular pitch. This is likely to be the foundation for further studies of the neural basis of musical perception. Meanwhile, I’m enjoying the talents of people whose sense of pitch is better tuned than mine.
Amino acids come in two kinds, right-handed and left-handed, that are mirror images of each other. But on earth, only the left-handed kind occurs naturally in living things. No one knows why; one idea is that both kinds arose on earth but for some reason only the left-handed ones made it. Some recent lab work bears out another hypothesis, which is that amino acids first formed in space, where a particular type of radiation preferentially wiped out right-handed ones. The left-handed amino acids were then carried to earth by comets, seeding our planet, and several billion years later, here we are. The radiation also comes in two different kinds, so if some other solar system had the other kind of radiation, it would wind up with more right-handed amino acids than left-handed ones.