Last May some news came out about how SSRIs (the class of antidepressant drug that includes Prozac) promote the growth of new brain cells (neurogenesis) in the hippocampus, a part of the brain active in learning and memory. Now a researcher at the Karolinska Institutet in Sweden has looked at the effects of exercise in rats and found that exercise also stimulates neurogenesis in the hippocampus, which would explain why exercise is sometimes useful in treating depression. I’ve found exercise to be helpful in keeping my own spirits up, and now I know a little more about why. This press release from Science Daily gives some more information. I’m going to go take a long walk now.
The reasons that humans help others are complicated, and certain aspects of human altruism have been thought to be unique to us. Even our close relatives, the chimpanzees, were thought to lack certain key components of altruism, like being willing to help someone who is not related without expecting some kind of payback. Recent research carefully examined helping behavior in chimps and in human toddlers and discovered some interesting things indicating that perhaps our altruistic behavior is rooted in capabilities also possessed by chimps. In two experiments that compared chimps and 18-month-old humans, researchers found that both showed a similar propensity for helping a stranger, even when no reward was involved and even when helping the stranger involved some effort. (The only difference was that the humans were a little faster and the chimps were more likely to need additional cues that help was needed before they would respond.) A third experiment looked only at chimps, and indicated that chimps are able to use a newly learned skill to help another chimp get to food, without pestering the other for a share. The paper in PLoS Biology contains all the details, including some video sequences, and an author summary at the top if you want just the basics.
The New York Times has posted a couple of articles about human evolution. This article by Nicholas Wade talks about some of the ways that the human genome has diverged in populations that live in different areas of the world. Thanks to a new type of genetic research that looks for genes that are under selective pressure, scientists can identify ways that the genomes of different populations appear to be responding to local conditions (e.g., diseases or differences in diet). One of the best known local variants in metabolism is adult lactose tolerance, which is widely present only in groups that live in places where using dairy products from livestock is practicable. Interesting, adult lactose tolerance evolved several different times in humans as a result of different genetic mutations; this is a nice example of convergent evolution in humans.
This article by John Noble Wilford covers some developments on the hominid ancestor front. Over the past ten years or so, scientists have pushed further and further back in time, examining fossils that are relatively close to the human/chimp split somewhere between six and eight million years ago. The further back you go, the more confusing (and more interesting) it gets. Looks like this will be an exciting area of research for some time to come.
This press release from the Harvard School of Public Health makes for sobering reading. It describes a “silent pandemic” of neurological problems caused by exposure to harmful chemicals. The developing brains of fetuses, infants, children, and adolescents are especially vulnerable to the neurotoxic effects of many industrial chemicals, yet such chemicals are generally insufficiently researched and regulated. The authors of a recent review suggest that the minds of children around the world are at risk (and have been at risk for years) from harmful substances that disrupt the delicately timed sequences of events by which a brain grows into its full powers. These chemicals can reduce intelligence and change behavior for the worse (e.g., making children more aggressive), and may be implicated in some neurological disorders. (I wish I had some action to suggest; I suppose this is an issue to keep in mind when you interact with your elected representatives.) Thanks to Mark, who passed this story along with the comment “It seem like a shame, if not a crime, to damage the meat before it has a chance to think.” Amen.
To follow up on an earlier post about mindfulness and the awareness of emotions, here’s a press release from the University of Pennsylvania that describes some research into the cognitive abilities of meditators. Mindfulness meditation appears to enhance the ability to focus the attention and to rapidly shift the focus of attention, among other things. You know how in a press release they always have to include some note about possible applications, and the applications they mention here involve workplace learning and performance. I’m not sure how I feel about that. On the one hand, the potential to improve your sharpness at personally meaningful pursuits is a wonderful thing. On the other hand, “workplace performance” is more likely to be about making people more productive at work that is not all that personally meaningful or rewarding. Turning Buddhist meditation techniques into increased efficiency at the office seems contrary to the original intent. But all that aside, the benefits of mindfulness meditation may be considerable. If you attain them, apply them as you will.
We talk about musical notes being either high or low, and they march up and down the staves, but that’s just a metaphor…or is it? A recent study links tone-deafness (also known by the more poetic term amusia) and difficulty with a spatial task (mentally rotating 3D objects). In a study at the University of Otago in New Zealand, tone-deaf subjects had a harder time with the spatial task than other subjects. Furthermore when they had to simultaneously manage the spatial task and identify musical notes, they found it easier than the others did. This suggests that the mental machinery that processes musical pitches is also involved in spatial processing, so that those who are not tone-deaf were juggling two competing activities. Seems unexpected but there it is, and this line of research may someday shed light on how music is perceived, and what exactly we mean when we talk about high notes and low notes. You can read more in this press release.
I’ve kept a journal, off and on, for just about as long as I can remember (as long as I’ve been able to write, anyway). To me there is something valuable in naming and trying to understand emotional experience in particular, either through writing about it or talking it through with someone I trust, and I’ve always been interested in the idea of being an observer of your own emotional states, experiencing them but being aware of what they are and not getting totally swept up in them. Not that I can always do it, mind you, but it seems like a good idea.
Some of what I’ve read about mindfulness meditation indicates that it fosters that kind of awareness. Recent research into brain activity and mindfulness shows why naming emotional states might be valuable. The amygdala, an area of the brain important in experiencing emotions and mediating the physiological responses to them, is activated when we see faces bearing the expressions of particular emotions. In a recent study, people who saw faces expressing strong emotions like anger or fear and were given emotional labels to describe them showed less activity in the amygdala and more in an area of the cortex called the right ventrolateral prefrontal cortex. This indicates that their raw emotional responses were held in check to some degree by that part of the cortex, which is involved in processing emotions and inhibiting behavior (although its exact role is not known). Furthermore, the shift of activity to the right ventrolateral prefrontal cortex was more pronounced in those who were more mindful, in the sense of using the Buddhist technique of labeling emotions as they arise and then letting them go. So maybe the Buddha’s ancient advice about observing and labeling your emotions is helpful because it shifts us out of a reactive mode and into a more reflective mode. You can read more about it in this article from EurekAlert.
Around 35,000 years ago in what is now part of Germany, an early modern human was carving figurines out of woolly mammoth ivory. Archaeologists recently discovered five such figurines, including representations of a lion and a mammoth. These tiny artworks, recently unearthed, are among the oldest examples of figurative art ever found. (For comparison, the oldest known cave/rock paintings go back to 32,000-40,000 years ago. The paintings at Lascaux in France and Altamira in Spain are somewhere around 15,000 years old.) This article from Spiegel Online has more information. It’s worth clicking the link to the photo gallery; you get a nice close-up view of several of the recently discovered pieces.