One of the most interesting things about brain science is the possibilities it offers for figuring out how to optimize the use of your brain. Curious thinking meat, realizing it has this wonderful but tricky instrument more or less at its disposal, wants to know what to eat, how much and when to sleep, and how best to study. I’m going to try to keep an eye out for useful information that answers this type of question (like the post last week about napping)–applied thinking meat, if you will. For a start, here’s a memory toolbox from the Online Education Database that offers a nice summary of some techniques and tips for effective learning and memory. It also provides links to some interesting background information, e.g., about some of the brain science involved.
You have nothing to lose but your weariness! At any rate, that’s the gist of this article from Science Daily. In a recent study of normal sleepers, napping during the day improved cognitive performance on the following day without affecting night-time sleep. It’s not entirely clear from the article, but it sounds like the study participants were all over 60, so I’m not sure how much this applies to younger people. But by George, napping sure sounds good to me. This Science Daily article from 2002 discusses the role of napping and early-morning sleep in avoiding burnout and learning new skills, respectively. Also, napping might be part of our biological heritage from earlier humans. Human circadian rhythms include a dip in energy levels at some point in the afternoon, perhaps a reflection of an earlier bi-phasic sleep pattern that included a longer period of sleep at night and a shorter period during the day. Long live the siesta!
When my sons were very small I recorded their accomplishments and the milestones of their lives in baby books. As parents often do in baby books, I wrote down their first words and noted the date for each word’s appearance. For the first few words, this is possible; then babies start to pick up the pace and it’s harder to keep up, and sometime around 18 months of age, babies typically go through a great jump in the number of words they know. (After that parents record only the exceptionally cute things their kids say.)
The reason for this dramatic burst of vocabulary growth has been a subject of speculation, and various mechanisms have been proposed to explain it. However, a researcher at the University of Iowa modeled the process mathematically and concluded that the whole thing is statistically inevitable given two assumptions: That babies are learning more than one word at a time, and that difficult words outnumber easy words in a language. Other mechanisms may be at work, but these two initial conditions guarantee the leap in vocabulary. (It’s curious, though, that older learners don’t show the same pattern.) You can read more about it in this article from The Guardian and this one from New Scientist. (Good articles, but I will point out that the expert quoted near the end of the latter, Lisa Gershkoff-Stowe, runs the Baby Language Lab at Indiana University, not the non-existent University of Indiana.)
Well, actually what scientists have seen is a rat’s brain learning. Scientists at the University of California, Irvine have used a sophisticated method of microscopy to observe changes in the shape of the synapses in rats’ brains as the rats figured out how to get around in a new environment. When the physical changes were blocked with a drug, the rats failed to learn, confirming that the changes the researchers were seeing are indeed related to the associations the rats were forming. This is the first time anyone has seen the synaptic changes involved in learning something new, and it opens the way to mapping the way memory is distributed across the brain. This press release from UC Irvine has some more details.
Variants in two genes that are associated with brain development, ASPM and Microcephalin, appear to affect how easy it is to learn a tonal language like Chinese. In a tonal language, the pitch with which a word is spoken affects its meaning, so that the same combinations of letters spoken with different pitches can mean different things. Few European languages are tonal, but many of the languages of sub-Saharan Africa and East Asia are. A recent study shows that people who live where non-tonal languages, such as English and most other European languages, are spoken are more likely to have more recently evolved variants on the ASPM and Microcephalin genes. One of the implications is that the earliest languages might have been tonal, with non-tonal languages arising later in our evolutionary history. It sounds like we still have a lot to learn about how the later gene variants associated with non-tonal languages emerged.
Tonal languages can be difficult to learn for those who are used to a non-tonal language. Some English speakers find it easier to learn tonal languages than others, and previous work has demonstrated differences in brain anatomy between the two groups; future work may investigate whether the anatomical differences also appear between people with the more recent ASPM and Microcephalin variants and those without.
It’s been known for awhile that when we sleep, we process our memories in a way that makes them stronger and better established. Some new research indicates that in addition, we’re better able to see the connections between things we have learned if we have a chance to sleep on it, and to generalize rules and overall themes. This short article from New Scientist gives some more info.
If you immerse yourself in the early stages of learning a new language, you might start to lose your grasp on the old one for awhile; this phenomenon has the depressing name of “first language attrition”. Researchers from Spain and the US investigated what’s going on when this happens, and concluded that when people focus on words in the new language, they appear to be actively suppressing the memory of the old familiar words in their first language. This effect goes away when people become fluent in the second language (so it’s not a depressing zero-sum sort of thing, as it appears at first); perhaps it’s a useful brain strategy that helps cement the new language more firmly in memory by ignoring the old one temporarily. You can read this article from Science Daily or check out the paper (in PDF format). I was amused at the intro to the Science Daily piece, which mentions one of the researchers musing about how it could be “possible to forget, even momentarily, words used fluently throughout one’s life.” Sadly enough it happens to me all the time, and not in the context of learning a second language either.
Recently a couple of news stories came out about dendritic spines, a crucial part of the synaptical connections between neurons. A dendritic spine is a tiny, tiny projection on a dendrite, one of the many filaments that link a neuron to other neurons. In the synapses, the gaps between neurons, neurotransmitters are exchanged and much of the interesting business of the brain takes place. Dendritic spines cover most neurons like thick grass, and extend the surface area available for the receptors that bind neurotransmitters. Three recent papers by a group of researchers describe the functioning of dendritic spines. The group used some innovative imaging techniques to investigate the electrical activity of these infinitesimal but vital structures, and came to the conclusion that they act as electrical filters that give neurons the ability to sum up inputs linearly. These findings could help lay the groundwork for an understanding of how the brain performs its computations, including what role the spines play in learning and why human brains have a greater ability to learn. This press release from the Howard Hughes Medical Institute describes the work and the results.
The second news story describes some work that looked at how the synapses can be stable enough to hold our memories when they are in such chemical flux. The strength of our memories (and of our identities, to some degree, since who we think we are is based at least partly on our memories of ourselves and our lives) depends on the strength of the connections between neurons. Two researchers at the University of Utah found that the proteins that are essential for strengthening synaptical connections remain in place because of the presence of anchoring proteins that hold them there. You can read about it in this press release.
Thanks to Mark for passing along these two news stories.