Caffeine and Memory

I have a great fondness for my morning cup of coffee.  I'm pretty happy about my second morning cup of coffee, too.  Although my children like to taunt me about having an addiction, they also know better than to bother me before my first cup of joe in the morning.  And occasionally I indulge in an afternoon pick-me-up, yet another steaming mug.  Coffee wakes me up, gets me going, makes me alert and creative.  Once, in a foolish fit of well-meaning, I gave up coffee for a year.  It was the most dull, flat, uninspired year of my life.  I’ll keep the coffee, thanks.

And so it always pleases me to read about positive effects of caffeine.  The February 2014 issue of Nature Neuroscience includes an article showing that caffeine increases memory consolidation.  Caffeine has been shown in the past to increase alertness and attention, but a proven role in memory in humans has been lacking. 

This recent study, authored by Borota et al. out of Johns Hopkins University, had subjects study pictures of objects, asking them to consider whether each one would be used indoors or outdoors.  Afterwards, they were either given 200 mg of caffeine, or a placebo.  The next day, the people came back to the lab and were shown another series of pictures.  Some pictures were the same ones they had seen the previous day, some were completely new, and some were “lure” pictures, similar to those seen on the previous day, but not identical.  The subjects had to try to remember what they had seen the previous day, and say whether each picture was new, old or similar.  The researchers found that people were pretty good at distinguishing new from old pictures, but the tricky part of the task was the lure pictures.  People who had taken the caffeine pills were better at recognizing these pictures as similar but not the same as those they had previously seen.

Memory processes go through several stages.  The first is encoding, when we get new information and store it in our brain, laying down a memory trace.  The next step is consolidation, in which memories become resistant to interference from competing memories, and become strengthened.  In a research setting, this is usually seen as better performance on a memory task.  Some consolidation of memories can occur while we’re awake, but there is a large body of evidence showing that memory consolidation during sleep is critical for strengthening memories.  The last memory process used by the subjects in this research study is memory retrieval, where memories are pulled out for use in a memory task.

Because in this study the caffeine was administered after the subjects had studied the pictures for the first time, we cannot tell anything about the effect of caffeine on memory encoding (although other studies have not shown any real effect).  And saliva tests showed that there was no residual caffeine in the subjects’ systems at the time of memory testing, so this study doesn’t implicate caffeine in memory retrieval either.  This study shows that caffeine boosts memory consolidation.  Excellent!  I think I’ll go and make myself another cup.

Reference

Borota, D., Murray, E., Keceli, G., Chang, A., Watabe, J.M., Ly, M., Toscano, J.P., and Yassa, M.A. (2014). Post-study caffeine administration enhances memory consolidation in humans. Nature Neuroscience 17:201-203.

Musical Training has Long-Lasting Effects

The other day, as I was dropping off my son at school, I was approached by another mom, who asked for my business card and said she was thinking about putting her 6-year-old daughter in piano lessons.  She told me that she’d been reading a lot in the news about how studying music was good for brain development.

I’ve noticed this too:  a flurry of news articles in the last few weeks extolling the benefits of musical training for children’s brains.  Music training altering the brain isn’t really news, but here's what is: several recent research studies show that a relatively short period of musical training early in life can have long-lasting effects on the brain.

Nina Kraus’ lab at Northwestern University has published a stack of papers showing that musical training alters the way the brain processes sound.  One of the ways they study auditory processing is by looking at the electrical responses of the brainstem in response to sounds such as speech.  One particular type of sound in speech that can be difficult to process is the transition between consonants and vowels.  Because this transition happens so quickly, it can be hard to tell apart the sound "da" from the sound "ba", for example.  A fast brainstem response to consonant-vowel transitions indicates that this type of auditory input is well-processed, and this in turn leads to enhanced language abilities.  Kraus’ lab has shown in the past that musicians’ brains have faster responses to these types of transitions than the brains of non-musicians.

A new study from Kraus’ lab, published this month in the Journal of Neuroscience, compares brainstem responses to consonant-vowel transitions in older adults who either had no musical training, a small amount of musical training (1-3 years) as a child, or a moderate amount of musical training (4-14 years) as a child.  Note that all of the musical training had occurred while the subjects were children, and so it had been roughly 50 years since these people had had music lessons.

Despite the fact that it had been so long since musical training ended, there were noticeable differences in the responses to consonant-vowel transitions in the brains of the three different groups.  The fastest responses were from the people with the most musical training, while the people with no musical training had the slowest responses.

From White-Schwoch et al. (2013).  Group average brainstem responses to the sound “da”.  The blue lines (fastest response) are the subjects with moderate musical training, orange is little musical training, and grey lines are the responses from people with no musical training.

This study shows that the effects of musical training can persist long after the musical training has stopped.  Why would this be?  We tend to think of our brain capabilities in a “use it or lose it” fashion – for example, if you don’t play the piano for 50 years, you’re probably not going to be able to play it very well.  But in this case, what the musical training did was to alter the way the brain processes sound, and since processing sound is something that we do in everyday life, the enhanced neural responses to sound continued to be used after the end of musical training.  The authors of this study suggest that early musical training primes the brain’s auditory system for further plasticity in response to sound, setting the stage for future auditory effects on the brain.

Another study, presented at the recent annual meeting of the Society for Neuroscience, showed that people who had musical training that started before the age of seven had thicker gray matter in certain areas of the brain than those who started musical training later.  This research, authored by Yunxin Wang at Beijing Normal University, indicates that starting lessons before the age of seven is more likely to lead to long-lasting brain changes, something that has been suggested by previous research.  What is slightly different about Wang’s study, though, is that the subjects were not all currently musicians; some had had only a small amount of musical training in childhood and not continued with lessons.  Nevertheless, that early musical training seems to have left an impression in their brains.  Whether the differences in brain anatomy lead to any change in brain function is not yet known, but this type of result certainly suggests that starting music lessons earlier is more likely to lead to long-lasting neurological benefits.

References

Wang, Y., Xei, L., Zhu, B., Liu, Q., and Dong, Q. (2013). It matters when you start: The age of onset of music training predicts brain anatomy.  Program No. 765.07, Neuroscience 2013 Abstracts, San Diego, CA: Society for Neuroscience, Online.

White-Schwoch, T., Carr, K.W., Anderson, S., Strait, D.L., and Kraus, N. (2013). Older adults benefit from music training early in life: biological evidence for long-term training-driven plasticity. J. Neurosci. 33, 17667–17674.