In memoriam

I want you to recall something simple.  A few to choose from:

• your own middle name
• the street you grew up on
• your best friend in elementary school
• the name of your first pet
• your second-grade teacher's name

Now, I'm presuming that none of you were actively thinking about any of those before I asked.  So, here are a couple of questions:

Where was that information before I asked you about it?  And how did you retrieve it from wherever that was?

The simple answer is, "we don't know."  Well, we have a decent idea about where in the brain specific kinds of information are stored, mostly from looking at what gets lost when people have strokes or traumatic brain injury.  (A technique my Anatomy and Physiology professor described as "figuring out how a car functions by smashing parts of it with a hammer, and then seeing what doesn't work anymore.")

But how exactly is that information is encoded?  That's an ongoing area of research, and one we're only beginning to see results from.  The prevailing idea for a long time has been that interactions between networks of neurons in the brain allow the storage and retrieval of memories -- for example, you have networks that encode memory of faces, ones that involve familiarity, ones that activate when you feel positive emotions, possibly ones that fire for particular stimuli like gray hair, glasses, being female, being elderly, or tone of voice -- and the intersection of these activate to retrieve the memory of your grandmother.

The problem is, all attempts to find a Venn-diagram-like cross-connected network in the brain have failed.  Even so, the idea that there could be a much smaller and more specific neural cluster devoted to a particular memory was ridiculed as the "grandmother cell model" -- the term was coined by neuroscientist Jerome Lettvin in the 1960s -- it was thought to be nonsense that we could have anything like a one-to-one correlation between memories and neurons.  As neuroscientist Charles Edward Connor put it, the grandmother cell model had "become a shorthand for invoking all of the overwhelming practical arguments against a one-to-one object coding scheme.  No one wants to be accused of believing in grandmother cells."

[Image is in the Public Domain courtesy of photographer Michel Royon]

The problem came roaring back, though, when neurosurgeons Itzhak Fried and Rodrigo Quian Quiroga were working with an epileptic patient who had electrical brain-monitoring implants, and found that when he was shown a photograph of Jennifer Aniston, a specific neuron fired in his brain.  Evidently, we do encode specific memories in only a tiny number of neurons -- but how it works is still unknown.  

We have over eighty billion neurons in the brain -- so even discounting the ones involved in autonomic functioning, you'd still think there's plenty to encode specific memories.  But... and this is a huge but... there's no evidence whatsoever that when you learn something new, somehow you're doing any kind of neural rewiring, much less growing new neurons.

The upshot is that we still don't know.

The reason this comes up is because of a study at Columbia University that was published last week in Nature Human Behavior, that looked at a newly-discovered type of brain wave, a traveling wave -- which sweeps across the cerebrum during certain activities.  And what the researchers, led by biomedical engineer Joshua Jacobs, found is that when memories are formed, traveling waves tend to move from the back of the cerebrum toward the front, and in the opposite direction when memories are retrieved.

Of course, nothing in the brain is quite that simple.  Some people's brain waves went the other direction; it seems like the change in direction is what was critical.  "I implemented a method to label waves traveling in one direction as basically 'good for putting something into memory,'" said Uma Mohan, who co-authored the paper.  "Then we could see how the direction switched over the course of the task.  The waves tended to go in the participant’s encoding direction when that participant was putting something into memory and in the opposite direction right before they recalled the word.  Overall, this new work links traveling waves to behavior by demonstrating that traveling waves propagate in different directions across the cortex for separate memory processes."

The other limitation of the study is that it doesn't discern whether the traveling waves, and the change in direction, are a cause or an effect -- if the change in direction causes recall, or if the shift in wave direction is caused by some other process that is the actual trigger for recall -- so the direction change is merely a byproduct.  But it certainly is an intriguing start on a vexing question in neuroscience.

Me, I want to know what's going on with the "tip of the tongue" phenomenon.  Just about everyone experiences it -- you know the memory is in there somewhere, you can almost get it, but... nope.  Most puzzling (and frustrating), I find that giving up and going to The Google often triggers the memory to appear before I have the chance to look it up.  This happened not long ago -- for some reason I was trying to come up with the name of the third Musketeer.  Athos, Porthos, and... who?  I pondered on it, and then finally went, "to hell with it," and did a search, but before I could even hit "return" my brain said, "Aramis."

What the fuck, brain?  Do you do this just to taunt me?

At least I comfort myself in knowing that we don't really understand how any of this works.  Which is slim consolation -- but at least it means that my own brain is no more baffling than anyone else's.

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The beat goes on

A loyal reader of Skeptophilia sent me a link yesterday with the question, "Could there be anything to this?"

The link was to a website called "Binaural Beats: A Meditation Shortcut."  The idea, apparently, is that you listen to two sounds simultaneously, which differ slightly in frequency (the example given was a 114 hertz tone in the left ear and a 124 hertz tone in the right).  This will result in your hearing a "beat frequency" or "binaural beat," whose frequency is equal to the difference between the two (in this case, 10 hertz).

[image courtesy of the Wikimedia Commons]

So far, nothing too strange, and a phenomenon that would be familiar to anyone who has tried to tune the strings of a guitar.  But what this site, and others like it, claim is that the induced beat frequency will change the frequency of your brain waves, and cause... well, all sorts of things.

The site he sent says that it will bring on a "meditative state:"

When you listen to sounds of a certain frequency, your brain waves will synchronize with that frequency.  You entrain every time you hear a musical beat that has you bobbing your head or tapping your foot. 

By listening to MP3s or CDs that produce brainwave entrainment, you can induce a desired brainwave pattern quickly and reliably.  Binaural beats is one of the most popular methods to utilize the phenomenon of brainwave entrainment... 

Using binaural beats provides an easy shortcut.  All you have to do is put on a set of headphones or earbuds, relax, and listen.  For many people, this brings their brains into the same state as deep meditation quickly.

Which was interesting enough, so I decided to do a little digging.  I found out quickly that meditative states aren't the only things that binaural beats allegedly can induce.  If you hit the right binaural beat frequency, supposedly you can:

• lucid dream
• boost your memory
• get past creative blocks
• (safely) simulate the mental effects of drugs such as marijuana, cocaine, and ecstasy
• lose weight and increase your metabolic rate
• jumpstart your physical and mental energy levels
• have a "mind-blowingly intense hands-free orgasm"

So naturally, I had to investigate all this.  I skipped the first three, given that (1) I already sleep poorly and have weird dreams, and have no particular desire to make this any worse, (2) I'm too impatient to conduct a long enough experiment to see if my memory improves, and (3) I do pretty well in the creativity department already.

The fourth one, on the other hand, was intriguing.  I thought it might be interesting to see if I felt high and/or stoned after listening to some tones going "wah-wah-wah" in my ears, so I gave it a shot.

If a sample size of one means anything, I can report back... nothing.  I didn't feel any loopier after listening to drug-simulating binaural beats for fifteen minutes than I did before.  So I went on to the "jumpstart your energy levels" one (I really don't need to lose weight), and once again... nada.

Then -- purely in the interest of scientific research, of course -- I had to try the last one.

I found two places that supposedly had orgasm-inducing binaural beats.  Listening to the first one was about as arousing as listening to a washing machine on spin cycle.  So I thought, "Maybe my sex frequency isn't attuned to that one, or something."  So I clicked on the second one, and I found out that on this recording, the binaural beat frequency was overlain with the sounds of a couple in the throes of noisy, and apparently extremely pleasurable, sex.  (And no, I'm not going to provide a link.  You'll have to track that one down yourself.)

So it was not exactly a well-controlled experiment.  Of course, I didn't listen for all that long, because otherwise my wife would have come down to my office to see what the hell I was doing down here.  ("Research, honey!  Empirical research!  Really!")

In any case, my own investigation of binaural beats was kind of a bust.  So I decided to see if there'd been any good studies done of the effect, and I found a site that had what seemed to me to be fair and unbiased summaries of the research.  And the general conclusion is...

... it doesn't seem to work. Most of the effects recorded were small and very temporary, and the consensus is that your expectations going into the experience have a major effect on what you'll get from it.  If you think it's going to relax you, then you relax.  If you think it's going to energize you, then you're energized.  If you think you're going to have a spectacular orgasm...

... well, you get the idea.  Although I have to add that throwing in the sex noises was hardly fair.

I suppose the whole thing is harmless enough, of course, and if it helps you to attain whatever it is you're after, then more power to you.  I've done a bit of meditating over the years -- never consistently enough to make it a practice, but enough to get the flavor of it -- and found it to be great for calming the mind and centering the body.  If "binaural beats" helps you to get there faster and deeper, cool.

As for the rest of it -- have fun experimenting, but if you're approaching it skeptically, keep in mind that the results might be less than "mind-blowingly intense."

Aesthetic synchrony

Probably most of you have had the fortunate experience of being in a situation where you were completely engaged in what you were doing.  This can be especially powerful when you are being given the chance to experience something novel -- listening to a lecture by a truly masterful speaker, attending a performance of music or theater, visiting a place of great natural beauty -- when you are having what writer Sir Ken Robinson (speaking of masterful lecturers) calls in his talk "Changing Education Paradigms" "an aesthetic experience, when your senses are operating at their peak, when you're present in the current moment, when you're resonating with the excitement of this thing you're experiencing, when you are fully alive."

When this happens, we often say we are "on the same wavelength" with others who are sharing the experience with us.   And now, a team led by Suzanne Dikker of New York University has shown that this idiom might literally be true.

Dikker's team had thirteen test subjects -- twelve high school students and their teacher -- wear portable electroencephalogram headsets for an entire semester of biology classes.  Naturally, some of the topics and activities were more engaging than others, and the researchers had students self-report daily on such factors as how focused they were, how much they enjoyed their teacher's presentation, how much they enjoyed the students they interacted with, and their satisfaction levels about the activities they were asked to take part in.

[image courtesy of the Wikimedia Commons]

Dikker et al. write:

The human brain has evolved for group living.  Yet we know so little about how it supports dynamic group interactions that the study of real-world social exchanges has been dubbed the "dark matter of social neuroscience."  Recently, various studies have begun to approach this question by comparing brain responses of multiple individuals during a variety of (semi-naturalistic) tasks. These experiments reveal how stimulus properties, individual differences, and contextual factors may underpin similarities and differences in neural activity across people...  Here we extend such experimentation drastically, beyond dyads and beyond laboratory walls, to identify neural markers of group engagement during dynamic real-world group interactions.  We used portable electroencephalogram (EEG) to simultaneously record brain activity from a class of 12 high school students over the course of a semester (11 classes) during regular classroom activities.  A novel analysis technique to assess group-based neural coherence demonstrates that the extent to which brain activity is synchronized across students predicts both student class engagement and social dynamics.  This suggests that brain-to-brain synchrony is a possible neural marker for dynamic social interactions, likely driven by shared attention mechanisms.  This study validates a promising new method to investigate the neuroscience of group interactions in ecologically natural settings.

Put simply, what the researchers found is that when the students reported feeling the most engaged, their brain activity actually synced with that of their classmates.  It squares with our subjective experience, doesn't it?  I know when I'm bored, irritated, or angered by something I'm being required to participate in, I tend to unhook my awareness from where I am -- including being less aware of those around me who are suffering through the same thing.

It's no wonder we call this kind of response "disengaging," is it?

So apparently misery doesn't love company; what loves company is engagement, appreciation, and a sense of belonging.  "The central hub seems to be attention," Dikker says.  "But whatever determines how attentive you are can stem from various sources from personality to state of mind.  So the picture that seems to emerge is that it's not just that we pay attention to the world around us; it's also what our social personalities are, and who we're with."

All the more reason we teachers should focus as much on getting our students hooked on learning as we do on the actual content of the course.  My experience is that if you can get students to "buy in" -- if (in my case) they come away thinking biology is cool, fun, and interesting -- it doesn't matter so much if they can't remember what ribosomes do.  They can fit the facts in later, these days with a thirty-second lookup on Wikipedia.

What can't be looked up is being engaged to the point that you care what ribosomes do.

Unfortunately, in the educational world we've tended to go the other direction.  The flavor of the month is micromanagement from the top down, a set syllabus full of factlets that each student must know, an end product that can fit on a bubble sheet, "quantifiable outcomes" that generate data that the b-b stackers in the Department of Education can use to see if our teachers are teaching and our students learning.  A pity that, as usual, the people who run the business of educating children are ignoring what the research says -- that the most fundamental piece of the puzzle is student engagement.

If you have that, everything else will follow.