Remembrance of stress past

About eighteen years ago, my wife and I went on a vacation to Hawaii.  The trip was awesome, and we had a fantastic time in Kauai, appreciating the beauty of the Garden Island, where "chill out" is the order of the day and there are signs that say "No shoes, no shirt, no problem."

Then we started on the voyage home.

I won't belabor you with the entire story.  Suffice it to say that it involved:

• two missed connections
• sleeping on the tile floor of two different airports on two successive nights
• a teenager breaching the security checkpoint, resulting in evacuating the entire airport and everyone having to be re-checked-in
• the airline crew "timing out," meaning they had to take a mandatory eight hours of rest while the passengers sat and waited
• a whole case of fine California wine... and no corkscrew
• a blackout that shut down the electrical grid in the entire northeastern United States for a day and a half
• a limo ride ending with the limo overheating and conking out just outside of Scott Run, Pennsylvania

Of course, I'm entirely to blame, because after each increasingly-ridiculous mishap, I said to my wife, "Well, what else could go wrong?"

Never ever say those words.  I'm not superstitious, but in this case I'm convinced that the universe waits for some hapless schlub to say that before dropping a piano on his head.

What is interesting about this whole thing -- besides the fact that in retrospect, it makes a hilarious story -- is that I remember the unpleasantness and stress of the trip back much better than I remember the relaxing and enjoyable vacation we were coming back from.  I'm hard-pressed to recall a single specific detail from being in Hawaii, other than a vague memory of sun, hiking, scuba diving, and drinks with little umbrellas -- but the memories of what it was like trying to return from Hawaii are so vivid it's like they happened yesterday.

Turns out, I'm not alone in finding that stressful experiences stick in our brains better than pleasant ones do.  A study released last week in Current Biology found that pretty much all of us remember trying situations much more vividly than we do positive ones.

[Image licensed under the Creative Commons Psy3330 W10, Sleeping while studying, CC BY-SA 3.0]

What's more, the researchers who did the study -- a team made up of Anne Bierbrauer, Marie-Christin Fellner, Rebekka Heinen, Oliver Wolf, and Nikolai Axmacher, of the Ruhr-Universität Bochum in Germany -- found the underlying mechanism for why awful memories seem to have such durability.  When a memory is connected with a stressful experience, the "memory trace" (neural firing pattern associated with recalling the memory) is linked through the amygdala -- a part of the brain associated with anxiety, fear, anger... as well as emotional learning and memory modulation.

The researchers write:

Recent evidence has further shown that amygdala neurons do not only respond to fearful or stress-related stimuli, but exhibit mixed selectivity as well: their firing may represent various different emotional and social dimensions, depending on task and context.  In humans, amygdala neurons respond to faces and to perceived emotions, and fMRI studies showed that the amygdala represents both fear memories and the subjective valence of odors.  Such multidimensional representations may serve to bind the diverse aspects of an emotional experience into one integrated episode.

Which certainly is the case with my memory of the Hawaii debacle.  My pleasant memories from the holiday -- which took place over six days -- are fragmentary and vague as compared with the memory of the trip back, which took only two days but plays out in my mind as a single coherent story.

When you think about it, it makes evolutionary sense.  Thag and Ogg having a vivid, detailed memory of the nice mammoth dinner they had two weeks ago is far less critical to survival than the memory of where they almost got killed by a saber-toothed tiger.  (That's an oversimplification, of course; complex behaviors are almost never the result of a single evolutionary driver.  But the value of remembering dangerous situations more strongly than happy ones can't be denied.)

The downside, of course, is that really negative memories get seared into our consciousness more or less permanently.  This can result in memory patterns that actively interfere with our ability to live a normal life -- better known as post-traumatic stress disorder.  So getting to the bottom of how this happens in the brain is the first step toward addressing that debilitating condition.

As for me, my silly return-voyage story doesn't cause me any anguish, and in fact, I've told it many times to various friends over pints of beer, to the general amusement of all.  The experience did, however, stop me from ever saying "What more could go wrong?"  Because I've found that not only is there always something else that can go wrong, when it does, you'll remember it forever.

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My dad once quipped about me that my two favorite kinds of food were "plenty" and "often."  He wasn't far wrong.  I not only have eclectic tastes, I love trying new things -- and surprising, considering my penchant for culinary adventure, have only rarely run across anything I truly did not like.

So the new book Gastro Obscura: A Food Adventurer's Guide by Cecily Wong and Dylan Thuras is right down my alley.  Wong and Thuras traveled to all seven continents to find the most interesting and unique foods each had to offer -- their discoveries included a Chilean beer that includes fog as an ingredient, a fish paste from Italy that is still being made the same way it was by the Romans two millennia ago, a Sardinian pasta so loved by the locals it's called "the threads of God," and a tea that is so rare it is only served in one tea house on the slopes of Mount Hua in China.

If you're a foodie -- or if, like me, you're not sophisticated enough for that appellation but just like to eat -- you should check out Gastro Obscura.  You'll gain a new appreciation for the diversity of cuisines the world has to offer, and might end up thinking differently about what you serve on your own table.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Anxiety shrinkage

I think one of the reasons I'm so interested in neuroscience is because there is still so much to be explored.  In my Intro Neuroscience class, I frequently have to answer questions students ask with the frustrating statement "That's unknown at this time."  Even such simple things as how memories are stored and recalled are poorly understood, although we are making significant progress in finding out how they work.

My friend and mentor Rita Calvo, Professor Emeritus of Human Genetics at Cornell University, once told me that we are currently at the point in understanding the brain that we were in understanding genetics in 1915.  We have some knowledge of what's happening, a lot of descriptive information, and little in the way of comprehension of the underlying mechanisms.  I still recall her telling me that if she were a college student in biology now, she'd go into neuroscience.

"The 20th century was the century of the gene," she said.  "The 21st will be the century of the brain."

So any time there's an advance, I'm pretty keen on finding out about it.  Which is why the article my wife sent me yesterday was such an eye-opener.  Entitled "Neuroplasticity in Response to Cognitive Behavior Therapy for Social Anxiety Disorder," this study (published this week in Translational Psychiatry) has found that social anxiety might be due to a hyperactive part of the brain called the amygdala, which has been known to be involved in fear, anxiety, and the fight-or-flight response.  More interesting still, they found that cognitive behavioral therapy can literally cause this hyperactive bit to shrink.

K. N. T. Månsson of Linköping University in Sweden, who led the group that did the study, writes:

[W]e demonstrate interrelated structural plasticity and altered neural responsivity, within the amygdala, after CBT for social anxiety.  Both GM volume and neural responsivity in the bilateral amygdala diminished after effective treatment.  Left amygdala GM volume was positively associated with symptom severity before treatment, and amygdala volume decreased significantly with CBT, correlating positively with symptom improvement in both hemispheres...  [O]ur results reinforce the notion that structural neuroplasticity in the amygdala is an important target for psychosocial treatments of anxiety, as previously suggested for pharmacological treatments of post-traumatic stress disorder.

Did you get that?  Cognitive behavioral therapy -- essentially, a kind of talk therapy -- actually had an equivalent result to anti-anxiety medication, and caused the part of the brain that was hyperactive to become physically smaller.

Are you amazed as I was at this result?  Because I read this with my mouth hanging agape.  The idea that cognitive behavioral therapy actually has a measurable result in the form of an anatomical change is absolutely mind-blowing.

Pun (lame though it is) intended.

I have another reason to find this result fascinating.  I have suffered for years from serious social anxiety, starting when I was in my mid-twenties and becoming progressively worse for the following thirty years.  Those of you who read Skeptophilia but don't know me personally might have a hard time picturing someone who is as verbose as I am being a social-phobe, but you'll have to take my word for it; in most social situations, I get myself a glass of wine and then hope like hell that the hosts have a dog I can interact with.  I have gone entire evenings at friends' houses, listening politely, laughing at the right times, and not saying a word.

Michelangelo Buonarroti, The Last Judgment (1541) [image courtesy of the Wikimedia Commons]

I've also been in cognitive behavioral therapy for about a year to try and deal with some of this, with guardedly positive results.  I'm not expecting such a deep-seated and pervasive problem to go away quickly; Rome, as they say, wasn't built in a day.  But the idea that by participating in CBT I am not only working toward alleviating my anxiety, but am causing long-lasting anatomical alterations in my brain -- that is amazing.

Because I have to say that living with an anxiety disorder is not particularly enjoyable.  Anything I can do to shrink that overactive left amygdala is fine by me.

The partisan brain

I tend to avoid politics, both here on Skeptophilia and also in my personal life.  There are two reasons for this: first, I find most political issues such a snarled Gordian knot that I have no idea how anyone could be smart enough to solve them; and second, even on the issues about which I have strong opinions, I've found that arguing with people seldom changes minds on either side.  So entering into an argument that basically is "I think so because I think so," and is unlikely to convince anyone of anything, might be the very definition of the word "pointless."

[image courtesy of the Wikimedia Commons]

I do find it interesting, however, to consider why people so seldom shift their political views, even when presented with facts and data to the contrary.  It's like we're stuck in our worldview, unable to move away from the narrow little window we're looking out of.  And now, some scientific research might have an answer for why that is.

Darren Schreiber et al. of the University of Exeter published a fascinating paper last month called "Red Brain, Blue Brain: Evaluative Processes Differ in Democrats and Republicans" in the online journal PLOS-ONE, which has as its main claim that there are fundamental differences in brain function between liberals and conservatives.  Studies had already shown that there is a brain structure difference; liberals tend to have more gray matter in the anterior cingulate cortex, conservatives in the amygdala.  But suggestive as that is, differences in structure don't always imply differences in function, so it was premature to conclude that these structural differences caused individuals to adopt particular political stances.

In this case, however, it appears that the earlier researchers were on to something.  In particular, there seemed to be a biological underpinning to the well-demonstrated tendency of conservatives to be risk-averse and liberals to be risk-seeking.  The authors write:

(C)onservatives demonstrate stronger attitudinal reactions to situations of threat and conflict. In contrast, liberals tend to be seek out novelty and uncertainty.  Moreover, Democrats, who are well known to be more politically liberal, are more risk accepting than Republicans, who are more politically conservative.  While ideology appears to drive reactions to the environment, environmental cues also influence political attitudes.  For instance, external threats prime more conservative attitudes among liberals, moderates, and conservatives.

Schreiber et al. set out to see if the different attitudes toward risk would show up on a fMRI, which would indicate that there was a functional difference between the brains of liberals and conservatives:

To test a conjecture that ideological differences between partisans reflect distinctive neural processes, we matched publicly available party registration records with the names of participants (35 males, 47 females) who had previously taken part in an experiment designed to examine risk-taking behavior during functional brain imaging...  Individuals completed a simple risk-taking decision-making task during which participants were presented with three numbers in ascending order (20, 40, and 80) for one second each.  While pressing a button during the presentation of the number 20 on the screen always resulted in a gain of 20 cents, waiting to select 40 or 80 was associated with a pre-determined possibility of either gaining or losing 40 or 80 cents.  Therefore, participants chose between a lower “safe” payoff and a higher risky payoff.  The probabilities of losing 40 or 80 cents were calibrated so that there was no expected value advantage to choosing 20, 40 or 80 during the task, i.e. the overall pay-off would have been the same for each pure strategy.

They found that the two groups did, indeed, show different levels of activity in the two parts of the brain that earlier research had shown to differ:

Consistent with the findings of structural differences by Kanai et al, significantly greater activation was observed in the right amygdala for Republicans and in the left posterior insula (near the temporal-parietal junction) in Democrats when making winning risky versus winning safe decisions. No significant differences were observed in the entorhinal cortex or anterior cingulate cortex. All attempts to use behavior to distinguish Republicans from Democrats were unsuccessful, suggesting that different neural mechanisms may underlie apparently similar patterns of behavior.

The authors are clear in their conclusion that they, too, have established correlation, but are yet to show causation; "One might infer that the differing brain structures identified by Kanai et al. suggest genetic foundations for the differences in ideology," they write, in their discussion of results.  "However, recent work has shown that changes in cognitive function can lead to changes in brain structure."  So how much of the difference they and others have shown is genetic in origin, and how much due to remodeling of the brain's circuitry because of the environment, is still uncertain.

It does support, however, the fruitlessness of political argument.  If there is a biological underpinning to political stance, it's to be expected that it's not going to be easy to change.  There are cases, of course, where it's important to try -- in issues of social justice and care for the environment, for example.  But this research shows pretty clearly that such battles aren't going to be easy to win.

And you have to wonder what a fMRI would show for a generally apolitical person like myself.  No brain activity whatsoever?

Maybe I'm better off not knowing.

Fear, the amygdala, and "Whistle"

I find fear fascinating.

Fear is an eminently useful evolved characteristic; the ability to recognize and avoid threats has an obvious survival benefit.  Fears can be learned, but as the famous "Little Albert experiment" showed, the object of our fear can result in overgeneralization, which is probably the origin of phobias and other irrational fears.  (For those of you unfamiliar with this interesting, but dubiously ethical, experiment, researchers back in 1920 showed a toddler a variety of objects, including a white rat -- and when the baby reached for the rat, they made a loud noise.  Soon, "Little Albert" would cry when shown the rat, but also when shown other white objects, including a rabbit, a stuffed bear, and a Santa mask.)

All of this comes up because of some recently-published research at Cold Spring Harbor Laboratory, where neuroscientist Bo Li and his colleagues have discovered how we encode fear in the brain -- and how those memories result in behavior.

It has been known for some time that the fear response results from activation of neurons in the amygdala, an almond-shaped structure deep inside the brain.  In 1998, K. S. LaBar et al. used fMRI studies to demonstrate the role of the amygdala in responding to fear stimuli, but it was still unknown how that structure actuated the behaviors associated with the fear response -- sweating, increased pulse, freezing in place, and the fight-or-flight reaction.

Now Li and his colleagues at Cold Spring Harbor have found that there are neurons that connect the amygdala to the brainstem, and that activation of a fear response causes a feedback between the amygdala and brainstem via those neurons -- thus turning an emotional response into a behavior.

"This study not only establishes a novel pathway for fear learning, but also identifies neurons that actively participate in fear conditioning," says Li.  "This new pathway can mediate the effect of the central amygdala directly, rather than signaling through other neurons, as traditionally thought."  Li hopes that his study will be useful in understanding, and perhaps remediating, cases of severe phobias and post-traumatic stress syndrome.

I find myself wondering, however, how this evolved system, with its elaborate architecture and neurochemistry, can explain why some people seek out fear-inducing experiences.  I've been drawn to horror stories since I can remember, and have written more than one myself.  The cachet that writers like Stephen King and Dean Koontz have is hard to explain evolutionarily -- given the fact that fear is unpleasant, intended to drive us to avoid whatever the evokes the response, and is supposed to communicate to our brains the message, "Danger!  Danger!  Run!"

[image courtesy of the Wikimedia Commons]

Take, for example, one of my favorite scary stories -- one I remember well from my youth.  My grandma, who was an avid book collector, had a little paperback copy of a book by C. B. Colby called Strangely Enough.  This book had dozens of odd little one-to-two page stories, most of which fell into the "urban legend" or "folk tale" categories and were entertaining but not particularly memorable.  But one of them, a story called "The Whistle," has stuck with me -- and evidently not only me.  When researching this post, I looked up Colby, and found his little book had been mentioned more than once in websites about scary stories -- and damn near everyone mentioned "The Whistle" as being the scariest of the lot.

I don't have to tell you the story, though, because two film directors, Eric Walter and Jon Parke, thought it was good enough to make a short film based on the story.  It's only seven minutes long, but it captures the essence of what is chilling about Colby's story -- without a single word of dialogue.  It's not gory (for those of you who dislike such things), just viscerally terrifying.  And all of you should right now take seven minutes and watch "Whistle."

There.  Did I tell you?  What I find the scariest about this film is that... almost nothing happens.  You never see the monster, if monster it was.  All there is is a whistling noise.  But it's got all the elements; a widowed woman living alone; a dog who tries to warn her that something is amiss; an old house; a radio that mysteriously malfunctions.

But why is it scary?  It is, I think, precisely because we fear the unknown.  What is known is (usually) harmless; what is unknown is (possibly) deadly.  We've undergone millions of years of evolutionary selection to create brain wiring that keeps us from making stupid decisions, such as confronting a predator while weaponless, trusting a stranger without caution... or staying outside when there's a strange, unearthly noise.

Perhaps that explains why we're drawn to horror fiction.  The character trapped in the story is in danger, perhaps mortal danger, from which (s)he may not be able to escape.  We, on the other hand, can experience the character's fear on a visceral level, but then we can turn the movie off, close the book, go back to our safe, normal lives, secure in the fact that we're not going to die, or at least not yet.  We can get the rush of terror, but then when the scary story is over, the pleasure-and-reward circuits that our brain also evolved can turn on and reassure us that the monsters didn't get us, that we've survived for another day.

And now Bo Li and his colleagues have discovered how the brain helps us to do that.  As for me, I'm going to go have some coffee, and wait until my amygdala calms down, because while I was doing this post, I had to watch "Whistle" again, and now I'm all creeped out.