Archive for the 'Brain & Behavior' category

A Sense of Wonder and Awesome Slime Molds

Mar 30 2011 Published by under Brain & Behavior, Humor

I've never understood the claim that science somehow detracts from the beauty of the natural world.

I think xkcd sums it up the sense of wonder scientists get with a new discovery pretty nicely:

The sense of wonder at a new scientific discovery is similar to but not identical with the "sensawunda" you can get reading science fiction. It's an excitement at learning the previously unknown, at uncovering the mechanisms that underlie the complexity of life and the vastness of the universe, or of discovering an unexpected flower growing in your yard.

But unlike the fantastic but imaginary science of science fiction, the scientific sense of wonder comes from the discovery of how the universe - from quasars in distant galaxies to the smallest viruses* - is organized and functions.

And I think  it goes without saying that slime molds are indeed really cool.

Dog Vomit Slime Mold (Fuligo septica) at China Camp State Park, California.
By Franco Folini on Flickr.

The pretty yellow color is from the pigment  fuligorubin A.  Dog vomit slime molds are also unusually resistant to the toxic metals zinc and cadmium.  There is indeed evidence that fuligorubin pigment can bind the usually toxic metals.**

That's cool not only because it allows dog vomit slime molds to grow in inhospitable environments, but because it suggests slime molds might be used to help reclaim metal-contaminated soils (along with metal-accumulating plants).  The purified yellow pigment could someday be used to develop new treatments for zinc poisoning.

A different species of slime mold can apparently even solve a maze faster than a Japanese graduate student (technical paper)! I'm not sure anyone has tried similar experiments with Fuligo spetica, but just imagine the possibilities: a industrial wasteland reclaimed and ruled over by intelligent yellow overlords.

OK, maybe that's more sensawunda territory. But slime molds are cool. And new discoveries about unusual biochemistry of our fellow Earthly inhabitants are indeed wonderful.


* And, of course,  even smaller down to subatomic particles. But I think viruses are cooler than muons and gluons.

** A note on the importance checking original sources:

The Wikipedia article about Fuligo septica states:

"The mechanism of this metal resistance is now understood: F. septica produces a yellow pigment called fuligorubin A, which has been shown to chelate metals and convert them to inactive forms"

and cites:

Latowski D, Lesiak A, Jarosz-Krzeminska E, Strzalka K. (2008). "Fuligo septica, as a new model organism in studies on interaction between metal ions and living cells". Metal Ions in Biology and Medicine and Medicine 10: 204–9.

But the conclusions drawn by the authors of that paper (available in Google books) aren't quite as definitive as the Wikipedia article suggests:

Obtained results revealed that pigment fuligorubin A content was higher in Fuligo septica treated with zinc solutions (Figure 2). This could be the evidence of involvement of fuligorubin A in process of zinc ions detoxication and moreover it could ensure tolerance of Fuligo septica to high concentration of zinc and other toxic metal content.  [p.208; bold emphasis added]

There may be another paper out there more clearly demonstrating the function of fuligorubin A, but Wikipedia doesn't cite one and I couldn't find such a paper after a brief search.

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Stuttering and Genetics

Feb 24 2011 Published by under Brain & Behavior

Ever since the release of the award-winning movie The King's Speech, there has been a lot of discussion about stuttering in the media.

The movie is the fictionalized story of the struggle of King George VI - "Bertie" to his family - to overcome his stuttering with speech therapy.  That summary doesn't make it sound particularly interesting, but I found the story to be quite engaging. By the end I was rooting for Bertie to make it through his big speech.

It's estimated that almost 1% of adults stutter, just like Bertie. After decades of research, the underlying causes are only beginning to be understood.

At this past week's annual meeting of the American Association for the Advancement of Science (AAAS) in Washington DC, there was a symposium that focused on recent developments in cross-disciplinary stuttering research.  The most interesting study discussed in that session looked at how genetics may contribute to the speech disorder.

NIH geneticist Dennis Drayna and his colleagues have been studying closely-related families in Pakistan. They discovered three mutations associated with stuttering in those families. The three affected genes - GNPTAB, GNPTG, and NAGPA - are involved in directing glycoproteins to the lysosomes. Lysosomes are tiny organelles inside the cell that break down waste material and cellular debris. If the proper glycoproteins don't end up in the lysosomes, carbohydrates and fatty materials can build up to toxic levels in the body's cells.

It was already known that some mutations in GNPTAB and GNPTG cause mucolipidosis, a disease that affects both neurological and physical development.  In its severest form, mucolipidosis causes mental retardation and skeletal deformities. The people who carry the mutations in GNPTAB and GNPTG associated with stuttering don't have the severe neurological and physical problems associated with mucolipidosis.

It's not entirely clear how the mutations in genes involved in cellular metabolism might affect the development of the brain and cause speech problems, so there's still a lot of research to be done. But no matter what the mechanism is, finding these mutations provides support to the idea that the cause of stuttering is primarily physiological rather than behavioral or psychological.

But these genes are only a small part of the story.  Only about 6% of stutterers carry a mutation in GNPTAB, GNPTG or NAGPA.  Drayna's team and other research labs are searching for  additional associated mutations.  The hope is that the ongoing research into the genetics of stuttering will ultimately lead to new effective therapies.

Listen to the  AAAS Podcast on "The Mysteries of Stuttering" for more about the research presented at the symposium.

Additional reading:
• Michael Palin: "Stuttering: It's on everyone's lips now" Los Angeles Times (2011)

• Howell P. "Listen to the lessons of The King's Speech" Nature 470 (7) (2011) doi:10.1038/470007a

* Schenkman L. "First Gene Mutations Linked to Stuttering"  (Science NOW 2010)

• Willyard C. "Ancient Mutation to Blame for Stuttering" (Science NOW 2011)

• You can find more information about current research and resources for stutterers on the Stuttering Foundation of America's web site.   The National Institutes of Health also provides information on stuttering.

• Read the original research article: Kang C. et al. "Mutations in the Lysosomal Enzyme-Targeting Pathway and Persistent Stuttering" N Engl J Med 362:677-685 (2010)  doi: 10.1056/NEJMoa0902630 (free full text)

• Learn more about the research presented at the 2011 AAAS Meeting.

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The Neurochemistry of Love

Feb 14 2011 Published by under Brain & Behavior

Hearts (Explored!)My love is as a fever, longing still
For that which longer nurseth the disease,
Feeding on that which doth preserve the ill,
The uncertain sickly appetite to please.
My reason, the physician to my love,
Angry that his prescriptions are not kept,
Hath left me, and I desperate now approve
Desire is death, which physic did except.
Past cure I am, now reason is past care,
And frantic-mad with evermore unrest;
My thoughts and my discourse as madmen's are,
At random from the truth vainly express'd;
For I have sworn thee fair and thought thee bright,
Who art as black as hell, as dark as night.
~ Sonnet 147, William Shakespeare

The pursuit of romantic love is a greater driving force than the sex drive, according to Rutgers University anthropologist Helen Fisher, who studies the neuroscience of love.  As she describes it, symptoms of love are indeed quite powerful:

Romantic love begins as an individual comes to regard another as special, even unique. The over then intensely focuses his or her attention on this preferred individual, aggrandizing the beloved's better traits and overlooking or minimizing his or her flaws. Lovers experience extreme energy, hyper activity, sleeplessness, impulsivity, euphoria, and mood swings. They are goal-oriented and strongly motivated to win the beloved. Adversity heightens their passion [ . . . ] They reorder their daily priorities to remain in contact with their sweetheart , and experience separation anxiety when apart. And most feel powerful empathy for their amour; many report they would die for their beloved.

In fact, love can affect your brain like an addiction.  When love is reciprocated it's a constructive addiction, while rejection of love is a destructive addiction.  It's powerful effects have shaped and been shaped by evolution, and - Fisher argues - have even helped drive the development of human culture.

Here's an interesting lecture at UC San Diego where Fisher talks about the evolution and neuroscience of romantic love and the development of poetry and art (20 minutes):

If you are interested in more, also check out Fisher's 2008 TED talk about the brains in love (16 min.):

Happy Valentine's Day!

Technical reading:

Fisher HE et al. "Reward, Addiction and Emotion Regulation Systems Associated With Rejection in Love" J. Neurophysiol 104: 51-60 (2010)  (free pdf)

Fisher H "The Drive to Love: The Neural Mechanism for Mate Selection" in The New Psychology of Love, 2nd Edition. RJ Sternberg and K Weis (Eds.) New Haven: Yale University Press (2006) (free pdf)

Fisher HE et al. "Romantic love: a mammalian brain system for mate choice"  Phil Trans R Soc B 360: 2173-2186. (2006) (free pdf)

More of Fisher's publications.

Image: Hearts (Explored!) by qthomasbower, on Flickr

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Dance your PhD: How does your brain analyze incoming visual information?

Sep 24 2010 Published by under Art & Science, Brain & Behavior

The finalists in the 2010 Dance Your Ph.D. contest have been announced. The competition is open to all science PhDs (or soon-to-be-PhDs) willing submit a video of a dance interpretation of their PhD thesis. And yes, the author of the thesis has to be one of the dancers.

A finalist for each category - Physics, Chemistry, Biology, and Social Science - was announced last week. The finalist in biology was "How does your brain analyze incoming visual information?", by Utrecht University gradutate student Maartje de Jong.

She explains:

We tend to believe what we see with our eyes is real and accurate. What we often do not realize is that our eyes register only a reflection of the outside world. To reconstruct reality from this reflection we have to rely on inferences and assumptions. It is like putting together the pieces of a puzzle without any knowledge about the whole picture. Our brain does this without our conscious awareness. In a split second it organizes and interprets incoming visual information to form a stable and meaningful image of the world around us.

[. . . snip . . . ]

Our video explains the basics of how the brain analyzes visual information. You see a man (‘the observer’) watching a movie-clip on his laptop. The visual information presented on his laptop is registered by his eyes and translated into neural signals that enter his brain. Through dance we portray what happens inside the observer’s brain. The leading dancer in the video, who can be recognized by the brain depicted on his clothing, represents the observer’s internal neural factors, such as his goals and experiences. The dancers with an information-icon depicted on their clothing (‘the i-dancers’) represent the incoming visual information.

Read the rest of the explanation of her research - and the dance - here.

Check out the the finalists' videos and vote for your favorite at ScienceNOW. The overall winner will be announced on October 19th at the Imagine Science Film Festival in New York.

You can watch all the entries on the Gonzo Labs web site.

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Light and Darkness: How to Sleep

Sep 15 2010 Published by under Brain & Behavior

Jessa Gamble is an award-winning science writer based in Yellowknife, Canada, just a few hundred miles south of the Arctic Circle. Because of Yellowknife's high latitude, the length  of daylight  varies widely during the year - from 5 hours in December to 20 hours in June.

The cultural adaptation of traditional subarctic cultures to that dramatic seasonal variation in day length is how she begins her discussion of natural human sleep cycles in her brief TED talk:

As Gamble notes, before artificial light became common in people's homes, most people did not sleep in an unbroken eight hour block. Instead they went to bed at dusk, slept four hours or so, had a couple hours of wakefulness (used for meditation, sex, study or work), and then returned to sleep until dawn.

As a night owl, I find it hard to imagine going to bed when the sun goes down. Even if I wanted to change my sleeping habits, unless my husband and friends also changed their schedules along with mine,  I would find it socially isolating to hit the sack at 8pm. And that doesn't even take into account the difficulty of finding a truly dark place to sleep so early in the evening. Living in a suburb laced with street lights, it doesn't ever get completely dark outside.

I doubt I'm alone in thinking that "natural" sleep patterns aren't easily compatible with modern life. What Gamble suggests is that we should consider the cost of that attitude to our mental well being.

Gamble's book about the daily rhythms of life in different cultures - The Siesta and the Midnight Sun - will be published by Viking Canada in March 2011.

For a primer on human sleep patterns, you check out "Everything You Always Wanted To Know About Sleep (But Were Too Afraid To Ask)" at the old Blog Around the Clock.

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Women’s Equality and Neurosexism

Aug 28 2010 Published by under Brain & Behavior

"... for nothing terrifies the average man so much as a touch of science which he does not understand. And nothing gives a shallow-minded individual so much importance as to when he quotes a little false biology."
~ Woman Suffrage (1907) by Arnold Harris Mathew

This past week marked the 90th anniversary of the ratification of the 19th Amendment to the US Constitution, which granted women the right to vote. The right to vote was only achieved after decades of work by supporters of women's suffrage. The "false biology" Mathew refers to in the quote above is the belief that the anatomy of women's brains made them intellectually inferior to men, a claim that was used to argue that women were mentally unsuited to vote. As Mathew points out¹, the latest scientific evidence did not find any significant gender difference in brain size or overall intelligence.

But even when women and men were considered to have similar levels of intelligence, it was argued that gender differences in brain anatomy showed that men and women have different types of intelligence:

For example, prominent phrenologist2 Jessie Allen Fowler proposed:

Those parts [of the brain] which are most extensively developed in man are the seat of the intellectual attributes, creative and volitional, as opposed to the emotional and sensatory, which have their seat in the posterior and lower region; and those parts of the brain which are most extensively developed in woman are the seat of the emotional, domestic and affectionate attributes.

Thus man, as a result of this brain development of a differentiated character, shows a mind endowed with judgment, creative power and philosophic reasoning ability; and woman, on the other hand, shows an insight into the domestic relations, home life, and the social well being of mankind.

This does not mean that man has no affection and woman has no reasoning powers, but that the above named attributes predominate as a prerogative in each sex.

~ Brain Roofs and Porticos (1913), pp. 69-70

Fowler's conclusions about the gendered brain - that women are good at understanding emotions and men are good at problem solving - aren't too different from those published nearly a century later.  And while I think it's easy to dismiss Fowler's analysis of gender differences as  stereotypes dressed up as science3, current popular science books and articles

often cite recent scientific studies that presumably are more experimentally solid than phrenological skull measurements.

It turns out that even those books that appear to be scientific on the surface may distort the science to emphasize gender differences and downplay the similarities between men and women.

As Mark Liberman at Language Log has pointed out in his analysis of the misrepresentations of science in Louann Brizendine's book The Female Brain, the issue is not that there aren't differences between men and women, but that those differences are often misleadingly exaggerated:

There certainly are psychological and neurological differences between men and women, sometimes big ones. But even when they aren't promoting their ideas on the basis of "facts" that are apparently false, authors like Sax and Brizendine use a set of rhetorical tricks that tend to make sex differences seem bigger and more consequential than they really are. You can do it too, if you want -- just choose phenomena that emphasize differences, leaving out the ones where the sexes are more similar; pick studies that find stereotypic differences, leaving out the ones whose results disagree; and in all cases, talk and write as if (even relatively small) differences in group averages were essential characteristics of every member of each group.

(read Liberman's whole post if you haven't already)

Australian psychologist Cordelia Fine has looked more deeply at the issue in her recently published book, Delusions of Gender: How Our Minds, Society and Neurosexism Create Difference.  While I haven't read it yet, at least part of it appears to expand on Fine's 2008 paper in the journal Neuroethics - "Will Working Mothers' Brains Explode? The Popular New Genre of Neurosexism" (pdf).

In that article, she suggests why so many people find the claims that there are significant gender differences in brain function appealing:

What, exactly, is the draw of gender stereotypes dressed up as neuroscience? For men, perpetuation of the idea that they lack women’s hard-wired empathizing skills is a small price to pay for license to lay claim to more valued and potentially profitable psychological advantages. According to another popular book about gender difference, The Essential Difference [1], “[t]he female brain is predominantly hard-wired for empathy. The male brain is  predominantly hard-wired for understanding and building systems.” (p.1). As Levy [16] notes, this translates to the idea that “on average, women’s intelligence is best employed in putting people at their ease, while the men get on with understanding the world and building and repairing the things we need in it.” (pp. 319–320). Levy adds, “[t]his is no basis for equality. It is not an accident that there is no Nobel Prize for making people feel included.” (p. 323).

Fine suggests that women may use the information to rationalize the status-quo. For more about Delusions of Gender, see the interview with Fine in USA Today's Science Fair blog, the review post at Language Log, and the article about Fine's book in the Guardian.

So if there are indeed differences in the average male and female brain, and many men and women find those differences appealing, why is highlighting those differences a problem?

Even thought we may not consciously acknowledge gender stereotypes, they can unconsciously affect the way we perceive both ourselves and others. For example, women business leaders who conform to female stereotypes are often perceived as less competent, while those who do not conform are considered "too tough" or "too angry". Similarly a recent study by physicist Amy Bug showed that a physics lecture made by male actors received significantly higher performance ratings from male students than the identical lecture given by female actors.  Such biases are difficult to counter, since most people don't consciously realize they have them (you can try the Implicit Association Test, to assess your own unconscious biases).

It's has also been shown that just the knowledge of a negative stereotype about the group in which one belongs, can have a detrimental effect on performance.  For an examples of the effects of "stereotype threat", see Christina Agapakis's post explaining how cultural stereotypes about math ability appear to affect test scores.

Even if there are significant differences "on average" between male and female brains, such averages tell us nothing about a particular individual's abilities, aptitudes or interests. I'm not much of a stereotypical "girly" girl - don't care for chatting on the phone, have had the same hair style for a decade and enjoy science. On the other hand I tend to be soft spoken, and like watching Project Runway and cooking shows, and I think of myself as sentimental and sympathetic. Most women and men I know also have a mix of stereotypical "masculine" and "feminine" preferences and behaviors. Pop culture books that misrepresent neuroscience studies to suggest that only stereotypical behavior is "normal" or "natural" do us all a disservice.

I'm looking forward to voting in November.

Top photo: Image from the Library of Congress's Bain Collection on Flickr

Middle images: Illustrations from Jessie Allen Fowler's Brain Roofs and Porticos

Bottom image: National Institute of Biomedical Imaging and Bioengineering, Image courtesy of Dr. Paul Thompson, University of California, Los Angeles.

1. Mathew wrote Woman Suffrage in support of women's suffrage in the UK, but similar arguments about women lacking the intellect to vote were made in the US.
2. From Wikipedia: "Phrenology is based on the concept that the brain is the organ of the mind, and that certain brain areas have localized, specific functions or modules . . . Phrenologists believed that the mind has a set of different mental faculties, with each particular faculty represented in a different area of the brain. These areas were said to be proportional to a person's propensities, and the importance of the given mental faculty. It was believed that the cranial bone conformed in order to accommodate the different sizes of these particular areas of the brain in different individuals, so that a person's capacity for a given personality trait could be determined simply by measuring the area of the skull that overlies the corresponding area of the brain."
3. Fowler's book also has an chapter on how skull shape differences between races demonstrate different "temperaments".  It's not that surprising that she divides people "superior" and  "inferior races", given the racist attitudes of the early 20th century. But what I find a bit surprising is that the  "races" are broken down into much smaller national groups with apparently unique brain characteristics. For example the "Scotchman has a predominance of the bony and muscular structures, with more of the Motive than the Vital Temperament, hence he is characterized for action and thought ... is slow yet strong, steady and firm. ". That is, of course, quite different from the English, who are "the strongest type of the Caucasian", or the Welshman or Irishman.  The book's generalizations of the personality types of different Europeans and Asians and Africans is like a catalog of early 20th century stereotypes "supported" by the evidence of their shape of their skulls.  It's unlikely her analysis of gender differences in brain structure is any more scientific.

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Classical Conditioning?

Aug 21 2010 Published by under Brain & Behavior, Food & Cooking

Just hearing the midi-esque version of "She'll Be Coming Round the Mountain" of the local ice cream truck makes me salivate.

The one cruising my neighborhood has an additional tactic: the recording they use has a loud "Hello!" before each verse. That really got my attention.

I think I need some Ben and Jerry's.

Or if I'm not feeling too lazy after dinner, I may make a batch of this creamy frozen banana dessert, which is simply frozen banana chunks pureed in a blender. That whips in enough air to give the bananas a nice creamy texture.  It turns out to be even better if you add some lightly sweetened frozen strawberries and top with a little chocolate sauce. Yum!

Photo: Chocolate Chip Ice Cream by Lotus Head on Wikimedia Commons

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E. chromi and The Scatalog

Aug 17 2010 Published by under Brain & Behavior

This is for the new "Carnal Carnival". This month's theme is poop, and will be hosted by Bora at a Blog Around the Clock.

Pigments produced in "E. chromi"

E. coli Bacteria engineered to produce different pigments by a team from Cambridge for iGEM 2009

The International Genetically Engineered Machine competition (iGEM) is an annual contest in which student teams use a kit of "standard biological parts" to engineer bacteria with new and interesting properties.

There were 110 teams entered in the 2009 iGEM competition. Finalists included Valencia's  "bio-screen" lighting display and Groningen's heavy metal scavengers for cleaning polluted water. You can find information about all the team submissions on the official web site.

The winner of the competition was the Cambridge team, for their development of "E. chromi": bacteria engineered to express a rainbow of different colored pigments. Although the bacteria are colorful enough be used to create bacterial art, they were designed to be environmental sensors.

Displaying the Scatalog

Displaying the Scatalog at the iGEM2009 Jamboree

So what does that have to do with poop? The Cambridge iGEM team collaborated with designers Daisy Ginsberg and James King - who both use biotechnology in their art - to brainstorm potential applications for their design. One of the possibilities they came up with was The Scatalog, which proposes to use pigment producing bacteria for inexpensive personal disease monitoring.

The idea is pretty simple:  eat some tasty yogurt containing  E. coli bacteria  engineered to secrete different colored pigments in the presence of specific chemical signals. E. coli are a normal part of your intestinal flora, so the bioengineered bacteria should be able to colonize your gastrointestinal tract. In a healthy system, only one color - say blue - would be produced, resulting in blue poop. Any chemical changes in your system, such as exposure to toxins or development of a disease, would cause your poop to change color.  Just match your poop color to the reference turds in the Scatalog and you get an instant health assessment.

You can see close-ups of the Scatalog in Guerilla Science's photostream.

Sadly, the Scatalog hasn't been developed beyond its colorful plastic poo samples.  As experts  have pointed out, it may turn out to be too impractical to be implemented:

"I can see the popular appeal of this kind of E. chromi technology," said Rick Henrikson, who helps run the Point-of-Care Diagnostics Idea Lab at the University of California, Berkeley. "But as far as actual diagnostics, conceptually it's a little far off." Developing such a product, he explained, would require huge feats: getting the Food and Drug Administration to approve it, for example, and keeping the body's immune system from attacking the bacteria.

What a party pooper!

Here's a video of the creators explaining the project (there is unfortunately a lot of background noise that makes the audio a bit difficult to understand.):

Video: Jam09 05 - E.chromi interview with Daisy Ginsberg and James King from mac cowell on Vimeo .
Top image: Bacteria producing different pigments created by Team:Cambridge for iGEM 2009

Bottom image: Scatalog display at iGEM2009 Jamboree, taken by jimhaseloff on Flickr and shared under a Creative Commons Attribution-NonCommercial license.

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