Wiring the brain

This story is some kind of awesome:

For those who don’t want to watch the whole thing, the observation in brief is that color perception is affected by color language. The investigators compare Westerners with our familiar language categories for color (red, blue, green, yellow, etc.) to the people of the Himba tribe in Africa who have very different categories: they use “zoozu”, for instance, for dark colors, which includes reds, greens, blues, and purples, “vapa” for white and some yellows, “borou” for specific shades of green and blue. Linguistically, they lump together some colors for which we have distinct names, and they also discriminate other colors that we lump together as one.

The cool thing about it all is that when they give adults a color discrimination test, there are differences in how readily we process and recognize different colors that corresponds well to our language categories. Perception in the brain is colored (see what I did there?) by our experiences while growing up.

The study is still missing one part, though. It’s presented as an example of plasticity in wiring the brain, where language modulates color perception…but we don’t know whether people of the Himba tribe might also have subtle genetic differences that effect color processing. The next cool experiment would be to raise a European/American child in a Himba home, or a Himba child in a Western home (this latter experiment is more likely to occur than the former, admittedly) and see if the differences are due entirely to language, or whether there are some actual inherited differences. It would also be interesting to see if adults who learned to be bilingual late experience any shifts in color perception.

(Also on FtB)

Neuro student articles

I’m teaching an upper-level course in neurobiology this term, and as I usually do, I made all the poor suffering students go out and create blogs, and I also told them they had to write one post a week about neuroscience. Today I was asked if I was going to pharyngulate their blogs, and of course I said I would. So go forth and harrass them! A word of warning, though: as many people learned last time I did this, these are not passive, cowed students, but feisty upperclassmen who are comfortable with biting back; the worst thing you can do is be condescending or patronizing.

(Also on FtB)

How am I going to fit an MRI in the bedroom?

Maybe you’ve seen this before: it’s a diagram of the sensory and motor cortex of the brain, with a little man or homunculus drawn over it to illustrate the somatic areas associated with each region. You see where the little man’s knee is on the left image of the sensory cortex? Stick an electrode in there and zap it, and a patient/victim will feel a sensation in his knee. Put the patient in an MRI and tickle his knee, and that region of the brain will light up. Cool, huh?

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Another cute feature: look in the medial longitudinal fissure. You see the homunculus’s toes, and right down there, located beyond the toes, is where the genital sensory area is located. Poke at that with an electrode and…we’re talking happy time at the Mad Scientists’ convention. But notice, though, that in the diagram of the homunculus, the poor creature’s genitals are drawn, and they’re male. It’s a bit sexist, don’t you think?

This bias has now been corrected.

a team led by Lars Michels at University Children’s Hospital in Zurich, Switzerland, used functional magnetic resonance imaging to confirm that the position of the clitoris on the homunculus was in approximately the same position as the penis in men. Barry Komisaruk at Rutgers University in Newark, New Jersey, and his colleagues have now used the same method to map the position of the clitoris, vagina and cervix on the sensory cortex as women stimulated themselves.

I read these things, and I think to myself that I really went into the wrong research field. Oh, well.

They also discovered something else.

Komisaruk also checked what happened when women’s nipples were stimulated, and was surprised to find that in addition to the chest area of the cortex lighting up, the genital area was also activated. “When I tell my male neuroscientist colleagues about this, they say: ‘Wow, that’s an exception to the classical homunculus,'” he says. “But when I tell the women they say: ‘Well, yeah?'” It may help explain why a lot of women claim that nipple stimulation is erotic, he adds.

Now, as a true nerd and as a typical male who has always been mystified by the female sexual response, I feel a deep craving to plumb the mysteries with my own personal fMRI scanner. It’ll also be a research project that will go over well at the next Mad Scientists’ convention.

(Also on FtB)

What’s the matter with Andrew Brown’s brain?

He’s completely lost me again. Brown has a couple of posts up complaining about people referring to mental illness as a “brain disease” and confusing mind with brain — he seems to deplore the growing recognition that the mind is entirely a product of the brain, and that psychology is built on a physical substrate, which leads to what he thinks is a premature reduction of mind to brain. He’s not making an argument from dualism, though; the gist of his complaint is that you can’t deduce thoughts from the structure of the brain, therefore it’s an invalid approach.

That doesn’t make any sense. We also don’t have a consistent, predictable way of deriving the structure of the brain from behavior, but we don’t use that as an excuse to dismiss studying behavior, and it’s not an argument that we need to distinguish mind from brain. We’ll never have a complete description of any brain sufficient to derive thoughts from physiology; so? Time to face the truth and recognize that your mind is entirely produced by chemistry and electrophysiology and molecular biology of the brain, nothing more, and I find no reason to take offense when people are aware that a cup of coffee, the sun shining in your face, or a hug from your children cause biological changes to your brain.

I find the prospects exciting, not annoying. Here’s an example: scientists have created an artificial hippocampal nucleus on a chip. What they did was record the electrical activity from area CA1 of the hippocampus while rats were learning a memory task, and then stuck a device in their brains that played back that sequence into the hippocampus. When they pharmaceutically silenced CA1, which normally inhibits learning, and ran the chip instead, learning was restored. When they used the chip without the CA1 inhibitor, learning was enhanced.

Nobody understands exactly how this works, but there’s no denying that the function of this part of the brain is produced by patterned electrical activity. Incomplete understanding shouldn’t be a barrier to recognizing the reality staring us in our face.

Besides, I’d love to augment my brain with silicon. Although, to be honest, I’d rather test it on my students first — they won’t mind getting a chip implanted to help them learn, right?

Reading for non-psychopaths

I’ve met Jon Ronson a few times, including this past weekend, but I can’t say I really know him — we’ve exchanged a few words, I’ve heard him give a talk, I now him as the short intense guy with the very bad hair, slightly neurotic, expressive, and funny. But I read his book, The Psychopath Test: A Journey Through the Madness Industry(amzn/b&n/abe/pwll) this afternoon while on the train from Cheltenham to Heathrow, and I have this idea of who he is.

He’s Hemingway. Yeah, you know, the macho, hard-drinking man’s man who would run with the bulls or fish for the marlin or pretend to be a war correspondent, who was all about his image as a man of danger or adventure. Only Ronson is more of a nerd’s nerd, and instead of physical danger, he’s all about deep psychic weirdness. So he writes about conspiracy theorists in Them(amzn/b&n/abe/pwll), or weirdos with purported psychic powers in The Men Who Stare at Goats(amzn/b&n/abe/pwll), or he charges off to interview the Insane Clown Posse. And now, in this book, he hangs out with psychopaths. He’s much freakier than Papa.

So the book is a tour of psychopaths and the people who study them. I don’t quite understand how a guy as anxious as Ronson could do it, which again speaks to his nerd machismo. Early on, we get introduced to the criteria for psychopathy:

1 Glibness/superficial charm
2 Grandiose sense of self-worth
3 Need for stimulation/proneness to boredom
4 Pathological lying
5 Cunning/manipulative
6 Lack of remorse or guilt
7 Shallow affect
8 Callous/lack of empathy
9 Parasitic lifestyle
10 Poor behavioural controls
11 Promiscuous sexual behaviour
12 Early behaviour problems
13 Lack of realistic long-term goals
14 Impulsivity
15 Irresponsibility
16 Failure to accept responsibility for own actions
17 Many short-term marital relationships
18 Juvenile delinquency
19 Revocation of conditional release
20 Criminal versatility

I read that and mentally checked off which characteristics fit myself (I know you’re doing it yourself) — surprisingly, none of them fit me at all, which makes me a kind of anti-psychopath. But then, I started thinking…isn’t that just exactly what a psychopath would say? And all we’d need to do is be really good at #4 to conceal everything else. This is what happens as you read the book; everything gets all twisty and you start getting paranoid and confused, because you start applying the criteria to everyone you know.

Or to entire institutions. Just try assessing the Republican party or the Catholic church by that list. The psychos are everywhere.

It’s good reading, anyway. It kept me engrossed for the whole trip, and left me wide-awake and a little jumpy as I worked my way through the airport.

The new phrenology

Morphological variation is important, it’s interesting…and it’s also common. It’s one of my major scientific interests — I’m actually beginning a new research project this spring with a student and I doing some pilot experiments to evaluate variation in wild populations here in western Minnesota, so I’m even putting my research time where my mouth is in this case. There has been some wonderful prior work in this area: I’ll just mention a paper by Shubin, Wake, and Crawford from 1995 that examined limb skeletal morphology in a population of newts, and found notable variation in the wrist elements — only about 70% had the canonical organization of limb bones.

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I’ve also mentioned the fascinating variation in the morphology of the human aorta. Anatomy textbooks lay out the most common patterns, but anyone who has taught the subject knows that once you start dissecting, you always find surprises, and that’s OK: variation is the raw material of evolution, so it’s what we expect.

The interesting part is trying to figure out what causes these differences in populations. We can sort explanations into three major categories.

  1. Genetic variation. It may be the the reason different morphs are found is that they carry different alleles for traits that influence the developmental processes that build features of the organism. Consider family resemblances, for instance: your nose or chin might be a recognizable family trait that you’ve inherited from one of your parents, and may pass on to your children.

  2. Environmental variation. The specific pattern of expression of some features may be modified by environmental factors. In larval zebrafish, for instance, the final number of somites varies to a small degree, and can be biased by the temperature at which they are raised. They’re also susceptible to heat shock, which can generate segmentation abnormalities.

  3. Developmental noise. Sometimes, maybe often, the specific details of formation of a structure may not be precisely determined — they wobble a bit. The limb variation Shubin and others saw, for example, was almost entirely asymmetric, so it’s not likely to have been either genetic or environmental. They were just a consequence of common micro-accidents that almost certainly had no significant effect on limb function.

When I see variation, the first question that pops into my head is which of the above three categories it falls into. The second question is usually whether the variation does anything — while some may have consequences on physiology or movement or sexual attractiveness, for instance, others may really be entirely neutral, representing equivalent functional alternatives. Those are the interesting questions that begin inquiry; observing variation is just a starting point for asking good questions about causes and effects, if any.

I bring up this subject as a roundabout introduction to why I find myself extremely peeved by a recent bit of nonsense in the press: the claim that liberal and conservative brains have a different organization, with conservatives having larger amygdalas (“associated with anxiety and emotions”) and liberals having a larger anterior cingulate (“associated with courage and looking on the bright side of life”).

Gag.

I don’t deny the existence of anatomical variation in the brain — I expect it (see above). I don’t question the ability of the technique, using MRI, to measure the dimensions of internal structures. I even think these kinds of structural variations warrant more investigation — I think there are great opportunities for future research to use these tools to look for potential effects of these differences.

What offends me are a number of things. One is that the interesting questions are ignored. Is this variation genetic, environmental, or simply a product of slop in the system? Does it actually have behavioral consequences? The authors babble about some correlation with political preferences, but they have no theoretical basis for drawing that conclusion, and they can’t even address the direction of causality (which they assume is there) — does having a larger amygdala make you conservative, or does exercising conservative views enlarge the amygdala?

I really resent the foolish categorization of the functions of these brain regions. Courage is an awfully complex aspect of personality and emotion and cognition to simply assign to one part of the brain; I don’t even know how to define “courage” neurologically. Are we still playing the magical game of phrenology here? This is not how the brain works!

Furthermore, they’re picking on a complex phenomenon and making it binary. Aren’t there more than one way each to be a conservative or a liberal? Aren’t these complicated human beings who vary in an incredibly large number of dimensions, too many to be simply lumped into one of two types on the basis of a simple survey?

This is bad science in a number of other ways. It was done at the request of a British radio channel; they essentially wanted some easily digestible fluff for their audience. The investigator, Geraint Rees, has published quite a few papers in credible journals — is this really the kind of dubious pop-culture crap he wants to be known for? The data is also feeble, based on scans of two politicians, followed by digging through scans and questionnaires filled out by 90 students. This is blatant statistical fishing, dredging a complex data set for correlations after the fact. I really, really, really detest studies like that.

And here’s a remarkable thing: I haven’t seen the actual data yet. I don’t know how much variation there is, or how weak or strong their correlations are. It’s because I can’t. This work was done as a radio stunt, is now being touted in various other media, and the paper hasn’t been published yet. It’ll be out sometime this year, in an unnamed journal.

We were just discussing the so-called “decline effect”, to which my answer was that science is hard, it takes rigor and discipline to overcome errors in analysis and interpretation, and sometimes marginal effects take a great deal of time to be resolved one way or the other…and in particular, sometimes these marginal results get over-inflated into undeserved significance, and it takes years to clear up the record.

This study is a perfect example of the kind of inept methodology and lazy fishing for data instead of information that is the root of the real problem. Science is fine, but sometimes gets obscured by the kind of noise this paper is promoting.

I have to acknowledge that I ran across this tripe via Blue Girl, who dismisses it as “sweeping proclamations about the neurophysiological superiority of the liberal brain”, and Amanda Marcotte, who rejects it because “This kind of thing is inexcusable, both from a fact-based perspective and because the implication is that people who are conservative can’t help themselves.” Exactly right. This kind of story is complete crap from the premise to the data to the interpretations.

Optogenetics!

The journal Nature has selected optogenetics as its “Method of the Year”, and it certainly is cool. But what really impressed me is this video, which explains the technique. It doesn’t talk down to the viewer, it doesn’t overhype, it doesn’t rely on telling you how it will cure cancer (it doesn’t), it just explains and shows how you can use light pulses to trigger changes in electrical activity in cells. Well done!

The new pick-up line: “I have a very large MRI device…”

A team of neuroscientists has made the coolest nerd porn film ever. They gave 16 women vibrators and asked them to bring themselves to orgasm while they made a movie…of their brains, using an MRI scanner. It’s going to premiere at the Society for Neuroscience meetings.

While it sounds like they have some interesting results — there is a consistent, wide-spread pattern of brain activity during orgasm, and specific areas are known to fire up — the article is not going to do a lot for Professor Barry Komisaruk’s reputation. The interviewer asked a few too many trivial questions.

“In women, orgasm produces a very extensive response across the brain and body,” said Barry Komisaruk, professor of psychology at Rutgers University in New Jersey, who oversaw the research.

“In one experiment we asked women to self-stimulate and then raise their hands each time they orgasmed. Some women raised their hands several times each session, often just a few seconds apart,” Professor Komisaruk said. “So the evidence is that woman tend to have longer orgasms and can experience several of them.”

So…the women in Professor Komisaruk’s life have never had a satisfactory sexual experience with him, so he needed a multi-million dollar machine to figure this out? I’m glad he finally learned this!

(I joke—I’m sure there are interesting neurological results, this article just highlighted the obvious, as if it were news.)

We don’t have a single mind, we have a series of fabulator modules

Everyone should read this very good, very clear article in Seed magazine. It stomps on the concept of a soul from the perspective of modern neuroscience.

The evidence supports another view: Our brains create an illusion of unity and control where there really isn’t any. Within the wide range of works arranged along the axis of soulism, from Life After Death: The Evidence, by Dinesh D’Souza, to Absence of Mind, by Marilynne Robinson, it is clear there is very little understanding of the brain. In fact, to advance their ideas, these authors have to be almost completely unaware of neurology and neuroscience. For example, Robinson tells us, “Our religious traditions give us as the name of God two deeply mysterious words, one deeply mysterious utterance: I AM.” The translation might be, “indoctrination tells us we have a soul, it feels like we are a unified little god in control of our bodies, so we are.”

It’s all illusions, all the way through.

The sexist brain

It looks like I have to add another book to my currently neglected reading list. In an interview, Cordelia Fine, author of a new book, Delusions of Gender: How Our Minds, Society, and Neurosexism Create Difference(amzn/b&n/abe/pwll), has a few provocative things to say about gender stereotypes and the flimsy neuroscience used to justify them.

So women aren’t really more receptive than men to other people’s emotions?

There is a very common social perception that women are better at understanding other people’s thoughts and feelings. When you look at one of the most realistic tests of mind reading, you find that men and women are just as good at getting what their interaction partners were thinking and feeling. It even surprised the researchers. They went on to discover that once you make gender salient when you test these abilities [like having subjects check a box with their sex before a test], you have this self-fulfilling effect.

The idea that women are better at mind reading might be true in the sense that our environments often remind women they should be good at it and remind men they should be bad at it. But that doesn’t mean that men are worse at this kind of ability.

…

But it seems like a Catch-22: Women who pursue careers in math are being handicapped by the fact that there are so few women pursuing careers in math.

Gender equality is increasing in pretty much all domains, and the psychological effects of that can only be beneficial. The real issue is when people in the popular media say things like, “Male brains are just better at this kind of stuff, and women’s brains are better at that kind of stuff.” When we say to women, “Look, men are better at math, but it’s because they work harder,” you don’t see the same harmful effects. But if you say, “Men are better at math genetically,” then you do. These stem from the implicit assumption that the gender stereotypes are based on hard-wired truths.

Here we have a brain, receptive and plastic and sensitive to learning, constantly rewiring itself, with a core of common, human traits hardwired into it, and over here we have scientists who have been the recipient of years of training, often brought up in a culture that fosters an interest in science and math…and somehow, many of these scientists are resistant to the idea that the brain is easily skewed in different directions by the social environment. I don’t get it. I was brought up as a boy, and I know that throughout my childhood I was constantly being hammered by male-affirmative messages and biases, and I think it’s obvious that girls were also hit with lots of their gender-specific cultural influences. Yet somehow we’re supposed to believe that the differences between men and women are largely set by our biology? That women aren’t as good at math because hormones wire up their brain in a different way than the brains of men, and it’s not because our plastic brains receive different environmental signals?

Fine appeals to my biases about the importance of environmental influences, I’ll admit; the interview is a bit thin on the details. But I’ll definitely have to read her book.