The Neurocritic

59

2008-07-06T23:12:00.000-07:00

59 is the number of hot dogs consumed in 10 min by the two finalists in the world's most famous competitive eating contest.

128 lb Takeru Kobayashi vs. 210 lb Joey Chestnut at Nathan's Hot Dog Eating Contest held on July 4, 2008.

The contest went into "overtime," which was decided by a 5 hot dog eat-off.

Champ retains NYC hot-dog eating title in overtime
NEW YORK (AP) — Joey Chestnut achieved frankfurter immortality Friday, outdueling his celebrated Japanese rival in an epic hot-dog eating contest that pushed both of the gluttonous gladiators to the brink.
In a seesaw struggle for the ages, Chestnut and Takeru Kobayashi each consumed an eye-popping 59 hot dogs in 10 minutes, forcing an unprecedented showdown that tested the very depths of their distended stomachs.
Under the glare of ESPN and facing a boisterous and sweaty crowd of thousands on Coney Island, Chestnut, the reigning champ, and Kobayashi, the six-time title holder, were forced to gobble down another five hot dogs in overtime.

How do they do it? A Science Daily video from two years ago speculated that Competitive Eaters May Have Ability to Suppress Satiety Hormones:

"These competitive eaters are an interesting group of people who seem to have abilities that many people in the normal population don't have," David Metz, a gastroenterologist at University of Pennsylvania in Philadelphia, tells DBIS.
Many competitive eaters train for an event by chugging gallons of water to help stretch the stomach. Others eat large quantities of low-calorie, high-fiber foods, like cabbage, that stay in the stomach longer before breaking down. Doctors believe expert eaters may have the ability to keep eating after they're full by suppressing the stomach signals to the brain that indicate it's satisfied.

Sounds like a horribly wretched thing to do to your body. But is it dangerous? In an article entitled Competitive Speed Eating: Truth and Consequences, Levine et al. (2007) concluded:

We speculate that professional speed eaters eventually may develop morbid obesity, profound gastroparesis, intractable nausea and vomiting, and even the need for a gastrectomy. Despite its growing popularity, competitive speed eating is a potentially self-destructive form of behavior.

Wiry 128 lb. Takeru Kobayashi.

Of course, there do appear to be notable exceptions...

For great coverage of the Levine et al. article in the American Journal of Roentgenology, read Radiology of Competitive Speed Eating at Not Totally Rad. From the abstract:

The purpose of our investigation was to assess the stomachs of a world-class speed-eating champion and of a control subject during a speed-eating test in our gastrointestinal fluoroscopy suite to determine how competitive speed eaters are able to eat so much so fast.

The Wall Street Journal Health Blog also describes the paper (complete with gastrointestinal fluoroscopic images) and interviews radiologist Marc Levine. The study compared "an unnamed champion eater, ranked in the top 10 in the world, who was 29 years old, 5′10″ tall and weighed 165 pounds" to "just some guy who 'had a hearty appetite' (35 years old, 6′2″, 201 pounds)."

The regular guy went first, and stopped after seven dogs... Using fluoroscopy, an x-ray that gives a real-time view of what’s going on inside the body, the doctors saw what you’d expect: His stomach was indeed full of hot dogs and hadn’t stretched much from its original size.

Then they looked at the competitive eater. First, they noticed that his empty stomach showed virtually no peristalsis, the normal squeezing motion that helps the stomach break down food. He started eating hot dogs and his stomach got bigger and bigger. Ten minutes in, he’d eaten 36 dogs. He said he didn’t feel full, but the researchers told him they’d seen enough.
“His stomach now appeared as a massively distended, foodfilled sac occupying most of the upper abdomen, with little or no gastric peristalsis,” they wrote in their paper. Levine said the stomach was like no healthy stomach he’d seen in his 30-year career. He compared it to a “giant balloon that looks like it has no limit.” The eater’s previously flat belly swelled out as if he were pregnant.

Just how much fat, cholesterol, sodium nitrite, MSG, etc. is in 4-5 pounds of hot dogs, you ask? A serving of 36 Nathan's Famous Beef Franks has 6120 calories, 540 g fat, 1260 mg cholesterol, and 16,920 mg sodium. Organic fat-free veggie dogs, anyone?

Code Word Red: Waterboarding IS Torture

2008-07-04T15:37:00.000-07:00

You may have read by now the official lie about this treatment, which is that it “simulates” the feeling of drowning. This is not the case. You feel that you are drowning because you are drowning—or, rather, being drowned, albeit slowly and under controlled conditions and at the mercy (or otherwise) of those who are applying the pressure.

-Christopher Hitchens, in the August issue of Vanity Fair

It's July 4, Independence Day in America. A time for fireworks and baseball and apple pie and ice cream and watermelon.

In case you haven't been keeping up with issue of how the US condoned torture in the War on Terror:

[Four U.S. Congress Members] Briefed on Waterboarding in 2002

By Joby Warrick and Dan Eggen
Washington Post Staff Writers
Sunday, December 9, 2007

In September 2002, four members of Congress met in secret for a first look at a unique CIA program designed to wring vital information from reticent terrorism suspects in U.S. custody. For more than an hour, the bipartisan group ... was given a virtual tour of the CIA's overseas detention sites and the harsh techniques interrogators had devised to try to make their prisoners talk.

Among the techniques described, said two officials present, was waterboarding, a practice that years later would be condemned as torture by Democrats and some Republicans on Capitol Hill. But on that day, no objections were raised. Instead, at least two lawmakers in the room asked the CIA to push harder, two U.S. officials said.

However, in 2004, a quiet hero emerged from a most unlikely place -- from within the Bush Administration -- as described last year by Amy Goodman:

In a remarkable demonstration of commitment to his job, former acting Assistant Attorney General Daniel Levin, according to ABC News, underwent waterboarding when tasked by the White House to rework its official position on torture in 2004. Concluding that waterboarding is torture, he was forced out of his job.

Four years later, neoconservative pundit Christopher Hitchens says

Believe Me, It’s Torture

What more can be added to the debate over U.S. interrogation methods, and whether waterboarding is torture? Try firsthand experience. The author undergoes the controversial drowning technique, at the hands of men who once trained American soldiers to resist—not inflict—it.

You can watch a video of Hitchens on the waterboard:

How does it feel to be “aggressively interrogated”? Christopher Hitchens found out for himself, submitting to a brutal waterboarding session in an effort to understand the human cost of America’s use of harsh tactics at Guantánamo and elsewhere.

"Well, then, if waterboarding does not constitute torture, then there is no such thing as torture."

However, he ~~goes on to~~ appears to contradict himself just a couple of paragraphs later.

ADDENDUM: He presents the arguments on both sides of the debate "at their strongest" but has praise for those who endorse torture:

The team who agreed to give me a hard time in the woods of North Carolina belong to a highly honorable group. This group regards itself as out on the front line in defense of a society that is too spoiled and too ungrateful to appreciate those solid, underpaid volunteers who guard us while we sleep. ... As they have just tried to demonstrate to me, a man who has been waterboarded may well emerge from the experience a bit shaky, but he is in a mood to surrender the relevant information and is unmarked and undamaged and indeed ready for another bout in quite a short time. When contrasted to actual torture, waterboarding is more like foreplay. No thumbscrew, no pincers, no electrodes, no rack. Can one say this of those who have been captured by the tormentors and murderers of (say) Daniel Pearl? On this analysis, any call to indict the United States for torture is therefore a lame and diseased attempt to arrive at a moral equivalence between those who defend civilization and those who exploit its freedoms to hollow it out, and ultimately to bring it down. I myself do not trust anybody who does not clearly understand this viewpoint.

Maybe if Hitchens were forced to endure the experience of actually drowning for more than a few seconds, again and again and again, he just might change his mind. He is certainly not convinced by the words of Malcolm Nance, a former master instructor and chief of training at the U.S. Navy Survival, Evasion, Resistance and Escape School. Hitchens again:

I passed one of the most dramatic evenings of my life listening to his cold but enraged denunciation of the adoption of waterboarding by the United States. The argument goes like this:
1. Waterboarding is a deliberate torture technique and has been prosecuted as such by our judicial arm when perpetrated by others.

2. If we allow it and justify it, we cannot complain if it is employed in the future by other regimes on captive U.S. citizens. It is a method of putting American prisoners in harm’s way.

3. It may be a means of extracting information, but it is also a means of extracting junk information. ...

4. It opens a door that cannot be closed. Once you have posed the notorious “ticking bomb” question, and once you assume that you are in the right, what will you not do? Waterboarding not getting results fast enough? The terrorist’s clock still ticking? Well, then, bring on the thumbscrews and the pincers and the electrodes and the rack.

Who do you trust...Mr. Hitchens or Mr. Nance?

Everybody's a Neurocritic!

2008-07-03T18:38:00.000-07:00

It was fashionable and socially acceptable last week to criticize fMRI after Nikos Logothetis, one of the leading experts on the origin of the BOLD (Blood-Oxygen-Level Dependent) signal, published a high-profile article in Nature on What we can do and what we cannot do with fMRI:

Functional MRI is an excellent tool for formulating intelligent, data-based hypotheses, but only in certain special cases can it be really useful for unambiguously selecting one of them, or for explaining the detailed neural mechanisms underlying the studied cognitive capacities. In the vast majority of cases, it is the combination of fMRI with other techniques and the parallel use of animal models that will be the most effective strategy for understanding brain function.

He defends modularity¹ (although not exactly of the Fodorian variety), critiques the assumption of pure insertion², and points out the shortcomings of adaptation³ designs.

The 14 page Supplementary Information is comprehensive as well, covering topics such as MRI and fMRI Principles, Single and Multiple Unit Activity vs. Local Field Potentials, and Spatial Specificity, all documented by 112 references.

Finally, Logothetis has some sharp words not only for the fMRI pollyannas among us, but also for the naysayers (lest we get too dismissive):

Its popular fascination is reflected in countless articles in the press speculating on potential applications, and seeming to indicate that with fMRI we can read minds better than direct tests of behaviour itself. Unsurprisingly, criticism has been just as vigorous, both among scientists and the public. In fact, fMRI is not and will never be a mind reader, as some of the proponents of decoding-based methods suggest, nor is it a worthless and non-informative 'neophrenology' that is condemned to fail, as has been occasionally argued.

But what I really want to discuss here is a News Focus item in the 13 June 2008 issue of Science.

NEUROIMAGING: Growing Pains for fMRI

Greg Miller

As the use of functional magnetic resonance imaging has exploded, some researchers say the field could use a dose of rigor. Will new experimental approaches come to the rescue?

Science has never published an unrigorous fMRI paper? Let's look at the 23 May 2008 edition of "This Week in Science - Editor summaries of this week's papers."

Kindness or Fairness?
It's easy to propose that allocations of scarce resources should provide the greatest benefit to a group as a whole and be as fair as possible to individual members of the group, but what should be done when both aims cannot be optimized simultaneously? Hsu et al. (p. 1092... see the 9 May news story by Miller) use functional brain imaging, not to resolve these dilemmas, but to probe the underlying cognitive and emotional processes supporting one view (favoring equity, for instance) versus the other (maximizing the good). Brain regions involved in encoding reward relate also to calculations of total benefit, whereas the balancing of equity and utility seems to be the province of the insula, which connects with emotion-processing neural systems. Thus, judgments of fairness derive from emotion-based preferences, rather than those of pure reason.

Reverse inference anyone? See papers by Aguirre (2003) and Poldrack (2006). What did The Neurocritic say about the right and the good and the insula?

[The insula]'s a pretty large area. Besides being crowned the "seat of emotional reactions" (whatever that means), portions of the insula have been associated with interoceptive awareness, visceral sensation, pain, autonomic control, and taste, among other things... a lot of other things. Do a search of the BrainMap database using just two of the many insular foci reported by the Caltech researchers and you'll see activations related to action execution, speech, attention, language, explicit memory, working memory, and audition.

The 9 May news story by Miller mentions the 2001 Science paper on moral judgment and emotion (Greene et al., 2001).⁴ In that paper, the authors

reported that the medial frontal gyrus and other brain regions linked to emotion become more active when people contemplate "personal" moral dilemmas--such as shoving the man onto the trolley tracks or removing a man's organs against his will to save five transplant recipients--compared with when they weigh impersonal moral dilemmas--such as flipping a switch to save the workers or declaring bogus business expenses on a tax return.

Besides the medial frontal gyrus [BA 9/10, which did not replicate in Experiement 2], what were these other brain regions linked to emotion? Did they include the insula? No, they did not. They included the posterior cingulate gyrus (which has some grounding in reality) and the L and R angular gyri (which does not⁵).

Ironically, the 13 June story by Miller interviewed Russell Poldrack on the infamous New York Times Op-Ed piece (and the moral judgment paper):

Neuroimagers gone wild
What irked Poldrack and others most about the Times's op-ed was the way the authors inferred particular mental states from the activation of particular brain regions: Activity in the anterior cingulate cortex indicated mixed feelings about Hillary Clinton, for example, whereas amygdala activation indicated "voter anxiety" about Republican candidate Mitt Romney.
. . .
He and others argue that reverse inferences are particularly common in newer fields such as social cognitive neuroscience and neuroeconomics (not to mention neuropolitics), fields in which researchers are still trying to identify the cognitive processes underlying the behaviors they study. As an example, Poldrack points to a widely cited paper that used fMRI to investigate brain activity in subjects pondering moral dilemmas (Science, 14 September 2001, p. 2105); some of the brain regions that lit up had been linked in previous studies to emotional and "rational" cognitive processes, and the authors concluded that these two types of processes are active, to different degrees, in different types of moral judgments. But the strength of such arguments hinges on how specifically a given brain area is linked to a given mental process. Poldrack points out, for example, that some of the "emotional" brain regions in the morality study have also been connected to memory and language--a caveat that is rarely mentioned in media coverage of the work (Science, 9 May, p. 734).

So it appears that Science isn't exactly following its own advice... Granted, 14 September 2001 was a while ago, but 23 May 2008 was not.

Footnotes

¹ Logothetis views

the modular organization of many brain systems as a well established fact, and discuss only how far fMRI can go in revealing the neuronal mechanisms of behaviour by mapping different system modules and their dynamic inter-relationships. In this context the term module captures the classical local neuronal circuits repeated iteratively within a structure (for example, the columns or swirling, slab-like tangential arrangements of the neocortex), as well as the entities within which modules might be grouped by sets of dominating external connections.

² Pure insertion

asserts that a single cognitive process can be inserted into a task without affecting the remainder, an assumption that all too often is not tenable... Even if an experimental design could satisfy this assumption at the cognitive level, the assumption would be condemned to fail at the level of its neuronal instantiation owing to the highly nonlinear nature of most brain processes. To overcome this kind of problem and ensure better interpretation of the neuroimaging data it is necessary to perform a detailed task analysis to determine subtraction components and their interactions. Yet most neuroimaging studies provide no formal task analysis that would ensure that the particular cognitive process of interest is indeed being isolated by the subtraction.

³ In adaptation designs,

a stimulus is presented repeatedly with the expectation that it will eventually induce response adaptation in neurons selective for its various properties. In general, repetition of an identical stimulus does indeed produce a reduction in the fMRI signal. After adaptation, the subject is presented with a stimulus that is varied along one dimension (for example, the direction of a moving pattern or the view of a human face) and the possibility of a response rebound is examined. If the underlying neural representation is insensitive to the changes in the stimulus then the fMRI signal will be reduced, similar to the reduction produced by the repetition of identical stimuli. Alternatively, if the neurons are sensitive to the transformation, the signal will show a clear rebound to its original, pre-adaptation level.

⁴ Everyone always uses the "Trolley Problem" to illustrate a personal moral dilemma, but my favorite is actually "Smother for Dollars":

You are in hospital lounge waiting to visit a sick friend. A young man sitting next to you explains that his father is very ill. The doctors believe that he has a week to live at most. He explains further that his father has a substantial life insurance policy that expires at midnight.
If his father dies before midnight, this young man will receive a very large sum of money. He says that the money would mean a great deal to him and that no good will come from his father's living a few more days. He offers you half a million dollars to go up to his father's room and smother his father with a pillow.
Is it appropriate for you to kill this man's father in order to get money for yourself and this young man?

⁵ If you read the 17 abstracts carefully, you'll note that activation of the angular gyrus was mostly associated with things like cognition and mathematical processing, not emotion. Compare that search to the 170 papers in PubMed related to posterior cingulate and emotion.

References

Aguirre GK (2003). Functional Imaging in Behavioral Neurology and Cognitive Neuropsychology. In: T.E. Feinberg & M.J. Farah (Eds.), Behavioral Neurology and Cognitive Neuropsychology. New York: McGraw Hill.

Greene JD, Sommerville RB, Nystrom LE, Darley JM, Cohen JD. (2001). An fMRI investigation of emotional engagement in moral judgment. Science 293:2105-8.

Logothetis NK. (2008). What we can do and what we cannot do with fMRI. Nature 453:869-78.

Miller G. (2008). Neurobiology. The roots of morality. Science 320:734-7. (9 May 2008).

Miller G. (2008). Neuroimaging. Growing pains for fMRI. Science 320:1412-4 (13 June 2008).

Poldrack RA (2006). Can cognitive processes be inferred from neuroimaging data? Trends in Cognitive Sciences 10: 59-63.

Martin Creed, Work No. 850

2008-07-02T00:46:00.000-07:00

at the Tate Britain in London.

"Running fast is like the exact opposite of death - it's an example of aliveness."

Work No. 850 centres on a simple idea: that a person will run as fast as they can every thirty seconds through the gallery. Each run is followed by an equivalent pause, like a musical rest, during which the grand Neoclassical gallery is empty.

This work celebrates physicality and the human spirit. Creed has instructed the runners to sprint as if their lives depended on it. Bringing together people from different backgrounds from all over London, Work No. 850 presents the beauty of human movement in its purest form, a recurring yet infinitely variable line drawn between two points.

More coverage here:

Martin Creed's Tate Britain artwork shows sprinting runners

By Anita Singh, Showbusiness Editor
Last Updated: 3:56PM BST 01/07/2008

When Martin Creed won the Turner Prize for exhibiting a light bulb going on and off, critics said conceptual art had finally run out of puff.
With his latest masterpiece, he is out to prove them wrong.
The artist's new installation, Work No 850, consists of a runner sprinting the length of Tate Britain's neo-classical sculpture galleries.
Every 30 seconds between 10am and 6pm, an athlete will make the 86-metre dash from one end to the other - for four months.

The Little Watermelon Pill

2008-07-01T03:00:00.000-07:00

Watermelon Viagra?

Who could possibly resist writing about such a concoction... er... uh... ridiculing such a juxtaposition:

Watermelon may have Viagra-effect
COLLEGE STATION -- A cold slice of watermelon has long been a Fourth of July holiday staple. But according to recent studies, the juicy fruit may be better suited for Valentine's Day.
That's because scientists say watermelon has ingredients that deliver Viagra-like effects to the body's blood vessels and may even increase libido.

Does the press release cite any papers proving that watermelon is an aphrodisiac? Need I even ask this question? Try typing watermelon libido in PubMed. No items found. Same result for watermelon aphrodisiac. And "citrullus" was automatically included as a search term.

The Texas A&M University - Agricultural Communications department doesn't seem to care, so they continue:

Beneficial ingredients in watermelon and other fruits and vegetables are known as phyto-nutrients, naturally occurring compounds that are bioactive, or able to react with the human body to trigger healthy reactions, [Dr. Bhimu] Patil said.
In watermelons, these include lycopene, beta carotene and the rising star among its phyto-nutrients – citrulline – whose beneficial functions are now being unraveled. Among them is the ability to relax blood vessels, much like Viagra does.
Scientists know that when watermelon is consumed, citrulline is converted to arginine through certain enzymes. Arginine is an amino acid that works wonders on the heart and circulation system and maintains a good immune system, Patil said.
"The citrulline-arginine relationship helps heart health, the immune system and may prove to be very helpful for those who suffer from obesity and type 2 diabetes," said Patil. "Arginine boosts nitric oxide, which relaxes blood vessels, the same basic effect that Viagra has, to treat erectile dysfunction and maybe even prevent it."

But here's the Alternative Medicine Review on citrulline:

...some supplement companies are marketing L-citruilline--a by-product of the arginine-to-nitric oxide pathway--as a substance to increase nitric oxide synthesis in vascular endothelial cells. Although safe, citrulline does not directly convert to nitric oxide, but instead is recycled to L-arginine (an ATP-dependent process), which then converts to nitric oxide. Ferid Murad, MD, PhD, Nobel-prize winner for his research on nitric oxide, has said the use of L-citrulline to increase nitric oxide is only marginally effective.

Nevertheless, an increase in watermelon sales is predicted...

ABC News Says: 'Trust Drug' Oxytocin Unbelievable For Now

2008-06-25T23:48:00.000-07:00

BUT

'Adventure Center' Explains Why Brain Craves New Sensations

Newness Factor Weighs in on Brain

By ALLYSON T. COLLINS
ABC News Medical Unit
June 25, 2008—
...
Humans may be wired to seek out new experiences, according to a study published Wednesday in the online edition of the journal Neuron [Wittmann et al., 2008].
...
During the study, [Bianca] Wittmann and her colleagues looked at people's brain activity through functional magnetic resonance imaging (fMRI)...
When people chose new images, Wittmann says that an area deep in the brain called the ventral striatum lit up on the fMRI scans. The ventral striatum is thought to be involved in emotions and behavior, including addictions.
"When people shoot up stimulant drugs like cocaine, they tend to trigger activity in this system," [Dr. David] Spiegel says.
When activated, nerve cells in the ventral striatum release a chemical called dopamine, which stimulates feelings of enjoyment and pleasure.
Even for the average person, not just people who use drugs, Wittmann says that the emotions brought about by the release of dopamine are "a large part of what keeps us going and what makes us get up in the morning"; they are our internal reward system for certain behaviors.
It may be these feel-good sensations that caused the participants to keep selecting the new images.

Because choosing a new picture in a psychology experiment is just like intravenous cocaine...

Left panel taken from Fig. 1 of Wittmann et al. (2008).

How nice. I guess their hard-hitting criticism of the oxytocin media neurohype was short-lived...

Dialogues and Dilbert on Prediction Errors

2008-06-24T20:02:00.000-07:00

A new article in TICS (Trends in Cognitive Sciences) by Niv and Schoenbaum makes use of Dilbert cartoons and a Q&A format to discuss the neural correlates of prediction error signals:

The goal of this ‘dialogue style’ review (which loosely follows a series of question and answer e-mails between the authors) is to make clear to those not versed in reinforcement learning theory what temporal difference prediction errors are and how this theory interacts with neuroscientific research.

A popular view is that midbrain dopamine neurons respond to discrepancies between a predicted reward and the actual outcome (Schultz, 2006). The TICS article begins by giving a whirlwind tour of the Rescorla-Wagner model of classical conditioning, then differentiates between the Rescorla-Wagner and the temporal difference (TD) models. Next it's on to dopamine...

Q5: The influential reward prediction error hypothesis of dopamine arose from comparing monkey electrophysiological data to the characteristics of a TD prediction error (Schultz et al., 1997). Today, other forms of neural recordings have targeted this same signal. What are the basic criteria for establishing that a recorded signal is, indeed, a TD prediction error?

Three criteria can be considered the ‘fingerprint’ of a reward prediction error signal: a phasic increase to unexpected rewards (a positive prediction error), no change to predicted rewards and a phasic decrease (a negative prediction error) when an expected reward is omitted (or vice-versa – decreases to positive errors and increases to negative errors).

Figure 1 (Niv & Schoenbaum, 2008). The time course of the reward, value and prediction error signals in the TD model. The first predictive stimulus is the label on the wine bottle, after which wine is poured into the glass and finally consumed. Cue-related phasic neural signals whose magnitude reflects the future predicted reward can be called prediction error signals, but sustained neural signals corresponding to the value of the predicted reward throughout the trial are designated value signals.

...although the authors acknowledged that such signals can also occur elsewhere in the brain. Yet, Niv and Schoenbaum are critical of these latter activations observed in neuroimaging studies:

Q8: Correlates of prediction errors in functional imaging studies are frequently found not in the midbrain but, rather, in areas such as the striatum, amygdala, and orbitofrontal cortex. Do all these areas signal prediction errors?

This is a tricky issue that has caused much confusion. Imaging studies have indeed found blood-oxygen-level level dependent (BOLD) signals that correlate with a precise, computationally derived TD prediction error in a variety of brain areas. Furthermore, a handful of single-unit recording studies have reported that activity in other brain areas – amygdala, striatum, orbitofrontal cortex and elsewhere – is reliably modulated by whether rewards or punishments are expected...
However, current thought has it that the BOLD signal does not directly reflect firing activity in an area but, rather, correlates with the local field potential and local processing, which are driven by subthreshold activity and synaptic inputs to the area. Thus, perhaps it is appropriate to view the imaging results as reflecting the information that an area is receiving and processing, whereas single-unit activity reflects the information that an area is transmitting to downstream regions.

Speaking of BOLD critics, see Nikos Logothetis on What we can do and what we cannot do with fMRI (in Nature) and Logothetis doesn’t like to be BOLD … alone, which summarizes a lecture he gave in Copenhagen (in the BRAINETHICS blog).

References

NIV Y, SCHOENBAUM G. (2008). Dialogues on prediction errors. Trends in Cognitive Sciences. DOI: 10.1016/j.tics.2008.03.006.

The recognition that computational ideas from reinforcement learning are relevant to the study of neural circuits has taken the cognitive neuroscience community by storm. A central tenet of these models is that discrepancies between actual and expected outcomes can be used for learning. Neural correlates of such prediction-error signals have been observed now in midbrain dopaminergic neurons, striatum, amygdala and even prefrontal cortex, and models incorporating prediction errors have been invoked to explain complex phenomena such as the transition from goal-directed to habitual behavior. Yet, like any revolution, the fast-paced progress has left an uneven understanding in its wake. Here, we provide answers to ten simple questions about prediction errors, with the aim of exposing both the strengths and the limitations of this active area of neuroscience research.

Schultz W. (2006). Behavioral theories and the neurophysiology of reward. Annu Rev Psychol. 57:87–115.

Schultz W, Dayan P, Montague RR (1997). A neural substrate of prediction and reward. Science 275: 1593–99.

Jumping Into "The Fray" on Cerebral Asymmetry and Sexual Orientation

2008-06-21T21:48:00.000-07:00

Fig. S1 (Savic & Lindström, 2008). Part of the left cerebral hemisphere VOI in a male heterosexual subject. Subject’s right side is to the right in the image.

At The Fray, a reader discussion forum at Slate Magazine, a knowledgeable commenter named shusaku provided his own critique of the Savic and Lindström article that purportedly demonstrated the Symmetry Of Homosexual Brain Resembles That Of Opposite Sex.

Slate --> The Fray --> Human Nature

a scientific criticism of the article presented
by shusaku

Since PNAS is not, to my knowledge, a true peer-reviewed journal. I've decided to post a little review of the article addressing its validity.

[NOTE: that is not entirely true. Read the footnote¹ for an explanation.]

Shusaku continues with this biting critique:

1) Structural MRI measruements - the regions of interest (ROIs) demarcated in this study included the ventricles, which are not gray or white matter. This indicates that the measurements of structural asymmetry can easily be confounded by differences in ventricular size. In which case, it is equally likely gray or white matter asymmetry cannot be determined by the results presented. There result of differences in structural asymmetry are further undermined by the fact that the cerebellum demarcations only contain gray/white matter and show no differences in asymmetry between subject groups.

Ouch. Why the authors chose to use that particular metric (as opposed to, say, regional brain volumes or cortical thickness) isn't at all clear from the Introduction. In the Discussion, Savic and Lindström stated:

Among studies explicitly comparing the entire hemispheres most, although not all, suggest that the right hemisphere is larger in men (32, 34, 38, 39).

By contrast, in a study on sex differences in cortical thickness, Sowell et al. (2007) opined:

Given the apparent specificity of differences in male and female cognitive advantages, and regional specificity of brain–behavior relationships, global differences in brain size between the sexes that have been readily observed with relatively gross methods might not be the most relevant structural dimorphism when investigating neural substrates of sex differences in cognition.

This is a very important point, because a major result in their study was that gray matter thickness in the right inferior parietal and posterior temporal cortices was 0.45 mm thicker in women than in men [all of unknown sexual orientation], as illustrated below.

Fig. 1 (Sowell et al., 2007). (A) Maps of differences between the sexes in thickness of gray matter (males coded 1, females coded 0 for all maps displayed) for the entire group of 176 subjects showing differences in gray matter (in millimeters) between the male and female subjects according to the color bar on the right. Warmer colors (less than 0 on the color bar) are regions where gray matter thickness is greater in the female than in the male subjects, and cooler colors (greater than 0) are regions where the males have greater gray matter thickness than the female subjects. Note the approximately 0.45 mm increase in cortical thickness in females in the right posterior temporal lobe.

And that's only by way of illustrating Shusaku 's point #1 contra Savic and Lindström. He also criticized the amygdala functional connectivity analysis (a whole 'nother topic), the assumption that learning and environment cannot account for the results, and the exclusion of bisexuals (although all studies seem to exclude them, so that one's not really fair).

But all's fair in science and revulsion:

There are many more technical problems with the analytical techniques used in this study. I'm not going to bother going through all of them. Needless to say, this study proves absolutely nothing, and is just another example of bad science. As an MRI researcher, this article offends me personally, for it gives MRI and PET research a bad rap; I'm going to go throw up now.

Footnote

¹ There are multiple routes to publishing in PNAS. One track is direct submission to the editors, who send it out for peer review. Another track is for a member of the National Academy of Sciences to either sponsor ("communicate") a paper by other authors or to submit ("contribute") his/her own paper (both without peer review from the PNAS Editorial Board). Savic and Lindström submitted to the Editorial Board, so the paper did go out for peer review. However, I noticed something that's not usually allowed, i.e., the acting Editor for the manuscript is affiliated with the same institution as the authors (Karolinska Institutet).

References

Savic I, Lindström P. (2008). PET and MRI show differences in cerebral asymmetry and functional connectivity between homo- and heterosexual subjects. Proc Natl Acad Sci. June 16, 2008, 10.1073/pnas.0801566105.

Sowell ER, Peterson BS, Kan E, Woods RP, Yoshii J, Bansal R, Xu D, Zhu H, Thompson PM, Toga AW. (2007). Sex Differences in Cortical Thickness Mapped in 176 Healthy Individuals between 7 and 87 Years of Age. Cerebral Cortex, 17(7), 1550-1560. DOI: 10.1093/cercor/bhl066.

Mirror Neurons Control Hard-ons?

2008-06-19T01:10:00.000-07:00

from MR BEAN IN TOILET

Everyone knows that mirror neurons control the universe. Now, a study by Mourus and colleagues supposedly tells us that mirror neurons control the most important thing in the universe!

Mirror neurons control erection response to porn
14:15 16 June 2008
NewScientist.com news service
Alison Motluk
. . .

Harold Mouras, at University of Picardie Jules Verne in Amiens, France, and his colleagues wanted to understand the cerebral underpinnings of visually-induced erections.
They suspected there might be a role for mirror neurons, a special class of brain cell that fires both when people perform an action and when they observe it being performed.
The researchers invited eight young men into the lab and asked them to view three types of video clips. Along with late-night fishing documentaries and snippets of Mr Bean, the volunteers got to see erotic videos of [XXX]...¹

This isn't the first study to invoke the specter of mirror neurons as a critical aspect of responsiveness to viewing porn. Ponsetti et al. (2006) showed pictures of male and female sexually aroused genitals to gay and straight male and female participants [see An "Endophenotype" For Sexual Orientation? for a full description of that study]. The authors summarized their results as follows:

Consistent with our prediction, the ventral striatum and the centromedian thalamus, showed a stronger neuronal response to preferred relative to non-preferred stimuli. Likewise, the ventral premotor cortex which is a key structure for imitative (mirror neurons) and tool-related (canonical neurons) actions showed a bilateral sexual preference-specific activation, suggesting that viewing sexually aroused genitals of the preferred sex triggers action representations of sexual behavior.

At the time, I said:

Here's a thought. According to Wikipedia,
a mirror neuron is a neuron which fires both when an animal performs an action and when the animal observes the same action performed by another (especially conspecific) animal. Thus, the neuron "mirrors" the behavior of another animal, as though the observer were himself performing the action.
The Neurocritic is as skeptical as anyone about the mirror neuron craze, but if the PMv activity in this experiment is really imitative in nature, or even "empathetic" (instead of motor imagery or motor preparation), then wouldn't same-sex genitals elicit greater activity than opposite-sex genitals, regardless of sexual orientation?

Anyway. Now on to the present study. Here, Mourus et al. went further by using penile plethysmography:

To investigate the hypothesis that the activation of the mirror-neuron system could be part of the neural mechanisms regulating visually-induced sexual arousal, including the erectile response, we examined whether the response of the mirror-neuron system to sexually stimulating video clips is correlated with the erectile response of healthy volunteers.

The participants were ten healthy heterosexual males somewhere between the ages of 18 and 60. The authors hypothesized that

a neural pathway linking the mirror-neuron system to neural structures controlling erection could be represented by the efference of the frontal operculum – a region containing mirror neurons - to the insula.²

The ventral premotor cortex in Brodmann area 6 is posterior to the frontal operculum (Tomassini et al., 2007). Do we really know that the frontal operculum contains mirror neurons? The most [only] definitive evidence for mirror neuron-type activity is from single-unit recording, not from fMRI. Do monkeys even have a frontal operculum? Yes, but it seems to be mostly gustatory.

Mirror Neuron Erection Study a "BOLD" One

...at least, according to Ramachandran:

Vilayanur Ramachandran, at the University of California at San Diego, who also studies mirror neurons, calls it a "bold" study, and congratulates the group on defying the taboo on studying human sexual physiology.
While he thinks it is perfectly plausible that mirror neurons play a role in how porn turns us on, he says more needs to be done to understand what that role is. For a start, he says, a large number of the brain's structures seem to be involved, not just the pars opercularis, and the interaction between these regions in response to porn is unclear.
"It doesn't give you an experimental lever into the problem," he adds.
And while Ramachandran agrees that the timing of mirror neuron activation and erection is probably critical, fMRI isn't accurate enough to show clearly what is going on with these brain regions over such short time frames.

Ramachandran isn't usually one to show restraint in interpreting data, but here he's right that the BOLD signal was correlated positively with the plethysmographic signal in multitude of brain regions. The authors focus on Frontal operculum, Precentral gyrus, Middle frontal gyrus, Postcentral gyrus, Inferior parietal lobule, Postcentral sulcus, Supramarginal gyrus, Anterior insula, and Posterior insula in the main body of the text, but one can...

(see exhaustive list of regions in Tables 1 and 2 of the online electronic supplementary material)

...once they're online (they're not yet).

ADDENDUM: My criticism of this statement, "Pars opercularis (Brodmann area [BA] 44) is a likely homologue of a subdivision of area F5 of monkeys" appears to be justified. In a recent review of 24 fMRI studies, Morin and Grèzes (2008) discovered that

Observing biological actions with a physical target, compared to a visual control showing no action at all, consistently activated the ventral premotor cortex (BA 6), and did so significantly more than observing target-less actions (with the same control). In contrast, the activity in BA 44 ("Broca’s area") was not modulated by the presence or absence of targets. We propose that the ventral precentral gyrus, and not BA 44, shares the visual properties of "mirror" neurons found in area F5 of the macaque brain.

Footnotes

¹ Edited to avoid search engine hits to this blog from terms like "s*roking n**ed women, enjoying f***atio and engaging in interco**se."

² The insula -- it's not just for the concept of fairness any more!

References

MOURAS H, STOLERU S, MOULIER V, PELEGRINI-ISSAC M, ROUXEL R, GRANDJEAN B, GLUTRON D, BITTOUN J. (2008). Activation of mirror-neuron system by erotic video clips predicts degree of induced erection: an fMRI study. NeuroImage DOI: 10.1016/j.neuroimage.2008.05.051.

Although visually-induced erection is a common occurrence in human male behaviour, the cerebral underpinnings of this response are not well-known. We hypothesized that the magnitude of induced erection would be linearly correlated with the activation of the mirror-neuron system in response to sexually explicit films. When presented with sexual video clips, eight out of ten healthy subjects had an erectile response demonstrated through volumetric penile plethysmography. The level of activation of the left frontal operculum and of the inferior parietal lobules, areas which contain mirror neurons, predicted the magnitude of the erectile response. These results suggest that the response of the mirror-neuron system may not only code for the motor correlates of observed actions, but also for autonomic correlates of these actions.

Morin O, Grèzes J. (2008). What is "mirror" in the premotor cortex? A review. Neurophysiol Clin. 38:189-195.

Ponseti J, Bosinski HA, Wolff S, Peller M, Jansen O, Mehdorn HM, Buchel C, Siebner HR. (2006). A functional endophenotype for sexual orientation in humans. Neuroimage 33:825-833.

Tomassini V, Jbabdi S, Klein JC, Behrens TE, Pozzilli C, Matthews PM, Rushworth MF, Johansen-Berg H. (2007). Diffusion-weighted imaging tractography-based parcellation of the human lateral premotor cortex identifies dorsal and ventral subregions with anatomical and functional specializations. J Neurosci. 27:10259-69.

Dr. Suzanne Corkin, "Gay Brain" Skeptic

2008-06-16T17:23:00.000-07:00

Just a quick post for now on the brand new PNAS article by Savic and Lindström that spawned the "Gay Men, Straight Women Have Similar Brains" story. Professor Suzanne Corkin of MIT (famous for her studies of the amnesic patient H.M., among other things) was interviewed about this finding, and here are her comments:

While the results were striking, they would be more convincing if the authors had matched the groups for IQ, education and measures of depression and anxiety, said Suzanne Corkin, a professor of behavioral neuroscience at the Massachusetts Institute of Technology, in an e-mailed statement. Also, the authors are "overly dismissive'' of the potential role of environmental influences, Corkin said.

"In short, I would be reluctant to draw strong conclusions about heterosexual versus homosexual brain structure and connectivity from this single experiment,'' Corkin said. She wasn't involved in the study.

That quote came from an article written by Elizabeth Lopatto, which is commendable for interviewing experts and providing background on the subject. Read the whole article (excerpt below).

Gay Brain Structure Similar to Straight Opposite Sex (Update1)
By Elizabeth Lopatto

June 16 (Bloomberg) -- Gay men and straight women share brain characteristics that suggest sexual preferences may be innate rather than learned, researchers said. Lesbians and heterosexual men also had similar brain tendencies.

A study of 90 adults showed similarities between gay men and straight women in a part of the brain linked to emotional response called the amygdala, and a similar finding for lesbians and straight men. The research also found lesbians and heterosexual men had larger right brains, the side associated with spatial ability, while the left and right brains of both gay men and straight women were more symmetrical.

The study, published in the Proceedings of the National Academy of Sciences, adds to research that suggests a biological basis for homosexuality, researchers said. Earlier studies have mostly focused on behavioral differences and similarities.

Reference

Savic I, Lindström P. (2008). PET and MRI show differences in cerebral asymmetry and functional connectivity between homo- and heterosexual subjects. PNAS. June 16, 2008, 10.1073/pnas.0801566105.

The Right and The Good and The Insula

2008-06-16T02:10:00.000-07:00

‘...how narrow [banausisch] a matter it would be if there were cells of morality and immorality, such as virtue cells, murder cells, or cells responsible for rage. Things will surely be more complicated.’
-German psychiatrist Julius Koch (1894: 40–1), as quoted by Verplaetse (2004)

Those who cannot remember the past are condemned to repeat it.
-George Santayana, The Life of Reason, Volume 1, 1905

Children of Uganda

Children of Uganda supports two orphanages in Uganda, as well as children living with HIV-positive widowed mothers, and has over 600 children under its care.

Localization studies of morality (see Dolan, 1999 on the "neurology of morals") date back to the days of Franz Joseph Gall and John M. Harlow, the doctor who treated Phineas Gage¹. Gall's phrenology was largely discredited by the mid-19th century. That didn't stop Moritz Benedikt, however, from postulating that morality was located in the occipital lobes! (Verplaetse, 2004). Among Benedikt's contemporaries,

The localization of morality was discussed with equal reserve. Criminal anthropologists who looked eagerly for neurological and biological mechanisms to explain human immorality and criminal behaviour unanimously denied the existence of an isolated moral centre or moral organ that might be pathologically damaged. The French criminal anthropologists Gabriel Tarde and Alexandre Lacassagne dismissed the idea of a localizable moral sense as impossible or even ridiculous (Lacassagne, 1908: vii; Tarde, 1899: 240). ... Hans Kurella firmly asked that criminal anthropology should entirely abandon old-fashioned concepts such as an innate conscience, whether it was thought of as a localizable brain centre or not (Kurella, 1893: 204).

But really, the occipital lobes? Where did he get that idea? Verplaetse (2004) continues, quoting Benedikt:

When I freed the first brain (the brain of a robbing murderer) from the cranial cavity, his crime became clear to me with an unprecedentedly anatomical transparency. The occipital lobes did not cover the cerebellum and in this discovery I discerned the crucial distinction between man and animal.

OK, then. Onward and upward, to 2008 and the neural encoding of distributive justice.

How Fairness Is Wired in the Brain
...researchers at the California Institute of Technology have discovered that reason struggles with emotion to find equitable solutions, and have pinpointed the region of the brain where this takes place. The concept of fairness, they found, is processed in the insular cortex, or insula, which is also the seat of emotional reactions.
"The fact that the brain has such a robust response to unfairness suggests that sensing unfairness is a basic evolved capacity," notes Steven Quartz, an associate professor of philosophy at Caltech and author of the study, voicing a sentiment that anyone who has seen children fight over a treat can relate to.
"The movement to look into the neural basis for ethical decision making is only about seven years old," Quartz adds. "This is the first study where people made real decisions with real consequences."

So the insula is the seat of emotional reactions!! And investigations of the neural basis for ethical decision making are only 7 years old!

Lobus insularis [Insula] (labels in English and Japanese)

According to Wikipedia, the insula "lies deep to the brain's lateral surface, within the lateral sulcus which separates the temporal lobe and inferior parietal cortex. These overlying cortical areas are known as opercula (meaning "lids"), and parts of the frontal, temporal and parietal lobes form opercula over the insula."

It's a pretty large area. Besides being crowned the "seat of emotional reactions" (whatever that means), portions of the insula have been associated with interoceptive awareness, visceral sensation, pain, autonomic control, and taste, among other things... a lot of other things. Do a search of the BrainMap database using just two of the many insular foci reported by the Caltech researchers and you'll see activations related to action execution, speech, attention, language, explicit memory, working memory, and audition.

Distributive Justice and the Insula

In an earlier post, Neuroscientifically Challenged explained The Neuroscience of Distributive Justice. What is distributive justice, you might ask?

...how goods and benefits should be dispersed throughout a society in a fair and just manner. As an extreme example of this dilemma, imagine you are commissioned to deliver 100 lbs. of food to a famine-stricken region that consists of two villages a hundred miles apart. If you deliver half of the food to the first village, then travel to the second, 30 lbs. of the food will spoil during the trip...

Philosophers have offered several solutions to debates of this nature. Utilitarianism... asserts that one’s primary goal should be the achievement of a maximal amount of good or happiness. In the situation described above, a utilitarian might opt to deliver all of the food to the first village. ..... Another approach to such a quandary is known as deontological ethics, which emphasizes not the consequences of one’s actions, but whether the actions are right or wrong, just or unjust. From a deontological perspective, it would be unjust to distribute the food unequally.

To examine the trade-off between equity and efficiency, Hsu et al. (2008) devised a task in which the participants decided on how to allocate money to children living in an orphanage in northern Uganda.

In each trial, participants decided whether varying allocations of money, denominated in meals, would be taken away from either of two groups of children; the participant’s choice was to decide from whom to take.

You can see an example of an experimental trial in this must-see movie from the paper's Supporting Online Material (embedded below).

Movie s2
No Switch Trial. Illustration of a trial where the subject does ~~not~~ switch the lever. Animation speed is increased for illustration purposes. See Fig. 1 for actual duration of events and screens.

During the Switch, insular activity was correlated with the level of inequity, but so was activity in the right postcentral gyrus and the medial frontal gyrus (Table S12). Before the Switch (during the Display), inequity correlated with insular activity and with activity in R Brodmann area 10, L inferior temporal gyrus, R medial frontal gyrus, L posterior cingulate, L BA 39, R superior temporal gyrus, R precuneus (Table S11)... I needn't go on.

The authors conclude:

Against utilitarianism, our results support the deontological intuition that a sense of fairness is fundamental to distributive justice but, as suggested by moral sentimentalists, is rooted in emotional processing. More generally, emotional responses related to norm violations may underlie individual differences in equity considerations and adherence to ethical rules.

I don't doubt that, really I don't.

Conservatives are Happier than Liberals Because...

...rationalization of inequality statistically mediates the relationship between conservatism and happiness. In other words, it suggests that at least part of the reason conservatives are happier than liberals is that they're more likely to rationalize inequality.

But did we need fMRI to tell us that? Is it really all in the insula? Couldn't we have more or less learned the same thing by obtaining peripheral autonomic measures, like heart rate, blood pressure, and skin conductance?

Footnote

¹ At least, if not earlier. Any historians of neuroscience out there?

References

Hsu M, Anen C, Quartz SR. (2008). The Right and the Good: Distributive Justice and Neural Encoding of Equity and Efficiency. Science, 320(5879), 1092-1095. DOI: 10.1126/science.1153651

Koch J. (1894) Die Frage nach dem geborenen Verbrecher (Ravensburg: Otto Maier).

Verplaetse J. (2004). Moritz Benedikt's (1835-1920) Localization of Morality in the Occipital Lobes: Origin and Background of a Controversial Hypothesis. History of Psychiatry, 15(3), 305-328. DOI: 10.1177/0957154X04039354