October 8, 2009

More On Amygdala, Anxiety, and MRIs

After the last post, I thought, "perhaps I was too broad.  Maybe too political, maybe I didn't have enough concrete examples."

Then I opened my mail.

What I found was the most recent issue of Primary Psychiatry, in which appears Imaging and Genetics: Future Applications in the Emergency Room

It reviews the literature on the neurobiology of aggression in precisely the way I was railing against in the earlier post: sufficiently vague that it makes people think this is alerady established, common knowledge.

The amygdala, located in the temporal lobe, has been shown to be associated with aggression and violence. Studies(29) have found a high rate of atrophy, as much as 20%, of the amygdala in aggressive and violent patients.
Note: studies (plural) but one reference.  Note: you can't tell if 20% is a high rate of atrophy, or if it means "high rate of people who have 20% atrophy."  And you're not supposed to know, because the point is simply to make you feel secure that his overall thesis is well supported.

But, according to reference 29, in a study of aggressive patients, only 20% of them had any amygdala atrophy (e.g. the other 80% didn't.)  The amount of atrophy was fairly small. 

Furthermore, that reference was a study of aggressive vs. non-aggressive epileptics.  In addition to differences in aggression, the subjects also differed in IQ (lower IQ in aggressive group) and a history of encephalitis (associated with smaller amygdalas.)  The study could well have been resubmitted: "A Couple Of People With Low IQs And A History Of Encephalitis Have Kind Of Smaller Amygdalas.  We Think."

Here is the next sentence:

Imaging studies9,10 have also shown abnormalities in amygdala functioning, including decreased activation of the amygdala during affective stimuli in psychopaths
I'm sure whatever imaging studies they were doing 12 years ago were crackerjack, and based on two of these (which are the same data), the reviewer concludes psychopaths have decreased activation in the amygdala. 

Which isn't what the studies found anyway.

First, the study didn't measure just psychopaths (e.g. antisocial PD), but psychopathic murderers who were incarcerated and legally insane.  Note how the author extends these findings to psychopaths in general.

Second, it didn't find decreased activation in the amygdala, it found the opposite: higher activation on the right, and no difference on the left.  Do you know the relevance of it being right vs. left?  Of course not.
 
So the studies say: "psychopathic murderers have increased activation on the right."  The reviewer summarizes: "psychopaths in general have decreased activation overall."

You would think that difference matters, but it doesn't, because the point of the review article isn't to teach you information, e.g. what happens to the amygdala, it is to convince you that aggression is biologically mediated. These articles succeed because it is established that no one will check whether it is actually increased or decreased (note that three reviewers did not check), because no one cares whether it is increased or decreased, because we all know those are just silly details.

I may as well point out that the studies referenced here didn't even measure the amygdala, they measured the subcortex (amygdala, hippocampus, midbrain, thalamus, together).  Take that, precision instruments.

II.

In fairness to the psychiatry review author, the authors of the above references jumped to an even worse set of conclusions based on their own data

Raine et al. speculate that excessive subcortical activity contributes to an aggressive temperament in both types of murderers, but that "while predatory violent offenders have sufficient left prefrontal functioning to modulate such aggressive behavior in a way to bully and manipulate others to achieve desired goals, affectively violent offenders lack this prefrontal modulatory control over their impulses, resulting in more unbridled, dysregulated, aggressive outbursts." (bold mine, emphasis theirs)

and then published this in a forensic journal.  Do you see? 

The entire article is filler. All he wants to say is this single sentence:

In effect, research is supporting the notion that repetitive acts of aggression are grounded in a neurobiologic susceptibility.
This is simply not true.  There may be aliens in the universe, but it is false to say, today, "in effect, evidence is supporting the notion that aliens can and do live in the universe."  All we know is that there are studies that show a relationship between specific behaviors and specific anatomical areas.  However, we do not know the nature of that relationship.

We cannot accurately quantify the behaviors and distinguish them from similar behaviors (is it aggression out of fear, anger, horniness, temporary insanity, or a combo?), and we can't adequately control for billions of confounders (3 red wines/d vs. 3 beers/d, bad parents, too many horror movies, frequency of one night stands, etc).  How then can we relate them to inadequately  characterized anatomical regions using machinery with the precision of an icepick, and then conclude "predatory violent offenders have sufficient left prefrontal functioning to modulate such aggressive behavior in a way to bully and manipulate others?"

We tend to focus only on one error, e.g. MRI false positive rate.  But these studies don't take into account all of the other errors.  It is the problem of significant digits: 3.225 x 5.23441 x 7 does not equal 118.16680575.  It equals 100.

III.

You all think I'm exaggerating.  That I am punching windmills.

In keeping with this development, sometime in the future cord bloods will be taken routinely from birth and used to delineate the individual's DNA so that genetic information will be readily available under emergency conditions to assure proper assessment of violent people. Hence, a patient presenting with an episode of violence and a history to support that will have their DNA contrasted with norms to determine if they have a predisposition to aggression and violence...
I have enough rum to get through the rest of my life, but the rest of you would do well to heed my warning: if you do not rein in your social scientists, your civilization is doomed.






Comments

Wow, did he really write th... (Below threshold)

October 8, 2009 2:46 PM | Posted by Singleton: | Reply

Wow, did he really write that? I can't find that in the article.

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Yes, at the end of the firs... (Below threshold)

October 8, 2009 4:03 PM | Posted by Matt: | Reply

Yes, at the end of the first concluding paragraph.

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"A Couple Of People With... (Below threshold)

October 8, 2009 5:22 PM | Posted by Jack Coupal: | Reply

"A Couple Of People With Low IQs And A History Of Encephalitis Have Kind Of Smaller Amygdalas. We Think."

I have read several scientific articles recently on different topics that should have been reworded using weasel words like those.

Priceless! Thank you, Alone.

You have tackled sloppy and fraudulent scientific writing, and that will bring you well-paid and vocal enemies.

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Alone, you held back too mu... (Below threshold)

October 8, 2009 5:28 PM | Posted by Anonymous: | Reply

Alone, you held back too much in your post. This is the opening sentence of the article:

Prior to chromosomal studies and brain imaging, psychiatrists could only rely reasonably on the... Axis I diagnoses for establishing whether violent patients had a disease or whether they should be seen informally (at least since the ER is not a court of law) as responsible for the violent acts they committed—acts which caused injury or death

I am not a psychiatrist and I can't vouch for the accuracy of the studies, but the article is very much about questioning "responsibility" for violence. So if you're right that the evidence isn't that solid, then save some of that rum for me.

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This stuff sounds a lot lik... (Below threshold)

October 8, 2009 8:24 PM | Posted by BRat: | Reply

This stuff sounds a lot like phrenology, however my skull has large lumps over the ears, so I'm more interested in capitalizing on this phenomenon than I am in correcting it.

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I have to tell you TLP, you... (Below threshold)

October 9, 2009 10:44 AM | Posted by Daniel: | Reply

I have to tell you TLP, your blog has helped me like no other in explaining to the people around me the dangers of taking what you read and hear in the media (as well as elsewhere) at face value. You are doing a great service to the world here.

Dan
Casual Kitchen

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It's kind of silly that the... (Below threshold)

October 9, 2009 10:44 AM | Posted by Joseph Bergevin: | Reply

It's kind of silly that the law currently does differentiate punishment and guilt based on internal mental states. Who cares what story they were telling themself as they acted? It's the act that matters. A delusional person attacking someone results in the same suffering as a rational attacker. When a dog bites someone, it doesn't matter that it was a fluke or it was confused and saw a kid as a giant talking hamburger. It bit someone, and constitutes a future threat. It's taken out of the system.

I think that ultimately, under the varying layers of inner dialogue, rationalization, and attribution, we're all rather constrained by our brains. We all do things we didn't want to do, but usually this is confined to eating too much or procrastinating or snapping at a spouse. To try delineating intention and volition is hubris.

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Oh my. This is worse junk ... (Below threshold)

October 9, 2009 12:16 PM | Posted by Nadia: | Reply

Oh my. This is worse junk science than the two fat guys at Sam's Club tried to pass off about their $80 tea that "traps 40% of your carbs."

And not nearly as funny.

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See Gattaca for examples of... (Below threshold)

October 9, 2009 2:04 PM | Posted by Dylan: | Reply

See Gattaca for examples of this possible future.

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I've been reading for a lon... (Below threshold)

October 9, 2009 2:49 PM | Posted by Tim: | Reply

I've been reading for a long time, Alone, and this may be your best post yet.

Thanks for paying attention.

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sigh. i do these types of a... (Below threshold)

October 9, 2009 3:09 PM | Posted by medsvstherapy: | Reply

sigh. i do these types of analyses in lectures. i almost always pick some article that has recently been published in a prominent journal, AND has generated a news headline - thus relevant. i think i may start asking student to give me the article, and give me 10 minutes to look it over during our bathroom break, just so they can be more convinced that this level of "quality" is rampant.

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Where do you come from?... (Below threshold)

October 9, 2009 7:08 PM | Posted by A Visitor: | Reply

Where do you come from?

The "3.225 x 5.23441 x 7 does not equal 118.16680575. It equals 100," is absolutely priceless. I'm an engineer and when a group from our company is preparing field measurements and calculated results for customers I constantly have to harp that we can't lie to them! It's fraud and it's illegal.

Does anyone else here remember learning how to do empirical calculations properly in high school? I can't be the only one. And Ontario public education isn't that great by any means.

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..if you do not rein in ... (Below threshold)

October 10, 2009 9:07 AM | Posted by Jack Coupal: | Reply

..if you do not rein in your social scientists, your civilization is doomed.

Political scientists beat even the social scientists hands down in being agenda-driven, subjective, and deceptive in their published work. And, the polysci's do try very hard to put one over on us.

Math and physics still are the most credible sciences. Their work can usually be tested and repeated by others.

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Isn't the amygdala all the ... (Below threshold)

October 10, 2009 3:26 PM | Posted by Steve : | Reply

Isn't the amygdala all the new rage?

But it isn't, really. Linking psychopathy to the amygdala is hip. But linking the amygdala to schizophrenia is old hat. Somehow, though, the similar anatomical abnormalities in the amygdala seen in both of these disorders is only being used to suggest that psychopaths are not responsible for their conduct.

I have a theory as to why and it has nothing to do with biology.

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@medsvstherapy: Noam Choms... (Below threshold)

October 11, 2009 1:04 PM | Posted by Meat Robot: | Reply

@medsvstherapy: Noam Chomsky in public lectures intentionally uses examples from newspapers the day of or the day before the lecture he's giving, so no one thinks he's selectively choosing examples to fit his hypothesis from "Manufacturing Consent." I'd say go ahead and give the bathroom break exercise a try.

This post, and the whole Dead Fish rage, are just fantastic. Don't be too surprised to discover that many fMRI studies are heavily sponsored by fMRI manufacturers.

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damn you tlp. damn you.... (Below threshold)

May 21, 2010 11:58 PM | Posted by The (P)Irate Piper: | Reply

damn you tlp. damn you.


...that steak tasted so real until i remembered it didn't exit

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I gave up on getting my ast... (Below threshold)

February 8, 2011 4:35 PM | Posted by Anonymous: | Reply

I gave up on getting my astrophysics degree for these sorts of reasons. That, and institutions that exist mainly to conduct research (and thus write articles of this nature in the interests of getting funding for definite results rather than showing how they spent the funding to get a "who knows?") absolutely love to take my money and use it to weed me out by making things needlessly complex the point where I feel all I learn is how to be more like, well, the people who write these articles.

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So you're saying the Waterb... (Below threshold)

March 14, 2012 12:17 PM | Posted by Gabe Ruth: | Reply

So you're saying the Waterboy's momma has more credibility than Professor Sanders?

The dramatic conclusions social science types draw from fMRI data have long puzzled me (not that that means much, as I am not from that world), but I've never read anyone from that field (speaking generally) that heaps as much derision on their lack of epistemic realism and humility.

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People who use expressions ... (Below threshold)

March 14, 2012 10:31 PM | Posted, in reply to Gabe Ruth's comment, by Anonymous: | Reply

People who use expressions like "waterboy?" Are they just such freaking failures that such labels make them feel gleefully superior to at least someone?-Or is it just Gabe Ruth respectively?

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Damn nonny, how old are you... (Below threshold)

March 14, 2012 11:21 PM | Posted by Gabe Ruth: | Reply

Damn nonny, how old are you? It's a reference to a stupid movie I'm embarrassed to admit I've seen. Spot on regarding the failure though, how did you know?

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I do wish there were more p... (Below threshold)

January 4, 2014 2:49 AM | Posted by dian puspita: | Reply

I do wish there were more people like you around on the interwebs. Not many people are careful with their words, including myself sometimes. I have written things I would love to take back, goo work, keep it up

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