No Longer an Island, the Insula Is Now a Hub of High Fashion

Islands of the World Fashion Week, designer Hupfeld Hoerder from Fiji.


Last month Neuroskeptic brought us This Season's Hottest Brain Regions. The insula was not among them.¹ And as we all know from watching Heidi Klum on Project Runway, "one week you're in, the next you're out." The journal Brain Structure and Function will soon have a Special Issue of 22 articles on insular cortex, introduced by Mr. Insula himself (A. D. "Bud" Craig, Ph.D.):

Once an island, now the focus of attention

The insula (originally called the “island of Reil”) is emerging from its hiding place inside of the human brain. It is easy to find articles and textbooks which show the lateral aspect of the brain but barely mention the insula, if at all (http://www.ninds.nih.gov/disorders/brain_basics/know_your_brain.htm) or treat it as a deep brain structure, like the amygdala (http://www.scientificamerican.com/article.cfm?id=faulty-circuits). In fact, in Brodmann’s famous map of cortical cytoarchitectonic areas, it was not even worthy of a number! [See Kurth et al. 2009, PMID: 19822572; Brodmann (1909) described only a posterior granular and an anterior agranular region in the human insular cortex.] Older neuroscientists remember the insula as a portion of the visceral brain, based on prominent writings by Penfield, Mesulam, Saper, and others (Penfield and Faulk 1955; Mesulam and Mufson 1982; Saper 2002); some investigators simply call it a multi-modal region and cite the brief reviews by Augustine (1985, 1996); but for many new investigators who find it unexpectedly activated in their functional imaging study, it is simply an enigma.

The trendiness of insular cortex, a region implicated in interoceptive awareness of bodily states (Craig, 2009),² has been rising for several years now. The 2008 meeting of the Cognitive Neuroscience Society featured a symposium on A Common Role of Anterior Insula in Feelings, Empathy, and Risk?

Craig's (2010) introductory article continues:

In order to provide an overview of this vast literature for a 2009 opinion article (Craig 2009), I compiled reports from disparate and unfamiliar branches of neuroscience. To my mind, this burgeoning literature compelled the hypothesis that the anterior insula engenders human awareness, yet only one article had directly addressed this possibility (Klein et al. 2007), and an astonishing number of authors had reported strong activation of the insula without comment. The immediate need for an anthology became obvious, in which leading primary investigators from these disparate fields could re-appraise the role of the insula in light of the new perspective provided by this extraordinary convergence of evidence.

It's an impressive collection of articles, covering a wide range of topics including clinical aspects, neuroanatomical organization, affective bodily feelings, subjective emotional feelings, perception, cognition, performance, and attention. Craig ends on a note of optimism and awe, encouraging contributions from junior investigators:

The overall goal of this set of articles is to provide a solid starting point for new investigators by identifying the issues and the opportunities for advances in our knowledge of this unique portion of the human brain. The authors were encouraged by the peer reviewers and the editors to be thorough and prospective, and to express their individual viewpoint as lucidly as possible. We hope that young neuroscientists will find fertile ground here. Indeed, we are all excited by the prospects for awe-inspiring discoveries in the convergence of these disparate fields of neuroscience.

Footnotes

¹ Which surprised me at the time:

For sheer volume you have to include the insula. From 1985-2009 there was a total of 197,256 articles (compare to 82,438 for the hippocampus). The number of PubMed hits for insula in 1985 was 3,906; in 2008 it was 13,375.

² Among many other behavioral domains...

Reference

Craig AD. (2009). How do you feel--now? The anterior insula and human awareness. Nat Rev Neurosci. 10:59-70.


Contents

Once an island, now the focus of attention
A. D. Craig
DOI: 10.1007/s00429-010-0270-0

The von Economo neurons in frontoinsular and anterior cingulate cortex in great apes and humans
John M. Allman, Nicole A. Tetreault, Atiya Y. Hakeem, Kebreten F. Manaye, Katerina Semendeferi, Joseph M. Erwin, Soyoung Park, Virginie Goubert and Patrick R. Hof
DOI: 10.1007/s00429-010-0254-0

Anterior insula degeneration in frontotemporal dementia
William W. Seeley
DOI: 10.1007/s00429-010-0263-z

Taste representation in the human insula
Dana M. Small
DOI: 10.1007/s00429-010-0266-9

Saliency, switching, attention and control: a network model of insula function
Vinod Menon and Lucina Q. Uddin
DOI: 10.1007/s00429-010-0262-0

The hidden side of intentional action: the role of the anterior insular cortex
Marcel Brass and Patrick Haggard
DOI: 10.1007/s00429-010-0269-6

Insula and drug cravings
Hugh Garavan
DOI: 10.1007/s00429-010-0259-8

Risk and risk prediction error signals in anterior insula
Peter Bossaerts
DOI: 10.1007/s00429-010-0253-1

The role of the human anterior insular cortex in time processing
P. Kosillo and A. T. Smith
DOI: 10.1007/s00429-010-0267-8

Anterior insula activations in perceptual paradigms: often observed but barely understood
Philipp Sterzer and Andreas Kleinschmidt
DOI: 10.1007/s00429-010-0252-2

The insula and drug addiction: an interoceptive view of pleasure, urges, and decision-making
Nasir H. Naqvi and Antoine Bechara
DOI: 10.1007/s00429-010-0268-7

The contribution(s) of the insula to speech production: a review of the clinical and functional imaging literature
Hermann Ackermann and Axel Riecker
DOI: 10.1007/s00429-010-0257-x

Right insula for our sense of limb ownership and self-awareness of actions
Hans-Otto Karnath and Bernhard Baier
DOI: 10.1007/s00429-010-0250-4

The insular cortex: a comparative perspective
Camilla Butti and Patrick R. Hof
DOI: 10.1007/s00429-010-0264-y

Conscious perception of errors and its relation to the anterior insula
Markus Ullsperger, Helga A. Harsay, Jan R. Wessel and K. Richard Ridderinkhof
DOI: 10.1007/s00429-010-0261-1

Clinical effects of insular damage in humans
Agustin Ibañez, Ezequiel Gleichgerrcht and Facundo Manes
DOI: 10.1007/s00429-010-0256-y

A link between the systems: functional differentiation and integration within the human insula revealed by meta-analysis
Florian Kurth, Karl Zilles, Peter T. Fox, Angela R. Laird and Simon B. Eickhoff
DOI: 10.1007/s00429-010-0255-z

The sentient self
A. D. (Bud) Craig
DOI: 10.1007/s00429-010-0248-y

Conjoint activity of anterior insular and anterior cingulate cortex: awareness and response
Nick Medford and Hugo D. Critchley
DOI: 10.1007/s00429-010-0265-x

Role of the anterior insula in task-level control and focal attention
Steven M. Nelson, Nico U. F. Dosenbach, Alexander L. Cohen, Mark E. Wheeler, Bradley L. Schlaggar and Steven E. Petersen
DOI: 10.1007/s00429-010-0260-2

Interoception in anxiety and depression
Martin P. Paulus and Murray B. Stein
DOI: 10.1007/s00429-010-0258-9

The role of anterior insular cortex in social emotions
Claus Lamm and Tania Singer
DOI: 10.1007/s00429-010-0251-3

Nu Woman magazine; Island fashion.

New York Times on Addiction and The Insula

In Clue to Addiction, Brain Injury Halts Smoking

By BENEDICT CAREY
Published: January 26, 2007

Scientists studying stroke patients are reporting today that an injury to a specific part of the brain, near the ear, can instantly and permanently break a smoking habit. People with the injury who stopped smoking found that their bodies, as one man put it, “forgot the urge to smoke.”

The finding, which appears in the journal Science, is based on a small study [Naqvi et al., 2007]. But experts say it is likely to alter the course of addiction research, pointing researchers toward new ideas for treatment.

While no one is suggesting brain injury as a solution for addiction, the finding suggests that therapies might focus on the insula, a prune-size region under the frontal lobes that is thought to register gut feelings and is apparently a critical part of the network that sustains addictive behavior.

Hey, wait a minute!

Didn't the NYT just publish an authoritative piece to the contrary? In You Love Your iPhone. Literally., Martin Lindstrom claimed the insula was a signifier of love and compassion, not addiction:

WITH Apple widely expected to release its iPhone 5 on Tuesday, Apple addicts across the world are getting ready for their latest fix.

But should we really characterize the intense consumer devotion to the iPhone as an addiction? A recent experiment that I carried out using neuroimaging technology suggests that drug-related terms like “addiction” and “fix” aren’t as scientifically accurate as a word we use to describe our most cherished personal relationships. That word is “love.”

. . .

But most striking of all was the flurry of activation in the insular cortex of the brain, which is associated with feelings of love and compassion. The subjects’ brains responded to the sound of their phones as they would respond to the presence or proximity of a girlfriend, boyfriend or family member.

OK, OK, we all know by now that royal proclamations of brain function based on logical fallacies and unpublished (and never-to-be-peer-reviewed) commercial studies are not to be believed. NYT did publish a retort to this silliness, a Letter to the Editor (The iPhone and the Brain) in which "Forty-five neuroscientists respond to a recent Op-Ed about using brain imaging to analyze our attachment to digital devices." We also know that the insula is activated in a substantial percentage of all neuroimaging studies (Yarkoni et al. 2011; PDF). Reflecting this ubiquity, The Neurocritic blog archive contains 73 unique posts with the word "insula."

But what of addiction and the insula? In their 2007 Science paper, Naqvi and colleagues performed a retrospective study of 69 stroke patients (all smokers): 19 with lesions in the insula and 50 with lesions elsewhere. The color coding in the figure below depicts the number of individuals with damage in specific brain regions.

Fig. 1 (Naqvi et al., 2007). Number (N) of patients with lesion in each of the regions identified in this study, mapped onto a reference brain. Boundaries of anatomically defined regions are drawn on the brain surface. Regions not assigned a color contained no lesions. (Top) All patients. The horizontal line marks the transverse section of the brain shown in the top row. The vertical line marks the coronal section shown in the bottom row. (Middle) Patients with lesions that involved the insula. (Bottom) Patients with lesions that did not involve the insula.

The likelihood of post-stroke smoking cessation did not differ between the insula and non-insula groups, but those with insula lesions who did quit smoking reported that it was easy to do so. The authors concluded that...

...smokers with brain damage involving the insula, a region implicated in conscious urges, were more likely than smokers with brain damage not involving the insula to undergo a disruption of smoking addiction, characterized by the ability to quit smoking easily, immediately, without relapse, and without persistence of the urge to smoke.

The problem with this assertion is that it relies on memory for events that occurred an average of 8 yrs earlier, which could be subject to recall bias (Vorel et al., 2007). A better design would be a prospective study that follows patients from the time of stroke and then assesses subsequent smoking behavior. In fact, Bienkowski et al. (2010) performed such a study and failed to see a difference between their insula and non-insula groups at a 3 month follow-up. This suggests that the insula does not play a special role in addiction.

What does this mean for iPhone love? Is Lindstrom right? Unlikely! He would have to demonstrate that insular strokes cause an inability to feel love for iPhones (or anything else, for that matter). Such a finding would suggest that an intact insula is necessary for the experience of love and compassion, and that the activity in his fMRI experiment was not a mere epiphenomenon.

In the real world of peer-reviewed neuroimaging research, however, that sort of converging evidence is rarely obtained.


Further Reading

NYT Editorial + fMRI = complete crap

the New York Times blows it big time on brain imaging

Neuromarketing means never having to say you're peer reviewed (but here's your NYT op-ed space)

fMRI Shows My Bullshit Detector Going Ape Shit Over iPhone Lust

...and pollyannaish comment by Martin Lindstrom

NYT Letter to the Editor: The uncut version

Articles on insular cortex from The Amazing World of Psychiatry: A Psychiatry Blog

The Insula Is The New Black...

No Longer an Island, the Insula Is Now a Hub of High Fashion


References

Bienkowski P, Zatorski P, Baranowska A, Ryglewicz D, Sienkiewicz-Jarosz H. (2010). Insular lesions and smoking cessation after first-ever ischemic stroke: a 3-month follow-up. Neurosci Lett. 478:161-4.

Naqvi, N., Rudrauf, D., Damasio, H., & Bechara, A. (2007). Damage to the Insula Disrupts Addiction to Cigarette Smoking. Science, 315 (5811), 531-534 DOI: 10.1126/science.1135926

Vorel SR, Bisaga A, McKhann G, Kleber HD.(2007). Insula damage and quitting smoking. Science 317:318-9; author reply 318-9.

Yarkoni T, Poldrack RA, Nichols TE, Van Essen DC, Wager TD. (2011). Large-scale automated synthesis of human functional neuroimaging data. Nat Methods 8:665-70.

I Can't Feel Anything...

...and I can't describe it, either.


from Jackson, Meltzoff, & Decety (2005)

The Neurocritic has just noticed a new neuroimaging paper on empathy in individuals with alexithimia, which is an inability to describe one's own feelings. Coincidentally, Dr. Richard G. Petty has just posted on the topic, and I will quote from his description and send you over there for more information on the clinical syndrome.

The Harvard psychiatrist Peter Sifneos originally coined the term in 1972 to describe people who had extreme difficulty in emotional cognition. The word “alexithymia” literally means “no words for mood.” People with this problem lacked the ability to understanding, processing or describing their feelings verbally. As a result, most people who have the problem are largely unaware of their own feelings or what they signify. As a result they only rarely talk about their emotions or their emotional preferences, and they are largely unable to use their feelings or imagination to focus and fuel their drives and motivations.

People with alexithymia seem unable to fantasize and many report multiple somatic symptoms. However, alexithymia is also associated with a number of other complaints, such as hypertension, irritable bowel syndrome, substance use disorders, and some anxiety disorders. Their speech is often concrete, mundane and closely tied to external events. So they will describe physical symptoms rather than emotions, and don’t understand that their bodily sensations are signals of emotional distress.

Alexithymia lies on spectrum... For some people it is little more than an inability to get in touch with their emotions. But at the other end of the spectrum are a number of illnesses in which alexithymia may occur, including schizoid personality disorder, posttraumatic stress disorder, anorexia nervosa or Asperger's syndrome. It is also much more common in victims of trauma.

In the fMRI paper of Moriguchi and colleagues, the warm and fuzzy and trendy topic of empathy for other people's pain was under study, this time in individuals with alexithimia. The question here was whether a lack of knowledge of one's own emotional experiences would be associated with a lack of empathy for another's pain. Hence the ouch!-inducing photos in the figure above, which were contrasted with similar but non-owie pictures.

Moriguchi Y, Decety J, Ohnishi T, Maeda M, Mori T, Nemoto K, Matsuda H, Komaki G. (2006). Empathy and Judging Other's Pain: An fMRI Study of Alexithymia. Cereb Cortex. Dec 5 [Epub ahead of print].

Because awareness of emotional states in the self is a prerequisite to recognizing such states in others, alexithymia (ALEX), difficulty in identifying and expressing one's own emotional states, should involve impairment in empathy. Using functional magnetic resonance imaging (fMRI), we compared an ALEX group (n = 16) and a non-alexithymia (non-ALEX) group (n = 14) for their regional hemodynamic responses to the visual perception of pictures depicting human hands and feet in painful situations. Subjective pain ratings of the pictures and empathy-related psychological scores were also compared between the 2 groups. The ALEX group showed less cerebral activation in the left dorsolateral prefrontal cortex (DLPFC), the dorsal pons, the cerebellum, and the left caudal anterior cingulate cortex (ACC) within the pain matrix. The ALEX group showed greater activation in the right insula and inferior frontal gyrus. Furthermore, alexithymic participants scored lower on the pain ratings and on the scores related to mature empathy. In conclusion, the hypofunction in the DLPFC, brain stem, cerebellum, and ACC and the lower pain-rating and empathy-related scores in ALEX are related to cognitive impairments, particularly executive and regulatory aspects, of emotional processing and support the importance of self-awareness in empathy.

So what does all that mean? What is the significance of brain activation differences between the alexithymic and the control participants?

First, let's look at the empathy scores and pain ratings of the two groups. Before the experiment, Japanese versions of the emotional empathy scale (EES), the interpersonal reactivity index (IRI), and the stress coping inventory (SCI) were administered to all participants. During the experiment, each picture was shown for 2 s, followed by a 4-point pain-rating scale (no pain, a little pain, moderate pain, and worst possible pain). To no one's surprise,

Alexithymic participants showed lower pain ratings than non-alexithymics, indicating that they attributed lower levels of pain to the people depicted in the painful situation pictures. They scored lower on the IRI scales assessing "perspective taking" and "empathic concern," suggesting that they were less able to take the perspective of another and had less empathy. On the EES, alexithymics scored less on "warmth." Alexithymics scored lower on the SCI scales of "cognitive," "problem solving," and "positive reappraisal," indicating that they were less likely to use these approaches to manage emotional stimuli. On the other hand, alexithymics had significantly higher "personal distress" scores on the IRI.

What about the fMRI results?


from Moriguchi et al. (2006)

The top panel shows regions that were less active in alexithimics than controls, and include the left dorsolateral prefrontal cortex, the caudal anterior cingulate cortex, the dorsal pons (in the brainstem), and the cerebellum. The bottom panel shows regions that were more active in alexithimics, and include the anterior insula, the posterior insula, and the inferior frontal gyrus (all in the right hemisphere). Huh. The insula. More active for people lacking empathy. The insula has been shown previously to be associated with empathy for pain (e.g., Saarela et al., 2006; Singer et al., 2006). Hmm...what do the authors have to say about this?

Anterior insula:

Hemodynamic increases in the prelimbic area and decreases in the prefrontal cortex were reported in response to sadness, although these 2 areas demonstrated the inverse correlation as a person recovered from a depressive state (Mayberg et al. 1999). If an individual engages less cognitive processing for the painful pictures, the suppression of activation in the anterior insula would be decreased. The ALEX group, which has more impairment in cognitive aspects, may have had more activation in the anterior insula compared with the non-alexithymics as a result of decreased suppression.

Got that? Posterior insula:

...the dorsal posterior insula involves the primary (not metarepresentational) interoceptive representation of the inputs of physiological condition from all tissues of the body, including pain, temperature, itch, sensual touch, muscular and visceral sensations, vasomotor activity, hunger, thirst, and "air hunger." Thus, the posterior insula is related to lower level representation of the physical state. Considering that neural activity in this region positively correlated with the personal distress scale and negatively with cognition-related stress coping scales, the result of stronger activity in the posterior insula in the ALEX group indicates that individuals with ALEX might be stuck in lower level representation of one's own physical state.

The alexithimics attributed lower levels of pain to the people depicted in the owie pictures, yet they have more activity in an area that represents physical states. Fine, there is a disconnect between bodily sensations and emotion, but then they go on to say,

The posterior insula is associated with personal distress (self-oriented response), whereas the anterior insula is associated with empathy (other oriented emotional responses).

But, but... isn't empathy just what they're lacking? Have we learned anything useful from this study? I suppose the alexithimic individuals did show less activation than controls in other "empathy for pain" areas (namely the anterior cingulate). And there's more to read on impairments in self-awareness and theory of mind in these same individuals (Moriguchi, Ohnishi, et al., 2006).

References

Jackson PL, Meltzoff AN, Decety J. (2005). How do we perceive the pain of others? A window into the neural processes involved in empathy. Neuroimage 24: 771–779.

Moriguchi Y, Ohnishi T, Lane RD, Maeda M, Mori T, Nemoto K, Matsuda H, Komaki G. (2006). Impaired self-awareness and theory of mind: an fMRI study of mentalizing in alexithymia. Neuroimage 32: 1472-82.

Saarela MV, Hlushchuk Y, Williams AC, Schurmann M, Kalso E, Hari R. (2006). The Compassionate Brain: Humans Detect Intensity of Pain from Another's Face. Cereb Cortex 2006 Feb 22; [Epub ahead of print].

Singer T, Seymour B, O'doherty JP, Stephan KE, Dolan RJ, Frith CD. (2006). Empathic neural responses are modulated by the perceived fairness of others. Nature 439:466-9.

"Love at first sight is a myth," say Chicago researchers

Social Neuroscience power couple, John T. Cacciopo and Stephanie Cacciopo

This, my friends, is a belated Valentine's Day tale that went oh so wrong...


On Feb 14, Scientific American ran a piece about When Scientists Are Mad about Each Other. The cutesy narrative on the Cacciopos described a wonderful story of love at first sight:

He was studying loneliness and isolation. She was studying love and desire. When they found themselves together, they gravitated toward her end of the continuum of social connection.

John Cacioppo was living in Chicago and Stephanie Ortigue in Geneva when they met—in Shanghai. ... On the last night of the conference, they happened to be seated next to one another at an official dinner, and soon became absorbed in conversation. “She was wonderful and brilliant and funny and I was completely taken by her,” Cacioppo says.

They both felt the chemistry but had to return to their respective homes the next day. Before parting ways they walked out of the restaurant together and noticed a beautiful moon hanging over the city. He snapped a picture of it. “A couple weeks later, she e-mailed me and asked if I could send her the picture,” Cacioppo says—a request his wife now confesses was just an excuse to strike up another conversation.

Within weeks they arranged to meet again, and from there their love unfurled. ... Within eight months they were engaged, and a season later they had married.

Their romantic story and collaborative work has been covered by a number of professional and popular media outlets, including the press office at the University of Chicago. The newsroom issued a press release on February 13, 2014 to coincide with Valentine's Day:

Researchers find brain’s ‘sweet spot’ for love in neurological patient

A region deep inside the brain controls how quickly people make decisions about love, according to new research at the University of Chicago.

The finding, made in an examination of a 48-year-old man who suffered a stroke, provides the first causal clinical evidence that an area of the brain called the anterior insula “plays an instrumental role in love,” said UChicago neuroscientist Stephanie Cacioppo, lead author of the study.

The study (Cacioppo et al., 2013) showed no such thing (in my opinion), and I'll return that in a moment. But for now I'll point out the Cacioppo spin didn't translate so well to other reports about this neurological patient. According to the Fox News affiliate in Little Rock, AK:

Love at first sight does not exist, claim researchers in the Current Trends in Neurology journal.

A stroke patient had a damaged anterior insula -- which is the part of the brain which controls how quickly we fall for someone.

They found that he could make decisions about lust normally but needed longer to think about love.

The researchers say this finding "makes it possible to disentangle love from other biological drives".

The Chicago researchers never said that love at first sight is a myth. But that didn't stop the British tabloid Metro from running that headline, while the Times of India declared:

'Love at first sight' doesn’t exist!
Feb 18, 2014, 04.52 PM

A new study suggests that love at first sight is a myth and it does not exist.

According to the study, the speed at which we fall for someone is controlled by a region in the brain called the anterior insula, Metro.co.uk reported.

All this curt tabloid fodder contradicts the meet-cute trope of the Cacciopo's own relationship. But their study itself is also quite problematic. It doesn't support the authors' contention, in my view, and here's why.


The Martin Lindstrom School of Anterior Insula Studies

Remember this classic op-ed piece in the New York Times?

You Love Your iPhone. Literally.

By MARTIN LINDSTROM
Published: September 30, 2011

WITH Apple widely expected to release its iPhone 5 on Tuesday, Apple addicts across the world are getting ready for their latest fix.

But should we really characterize the intense consumer devotion to the iPhone as an addiction? A recent experiment that I carried out using neuroimaging technology suggests that drug-related terms like “addiction” and “fix” aren’t as scientifically accurate as a word we use to describe our most cherished personal relationships. That word is “love.”
. . .

...most striking of all was the flurry of activation in the insular cortex of the brain, which is associated with feelings of love and compassion. The subjects’ brains responded to the sound of their phones as they would respond to the presence or proximity of a girlfriend, boyfriend or family member.

Here Lindstrom committed the logical fallacy of reverse inference – one cannot directly infer the participants' cognitive or emotional state from the observed pattern of brain activity in neuroimaging experiments. ¹ Fortunately, Russ Poldrack and Tal Yarkoni (and I) wrote posts about the debacle: NYT Editorial + fMRI = complete crap and the New York Times blows it big time on brain imaging and Neuromarketing means never having to say you're peer reviewed. We all corrected the completely erroneous assumption that activation of insular cortex = love.

As Dr. Poldrack said:

In Tal Yarkoni’s recent paper in Nature Methods [PDF], we found that the anterior insula was one of the most highly activated part of the brain, showing activation in nearly 1/3 of all imaging studies!

Here's where the Cacciopos and their anterior insulae come in...


The Common Neural Bases Between Sexual Desire and Love

That was the title of a review article that conducted a statistical meta-analysis of the neuroimaging literature on "love" compared to "lust" (Cacioppo et al., 2012). The emphasis was on the similarity of brain regions activated by purported experimental elicitors of these complex behavioral and cognitive states (e.g., "look at a picture of your spouse" vs. close friend, or "watch porn" vs. non-porn). However, they did report a "gradient" of differential activation from the anterior "love" insula to the posterior "lust" insula, as shown below.

Fig. 1 (modified from Cacioppo et al., 2012). Brain networks related to sexual desire (blue) vs. love (red). (B) Lateral view of regions uniquely activated by desire based on the quantitative multilevel kernel density analysis. (C) Regions uniquely activated by love.


In their more recent paper, Cacioppo et al. (2013) wanted to move beyond correlational data by testing a neurological patient with damage in the anterior insula. This is generally a good strategy to evaluate whether your highly vaunted theory based on fMRI data can hold up to causal manipulations, or in this case an accident of nature. If a person with anterior insula damage cannot feel love, then you'd say that region is necessary for feelings of love. If their ability to love is unaffected, then you'd say the anterior insula is not very important.

We can go even further and ask if that patient with damage to anterior insula – but sparing of posterior insula – can still feel lust but not love. In that case, you'd say there's a dissociation between love and lust in the anterior vs. posterior insula. ² 

But that's not what the study was about!! Instead, it was about a speeded response task: look at pictures and quickly decide whether the person evokes feelings of love (or desire, in separate blocks). From the outset, I'll say that reaction times (RTs) in this task really have nothing to do with love, even as it was conceived in the fMRI experiments (i.e., "look at a picture of your spouse" and even "look at a picture of your child" - !!)

The participant in the study was a 48 year old heterosexual man who had a stroke affecting a fairly large portion of the right insula [I think], which is good for the investigators because "lust" seems to "localize" to the left posterior insula in their schematic above. We don't know a whole lot about this man (like, how long ago was his stroke?), other than that "At the moment of evaluation, the patient showed no symptoms and his neurological exam was normal." We'll just have to trust them on that...

Oh, and he was cognitively normal on some brief screening tests, not depressed or anxious, and fine in two social cognition tasks (including empathy for pain, a task where other persons with anterior insular lesions show deficits).

On to the task. The patient and 7 age- and sex-matched controls viewed 40 pictures in blocks of 20. In two of the blocks, the participants decided whether the sexily dressed girl/young woman (aged 18-30) in the photo was "relevant to sexual desire" (yes/no) or "relevant to love" (yes/no). Each image was viewed twice. Only the RTs on "yes" responses were evaluated, for some unknown reason, so we don't know if the patient was faster/slower than controls to reject a photo.

The patient behaved similarly to controls in the "lust" task. It took him just under a second, 926 milliseconds (ms), to respond "yes" when he desired the sexy young girl in the picture, compared to 959 ms for controls [remember, these guys are 48 and the girls are as young as 18], which did not differ. The patient said "yes" to lust 58% of the time vs. 61% for controls. The authors write (PDF):

The anamnesis indicated that the patient was unaware of any differences in his feelings of love or desire, whereas behavior testing revealed a selective deficit for love (but not sexual desire).

In the "love" task, the patient said "yes" to love 35% of the time vs. 43% for controls (which again did not differ). For RT, the patient took 1279 ms to say "yes" to love vs. 1020 ms for controls. And this constitutes his selective deficit for love!! It took him 259 ms longer to decide that a stranger in a photo in a laboratory task was "relevant to love." And we don't know how long it took him to say "no." And he reported no subjective change in his feelings of love, and no significant others or family or friends were queried about this.

The patient could have been slower to make that decision for any number of reasons that have nothing to do with “playing an instrumental role in love.” I won't belabor the point, but this particular region of the brain is implicated in many different functions.

With all due respect to the authors, I don't understand how this paper was published in its current form.³ 

Might as well do fMRI and neuropsychological studies of Celebrity "F#@k, Marry, Kill"...

Footnotes

¹ See papers by Aguirre (2003) and Poldrack (2006) for detailed explanations.

² To complete the package with a double dissociation, a posterior insula lesion that affects lust but not love would confirm the hypothesis.

³ Current Trends in Neurology isn't exactly a stellar journal... it's published by Research Trends of India (not the prestigious Cell Press Trends series), and noted as "questionable" by scholarly publishing watchdog Jeffrey Beall. The paper is not listed in PubMed, nor can it be found at the journal website. A Google Scholar search only turns up a PDF at the authors' own labs.


References

Cacioppo S, Bianchi-Demicheli F, Frum C, Pfaus JG, & Lewis JW (2012). The common neural bases between sexual desire and love: a multilevel kernel density fMRI analysis. The journal of sexual medicine, 9 (4), 1048-54 PMID: 22353205

Cacioppo S, Couto B, Bolmont M ... Cacciopo JT (2013). Selective decision-making deficit in love following damage to the anterior insula Current Trends in Neurology, 7, 15-19 PDF


Dedication: For my wife.

> I love you
>
> Now and always
>
> Across space and time

The Stylized Neuroscience of Psychopaths

The eighth and final season of the hit series Dexter takes a scientific look at serial killers. British actress Charlotte Rampling plays Dr. Evelyn Vogel, a neuropsychiatrist who has written the definitive book on the brains of psychopaths. She's consulting with Miami Metro Homicide on an unusual case where the killer saws open the skull post mortem and scoops out part of the brain (with a melon baller).

Neuroscience is depicted as a somewhat ghoulish yet artistic and stylish endeavor (the corpse with a sawed off head is not shown in this still). This autopsy scene is particularly artsy with its use of red lit retro cabinetry and colorized MRI films on an old school light box.

Dr. Vogel is philosophical about her chosen field. In a conversation with our favorite serial killer and "blood spatter guy" she says:

"I was drawn to forensics too, but I chose to focus on neuroscience. Psychopaths. We both chose murder. Maybe we're both a little crazy."

"Maybe," Dexter replied.

Dr. Vogal continued: "Mad scientists' strange look at this -- a biological mass -- a body part -- yet somehow from all those firing of neurons something intangible emerges -- emotions, trust, morality, love. Unless you're a psychopath. But even then belief systems emerge."


WARNING! Fake grisly fake image below the jump reveals the role of the anterior insula in psychopathy.

Read more »

No More Drama

No more pain (no more pain)
No more pain (no more pain)
No drama (no more drama in my life, no ones gonna make me hurt again)
No more in my life

No More Drama
-----Mary J. Blige

Women who are victims of intimate partner violence (IPV) can suffer from post-traumatic stress disorder (PTSD), cognitive impairments (Twamley et al., 2009), and alterations in brain activity when anticipating aversive or threatening events (Simmons et al., 2008).

In a neuroimaging study, 15 women with IPV-related PTSD were compared to 15 non-traumatized control women in a task that cued the presentation of either positive or aversive images (Simmons et al., 2008). The authors hypothesized that the women with PTSD would show exaggerated neural responses in the insula in anticipation of negative stimuli. This brain region is implicated in interoceptive awareness of bodily states (Craig, 2009), and is responsive to scenes and expressions of disgust (Stark et al., 2007).



Figure 1 (Simmons et al., 2008). Anticipation Task. The fMRI task combined a continuous performance task with the interspersed presentation of affective stimuli. Subjects were asked to press the left or right button on a touch pad on the basis of the shape on the screen. Subjects were instructed before the task that a switch from a blue to a green shape accompanied by a low tone would indicate that a positive image was going to appear on the screen. In contrast, a switch from a blue to a red shape accompanied by a high tone signaled an impending negative image.

A priori regions of interest (ROIs) were selected in bilateral anterior insula and right anterior/middle insula. These ROIs showed greater activation in anticipation of negative vs. positive images in both groups. Furthermore, the PTSD group showed greater signal change than controls in the right anterior/middle insula, as shown below.


Figure 3 (Simmons et al., 2008). Anticipation of negative images versus positive images leads to increased activation in bilateral anterior insula (A shows right-sided activation and B shows left-sided activation) and (C) right anterior/middle insula, which was significantly more active in IPV relative to NTC subjects.

Additional connectivity analyses suggested that correlations between activation in the insular regions and the amygdala were weaker in the IPV-PTSD group. The authors speculate that:

...the increased activation in anterior/middle insula observed in IPV subjects with PTSD, in particular on the left side, might represent a neural substrate linking emotional distress, anticipatory processing, and autonomic arousal, which can advance action planning to reduce exposure to the aversive stimuli. Therefore, the anterior/middle insula activation might be interpreted as a “warning signal” that is associated with the anticipation of aversive symptoms such as hyperarousal. This interpretation is supported by the strong functional connectivity between anterior/middle insula and amygdala observed in the current study...

Hyperarousal takes its toll on cognition, however, as demonstrated in another experiment that assessed neuropsychological functioning in a group of women with IPV-PTSD, who showed slower cognitive processing speed than controls (Twamley et al., 2009):

We speculate that the cognitive slowing seen in PTSD may be attributable to reduced attention due to a need to allocate resources to cope with psychological distress or unpleasant internal experiences.

A goal for the future is to see whether appropriate clinical treatment ameliorates this deficit. Overall, however, the best strategy is to stop the violence before it occurs. WHO, CDC, and womenshealth.gov have information on the prevention of intimate partner violence. You can also call the National Domestic Violence Hotline. Feel free to list addition resources in the comments.

References

Craig AD. How do you feel--now? The anterior insula and human awareness. (2009). Nat Rev Neurosci. 10:59-70.

SIMMONS, A., PAULUS, M., THORP, S., MATTHEWS, S., NORMAN, S., & STEIN, M. (2008). Functional Activation and Neural Networks in Women with Posttraumatic Stress Disorder Related to Intimate Partner Violence. Biological Psychiatry, 64 (8), 681-690. DOI: 10.1016/j.biopsych.2008.05.027

Stark R, Zimmermann M, Kagerer S, Schienle A, Walter B, Weygandt M, Vaitl D. (2007). Hemodynamic brain correlates of disgust and fear ratings. Neuroimage 37:663-73.

TWAMLEY, E., ALLARD, C., THORP, S., NORMAN, S., HAMI CISSELL, S., HUGHES BERARDI, K., GRIMES, E., & STEIN, M. (2009). Cognitive impairment and functioning in PTSD related to intimate partner violence. Journal of the International Neuropsychological Society, 15, 879-887. DOI: 10.1017/S135561770999049X

WATCH - No More Drama

Neuromarketing means never having to say you're peer reviewed (but here's your NYT op-ed space)

There's a truly hideous op-ed piece in the New York Times by neuromarketing guru Martin Lindstrom:

You Love Your iPhone. Literally.

By MARTIN LINDSTROM
Published: September 30, 2011

WITH Apple widely expected to release its iPhone 5 on Tuesday, Apple addicts across the world are getting ready for their latest fix.

But should we really characterize the intense consumer devotion to the iPhone as an addiction? A recent experiment that I carried out using neuroimaging technology suggests that drug-related terms like “addiction” and “fix” aren’t as scientifically accurate as a word we use to describe our most cherished personal relationships. That word is “love.”

. . .

Earlier this year, I carried out an fMRI experiment to find out whether iPhones were really, truly addictive, no less so than alcohol, cocaine, shopping or video games. In conjunction with the San Diego-based firm MindSign Neuromarketing, I enlisted eight men and eight women between the ages of 18 and 25. Our 16 subjects were exposed separately to audio and to video of a ringing and vibrating iPhone.

In each instance, the results showed activation in both the audio and visual cortices of the subjects’ brains. In other words, when they were exposed to the video, our subjects’ brains didn’t just see the vibrating iPhone, they “heard” it, too; and when they were exposed to the audio, they also “saw” it. This powerful cross-sensory phenomenon is known as synesthesia. [NOTE: Not necessarily. It could also be called cross-modal activation.]

But most striking of all was the flurry of activation in the insular cortex of the brain, which is associated with feelings of love and compassion. The subjects’ brains responded to the sound of their phones as they would respond to the presence or proximity of a girlfriend, boyfriend or family member.

Oh boy.... Reverse inference alert! Reverse inference alert! Lindstrom committed a logical fallacy - one cannot directly infer the participants' cognitive or emotional state from the observed pattern of brain activity in neuroimaging experiments. See papers by Aguirre (2003) and Poldrack (2006).

Fortunately, Everybody's a Neurocritic! Reputable academic neuroimaging gurus Russ Poldrack and Tal Yarkoni have already written posts about this debacle: NYT Editorial + fMRI = complete crap and the New York Times blows it big time on brain imaging. Here they note the completely erroneous assumption that activation of insular cortex = love. As Yarkoni says:

The insula is one of a few ‘hotspots’ where activation is reported very frequently in neuroimaging articles (the other major one being the dorsal medial frontal cortex). So, by definition, there can’t be all that much specificity to what the insula is doing, since it pops up so often.

In fact,

In Tal Yarkoni’s recent paper in Nature Methods [PDF], we found that the anterior insula was one of the most highly activated part of the brain, showing activation in nearly 1/3 of all imaging studies!

In days of yore, The Neurocritic wrote 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 [Hsu et al., 2008] and you'll see activations related to action execution, speech, attention, language, explicit memory, working memory, and audition.

Then Who Can You Trust? deconstructed a Science paper entitled The Rupture and Repair of Cooperation in Borderline Personality Disorder by King-Casas et al. (2008). The study examined how well individuals with borderline personality disorder trusted others in an economic exchange game (called, conveniently enough, the Trust Game). In brief,

The authors linked the insular activation to the detection of social norm violations in interpersonal contexts, concluding that individuals with BPD are deficient in this regard. But what are the participants really thinking about during the 4-8 sec interval following a stingy offer? Do we have yet another example of reverse inference here?

Below is a figure generated from entering the x, y, z coordinates from the right insular focus into the Sleuth program (available at brainmap.org), which searched the available database of papers for matches. The resulting list of coordinates and experiments was then imported into the GingerALE program, which performed a meta-analysis via the activation likelihood estimation (ALE) method (see this PDF). The figure illustrates that this exact same region of the right insula was activated during tasks that assessed speech, language, explicit memory, working memory, reasoning, pain, and listening to emotional music.

So there we have it. Let's all read a peer reviewed Nature Methods paper [PDF] instead of buying Buyology...

Oh, and let's all sign a Letter to the Editor of the NYT.


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.

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

King-Casas B, Sharp C, Lomax-Bream L, Lohrenz T, Fonagy P, Montague PR (2008). The Rupture and Repair of Cooperation in Borderline Personality Disorder. Science 321: 806-810.

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

Yarkoni T, Poldrack RA, Nichols TE, Van Essen DC, Wager TD. (2011). Large-scale automated synthesis of human functional neuroimaging data. Nat Methods 8:665-70.


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."

Who Can You Trust?

As a sequel to the "Trust Your Insula" theme from last time (i.e., Borderline … feels like I'm goin' to lose my mind), The Neurocritic has consulted the BrainMap database, which revealed that the anterior insula is activated in a wide variety of cognitive, perceptual, and motor tasks. But first, a recap.



In their recent Science paper entitled The Rupture and Repair of Cooperation in Borderline Personality Disorder, King-Casas et al. (2008) examined how well individuals with borderline personality disorder trusted others in an economic exchange game (called, conveniently enough, the Trust Game). In this game, one player (the Investor) gives a sum of money to the other player (the Trustee). The investment triples, and the Trustee decides how much to give back to the Investor. Relative to the control group, the BPD group was more likely to make a small repayment after receiving a small investment. This reflected a lack of cooperation (or "coaxing" behavior) designed to induce the Investors to trust their partners.

For the fMRI portion of the study, the authors bypassed more general analyses comparing BPD and control brains during the point of investment and the point of repayment. Instead, the major neuroimaging result contrasted the receipt of low investment offers vs. high investment offers, as illustrated below. Control brains showed a nearly perfect linear correlation between $ offer and activity in the anterior insula (expressed here as a negative correlation, because low $ offers correlated with high insula activity). Such a relationship was not observed in BPD brains. In fact, no brain region in the BPD group showed a difference between high and low offers.



Fig. 3 (King-Casas et al., 2008). Response of 38 healthy trustee brains and 55 BPD trustee brains to level of cooperation. (Top). Results of within-group GLM [general linear model] analyses identified cortical regions with greater response to small investments (less than or equal to $5) relative to large investments (greater than $10). (Bottom). Percent change in hemodynamic signal was averaged from the 115 most significant voxels identified in the group-level GLM during the 4- to 8-s period following the revelation of investment. The means + SE of the resulting signal are plotted in $4 bins.¹ Responses in bilateral anterior insula in healthy trustees scale strongly and negatively with the size of investment (r = –0.97; bottom left). In contrast, similar analyses in individuals with BPD showed no such relation.

The authors linked the insular activation to the detection of social norm violations in interpersonal contexts, concluding that individuals with BPD are deficient in this regard.² But what are the participants really thinking about during the 4-8 sec interval following a stingy offer? Do we have yet another example of reverse inference here?

Below is a figure generated from entering the x, y, z coordinates from the right insular focus shown above into the Sleuth program (available at brainmap.org), which searched the available database of papers for matches. The resulting list of coordinates and experiments was then imported into the GingerALE program, which performed a meta-analysis via the activation likelihood estimation (ALE) method (see this PDF). The figure illustrates that this exact same region of the right insula was activated during tasks that assessed speech, language, explicit memory, working memory, reasoning, pain, and listening to emotional music.



Perhaps the control subjects in the King-Casas et al. study were muttering to themselves about the stingy offer. Maybe they were engaging working memory processes to a greater extent on those trials. Or maybe they were remembering a time when they were shortchanged at the grocery store. Do we conclude, then, that the BPD subjects did not do any of those things? Or that they engaged those types of processes to an equivalent extent after low and high offers?

To summarize, the extrapolation about the insula and social norm violations was based on a handful of trials from 38 different control participants. I'll leave you with a few questions to ponder. Can the study can really say anything specific about the insular response on those low $ offers? Do we trust that the rest of the brain is completely silent on the matter? We do know that the BPD group scored lower than controls on a self-report measure of trust (the Interpersonal Trust Scale), but do we know what they were really thinking about during the trust game? At the end of the day, does this finding "give psychiatrists a better diagnostic tool and a brain area to target with therapy or drugs when treating BDP"?

What do you think?


Footnotes

¹ Note that these 6 monetary bins were formed from a total of 10 trials per dyad.

² See The Right and The Good and The Insula for discussion of yet another Science paper; this one localized the concept of fairness to the insula.

Reference

B. King-Casas, C. Sharp, L. Lomax-Bream, T. Lohrenz, P. Fonagy, P. R. Montague (2008). The Rupture and Repair of Cooperation in Borderline Personality Disorder Science, 321 (5890), 806-810 DOI: 10.1126/science.1156902

The Right and The Good and The Insula

‘...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