Mirror neurons control erection response to porn

Does anyone find this surprising? Isn't it exactly the effect one would expect mirror neurons to have? (Past discussion here.) However, it is welcome to note basic research that has practical applications...

Mirror neurons control erection response to porn (6/16/08)

You don't have to be a scientist to observe that pornographic images lead to erections in men. But you would have to be one to show those images to volunteers while meticulously measuring the volume of response in the brain and penis.

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.

Not a terribly difficult guess to make. So what did they find?

While the volunteers watched the movies, the researchers watched their brains using functional magnetic resonance imaging (fMRI).

They also kept tabs on the tumescence of the other target organ, using a hand-crafted "penile plethysmograph" – essentially an airtight tube in which the enlarging penis causes measurable pressure changes.

As expected, all the subjects got erections and many parts of the brain lit up.

Interestingly, the volume of the erections correlated with the strength of activation in a part of the brain called the pars opercularis, which is known to display mirror neuron activity. Even more intriguing, the brain activation, say the researchers, precedes the penile response.

Tags: mirror neurons

Moral choice: fairness, utility, and the insula

We continue to learn more about the neuropsychological basis of moral thinking and moral emotions in humans:

Justice In The Brain: Equity And Efficiency Are Encoded Differently (5/8/08)

Which is better, giving more food to a few hungry people or letting some food go to waste so that everyone gets a share" A study appearing in Science finds that most people choose the latter, and that the brain responds in unique ways to inefficiency and inequity.

The study, by researchers at the University of Illinois and the California Institute of Technology, used functional magnetic resonance imaging (fMRI) to scan the brains of people making a series of tough decisions about how to allocate donations to children in a Ugandan orphanage.

There are two main issues regarding moral decision making here.

The first involves two separate principles often used in analyzing moral/ethical problems related to the distribution of goods within a group of people. (The group might be children in a family or different classes of people in a society, among many possibilities.) On one hand, it is generally regarded as "good" to maximize "equity" in moral decisions, so that some individuals are not favored over others without significant justification. (I prefer the term "fairness" for this.)

On the other hand, it is also regarded as "good" to maximize "efficiency", so that the greatest total amount of benefit accrues to a group as a whole. (I prefer the term "utility" for this.)

But these principles can come into conflict, and the research discussed here investigates a contrived, but sharp, example. Philosophers of ethics call such dilemmas the problem of "distributive justice".

The second issue concerns the style of thinking that a decision maker faced with this kind of dilemma does use, and also, perhaps, what style the decision maker "should" use. On one hand, the decider might try to systematically and logically apply some standard set of rules that are considered appropriate for the situation. But on the other hand, the decider might rely more on emotional factors that indicate what "feels right", the "gut feeling", about what seems "right" in a concrete situation.

Philosophers often describe these two alternatives as "cognitivist" vs. "sentimentalist". The former is sometimes associated with the philosopher Immanuel Kant, and the latter with David Hume.

What emerges from the research is (not surprisingly) that individual decision makers differ in the degree that they favor "equity" vs. "efficiency", and also whether they tend to rely more on logic or emotion to make their decisions.

More interestingly, most people normally process considerations of both equity and efficiency in order to reach a decision, but different parts of the brain are used for the two. Likewise, in making the decision, distinct parts of the brain which normally handle emotional or logical processing can become involved in processing the equity/efficiency trade-off.

One way to think of this is that there are separate calculations of both equity and efficiency that are made for each available choice. And then the result of those calculations are fed to separate subsystems to weigh the alternatives.

The different moral and ethical decisions that different people will arrive at can be attributed to individual differences as to how the various stages of the decision process are handled. For instance, an individual may favor equity over efficiency, and tend to use emotion rather than logic to reach the decision.

Here's what the study found:

In these trails, subjects overwhelmingly chose to preserve equity at the expense of efficiency, Hsu said. "They were all quite inequity averse." The findings support other studies that show that most people are fairly intolerant of inequity.

The animation, in conjunction with the fMRI, allowed the researchers to view activity in the brain at critical moments in the decision-making process. After analyzing the data, they found that different brain regions -- the insula, putamen and caudate -- were activated differently, and at different points in the process, Hsu said.

Activation of the insula varied from trial to trial in relation to changes in equity, while activity in the putamen corresponded to changes in efficiency, he said.

In contrast, the caudate appeared to integrate both equity and efficiency once a decision was made.

The role of the insula (or, more formally, insular cortex) is especially interesting, since this brain region has been associated with quite a few other types of social-emotional mental processing. We'll come back to that in a moment. But here are the conclusions of the researchers:

The involvement of the insula appears to support the notion that emotion plays a role in a person's attitude towards inequity, Hsu said.

The insula is known to play a key role in the awareness of bodily states and emotions. Studies have shown that it is activated in people experiencing hunger or drug-related cravings, and in those feeling intense emotions such as anger, fear, disgust or happiness. Other research has implicated the insula in mediating fairness. ...

Together, the results "show how the brain encodes two considerations central to the distributive justice calculus and shed light on the cognitivist/sentimentalist debate regarding the psychological underpinnings of distributive justice," the authors wrote.

Here's how another report about this research summed it up:

Your Brain on Ethics (5/8/08)

The fMRI scans contain hints of how these two factors might be encoded by the brain. The insula, a brain region linked to processing emotion, became more active when subjects considered more inequitable distributions of meals; it was also more active in subjects whose choices suggested a greater-than-average aversion to inequity. Activity in another region, the putamen, seemed to track the common good, rising in proportion to the total number of meals that could be donated in a given case.

Now let's have a quick overview of the insula. Turns out that it's involved in a lot more than just moral decision-making. Here's a general article from a bit over a year ago:

A Small Part of the Brain, and Its Profound Effects (2/6/07)

According to neuroscientists who study it, the insula is a long-neglected brain region that has emerged as crucial to understanding what it feels like to be human.

They say it is the wellspring of social emotions, things like lust and disgust, pride and humiliation, guilt and atonement. It helps give rise to moral intuition, empathy and the capacity to respond emotionally to music. ...

If it does everything, what exactly is it that it does?

For example, the insula “lights up” in brain scans when people crave drugs, feel pain, anticipate pain, empathize with others, listen to jokes, see disgust on someone’s face, are shunned in a social settings, listen to music, decide not to buy an item, see someone cheat and decide to punish them, and determine degrees of preference while eating chocolate.

Damage to the insula can lead to apathy, loss of libido and an inability to tell fresh food from rotten. ...

Of course, like every important brain structure, the insula — there are actually two, one on each side of the brain — does not act alone. It is part of multiple circuits.

The insula itself is a sort of receiving zone that reads the physiological state of the entire body and then generates subjective feelings that can bring about actions, like eating, that keep the body in a state of internal balance. Information from the insula is relayed to other brain structures that appear to be involved in decision making, especially the anterior cingulate and prefrontal cortices.

Stay tuned. We'll be discussing the insula quite a bit more here, I think.

Further reading:

The Right and the Good: Distributive Justice and Neural Encoding of Equity and Efficiency – Original research report published 5/8/08 at Science Express (sub. rqd. for full access)

Which Orphans Do You Want to Starve? – Blog article by Sharon Begley at Newsweek

How Fairness Is Wired In The Brain – 5/28/08 press release about the research dealing with fairness and the insula

Tags: morality, fairness, utility, neuroscience, neurobiology, insula, insular cortex

Study Lights Up The Political Brain

Since we've been looking at political science a bit recently (here and here), perhaps a little more might not be out of order. One interesting thing about the studies discussed so far is that they rely largely on experimental techniques of classical psychology – subjects pushing buttons when presented with various stimuli, for example.

One wonders whether more modern techniques have been used, such as fMRI. The answer: a little, but not very much, apparently. The following seems to be part of what may be the most noteworthy effort:

Emory Study Lights Up The Political Brain

When it comes to forming opinions and making judgments on hot political issues, partisans of both parties don't let facts get in the way of their decision-making, according to a new Emory University study. The research sheds light on why staunch Democrats and Republicans can hear the same information, but walk away with opposite conclusions.

The investigators used functional neuroimaging (fMRI) to study a sample of committed Democrats and Republicans during the three months prior to the U.S. Presidential election of 2004. The Democrats and Republicans were given a reasoning task in which they had to evaluate threatening information about their own candidate. During the task, the subjects underwent fMRI to see what parts of their brain were active. What the researchers found was striking.

"We did not see any increased activation of the parts of the brain normally engaged during reasoning," says Drew Westen, director of clinical psychology at Emory who led the study. "What we saw instead was a network of emotion circuits lighting up, including circuits hypothesized to be involved in regulating emotion, and circuits known to be involved in resolving conflicts."

There probably isn't going to be much disagreement that political appeals in democracies (or most other governmental arrangements) are based a lot more on emotion than on reason and logic. It's hardly a new idea. However, what is intriguing is the possibility that fMRI and similar brain-scanning techniques can eventually reveal, for example, what kinds of emotional appeals work best with different personality types, when (if ever) rational mechanisms in the cortex become involved, and so forth.

Further information:

Neural Bases of Motivated Reasoning: An fMRI Study of Emotional Constraints on Partisan Political Judgment in the 2004 U.S. Presidential Election – abstract of the research paper (sub. rqd. for full access)

Drew Westen – The Political Brain: The Role of Emotion in Deciding the Fate of the Nation – recent (6/2007) book

Tags: political psychology

Political affiliation could be all in the brain

For a long time I've felt that political science is just a branch of psychopathology. Now it appears that technology is approaching the point that political science can be studied by techniques of neuroscience:

Political affiliation could be all in the brain

A brain scan might one day predict your voting patterns. That is the implication of a study that found different brain activity among liberals and conservatives asked to carry out a simple button-pushing test. The study implies that our political diversity may be the result of neurological differences.

More: here (updated here), here, here, here, here, here, here, here

Related: here

References:

• Harold Lasswell – Psychopathology and Politics
  
• Theodor Adorno – The Authoritarian Personality
  
• James D. Barber – Presidential Character: Predicting Performance In The White House