Feeds:
Posts
Comments

Archive for the ‘social neuroscience’ Category

From time to time we bring you the quirky side of neuroscience here at BrainEthics. Now, we discover a funny little study in Psychiatry Research: Neuroimaging that bears the attractive title “The neural basis of unconditional love” by Mario Beauregard et al. Indeed, the study of the neural bases of preference formation, aesthetics and even love have gained much momentum since this field started just a few years ago. Fields such as neuroaesthetics and neuroeconomics seem to overlap when it comes to these studies, in which the core aim is to study the fundamental processes underlying preference formation.

In the study, Beauregard and colleagues wanted to establish the neural bases of unconditioned love. So the first tricky thing would be to define and operationalise what is meant by “unconditioned love”. IMO, such kind of love is the affectionate feelings one would call religious love, or ultimate altruism…(if such ever exists).But following the name, it does suggest a broader definition of affectionate feelings towards a person (or just any thing?) regardless of their origin, persona, deeds or misdeeds, family bonds and so forth.

Claimed amygdala activation, which rather looks like collateral sulcus/entorhinal cortex... (from Bartels & Zeki 2004)

Claimed amygdala deactivation during maternal love, which rather looks like collateral sulcus/entorhinal cortex... (from Bartels & Zeki 2004)

Similar studies of strong affectional feelings to other persons have been conducted recently. For example, in a study of maternal love (PDF) by Bartels and Zeki, mothers were scanned while looking at baby faces, in which sometimes their own newborn’s face was shown. The researchers found that when looking at their own babies, compared to looking at other infants, mothers demonstrated stronger activation in regions such as the ventral striatum/nucleus accumbens, ventro-anterior cungulate cortex and fusiform cortex.

In addition, and to the researchers’ surprise, they also found stronger bilateral activation of the anterior insula, a structure typically involved in aversive functions (but I will not follow the speculative account of the researchers on this activation). Deactivations were claimed to be found in regions such as the amygdala – which really is not amygdala, but rather collateral sulcus, judging from their figure (see figure on right). Isn’t is strange that prominent researchers such as Semir Zeki goes so wrong in neuroanatomy? The consequences from arguing for deactivation in the entorhinal cortex, compared to the amygdala, is dramatic. Instead of talking about emotions, one would be more prone to talk about complex visual processing. Yes, it does matter where you think your blobs are…

So what did Beauregard and colleagues do differently? First, they needed to describe the uncondition love construct, which they describe as:

(…) distinct from the empathy and compassion constructs. Empathy is commonly defined as an affective response that stems from the apprehension of another’s emotional state (e.g., sadness, happiness, pain), and which is comparable to what the other person is feeling (Eisenberg, 2000). This affective response is not unconditional and does not involve feelings of love. Compassion refers to an awareness of the suffering of another coupled with the desire to alleviate that suffering (Steffen and Masters, 2005). In contrast to compassion, unconditional love is not specifically associated with suffering.

Hm, not a particularly good definition to go hunting for neural correlates to. Nevertheless, the aim was to study the neural basis of unconditional love, something that has not been done before. So how did they do it? First, the authors had to select the subjects:

Participants were assistants in two l’Arche communities located in the Montreal area. L’Arche communities (founded by Jean Vanier in 1964) are places where those with intellectual disabilities, called core members, and those who share life with them, called assistants, live together. This special population was selected on the basis that one of the most important criteria to become an assistant is the capacity to love unconditionally. (We recruited) assistants with a very high capacity for unconditional love. We ensured that all recruited individuals understood the meaning of this form of love (based on the construct presented in Section 1) and found their work at l’Arche (community help service) very gratifying.

The hypotheses were 1) unconditional love is rewarding, and therefore it was expected to be associated with activation of the VTA and dorsal
striatal regions; and 2) since unconditional love experientially differs to a large extent from romantic love and maternal love, it was predicted that this form of love would be mediated by brain regions not involved in romantic love and maternal love. I particularly hate this second hypothesis: it’s not really a hypothesis, because ANY activation that is “different” can confirm this hypothesis. If it’s a fishing trip, let us know…

Let me try a bit of further deconstructionism of this study. In the methods section, it is described how the subjects were instructed to look at unfamiliar faces and either attempt to feel unconditioned love or think about the person’s intellectual capacity (sic.).

A blocked-design was used to examine brain activity during a passive viewing (PV) condition (control task) and an unconditional love (UL) condition (experimental task).

Note: using block designs are typically used to study differences in state (e.g. comparing neural activation during different attentional states).

Five blocks of pictures were presented during both conditions. Each block consisted of a series of four pictures. Each picture was presented during 9 s (pre-experimentation revealed that, on average, participants needed that long to feel unconditional love toward the individuals depicted in the pictures).

OK, so some of the activation differences between the UL condition and the PV condition may be due to task difficulty and reaction time, and not, as they would have wanted, the nature of the task.

Blocks were separated by periods of 30 s. Pictures depicted individuals (children and adults) with intellectual disabilities. These individuals were unfamiliar to the participants. Instructional cue words (“View”, “Unconditional love”) printed in white first appeared in the center of a black screen for 2 s. While the picture remained on the screen, participants performed the tasks specified by the prior cue. In the PV blocks, participants were instructed to simply look at the individuals depicted in the pictures. In the UL blocks, participants were instructed to self-generate a feeling of unconditional love toward the individuals depicted in the pictures.

OK, there are many assumptions here… Just to illustrate, do the following for me: close your eyes and for 20 seconds DO NOT THINK ABOUT AN ELEPHANT!!! What happens? Well, you’d probably be surprised to see that elephant does really appear in your mind even if you try to suppress it. Thought suppression studies have demonstrated this through the past many decades. So IMO, what the study might also be about is thought suppression – or comparing elephant thinking to elephant-suppression activation. IOW, I’m not sure that the viewing condition did not evoke some “unconditioned love”-suppression.

Therefore, the UL task involved both a cognitive component (self-generation) and an emotional–experiential component (feeling). Blocks were presented in alternation (PV, UL, PV, UL, etc.). At the end of each block for both experimental conditions, a four-point scale (1 = “No feeling”, 2 = “Some feeling”, 3 = “Moderate”, 4 = “Very intense”) for rating the extent to which they currently felt unconditional love was presented for 3 s.

Strangely, what the researchers found when doing the UL minus PV comparison, was stronger activation in “the middle insula, superior parietal lobule, right periaqueductal gray, right globus pallidus (medial), right caudate nucleus (dorsal head), left ventral tegmental area and left rostro-dorsal anterior cingulate cortex.” This can be seen in the figure below:

Regions showing stronger activation during "unconditional love" condition

Regions showing stronger activation during "unconditional love" condition

So what are the interpretations of these results? Does it surprise you that both hypotheses were confirmed? First, that unconditioned love was related to reward structure activation was not surprising. But the researchers over-interpret the results: they claim that this is prima facie proof that unconditioned love is rewarding. But hey, the results can just as well suggest that the unconditioned love state is just a framing of how we look at faces (for example, imaging you are either told that person/face X is a wonderful person OR an evil sadistic terrorist).

Second, is it surprising that they also found “activation not found for maternal or romantic love”? Not to me: the tasks are different, the selection of subjects are different, the confounds are plenty…

And what about that strong and bilateral insula activation? Yes, it’s right that it confirms the second hypothesis…but how does the insula play a role in unconditioned love? As I noted in my previous post, it does seem to play an important role in negative emotions and aversion. Here, the authors assert:

There is increasing evidence that the insula is implicated in the representation of bodily states that colour conscious experiences (or “background feelings”) (…) it is plausible that the middle insular activation noted during the UL condition was associated with the somatic and visceral responses elicited by the presented pictures.

Uh yes, but this is typically reflected in negative emotions. So how is unconditioned love related to aversion? Or maybe one could relate the findings to a recent review that suggest a role for the insula in addiction and urges? I don’t know, if you’re into speculating, go with whatever seems to work… Basically, this handwaving interpretations is not much better than old-style phrenology or hand-reading. They may be right, but only because they make the right guesses from previous studies.

Briefly put, although we enjoy the quirky side of neuroscience, and how it can be used to explore human nature, we at BrainEthics are also sceptical at the level at which quirky science turns into flaky science.

-Thomas

Advertisements

Read Full Post »

Can antidepressive medicine alter your decision behaviour? A recent paper in Science now demonstrates that alterations in subjects’ serotonin levels leads to significant changes in their decision making behaviour. In the study, subjects were set to play the Ultimatum Game repeatedly. Subjects had to do the task two times at two different days, and at one of the days they were administered an acute tryptophan depletion (ATD), i.e., their serotonin levels would drop for a period of time. The design was double-blind and placebo controlled.

The Ultimatum Game is an experimental economics game in which two players interact to decide how to divide a sum of money that is given to them. The first player proposes how to divide the sum between themselves, and the second player can either accept or reject this proposal. If the second player rejects, neither player receives anything. If the second player accepts, the money is split according to the proposal. The game is played only once, and anonymously, so that reciprocation is not an issue.

What the researchers found was that the ATD led subjects to reject more offers, but only unfair offers. That is, ATD did not interact with offer size per se, and there was no change in mood, fairness judgement, basic reward processing or response inhibition. So serotonin seemed to affect aversive reactions to unfair offers.

The study is a nice illustration of how we now are learning to induce alterations in preferences and decision making. Along with other studies using, e.g., oxytocin to increase trust in economic games (see also my previous post about this experiment), one may expect that increasing the serotonin level may actually make subjects less responsive to unfair offers.

This knowledge is also important to learn more about, as it poses a wide range of ethical problems. If our preferences and decisions are really influenced by these stimuli, can this be abused? It should be mentioned that many of these substances are not necessarily detected (oxytocin is odourless), so we may be influenced without our consent or knowledge. The wide applicances could include casinos, stores (e.g. for expensive cars), dating agencies and so on. If we did not accept subliminal messages in ads, how can we accept this?

-Thomas

Read Full Post »

I’m having the pleasure of reading The brain that changes itself by Norman Doidge, as a reviewer for a potential translation here in Denmark. Brain plasticity, or neuroplasticity, has always been a hot topic, from it’s (re)birth in modern neuroscience, and all the way up until today, where researchers are still fiercely debating how plastic the brain is and how functions relate to brain structures – aka the debate of modularism. In its early days, the neuroscientific community strongly believed that the modularity of the brain was established during childhood, and that little, if any, change could occur later on. Researchers suggesting otherwise were eschewed, heavily criticized on the ground that their data/ideas did not fit into the existing model. The land did not fit onto the map, so to say. This book is dedicated to the idea of neuroplasticity.

The book introduces brain plasticity in a very vivid and close-up manner, as Doidge tells the story from the inside, through some of the biggest names in this research, including the late Paul Bach-y-Rita, Michael Merzenich, and Gerald Edelman. Not only is the book very interesting to read as a historical background, but it also takes a look behind the scenes in two ways. Doidge has talked the researchers himself, and bring their experience of how plasticity came to go from a ignored (and carreer risky business) field, to a scientifically acceptable and highly influential topic. Even today, one may claim that we do not fully comprehend or apply the insights from this research.

Doidge also does a great job in describing patient cases of brain plasticity, including:

(…) a woman born with half a brain that rewired itself to work as a whole, a woman labeled retarded who cured her deficits with brain exercises and now cures those of others, blind people learning to see, learning disorders cured, IQs raised, aging brains rejuvenated, painful phantom limbs erased, stroke patients recovering their faculties, children with cerebral palsy learning to move more gracefully, entrenched depression and anxiety disappearing, and lifelong character traits altered.

(from the book cover)

The stories from both researchers and patients are written in a most vivid and entertaining way, and the first 100 pages alone makes the book a page-turner. The book as a whole is filled with these fantastic descriptions and stories that equal great writers such as Oliver Sacks.

So how about the sex part? Yes, this is where I got a little puzzled, too. Going from the insights of neuroplasticity, Doidge turns his attention to sexual disorders and abberations. This is, of course, both a very interesting, challenging and risky choice, but it is also a topic that Doidge is intimately close to through his clinical work. In much the same manner as the description of neuroplasticity cases, we are presented to patients of Doidge (or his peers) that suffer from psychological illnesses, in particular sex related problems. Interestingly, it seems that the insights from plasticity can be applied to these disorders and problems, and Doidge does a great job in presenting and discussing these issues.

My quarrel, however, is with Doidge’s theoretical position — psychoanalysis. Is it not itself strange to combine the insights from the edgy yet stringent scientific approaches of neuroplasticity with the unscientific theoretical (armchair) century old approach? Doidge does use the suggestions from Freud to interpret the psychological cases he presents. This includes the interpretation of dreams, a business receiving a lot of criticism, too. At best, I think this part of the book becomes an anachronism. The problem lies in why, at all, Doidge needs to invoke a theoretical position like psychoanalysis at all in order to understand what is going on. This is where science becomes fiction, and where the book breaks down. But not totally. If one is aware of the problems associated with psychoanalysis and science, the book is still a wonderful read.

-Thomas

Read Full Post »

In relation to our previous and well-visited post about oxytocin, we should mention a new study that uses this very substance in a neuroeconomic set-up. In the study, recently published by Neuron, and headed by Baumgartner et al., it was found that the administration of oxytocin affected subjects’ in a trust game. In particular, it was found that subjects that received oxytocin were not affected by information about co-players that cheated. Or, as put in the abstract:

(…) subjects in the oxytocin group show no change in their trusting behavior after they learned that their trust had been breached several times while subjects receiving placebo decrease their trust.

That is extremely interesting. This suggests that oxytocin, a mammalian hormone + neurotransmitter that is known to be related to maternal behaviour and bonding, also is modulating social trust. So the brain link is obvious. But what happens in the brain when oxytocin is administered during the trust game?

This difference in trust adaptation is associated with a specific reduction in activation in the amygdala, the midbrain regions, and the dorsal striatum in subjects receiving oxytocin, suggesting that neural systems mediating fear processing (amygdala and midbrain regions) and behavioral adaptations to feedback information (dorsal striatum) modulate oxytocin’s effect on trust.

So oxytocin reduces fear and aversion responses, and this leads to the lack of effect in responding to cheaters. Excellent, why not use this for treating anxiety, phobia and other fear-related problems? Sounds promising, and yet other more ethically problematic issues remain to be resolved. Think, for example, about whether oxytocin makes us more susceptible to gambling, shopping and marketing effects? Or what if it may work as the first scientifically proven aphrodisiac? What if your next pick-up line would be “Hi, I’m Thomas, how are you” just followed by a few ‘puff-puff’ sounds.

Joke aside, studies like this demonstrates that emotions and decisions are often influenced by factors not consciously available, or at least only partially so. As the marketing industry is increasingly interested in multi-sensory inventions, oxytocin may be the next step in this endaveour.

-Thomas

Read Full Post »

sadchild.jpegPhysorg reports about an interesting forthcoming MRI study linking paedophilia to regional changes in white matter. Analysing structural MRI using voxel-based morphometry, paedophiles were found to have significantly smaller white matter volumes in specific regions, as the abstract demonstrates:

The present investigation sought to identify which brain regions distinguish pedophilic from nonpedophilic men, using unbiased, automated analyses of the whole brain. T1-weighted magnetic resonance images (MRIs) were acquired from men who demonstrated illegal or clinically significant sexual behaviors or interests (n = 65) and from men who had histories of nonsexual offenses but no sexual offenses (n = 62). Sexual interest in children was assessed by participants’ admissions of pedophilic interest, histories of committing sexual offenses against children, and psychophysiological responses in the laboratory to erotic stimuli depicting children or adults. Automated parcellation of the MRIs revealed significant negative associations between pedophilia and white matter volumes of the temporal and parietal lobes bilaterally. Voxel-based morphometry corroborated the associations and indicated that the regions of lower white matter volumes followed, and were limited to, two major fiber bundles: the superior fronto-occipital fasciculus and the right arcuate fasciculus. No significant differences were found in grey matter or in cerebrospinal fluid (CSF). Because the superior fronto-occipital and arcuate fasciculi connect the cortical regions that respond to sexual cues, these results suggest (1) that those cortical regions operate as a network for recognizing sexually relevant stimuli and (2) that pedophilia results from a partial disconnection within that network.

Now, a few things strikes me odd in this analysis and interpretation. First of all, why is the comparison group nonsexual offenders? After all, that the crime is of a sexual nature is absolutely central to the present question, and especially that the sexual offender has been interested in children. The obvious choice would be to compare paedophilic sexual offenders to sexual offenders who had adult victims (typically a male offending a woman). Here, the act of sexual offence is similar between the two groups, while the sexual “object” is the vital difference. In the present study, any significant difference could just as well be explained by the nature of the crime as the sexual inclination of the subjects. It’s a classic case of poor control of confounding variables.

Second, I strongly dislike the over-interpretations offere in both the article and the news story. First, the authors find significant differences in the superior fronto-occipital and arcuate fasciculi, and link these regions to studies showing involvement in response to sexual stimuli. Following this, they suggest that paedophilia may occur due to a disconnection in this network. Just based on the reasons given in the previous section, these results may be interpreted just as well as brain alterations in sexual offence in general.

But more than this, if one just skims the literature on these regions (fasciculi), one can see that they have been implemented in language lateralization/function and hallucinations and delusions. So interpreting the differences as relevant to paedophilia is a long shot.

Furthermore, the physorg story suggest that this study:

challenges the commonly held belief that paedophilia is brought on by childhood trauma or abuse. This finding is the strongest evidence yet that paedophilia is instead the result of a problem in brain development.

This is a serious over-interpretation of the results. When understanding white matter (and any brain) changes during development, one should be cautious to claim that the changes observed are the mere cause of “brain development” and not experience-related phenomena. Here, we need to divide between two effects: neurogenetic and psychogenetic effects. Neurogenetic effects are, in this story, changes in the brain that are caused by biological factors. Age-related atrophy is a good example of this. The cause is the accumulation of junk within cells/neurons that eventually hinder cell division and function. Psychogenetic factors, on the other hand, are observed brain changes that are caused by behaviour, in its broadest sense. For example, if you learn to juggle, areas in the motor regions of the brain will alter their size and connectivity to a measurable extent. Likewise, London taxi drivers are known to have larger posterior hippocampi as a result of their prolonged training in navigation.

So in the case of paedophilia, observed changes in the brain cannot be said to support a brain-based (neurogenetic) interpretation, and to challenge psychogenetic causes. Rather, it has been suggested that many paedophiles have been subject to similar maltreatment when young. At the least, just because the brain shows a difference, one cannot conclude anything beyond this about causation.

As neuroscience enters the domain of social sciences, it holds the promise to both enlighten and naturalize these age-old discussions. However, the use of mere reporting and tailored interpretations are far from sufficient, and may even lead us astray in the goal to achieve a better understanding of these, and related, phenomena.

-Thomas

Read Full Post »

hooligans.jpgCan we rid ourselves of the meaningless violence and aggression seen in society today? A news story in Nature News this week shows that aggressiveness may be treated with a serotonin-acting ligand. At least in rats, but nevertheless the study holds the promise for human treatment as well. Serotonin levels are known to be associated with aggression. The lower the serotonin level, the more aggression. So what dd the present study find?

The team engendered violent characteristics by introducing feeble intruder rats that were bound to lose battles, each day for two or three weeks. After repeated victories over other rats, the test animals began to behave in a more pathologically violent manner, fighting all-comers more brutally — including weak females and senseless males which presented no threat to them.

Then the researchers looked at levels of the neurotransmitter serotonin in the rats’ brains. Although brain levels of serotonin don’t change in rats as a result of normal, ‘appropriate’ acts of aggression, the team found that these levels did sink in his pathologically aggressive rats.

So this is more or less a replication and strengthening of previous research, only this model seems to have additional advantages. But the big news came when the team tried to manipulate the serotonin levels in the rats. Here, they found that…

(…) they could alter the aggressive behaviour of their rats by manipulating the serotonin system. They gave the rats S-15535, a compound that binds exclusively to a neuron ‘autoreceptor’ that acts to dampen the serotonin system. This autoreceptor is called 5-HT1a. Binding to it seems to bring serotonin levels in the rats back to normal. When even very low doses of S-15535 were used to bind to the receptors, de Boer found that both the serotonin and the violence of the pathologically aggressive rats returned to normal levels.

Better still, the drug did not seem to affect other behaviour, and did not seem to be generally sedative. So the study suggests that (pathological) aggression might be controlled better using a serotonin-acting drug. The study described in the Nature News was headed by Sietse de Boer from the University of Groenigen. There’s also a story about de Boer study from this year’s SfN conference (I couldn’t make it there, duh), and a ScienceDaily article nicely relates this to other studies.

Of course, the ethical questions are unanswered still. Indeed, if we are able to synthesize these drugs, and they work, who should have them? Should they be forced upon a subject? And let’s make it even more edgy: should it be taken by people (men) going to football matches, and could one convict a hooligan to take a pill before attending a game? Is this the cure for domestic violence, bar fights, hooliganism?

-Thomas

Read Full Post »

sciencefraud.jpgMartha Farah just alerted me about her recent comment in the Neuroethics & Law blog. Yesterday, NY Times ran a story about neuro-politics. More precisely, they presented a study of how subjects’ brains responded to, e.g., different political words and pictures of US politicians involved in the 2008 presidental election. The article’s first author is Marco Iacoboni from UCLA. Basically, the researchers give subjects different kinds of tasks, report activations in different regions of the brain (that themselves are likely enough to be involved during the tasks). Then, the authors set out to interpret this activity, such as:

When we showed subjects the words “Democrat,” “Republican” and “independent,” they exhibited high levels of activity in the part of the brain called the amygdala, indicating anxiety

Didn’t I just say that the amygdala is involved in positive emotions, too? So what does amygdala activation mean, then? Studies have also shown that mere emotional uncertainty (e.g., a neutral face) may activate the amygdala. So maybe the political words are just more emotionally ambiguous? Let’s take another one from a different part of the article:

With Mr. Giuliani, the reactions are reversed. Men respond strongly to his initial still photos, but this fades after they see his video. Women grow more engaged after watching his video.

OK, where did men respond more strongly? The whole brain? WOW! Let’s continue to a third place in the article:

Our subjects also exhibited a much stronger empathetic response to a minute-long excerpt from a stump speech by Mr. Thompson than they did to an excerpt of a Giuliani speech.

So what was compared? Two speakers, two political opponents, two speeches, or ___ (add your favourite). OK that’s just three examples, but the article is full of such tea-leaf reading. It’s nothing short of magical thinking, astrology or healing. Put differently, the authors look at brain blobs and try to interpret their meanings in terms of previous knowledge. Is that bad? Yes it is, because it does not even attempt toput up testable hypotheses. And why don’t we get to know what is meant by “more active” or “respond more strongly”? What is this activation compared to? What is the contrast, the baseline? Even further, what is the statistical cutoff and how many other regions light up during conditions X, Y or Z? Where are all the tech specs that validate this study?

So is this really our brain on politics? Or is it the Iacobini team’s own ambition to get publicity (and maybe earn some money along the way)? I’d say the latter is the case here. The basic problem is that we don’t have a scientific reference, and only have to take the authors’ word for it. It’s a violation of every sensible way to report findings from a scientific method in the press. IMO, before you can do such a thing, you should at least (!) have a manuscript that is accepted, let alone published. And if you choose to do a test for the media, just “for fun”, then say so! This article pretends to be scientifically correct. It is not.

How this has come through the press is probably the most interesting story. And how it got through the science editors at NY Times is a mystery. Indeed, I hope that more criticism will force NY Times to send out a corrigendum.

-Thomas

NOTE: As I hoped for, this story has spurred a lot of discussion, e.g., here.

Read Full Post »

Older Posts »