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During the spring of 2009 I organized a course course entitled “Neuroeconomics”, together with Prof.s Elke Weber and Eric Johnson. In this course, we made a compendium of articles on neuroeconomics. Fortunately, almost all of those papers were to be found on the web.

On a new page on the BrainEthics site, we bring you the list of articles we used for the course. Consider this as a suggestion for required readings for those interested in neuroeconomics. We hope to update the list along the way, but still with the aim of retaining a recommended reading rather than comprehensive listing of articles.

- Thomas

-Thomas

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

The role of the insula in many human behaviors

The role of the insula in many human behaviors

Following up on my lead on Antoine Bechara’s upcoming visit, it is worthnotinv one of the new trends in decision making research. In particular, working from an extension of the somatic market theory and the role of ventromedial prefrontal cortex (vmPfC), Bechara and colleagues have recently demonstrated how the role of the insula seems to play an important role in decision making involving risk and aversion.

In the article entitled Differential effects of insular and ventromedial prefrontal cortex lesions on risky decision-making, the researchers compared patients with lesions to vmPfC and the insula to healthy controls and lesion controls on the Cambridge Gamling Task (nice demo here). The authors note that:

The vmPFC and insular cortex patients showed selective and distinctive disruptions of betting behaviour. VmPFC damage was associated with increased betting regardless of the odds of winning, consistent with a role of vmPFC in biasing healthy individuals towards conservative options under risk. In contrast, patients with insular cortex lesions failed to adjust their bets by the odds of winning, consistent with a role of the insular cortex in signalling the probability of aversive outcomes. The insular group attained a lower point score on the task and experienced more ‘bankruptcies’.

The results thus confirmed previous findings of a role of the vmPfC in gambling tasks, while the surprising finding was that insular lesions would also have detrimental effects on decision making. in particular, while vmPfC patients responded to reduced likelihood ratios of the gambles, betting behaviour in insular patients did not show much response to decreasing probabilities. This is demonstrated nicely in the following figure:

picture-11

The effect of ratio on betting behaviour in the four groups of participants: healthy controls, vmPFC lesions, insular cortex lesions and the lesion control group.

Furthermore, over the course of the entire gambling task, insular patients suffered significantly more bankrupcies than both the vmPfC group and control groups. This does suggest that one role of the insula is guiding behaviour through aversive coding. In other words, it may be that the insula is responsible for loss aversion (as well as risk aversion, judging from the task).

The researchers further suggest that the findings were expected from the somatic marker theory:

The detrimental effect of insular cortex damage on emotional decision-making is also predicted by the Somatic Marker hypothesis (Damasio, 1994; Bechara and Damasio, 2005), which posits a crucial role for the insular cortex in holding the representations of bodily states associated with different choice options.

The results are also relevant to other studies, including Lawrence et al. (2009), who report that using the Iowa Gambling Task, choices from disadvantageous versus advantageous card decks produced activation in the medial frontal gyrus, lateral orbitofrontal cortex, and insula. So does the insula play a role in other forms of decision making, and is it a cause in pathological gambling? To date, no conclusive studies have emerged, which is why our own research has now turned to aversion-related activations in gambling, and the study of the dynamics (and overlap) between aversion related and reward related neural functions. The recent study by Clark et al demonstrates that the insula is a structure – long ignored – to take into considerations in decision making studies.

-Thomas

Antoine Bechara (left) and Antonio Damasio

Antoine Bechara (left) and Antonio Damasio

As I mentioned in my previous post, I am currently giving lectures on an April course on neuroeconomics together with Prf.s Elke Weber and Eric Johnson. Needless to say, these lectures are probably as entertaining and useful for me, and my attending colleagues, as they are to the students.

However, change is coming to Copenhagen. Through our newly born Decision Neuroscience Research Group (homepage soon to come), we have additional high-profile researchers coming to Copenhagen to provide lectures and hopefully to be attracted to collaborations with us. In May, Antoine Bechara will be in our group for a couple of weeks. Bechara is well-known for his excellent work on decision making, and the role of emotions in decision making processes. Besides his decades of work on the Iowa Gambling Task, his recent publications are much about the role of the insula in emotions and decision making, in particular addiction. Therefore, our current project on loss/risk aversion in decision making (and in pathological gamblers) will definintely profit from his stay.

In the same vein, Copenhagen will see another great name in June: Antonio Damasio, who will become an honorary doctorate at the Copenhagen Business School. Damasio is well-known for his theory of (and work with Bechara on) somatic markers, and the role of emotions and the body in decision making. Recently, we have been attentive to his criticism to the discussion about mirror neurons, where he points back to his older papers on convergence-divergence zones in the brain, and how they may provide an alternative explanation (and a dethronement of) theories of mirror neurons.

This spring and summer, we therefore hope that anybody with interest in these researchers may consider coming to Copenhagen, even if it’s just for a brief visit.

The Decision Neuroscience Research Group is shaping up, and there is plenty of more to come.

-Thomas

picture-1Emergence of emergence abound, we are coming to life again. After a long a chilly winter here in Denmark, we have not been on the lazy side in our neuro-caves. At present, our newly founded (1-year old) Decision Neuroscience Research Group has grown rapidly from 2 persons to 9, and with an abundance of contacts all across the globe. Needless to say, we have been busy with this project, including setting up behavioural and scanning paradigms, applying for funding, giving talks, writing papers and so on.

But now, we hope to be back with more news from the quirky side of cognitive neuroscience, the problems associated by the science, and not the least the mind-blowing implications of research…

Currently, I am having the great pleasure of teaching a course in neuroeconomics together with Prof Elke Weber from Columbia University, and Prof. Eric Johnson from Columbia Business School. Obviously, we are teaching from our own outsets, and taking it as we go along. The best way to do teaching…

More is to come soon now, so stay tuned

-Thomas

The recent issue of the journal Hippocampus has an interesting article on the structure of the hippocampus throughout the menstrual cycle. By studying women two times during the menstrual cycle (pre- and post-menstrual) using volumetric MR scanning, researchers Xenia Protopopescu and her colleagues at Cornell University demonstrated structural changes in the hippocampus. Specifically, gray matter was relatively increased in the right anterior hippocampus and relatively decreased in the right dorsal basal ganglia (globus pallidus/putamen) in the postmenstrual phase.

Below is an image from that article, showing a t-map rendering showing increased anterior hippocampus (yellow) and decreased basal ganglia (pink) in the postmenstrual vs. premenstrual phase. Seems to me that the entorhinal cortex was also affected

Correspondingly, verbal declarative memory changed throughout the cycle: memory performance increased in teh postmenstrual vs. premenstrual phase. These results support models of estrogen-dependent cyclical alterations in hippocampal synaptic density and function proposed to account for neuronal and cognitive differences seen across the menstrual cycle.

The basal ganglia findings were rather unexpected, and the researchers suggest that:

(…) estrogens have been shown to increase striatal dopamine release, to influence striatal serotonergic and dopaminergic innervation density, and to promote striatal medium size spiny neuronal maturation in vivo (Korol, 2004b). The apparent opposite effect of high estrogen levels on hippocampal and basal ganglia gray matter may relate to the finding in rats that high estrogen promotes use of a hippocampally-mediated spatial (place or allocentric) learning strategy, while low levels promote use of a nonhippocampal, possibly striatally-mediated navigational (response or egocentric) strategy (Korol, 2004b). In humans, MRI studies have shown that navigational ability correlates with level of activity in the basal ganglia (putamen) (Epstein et al., 2005), and more specifically, that navigation using a response strategy is associated both with greater activity (Iaria et al., 2003) and gray matter (Bohbot et al., 2007) in the basal ganglia (caudate), though it should be noted that menstrual cycle effects were not assessed in any of these studies.

I can imagine the jokes that may come out of this… but leave it for now :D One thing that strikes me is the question of how these changes are related to the menopause. For example, would these changes mean that intra-individual variation during the month would be reduced after the menopause? As one knows from ageing research, such variance increases with age. So it is even conceiveable that the development goes the opposite way.

I also notice that the same researchers have recently demonstrated a link between changes in orbitofrontal cortex and emotional processing. It’s also worth a read.

-Thomas

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