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Archive for the ‘social neuroscience’ Category

chris-frith.jpgThe eminent neuropsychologist Chris Frith has recently retired from his job at FIL, the world famous factory for neuroimaging research in London. He is best known for his work on schizophrenia and, during the last ten years, mentalizing and social cognitive neuroscience. His many brillant reviews on these topics will probably be familiar to most of this blog’s readers. Now, Frith has written a book entitled Making Up the Mind – with the great subtitle “How the brain creates our mental world” – which, I suspect, will be widely reviewed and debated in the coming months. Certainly, we will have more to say about it later this summer here at BrainEthics. (Also, in a week or two I will put up a post about some recent papers on social cognitive neuroscience.)

-Martin

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humphrey.JPGIt was twenty years ago today. Sgt. Pepper taught the band to play.

Actually, last year it was 30 years ago that Nicholas Humphrey published his seminal paper “The social function of intellect” (pdf). Many people see this paper as the impetus to later work on the social brain hypothesis (pdf) and Theory of Mind. Humphrey suggested that, rather than the need for technology, it was in fact the need for advanced cognitive mechanisms for keeping track of conspecifics and interacting with other members of their social group that drove the expansion of brain and intelligence in hominids. This idea has provoked research into the role of cooperation and collaboration as well as deception and competition in primate social behaviour. It has prompted research into the importance of conspecifics being able to attend to a shared mental content. (Shared attention appears crucial to the transfer of knowledge in a social group, and is therefore probably a prerequisite for the establishment of cultural traditions.) Finally, it has been instrumental in getting neuroscientists interested in the neurobiological underpinnings of social cognition, including research into Theory of Mind and mirror neurons.

To commemorate Humphrey’s paper and track the above-mentioned ensuing research, the Royal Society of London staged a Dicussion Meeting last year. The papers presented at that meeting have now been published in the latest issue of the Philosophical Transactions of the Royal Society B. It is a veritable smorgardsbord of big names: There’s papers on social intelligence in birds, hyenas, dolphins and apes by, inter alia, Nathan Emery, Nicola Clayton, Kay Holekamp, and Richard Connor. Richard Byrne and Andrew Whiten discuss the animal cultures hypothesis. There’s papers by Michael Tomasello and Daniel Povinelli on ToM in primates. Vittorio Gallese explains the importance of mirror neurons, Chris Frith reviews what we know about the social brain, and Steven Mithen speculates that farming may have arisen from a misapplication of social intelligence. Naturally, Humphrey is also given the opportunity to revisit his 1976 paper.

If you are at all interested in the question of what makes some species social beings you will want to check out this issue.

-Martin

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eyes2.jpgResearch on the role of oxytocin, a neuropeptide, in social cognition has generated much interest during the last few years. We have earlier written about oxytocin’s role in social attachment; together with vasopressin, another neuropeptide, oxytocin is thought to be critical for linking social signals to structures in the mesolimbic part of the brain responsible for forming social attachment and pair bonding. In a study published in Nature Ernst Fehr and his group demonstrated that injecting people with a spray of oxytocin increases trust.

Now, in a pretty remarkable new study published in Biological Psychiatry, German researchers show that injecting subjects with a whiff of oxytocin will also improve be ability to infer, based just on eye cues, what a person is thinking about. Here’s the abstract:

Background

The ability to “read the mind” of other individuals, that is, to infer their mental state by interpreting subtle social cues, is indispensable in human social interaction. The neuropeptide oxytocin plays a central role in social approach behavior in nonhuman mammals.

Methods

In a double-blind, placebo-controlled, within-subject design, 30 healthy male volunteers were tested for their ability to infer the affective mental state of others using the Reading the Mind in the Eyes Test (RMET) after intranasal administration of 24 IU oxytocin.

Results

Oxytocin improved performance on the RMET compared with placebo. This effect was pronounced for difficult compared with easy items.

Conclusions

Our data suggest that oxytocin improves the ability to infer the mental state of others from social cues of the eye region. Oxytocin might play a role in the pathogenesis of autism spectrum disorder, which is characterized by severe social impairment.

Clearly, this suggests that oxytocin not only modulates mesolimbic brain structures. Earlier studies have implicated the fusiform face area and superior temporal sulcus in extracting social information from facial perception. May oxytocin also impact on these structures? Whatever turns out to be the case, I imagine that no politician or CEO will ever sit down at the negotiation table again without their trusty bottle of oxytocin.

-Martin

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social-neuroscience.jpgThe new issue (number 3-4, September-December 2006) of Social Neuroscience is a hefty double issue tome dedicated to the topic of Theory of Mind. It contains 20 papers by several of the leaders in the field, and is edited by Rebecca Saxe and Simon Baron-Cohen. One of the reasons for the enduring interest in ToM is that, in contrast to other capacities for social reasoning – for instance, the ability to represent facial features or the intentional motion of conspecifics’ bodies – the ability to reason about the contents of mental states may be an unique human ability (see, e.g., [1]). Recently, through fMRI research, ToM has been linked to a specific part of the human brain: the right temporo-parietal junction.

Reference

[1] Saxe, R. (2006): Uniquely human social cognition. Current Opinion in Neurobiology 16: 1-5.

-Martin

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ubuntu-logo.pngSuffering from a full computer breakdown, my IBM Thinkpad has become sucpiciously reluctant to re-install Windows. Instead, I’m now running Ubuntu linux. For the most part it is not just comparable to Windows, in many respects it’s even better.

So what does this computer havoc have to do with the brain, or ethics at all?

Ubuntu is a totally free computer software, a fully operational operative system that replaces Windows fully. As in the core spirit of the linux movement, everything is free. So who benefits — besides myself — from this genuine altruism? I’m actually quite puzzled as to how I could explain that someone would spend a lot of their time making software without charging me anything for it. (more…)

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mysticfigure.jpgA new report in Nature demonstrates that electrical stimulation of the temporoparietal junction in the brain induces a sensation of the presence of an illusory “shadowy person”. One of the hallmarks of certain forms of schizophrenia is just this phenomenon: the eery feeling of someone’s presence. Now, it has been demonstrated in a study using electrical brain activation in a person without a history of psychiatric problems.

Basically, the study was performed on a subject that was at the preoperative stage of surgery for epilepsy. A normal procedure is to anaesthesize the patient before opening the skull, and then wake the patient up before stimulating the brain. The aim of such stimulation is to find the location of epilepsy onset, as well as to stimulate the areas surrounding this region, in order to map functionally important regions (e.g. language that are important in language). Such preoperative procedures are known to lead to a better surgical sensitivity, i.e. the ability to remove all of the abnormal tissue, and a higher surgical selectivity, i.e. avoding removal of normal tissue. In this way, neurosurgeons often evoke a number of sensations and behaviours in patients, including the disruption of speech, visual phosphenes, and memory deficits.

In the present case, the neurosurgeons found that electrical stimulation lead to a feeling of the presence of another person. Moreover, the patient reported that this figure was taking the same posture as herself, and even sometimes interfering with a task she was performing:

When stimulated (…) the patient had the impression that somebody was behind her. Further stimulation induced the same experience, with the patient describing the “person” as young and of indeterminate sex, a “shadow” who did not speak or move, and whose position beneath her back was identical to her own (“He is behind me, almost at my body, but I do not feel it”). (…) Further stimulations [other location] were applied while the seated patient performed a naming (language-testing) task using a card held in her right hand: she again reported the presence of the sitting “person”, this time displaced behind her to her right and attempting to interfere with the execution of her task (“He wants to take the card”; “He doesn’t want me to read”).

Stimulation of the temporoparietal junction (shown with an arrow in the image above) thus seems to distort some kind of body image, or maybe even efference copy (PDF) of self-actions. Both functions that are dramatically affected in abnormal brain states following certain kinds of delusional schizoprenia and brain injury.

The finding also nicely relates to the Swiss group’s earlier study combining EEG, TMS and the study of an epilepsy patient, where it was found that disruption of the temporoparietal junction function led to an “impaired mental transformation of one’s own body”. Here, the researchers concluded that:

the [temporoparietal junction, TPJ] is a crucial structure for the conscious experience of the normal self, mediating spatial unity of self and body, and also suggest that impaired processing at the TPJ may lead to pathological selves such as [out-of-body experience].

Here is the full story:

Induction of an illusory shadow person
By Arzy et al
Nature 443, 287

Stimulation of a site on the brain’s left hemisphere prompts the creepy feeling that somebody is close by.

The strange sensation that somebody is nearby when no one is actually present has been described by psychiatric and neurological patients, as well as by healthy subjects, but it is not understood how the illusion is triggered by the brain1, 2. Here we describe the repeated induction of this sensation in a patient who was undergoing presurgical evaluation for epilepsy treatment, as a result of focal electrical stimulation of the left temporoparietal junction: the illusory person closely ‘shadowed’ changes in the patient’s body position and posture. These perceptions may have been due to a disturbance in the multisensory processing of body and self at the temporoparietal junction.
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1. Laboratory of Cognitive Neuroscience, École Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
2. Presurgical Epilepsy Evaluation Unit, University Hospital, Geneva 1211, Switzerland
3. Department of Neurology, University Hospital, Geneva 1211, Switzerland
4. Center for Cognitive Neuroscience, Dartmouth College, Dartmouth, New Hampshire 03755, USA

-Thomas

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amygdala.jpgCan a brain scan reveal your relationship to your mother? According to a recent study, this may well be the case.

One of the theories in modern psychology is about the relationship between a child and her parent, especially the mother. Among such attachment theories is the original theory by John Bowlby. For a good description of attachment theory see Wikipedia. There’s also a good article (PDF) in Developmental Psychology on the history of attachment.
Basically, the theory of attachment demonstrated that the dyadic relationship between the infant and the mother can take the form of different styles — attachment styles. Such styles include secure attachment where the infant can use the mother as a secure base from which the immediate environment is explored. Insecure attachment, however, can come in different forms, including avoidant, ambivalent and disorganized (see also here). Studies have shown that the attachment style at birth is likely to influence the social functions in adulthood, and that the attachment style in one female is inherited by her offspring through a process called transmission (see also this excellent paper). Normally, this transmission is thought to be socially transmitted, although I think it’s a dubious conclusion since children are both genetically and socially related to their mother. However, a convincing study (PDF) in 2003 by Bokhorst showed that while genetic influence on temperament was relatively high, the influence on attatchment style was negligible.

But let’s get to the case: does attachment style demonstrate measurable effects on the brain? Indeed, this is what Erwin Lemche and colleagues found in a study using functional MRI. Based on previous findings that insecure attachment is related to heightened sympathetic nervous system activity (e.g. heart rate increase and cortisol secretion), Lemche et al. demonstrated that performance during a stress, relative to a neutral, prime stimulus condition involved bilateral amygdalae activation.

The subjects were shownn two series of 32 sentence statements describing self-centred or other-centred information. They had to report whether they agreed or disagreed with the statements by pressing a button. Before the presentation of the target sentences, subliminal messages with negative content were presented on some occasions (stress condition), or with nonsense sentence content (neutral condition). For example, the negative prime could be “My mom rejects me” presented for 30 milliseconds. In the neutral condition the prime could be “Ym umu jrecest em”, also presented for 30 milliseconds.

The activation of the amygdalae after negative primes was the same for all subjects. However, for those subjects who demonstrated an insecure attachment style (determined by the Adult Attachment Interview) the amygdalae activation levels was significantly higher when presented with the unconscious negative primes.

So having an insecure attachment style leads to higher activation to attachment-related primes. Taken together, this result demonstrates a role for amygdala in mediating attatchment relevant behaviour. Indeed, it is interesting to see how a phylogenetic “old” limbic structure is involved in an interpersonal psychological process, which is normally thought to involve more prefrontal cortical regions.

-Thomas

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