Sex, sweat and your brain

From Zou and Chen, showing that two areas of women's brains respond to chemical signals in the sweat of sexually aroused men. Their edited abstract, and a figure:

Chemosensory communication of affect and motivation is ubiquitous among animals. In humans, emotional expressions are naturally associated with faces and voices. Whether chemical signals play a role as well has hardly been addressed. Here, we use functional magnetic resonance imaging to show that the right orbitofrontal cortex, right fusiform cortex, and right hypothalamus respond to airborne natural human sexual sweat (distinguishing it from neutral sweat, and a nonsocial control), indicating that this particular chemosensory compound is encoded holistically in the brain. Interestingly, with the exception of hypothalamus, neither the OFC nor the fusiform region is implicated in sexual motivation and behavior. Hence, our results implied that the chemosensory information from natural human sexual sweat was encoded more holistically in the brain rather than specifically for its sexual quality. Our findings provide neural evidence that socioemotional meanings, including the sexual ones, are conveyed in the human sweat.

Figure - Brain responses to social chemosensory compounds. a, Coronal view showing an activated area in the right orbitofrontal cortex. d. Sagittal view showing an activated region in the right fusiform gyrus.

(I might as well also repeat this link from a post several days ago, on the debate raging over MRI studies of social cognition that has been started off by a paper titled "Voodoo correlations in social neuroscience".)

Why we hiccup.

An article by Neil Shubin in the January Scientific American notes how a number of evolutionary hand-me-downs inherited from fish and tadpoles have left us with hernias, hiccups and other maladies. I thought this bit on why we hiccup was fascinating: it is because we once were tadpoles.

A spasm of the muscles in the throat and chest causes a hiccup. The characteristic “hic” sound results when we sharply inspire air while the epiglottis, a flap of soft tissue at the back of the throat, closes. All these movements are completely involuntary; we “hic” without any thought on our part. Hiccups occur for many reasons: we eat too fast or too much; even more severe conditions, such as tumors in the chest area, can bring them on. Hiccups reveal at least two layers of our history: one shared with fish, another with amphibians, according to one well-supported hypothesis. We inherited the major nerves we use in breathing from fish. One set of nerves, the phrenic, extends from the base of the skull and travels through the chest cavity and the diaphragm, among other places. This tortuous course creates problems; anything that interrupts the path of these nerves along their length can interfere with our ability to breathe. Irritation of these nerves can even be a cause of hiccups. A more rational design of the human body would have the nerves traveling not from the neck but from a spot nearer to the diaphragm. Unluckily, we became heir to this design from fishy ancestors with gills closer to the neck, not a diaphragm well below it. If the strange pathway of the nerves is a product of our fish origin, the hiccup itself may have arisen from the past we share with amphibians. It turns out that the characteristic pattern of muscle and nerve activity of hiccups occurs naturally in other creatures. And not just any creatures. More specifically, they turn up in tadpoles that use both lungs and gills to breathe. When tadpoles use their gills, they have a problem— they need to pump water into their mouth and throat and then across the gills, but they need to keep this water from entering their lungs. So what do they do? They shut the glottis to close off the breathing tube, while sharply inspiring. In essence, they breathe with their gills using an extended form of hiccup. (click on figure to enlarge it).

Species conservation - how being helpful hurts

Cornelia Dean makes note of a fact I had not thought much about. Conservation regulations that specify the minimum size of individuals that can be harvested, whether they be fish, bighorn sheep, or ginseng plants, increase the rate of evolution to favor smaller individuals that reproduce at an earlier age. This works against species health. Humans are harvesting mature adults, whereas natural predators would target smaller or weaker (old) individuals. Rates of evolutionary change are three times higher in species subject to “harvest selection” than in other species. Here is the abstract of Darimont et al.'s work.

Oxytocin makes a face in memory familiar

It is known that men treated with oxytocin perform better in inferring affective state from the eye region of human faces. Oxytocin also increases social behaviors like trust. Rimmele at al. show now that oxytocin delivered by a commercially available nasal spray (Syntocinon Spray from Novartis) selectively enhances memory encoding of faces in humans, but not of nonsocial stimuli. Here is their abstract:

Social recognition is the basis of all social interactions. Here, we show that, in humans, the evolutionarily highly conserved neuropeptide oxytocin, after intranasal administration, specifically improves recognition memory for faces, but not for nonsocial stimuli. With increased oxytocin levels, previously presented faces were more correctly assessed as "known," whereas the ability of recollecting faces was unchanged. This pattern speaks for an immediate and selective effect of the peptide strengthening neuronal systems of social memory.

Brain games for you, coming soon from Mattel

Justin Landwehr and PFSK point us to a concentration game coming from Mattel.

MRI of human social values?

I read something like this by Zahn et. al., and am fascinated at the same time I am wondering what the hell to make of it. (Here, by the way, is a disucssion of the debate raging over MRI studies of social cognition that has been started off by a paper titled "Voodoo correlations in social neuroscience".) My impression is that if you scan the MRI (magnetic resonance brain imaging) literature for all the functions that have been 'correlated with,' for example, the subgenual cingulate (in this case, guilt) or orbitofrontal-insular cortices (indignation, anger) you would find a hopelessly large list. Still, the prospect of stable neural architectures associated with different discrete social emotions is interesting. The authors suggest that social values emerge from coactivation of abstract conceptual representations within the anterior temporal lobe region (aTL, BA38/22), emotional states represented in mesolimbic and basal forebrain regions (hypothalamus, septum, VTA (ventral tegmental area), anterior insula) and emotion–action associations in OFC (orbitofrontal cortex) as well as sequential action outcomes in anterior medial PFC (prefrontal cortex) regions. They provide data...

...supporting a model in which social values draw upon stable representations of conceptual detail within the anterior temporal lobe region (aTL, BA38/22) and context-dependent representations of distinct moral sentiments within fronto-mesolimbic regions. They test a model of integration of the concepts and emotions that form social values in which social values change their emotional quality in a flexible way adapted to the context of agency. They suggest that a separation of stable context-independent representations in the aTL can be flexibly embedded within different contexts of action implementation and emotional qualities as encoded in fronto-limbic circuits to account for our ability to link social values to a wide range of interpersonal and cultural settings

The interdependency of context of actions and emotional evaluation has been a key component of the notion of values proposed by British philosophers during the 18th century. According to this stance, intuitive "moral sentiments" determine whether we perceive a behavior as constituting a virtue or vice and guide our approval or disapproval of that behavior...When we are the agent of an action conforming to our values, we may feel pride, whereas when another person is the agent, we may feel gratitude. On the negative side, when we act counter to our values, we may feel guilt and when another person acts in the same way toward us, we instead feel indignation or anger.

Here is the abstract of the paper:

Social values are composed of social concepts (e.g., "generosity") and context-dependent moral sentiments (e.g., "pride"). The neural basis of this intricate cognitive architecture has not been investigated thus far. Here, we used functional magnetic resonance imaging while subjects imagined their own actions toward another person (self-agency) which either conformed or were counter to a social value and were associated with pride or guilt, respectively. Imagined actions of another person toward the subjects (other-agency) in accordance with or counter to a value were associated with gratitude or indignation/anger. As hypothesized, superior anterior temporal lobe (aTL) activity increased with conceptual detail in all conditions. During self-agency, activity in the anterior ventromedial prefrontal cortex correlated with pride and guilt, whereas activity in the subgenual cingulate solely correlated with guilt. In contrast, indignation/anger activated lateral orbitofrontal-insular cortices. Pride and gratitude additionally evoked mesolimbic and basal forebrain activations. Our results demonstrate that social values emerge from coactivation of stable abstract social conceptual representations in the superior aTL and context-dependent moral sentiments encoded in fronto-mesolimbic regions. This neural architecture may provide the basis of our ability to communicate about the meaning of social values across cultural contexts without limiting our flexibility to adapt their emotional interpretation.

Finger length predicts successful financial trading!

This analysis by Coates et al. is a real hoot. They find that the second-to-fourth digit ratio predicts success among high-frequency financial traders:

Prenatal androgens have important organizing effects on brain development and future behavior. The second-to-fourth digit length ratio (2D:4D) has been proposed as a marker of these prenatal androgen effects, a relatively longer fourth finger indicating higher prenatal androgen exposure. 2D:4D has been shown to predict success in highly competitive sports. Yet, little is known about the effects of prenatal androgens on an economically influential class of competitive risk taking—trading in the financial world. Here, we report the findings of a study conducted in the City of London in which we sampled 2D:4D from a group of male traders engaged in what is variously called “noise” or “high-frequency” trading. We found that 2D:4D predicted the traders' long-term profitability as well as the number of years they remained in the business. 2D:4D also predicted the sensitivity of their profitability to increases both in circulating testosterone and in market volatility. Our results suggest that prenatal androgens increase risk preferences and promote more rapid visuomotor scanning and physical reflexes. The success and longevity of traders exposed to high levels of prenatal androgens further suggests that financial markets may select for biological traits rather than rational expectations.

Insults and joys of old age...

Dwight Garner offers a review of a recent book, "Somewhere towards the end," by former prominent London book editor, 91 year old Diana Athill. ( I regret that I - like many of you, I suspect - read more book reviews than actual books.) Here are some clips that I thought interesting:

A positive aspect of the waning of sex, Ms. Athill says, “was that other things became more interesting.” ... I was surprised that this longtime fiction editor has declared that she has “gone off novels.”...Why? She no longer feels the need to parse the intricacies of human relationships and love affairs, “but I do still want to be fed facts, to be given material which extends the region in which my mind can wander.” ...The elderly, she writes, can find great enjoyment in the company of younger people. But she warns: “One should never, never expect them to want one’s company, or make the kind of claims on them that one makes on a friend of one’s own age. Enjoy whatever they are generous enough to offer, and leave it at that.”

The book ends with her realization:

“There are no lessons to be learnt, no discoveries to be made, no solutions to offer. I find myself left with nothing but a few random thoughts. One of them is that from up here I can look back and see that although a human life is less than the blink of an eyelid in terms of the universe, within its own framework it is amazingly capacious so that it can contain many opposites. One life can contain serenity and tumult, heartbreak and happiness, coldness and warmth, grabbing and giving — and also more particular opposites such as a neurotic conviction that one is a flop and a consciousness of success amounting to smugness.”

The dead end of current economic models...

Here is a short and sweet statement of the futility of current models of economic recovery and growth, from a letter to the Nature editor from Hervé Philippe, a biochemist at the University of Montreal. It mirrors my own sentiment: that talk of 'restoring economic growth' in the absence of ruthless planning to achieve steady state sustainable energy fluxes on this planet is delusional.

...the prosperity [of Western societies] is mainly based on the use of non-renewable resources and therefore is probably spurious...Several hundred million years were needed to form the fossil energy that will be exhausted during a few hundred years. This is roughly equivalent to spending all one's annual income during the first 30 seconds of a year. In particular, the frenzy to automate processes in order to increase competitiveness leads to rapid exhaustion of available resources, for example through over-fishing or degradation of soils....All current growth-based economic models imply massive use of non-renewable resources and environmental degradation. These models are not sustainable, even in the short term....As early as 160 years ago, John Stuart Mill affirmed that "the richest and most prosperous countries would very soon attain the stationary state" (Principles of Political Economy Longmans, 1848). In contrast to that time, when resources were being used up at a rate that was several orders of magnitude slower than today, a phase of economic degrowth is necessary before a stationary state can be reached. It would be a major achievement of economics to achieve such a degrowth without social and political disasters.

A neurosciences site feed aggregator

I get an email a few weeks ago saying that Deric's MindBlog had been added to an "online magazine rack" called Alltop. If you are in the mood for even more sensory overload, you might check it out. (Later note: in the comment below, Justin points out that Alltop is a creation of entrepreneur Guy Kawasaki, a site

...that provides “all the top” stories for forty of the most popular topics on the Web. The headlines and first paragraph of the five most recent stories from forty to eighty sources for each topic are displayed. Alltop stories are refreshed approximately every ten minutes.

A good metaphor is that Alltop is an "online magazine rack" that displays the news from the top publications and blogs. Our goal is to satisfy the information needs of the 99% of Internet users who will never use an RSS feed reader or create a custom page. Think of it as "aggregation without the aggravation.”

Cartoon instructions for some neat sensory illusions.

This link is sent by a reader. Simple cartoon instructions from the Boston Globe for how you can cause changes in your visual images or body image, either by yourself or with a friend.

The neuroscience of love

Larry Young offers this latest installment in Nature's "Being Human" series on a topic I have mentioned in a number of previous posts. He notes that animal studies that demystified emotions such as fear and anxiety are beginning to illuminate the mental states associated with love. This has implications for the nature of human sexuality — and could even lead to drugs to enhance or diminish our love for another. Tierney comments (the graphic is from his article) on Young's essay , suggesting that

...the really good news, as I see it, is that we might reverse-engineer an anti-love potion, a vaccine preventing you from making an infatuated ass of yourself.

Here are some clips from Young:

We are not alone in being able to form intense and enduring social ties. Take the mother–infant bond. Whether or not the emotional connection between a ewe and her lamb, or a female macaque and her offspring, is qualitatively similar to human motherly love, it is highly likely that these relationships share evolutionarily conserved brain mechanisms. In humans, rats and sheep, the hormone oxytocin is released during labour, delivery and nursing. In ewes, an infusion of oxytocin into the brain results in rapid bonding with a foreign lamb...There is intriguing overlap between the brain areas involved in vole pair bonding and those associated with human love. Dopamine-related reward regions of the human brain are active in mothers viewing images of their child. Similar activation patterns are seen in people looking at photographs of their lovers.

Pair bonding in males involves similar brain circuitry to that in females, but different neurochemical pathways. In male prairie voles, for example, vasopressin — a hormone related to oxytocin — stimulates pair bonding, aggression towards potential rivals, and paternal instincts, such as grooming offspring in the nest. Variation in a regulatory region of the vasopressin receptor gene, avpr1a, predicts the likelihood that a male vole will bond with a female.

Similarly, in humans, different forms of the AVPR1A gene are associated with variation in pair bonding and relationship quality. A recent study shows that men with a particular AVPR1A variant are twice as likely as men without it to remain unmarried, or when married, twice as likely to report a recent crisis in their marriage. Spouses of men with the variant also express more dissatisfaction in their relationships than do those of men lacking it. For both voles and humans, AVPR1A genetic polymorphisms predict how much vasopressin receptor is expressed in the brain.

The view of love as an emergent property of a cocktail of ancient neuropeptides and neurotransmitters raises important issues for society. For one thing, drugs that manipulate brain systems at whim to enhance or diminish our love for another may not be far away. Experiments have shown that a nasal squirt of oxytocin enhances trust and tunes people into others' emotions. Internet entrepreneurs are already marketing products such as Enhanced Liquid Trust, a cologne-like mixture of oxytocin and pheromones "designed to boost the dating and relationship area of your life". Although such products are unlikely to do anything other than boost users' confidence, studies are under way in Australia to determine whether an oxytocin spray might aid traditional marital therapy.

We don't yet know whether the drugs commonly used to treat disorders from depression to sexual dysfunction affect people's relationships by altering neurochemistry. But both Prozac and Viagra influence the oxytocin system. The quality of patients' relationships should be included in the list of variables assessed in controlled psychiatric drug studies.

Followup on 'Reinventing the sacred'....

I relay here (with permission) an email comment on the 'Reinventing the Sacred' post and suggest that you look at several other thoughtful comments at the end of that post.

Perhaps philosophy has something to offer the 'hard core materialist'. I recently read "Illness" by Havi Carel which I must say was a truly moving experience. Meditations on death and meaning using the authors knowledge of Greek Philosophy and Phenomenology enabled her to 'live well' with illness. This is something that a naturalistic bioscience approach would have trouble with?

You might like the thoughts of the former Bishop of Edinburgh Richard Holloway "Looking in the distance -the human search for meaning" is one of his excellent books. Holloway, who is now in charge of the Arts Council,sees religion as poetry and metaphor rather than a competition with science which seeks to search for 'material' truth.....Most people appear to need a bit of both and there does seem a universal need for spirituality and engagement-which does not have to be gained by participation in organized religion. Some of the offshoots of immersion in religious practices and spiritual disciplines do appear to have material benefit too (in terms of health and cohesion of community) but this is another discussion perhaps.

Bees on cocaine...

Here is an item that falls into the 'random curious stuff' category of this blog's subheading:

A common speculation is that the cocaine that triggers reward pathways in our brains evolved as an insecticide that protects the coca plant. Barron et al. have now found a reward effect in bees. By examining the honey bee dance--the means by which bees signal the availability of resources to their hive-mates--they found that dosing the bees with cocaine increased both the likelihood and rate of dance after foraging; furthermore, the bees exhibited behavior consistent with a withdrawal effect when the drug was withheld after chronic treatment. They suggest that the response to the drug may be similar in humans and bees. Here is their abstract:

The role of cocaine as an addictive drug of abuse in human society is hard to reconcile with its ecological role as a natural insecticide and plant-protective compound, preventing herbivory of coca plants (Erythroxylum spp.). This paradox is often explained by proposing a fundamental difference in mammalian and invertebrate responses to cocaine, but here we show effects of cocaine on honey bees (Apis mellifera L.) that parallel human responses. Forager honey bees perform symbolic dances to advertise the location and value of floral resources to their nest mates. Treatment with a low dose of cocaine increased the likelihood and rate of bees dancing after foraging but did not otherwise increase locomotor activity. This is consistent with cocaine causing forager bees to overestimate the value of the floral resources they collected. Further, cessation of chronic cocaine treatment caused a withdrawal-like response. These similarities likely occur because in both insects and mammals the biogenic amine neuromodulator systems disrupted by cocaine perform similar roles as modulators of reward and motor systems. Given these analogous responses to cocaine in insects and mammals, we propose an alternative solution to the paradox of cocaine reinforcement. Ecologically, cocaine is an effective plant defence compound via disruption of herbivore motor control but, because the neurochemical systems targeted by cocaine also modulate reward processing, the reinforcing properties of cocaine occur as a `side effect'.

MRI in the courtroom as witness on pain?

Greg Miller notes, in his report on a Stanford Law School Event, that because pain pathways in the brain are better understood than those underlying lying, pain detection is more likely to be the first fMRI application to find widespread use in the courtroom.

...pain is an issue in about half of all tort cases, which include personal injury cases. Billions of dollars are at stake. Yet people with real pain are sometimes unable to prove it, and malingerers sometimes win cases by faking it...However, using fMRI as a painometer isn't straightforward. For starters, said Katja Wiech, a cognitive neuroscientist at University College London, pain sensitivity varies considerably from one person to the next. It's also influenced by psychological factors such as anxiety (which tends to make pain worse) and attention (focusing on pain makes it worse; distractions take the edge off). Such influences also show up in fMRI scans, Wiech said. Moreover, she and others noted that several studies have found broad overlap in the brain regions activated by real and imagined pain--something that could be exploited by plaintiffs with bogus claims.

A. Vania Apkarian, a neuroscientist at Northwestern University in Evanston, Illinois, was more optimistic. His group has found that activity in the medial prefrontal cortex and the right insula correlates well with pain intensity and the duration of chronic pain, respectively, in people with chronic back pain. "This is an objective measure of pain in these patients," Apkarian said. Based on these and other findings, he predicted that fMRI will be courtroom-ready sooner than others had suggested. "Maybe not in 2008, maybe in 2012," he said. "It's inevitable."

Apkarian's data looked promising to several legal experts in attendance. "You scientists care more about causation than we do in the law," said Stanford law professor Henry "Hank" Greely. "If the correlation is high enough, … we would see that as a useful tool." Indeed, Greely and others noted, even if fMRI can't provide a perfectly objective measure of pain, it may still be better than the alternatives. "We let people get on the stand … and say all kinds of things that may or may not be true," said William Fletcher, a judge on the U.S. Court of Appeals for the Ninth Circuit.

Sneakiness and brain size

I have a huge backlog of potential mindblog posts which haven't yet made it into the two posts per day routine I have set up. They are interesting, but keep getting pushed back in the queue by newer material that is appearing. Here is an engaging piece from Natalie Angier, motivated perhaps by the Madoff scandal, on deception in humans and other animals - the 'lying in everyday life' that lubricates human and animal social interactions.

...[there is] a direct relationship between sneakiness and brain size. The larger the average volume of a primate species’ neocortex — the newest, “highest” region of the brain — the greater the chance that the monkey or ape would pull a stunt like this one described in The New Scientist: a young baboon being chased by an enraged mother intent on punishment suddenly stopped in midpursuit, stood up and began scanning the horizon intently, an act that conveniently distracted the entire baboon troop into preparing for nonexistent intruders.

...researchers found that the college students told an average of two lies a day, community members one a day, and that most of the lies fell into the minor fib category...There is a counterintuitive motivation not to detect lies, or we would have become much better at it...you may not really want to know that the dinner you just cooked stinks, or even that your spouse is cheating on you.

The article notes a further number of interesting deceptive behaviors in humans and other animals.

We infer rather than perceive the moment we decided to act.

Banks and Isham do a further followup (see this post for a previous followup) on the famous Libet experiment that showed that the reported time of a decision to perform a simple action is at least 300 ms after the onset of brain activity that normally precedes the action. They propose that the reported time is not uniquely determined by any generator of the readiness potential (the commonly head view), but rather is the time participants select on the basis of available cues, chief among them being the apparent time of response. From their abstract:

In Experiment 1, we presented deceptive feedback (an auditory beep) 5 to 60 ms after the action to signify a movement time later than the actual movement. The reported time of decision moved forward in time linearly with the delay in feedback, and came after the muscular initiation of the response at all but the 5-ms delay. In Experiment 2, participants viewed their hand with and without a 120-ms video delay, and gave a time of decision 44 ms later with than without the delay. We conclude that participants' report of their decision time is largely inferred from the apparent time of response. The perception of a hypothetical brain event prior to the response could have, at most, a small influence.

Anxiety correlates with diminished prefrontal control of attention.

Sonia J Bishop, in an article in Nature Neuroscience, makes the case that trait anxiety (i.e. stable ongoing anxiety tendencies not related to a specific sudden threat) may be characterized by impaired recruitment of prefrontal mechanisms that are critical to the active control of attention when the task at hand does not fully govern the allocation of attention. She proposes that this deficit does not arise as a result of current or state levels of anxiety, but instead reflects an underlying trait characteristic that influences attentional processing regardless of the presence or absence of threat-related stimuli. This may interact with state anxiety influences on subcortical threat detection mechanisms to account for the threat-related attentional biases associated with clinical anxiety. It may also account for observations that anxious individuals show deficits across a range of non-affective tasks that place demands on attentional or cognitive control. Here is her abstract:

Many neurocognitive models of anxiety emphasize the importance of a hyper-responsive threat-detection system centered on the amygdala, with recent accounts incorporating a role for prefrontal mechanisms in regulating attention to threat. Here we investigated whether trait anxiety is associated with a much broader dysregulation of attentional control. Volunteers performed a response-conflict task under conditions that posed high or low demands on attention. High trait-anxious individuals showed reduced prefrontal activity and slower target identification in response to processing competition when the task did not fully occupy attentional resources. The relationship between trait anxiety and prefrontal recruitment remained after controlling for state anxiety. These findings indicate that trait anxiety is linked to impoverished recruitment of prefrontal attentional control mechanisms to inhibit distractor processing even when threat-related stimuli are absent. Notably, this deficit was observed when ongoing task-related demands on attention were low, potentially explaining the day-to-day difficulties in concentration that are associated with clinical anxiety.

How do you feel — now? The anterior insula and human awareness

In a perspectives article in Nature Neuroscience Bud Craig proposes that the anterior insula plays a fundamental role in human awareness (if you simply enter 'anterior insula' in google images you can see depictions of the structures for yourself, or see the figure below). Here is his abstract, followed by a description of the structure and then his model for the involvement of the insula in awareness:

The anterior insular cortex (AIC) is implicated in a wide range of conditions and behaviours, from bowel distension and orgasm, to cigarette craving and maternal love, to decision making and sudden insight. Its function in the re-representation of interoception offers one possible basis for its involvement in all subjective feelings. New findings suggest a fundamental role for the AIC (and the von Economo neurons it contains) in awareness, and thus it needs to be considered as a potential neural correlate of consciousness.

A photograph of the left insular cortex of a human patient. The human insular cortex is a distinct but hidden lobe of the brain. It is disproportionately (approx30%) enlarged in the human relative to the macaque monkey. It has 5–7 oblique gyri, but its morphology is quite variable, even between the two sides. Primary interoceptive representations are located in the dorsal posterior insula and re-represented in a polymodal integrative zone in the mid-insula and again in the anterior insular cortex (AIC). The primary interoceptive, gustatory and vagal representations extend to the anterior limit of the insula in macaques but only to the middle of the insula in humans, which suggests that the AIC of humans has no equivalent in the monkey. The most anterior and ventral (inferior) portion of the human insula that adjoins the frontal operculum is probably the most recently evolved, because this part (as well as the anterior cingulate cortex) contains von Economo neurons. as, anterior short insular gyrus; al, anterior long insular gyrus; ac, accessory gyrus; APS, anterior peri-insular sulcus; H, Heschl's gyrus; IPS, inferior peri-insular sulcus; ms, middle short insular gyrus; ps, posterior short insular gyrus; pl, posterior long insular gyrus; SPS, superior peri-insular sulcus. Photograph is courtesy of Professor Thomas P. Naidich, Mount Sinai Medical Center, New York.

Cartoons illustrating features of the proposed structural model of awareness. a | The posited integration of salient activity, progressing from the posterior insula (left) to the anterior insula (right). The primary interoceptive representations of feelings from the body provide a somatotopic foundation that is anchored by the associated homeostatic effects on cardiorespiratory function, as indicated by the focus of the colours in the chest. The integration successively includes homeostatic, environmental, hedonic, motivational, social and cognitive activity to produce a 'global emotional moment', which represents the sentient self at one moment of time. b | The top cartoon shows how a series of global emotional moments can produce a cinemascopic 'image' of the sentient self across time. The lower cartoon shows how the proposed model can produce a subjective dilation of time during a period of high emotional salience, when global emotional moments are rapidly 'filled up'. ACC, anterior cingulate cortex; DLPFC, dorsolateral prefrontal cortex; VMPFC, ventromedial prefrontal cortex.

A trick for appreciating the present moment

How natural or easy is it to relish our daily life experiences? Every self-help book you pick up says we should "stop and smell the roses." Kurtz looks at temporal scarcity as a motivator. His abstract:

Both psychological research and conventional wisdom suggest that it can be difficult to attend to and derive enjoyment from the pleasant things in life. The present study examined whether focusing on the imminent ending of a positive life experience can lead to increased enjoyment. A temporal distance manipulation was used to make college graduation seem more or less close at hand. Twice a week over the course of 2 weeks, college students were told to write about their college life, with graduation being framed as either very close or very far off. As predicted, thinking about graduation as being close led to a significant increase in college-related behaviors and subjective well-being over the course of the study. The present research provides support for the counterintuitive hypothesis that thinking about an experience's ending can enhance one's present enjoyment of it.