A Neural Signature of Self-Control

From Brass and Haggard, in a recent issue of the Journal of Neuroscience (PDF here):

Voluntary action is fundamental to human existence. Recent research suggests that volition involves a specific network of brain activity, centered on the fronto-median cortex. An important but neglected aspect of intentional action involves the decision whether to act or not. This decision process is crucial in daily life because it allows us to form intentions without necessarily implementing them. In the present study, we investigate the neural correlates of intentionally inhibiting actions using functional magnetic resonance imaging. Our data show that a specific area of the fronto-median cortex is more strongly activated when people prepare manual actions but then intentionally cancel them, compared with when they prepare and then complete the same actions. Our results suggest that the human brain network for intentional action includes a control structure for self-initiated inhibition or withholding of intended actions. The mental control of action has an enduring scientific interest, linked to the philosophical concept of "free will." Our results identify a candidate brain area that reflects the crucial decision to do or not to do.

Figure: A, Activation in the dFMC for the contrast of inhibition versus action trials. The z-map is thresholded at z > 3.09 (p <>

Nature's revenge - Cicadas crashing the internet

Because any interruption of my internet connection leaves me feeling as if one of my limbs had been severed, I notice small articles like this from the Aug. 30 Nature Magazine. A clip:

A cicada known as the kumazemi is descending on Japan en masse...cutting households off from their Internet. Apparently mistaking fibre-optic cables for withered branches, they have been punching their one-millimetre-diameter ovipositors into the cables and laying eggs. In at least 1,000 cases over the past two years, the cicadas have either severed the cable or opened up a hole, allowing water to seep in. The Osaka-based Nippon Telephone and Telegraph West Corporation has responded by creating new cables that lack the grooves that the cicadas target with their ovipositors ...

Sexual orientation in women - brain correlates

Ponseti et al. suggest that they can observe a brain correlate of prenatal androgenization in homosexual women - they have less grey matter in their perirhinal cortex than heterosexual women. The article starts with a useful review of the controversial literature on previously suggested brain differences between homosexual and heterosexual individuals of the same sex. Here is their abstract and two figures:

Is sexual orientation associated with structural differences in the brain? To address this question, 80 homosexual and heterosexual men and women (16 homosexual men and 15 homosexual women) underwent structural MRI. We used voxel-based morphometry to test for differences in grey matter concentration associated with gender and sexual orientation. Compared with heterosexual women, homosexual women displayed less grey matter bilaterally in the temporo-basal cortex, ventral cerebellum, and left ventral premotor cortex. The relative decrease in grey matter was most prominent in the left perirhinal cortex. The left perirhinal area also showed less grey matter in heterosexual men than in heterosexual women. Thus, in homosexual women, the perirhinal cortex grey matter displayed a more male-like structural pattern. This is in accordance with previous research that revealed signs of sex-atypical prenatal androgenization in homosexual women, but not in homosexual men. The relevance of the perirhinal area for high order multimodal (olfactory and visual) object, social, and sexual processing is discussed.

Figure 1. Areas of increased GM concentration in heterosexual women compared to homosexual women. Coronal sections from y = 8 to y = −6 (p<0.05;>homosexual) was implicit masked with the contrast heterosexual (women>men). That way the intersection of significant voxels of both contrasts was gathered. As a result we found one cluster that matches both comparisons. That is, this brain area showed both, a lower GM concentration in heterosexual men compared to heterosexual women and a lower GM concentration in homosexual women relative to heterosexual women.

Figure 2. Heterosexual men and homosexual women compared to heterosexual women.
Areas of decreased GM concentration in heterosexual men are shown in blue and areas of decreased GM concentration in homosexual women are shown in yellow. Reduced GM concentration of homosexual women (relative to heterosexual women) is located within a sex dimorphic brain area.

A mouse model for OCD?

An interesting article from Welch et. al. reports finding a mutation that causes mice to display obsessive-compulsive behaviors. From the review of this work by Hyman:

Roughly 2% of humans suffer from obsessive compulsive disorder, but a lack of animal models has impeded research into this condition. Could a genetically engineered mouse model provide an exciting lead?

The mice studied by Welch et al. showed excessive grooming, which resulted in hair loss and skin injuries, as well as anxiety-like traits. These mice lack the gene encoding SAPAP3 — a scaffolding protein that is found in excitatory, glutamate-responsive synapses and is highly expressed only in the striatum region of the brain. The behavioural abnormalities in these mice were reversed by local expression of Sapap3 in the striatal region, which indicates that loss of this gene is responsible for the observed behavioural abnormalities.

The authors also found that a drug from the SSRI class — which selectively enhance serotonin-mediated neurotransmission throughout the brain — that is used to treat OCD in humans decreases both grooming and anxiety in these mice. This is interesting because a condition responsive to an enhancer of serotonin neurotransmission does not signify a primary defect in serotonin-mediated signalling; instead, the defect is in glutamate-responsive synapses. So alterations in serotonin seem to modulate glutamate action. These findings are also noteworthy because Welsh and colleagues have generated a possible mouse model of OCD. Moreover, these observations add to the accumulating, if circumstantial, evidence that OCD and its associated disorders result from abnormalities in neural circuits spanning the frontal, striatal and thalamic regions of the brain.

And, a word of caution:

Even if we can gain assurance with additional research that the behaviours observed in Sapap3-deficient mice reflect abnormalities in circuits that produce human symptoms, we cannot assume that OCD-related conditions in humans involve variations in this gene. These disorders, like other major psychiatric diseases, seem to be heterogeneous with complex underpinnings — probably involving several genes — that, in interaction with developmental and environmental factors, could lead to abnormalities in frontal–striatal–thalamic circuits.

An enzyme that keeps old memories alive

Greg Miller writes a brief review of work by Shema et al. :

Many substances interfere with memory, as any hung-over partygoer can attest. But although booze and drugs can disrupt the making of new memories (such as the embarrassing antics at last night's party), they leave older memories intact. Neuroscientists think this is because, after a time, memories become wired into the brain in a way that makes them harder to wipe out: Long-term memories, in the generally accepted view, are maintained by structural changes to the synaptic connections between neurons.

The study [by Shama et al.] adds to other recent evidence that may challenge, or at least complicate, this view. A team of neuroscientists reports that injecting a drug that blocks an enzyme called protein kinase Mzeta (PKMzeta) into the cerebral cortex of rats makes the animals forget a meal that made them sick weeks earlier. The findings suggest that the continuing activity of PKMzeta is somehow necessary to maintain long-term memory, something that's not predicted by most current hypotheses on the mechanisms of memory. The work also hints at the possibility of future drugs that could tinker with memory--for therapeutic uses or for boosting brainpower.

"This is a somewhat mind-blowing conclusion," says David Glanzman, a neuroscientist at the University of California, Los Angeles. Enzymes similar to PKMzeta are known to be important in early stages of memory formation, Glanzman says, but most researchers had thought that these compounds were not needed to sustain memory once synaptic changes--such as the growth of new synapses or the strengthening of existing ones--had occurred.

...Going forward, it will be important to figure out how specific ZIP's memory-erasing effects are, says Lynn Nadel, a neuroscientist at the University of Arizona in Tucson. "It's possible that ZIP erases all learning, no matter how old," Nadel says. But if the drug works more selectively, it could one day have clinical applications, he says. For example, researchers and clinicians have been looking for compounds capable of eliminating the painful memories of trauma survivors (Science, 2 April 2004, p. 34). The flip side is cognitive enhancement, adds Richard Morris, a neuroscientist at the University of Edinburgh, U.K. "The next step might be to find out whether augmenting the action of PKMzeta can help sustain memories for longer than occurs normally."

Pruning of nerve connections during development.

As we grow from infancy to adulthood, specific connections (synapses) between nerve cells are formed, and excess connections pruned away. Approximately 40% of the connections (synapses) between nerve cells in our brains disappear during development. How does a nerve cell decide which synapses to destroy? Din et al., studying the nematode Caenorhabditis elegans provide evidence that the creation of adult synapses triggers the destruction of developmentally transient synapses forged by the same neuron. David Miller offers a summary figure in his review showing the molecular details of how a primary synapse region matures while a secondary synapse region is eliminated.


Disconnections (Click to enlarge). (Top) The developing HSNL motor neuron initially forms synapses with vulval muscles and motor neurons in two locations. (Bottom) The protein SYG-1 blocks proteolysis of synaptic proteins at primary synapses but allows destruction of secondary synapses. E2, E2 ubiquitin conjugating enzyme; RBX, Ring finger protein.

Dramatic out of body demonstrations in normal subjects

I've done several posts (for example here, here, and here) on how underlying brain processes might explain what have been taken to be paranormal experiences, particularly assuming part or all of one's body to be projected out into surrounding space. By now the evidence is overwhelming that our sense of of the location of our physical body can be projected in space wherever we wish. Sandra Blakeslee now comments (PDF here) on several recent very effective demonstrations of body projection in space reported in Science Magazine (here and here). You really should watch this video of one of the experiments from Blanke's group:

Steven Fry's secret life of the manic-depressive

A friend pointed out this video to me. Fascinating. This is part I, which at its end links you on to the subsequent installments in the series.

More on magic at Las Vegas

I've done several postings on this already, but want to pass on George Johnson's excellent article in the Aug. 21 Science Section of the NYTimes about a session I attended given by Las Vegas Magicians for the recent meeting of the Association for the Scientific Study of Consciousness (PDF here).

The four ages of functional neuroimaging

An essay offered by Brad Buchsbaum on his blog.

Really weird...

Passing this on from MindHacks: an unknown man with a brain tattooed on the top of his head, revealed by a picture of a peeled back tuna can.

Changes in brain control circuits during human development

A collaboration at Washington University between Fair, Raichle, and others has offered a fascinating glimpse at how brain networks controlling our behavior develop from childhood through adolescence to adulthood. Here is their abstract, followed by two figures from the paper (PDF is here).

Human attentional control is unrivaled. We recently proposed that adults depend on distinct frontoparietal and cinguloopercular networks for adaptive online task control versus more stable set control, respectively. During development, both experience-dependent evoked activity and spontaneous waves of synchronized cortical activity are thought to support the formation and maintenance of neural networks. Such mechanisms may encourage tighter "integration" of some regions into networks over time while "segregating" other sets of regions into separate networks. Here we use resting state functional connectivity MRI, which measures correlations in spontaneous blood oxygenation level-dependent signal fluctuations between brain regions to compare previously identified control networks between children and adults. We find that development of the proposed adult control networks involves both segregation (i.e., decreased short-range connections) and integration (i.e., increased long-range connections) of the brain regions that comprise them. Delay/disruption in the developmental processes of segregation and integration may play a role in disorders of control, such as autism, attention deficit hyperactivity disorder, and Tourette's syndrome.

Fig. 2. (click to enlarge) Graphs formed from putative task-control regions in children, adolescents, and adults. ROI (regions of interest) locations are drawn to correspond to topographic brain locations. Right-sided ROIs are displayed on the right and anterior ROIs at the top of each graph. (A) rs-fcMRI revealed two separate control networks in adults as previously described (6). (B) The top 75 connections in adolescents revealed a similar two-component system as seen in adults; however, the dACC/msFC region was incorporated into the frontoparietal network. (C) The top 75 connections in children revealed a significant deviation from the adult architecture. The two networks were connected by a bridge connection (aPFC–dlPFC). The dACC/msFC region was incorporated into the frontoparietal network. Children lacked connections from the dlPFC to IPS and IPL. (D) Fit LOWESS curves of connection strength (r) versus age. As connection strength between the dACC/msFC region and the dF cortex decreased with age, correlation strength increased between the dACC/msFC and aI/fO regions. The aPFC region also decreased its connection strength with the dlPFC region with age but was already strongly connected to the aI/fO region in children. The strength of the aI/fO–aPFC connection was maintained into adulthood.

Fig. 3. (click to enlarge) Increased long-range and decreased short-range connectivity with age. Direct comparisons of all possible connections between adults and children were performed to test the statistical reliability of between-group differences. Both left- and right-hemisphere regions are placed on a transparent brain to aid with visualization. Red and blue lines highlight significant between-group differences for connections with an r ≥ 0.1 in either children or adults (i.e., absolute difference). Light blue and pink lines highlight connections present in both children and adults (r ≥ 0.1) that differed significantly in connection strength between groups (relative difference; P ≤ 0.05). (A) The segregation of the dACC/msFC region from the frontoparietal network (Fig. 2) was statistically significant, as was the disconnection of the aPFC from the dlPFC region (P ≤ 0.05). Most of the connections that "grew down" with age constituted short-range connections. Connections that "grew up" with age are faded to highlight this observation. (B) Connections between the dACC/msFC region and the cinguloopercular network that grew stronger with age were statistically significant (P ≤ 0.05). The connections of left dlPFC to left IPS and left frontal to left IPS were already present in children but significantly increased in strength with age. Most of the connections that "grew up" with age constituted long-range connections. Connections that "grew down" with age are faded to highlight this observation. Selected LOWESS curves are presented in A and B.

Live Longer - Don't Worry

Check out the Worriers Anonymous site and its several mellow out options such as this, this, or this.

The Politics of God

Mark Lilla, Professor of the humanities at Columbia Univ., has generated an essay (adapted from his book "The Stillborn God: Religion, Politics and the Modern West") which appeared in the The New York Times Magazine of Aug. 19. It is beautifully written, focusing on Western political and religious history, and its interactions with Islam. I offer a few clips here:

The twilight of the idols has been postponed. For more than two centuries, from the American and French Revolutions to the collapse of Soviet Communism, world politics revolved around eminently political problems. War and revolution, class and social justice, race and national identity — these were the questions that divided us. Today, we have progressed to the point where our problems again resemble those of the 16th century, as we find ourselves entangled in conflicts over competing revelations, dogmatic purity and divine duty. We in the West are disturbed and confused. Though we have our own fundamentalists, we find it incomprehensible that theological ideas still stir up messianic passions, leaving societies in ruin. We had assumed this was no longer possible, that human beings had learned to separate religious questions from political ones, that fanaticism was dead. We were wrong.

The revival of political theology in the modern West is a humbling story. It reminds us that this way of thinking is not the preserve of any one culture or religion, nor does it belong solely to the past. It is an age-old habit of mind that can be reacquired by anyone who begins looking to the divine nexus of God, man and world to reveal the legitimate political order. This story also reminds us how political theology can be adapted to circumstances and reassert itself, even in the face of seemingly irresistible forces like modernization, secularization and democratization. Rousseau was on to something: we seem to be theotropic creatures, yearning to connect our mundane lives, in some way, to the beyond. That urge can be suppressed, new habits learned, but the challenge of political theology will never fully disappear so long as the urge to connect survives.


So we are heirs to the Great Separation only if we wish to be, if we make a conscious effort to separate basic principles of political legitimacy from divine revelation. Yet more is required still. Since the challenge of political theology is enduring, we need to remain aware of its logic and the threat it poses. This means vigilance, but even more it means self-awareness. We must never forget that there was nothing historically inevitable about our Great Separation, that it was and remains an experiment. In Europe, the political ambiguities of one religion, Christianity, happened to set off a political crisis that might have been avoided but wasn’t, triggering the Wars of Religion; the resulting carnage made European thinkers more receptive to Hobbes’s heretical ideas about religious psychology and the political implications he drew from them; and over time those political ideas were liberalized. Even then, it was only after the Second World War that the principles of modern liberal democracy became fully rooted in continental Europe.

As for the American experience, it is utterly exceptional: there is no other fully developed industrial society with a population so committed to its faiths (and such exotic ones), while being equally committed to the Great Separation. Our political rhetoric, which owes much to the Protestant sectarians of the 17th century, vibrates with messianic energy, and it is only thanks to a strong constitutional structure and various lucky breaks that political theology has never seriously challenged the basic legitimacy of our institutions. Americans have potentially explosive religious differences over abortion, prayer in schools, censorship, euthanasia, biological research and countless other issues, yet they generally settle them within the bounds of the Constitution. It’s a miracle.

...a number of Muslim thinkers around the world have taken to promoting a “liberal” Islam. What they mean is an Islam more adapted to the demands of modern life, kinder in its treatment of women and children, more tolerant of other faiths, more open to dissent. These are brave people who have often suffered for their efforts, in prison or exile, as did their predecessors in the 19th century, of which there were many. But now as then, their efforts have been swept away by deeper theological currents they cannot master and perhaps do not even understand. The history of Protestant and Jewish liberal theology reveals the problem: the more a biblical faith is trimmed to fit the demands of the moment, the fewer reasons it gives believers for holding on to that faith in troubled times, when self-appointed guardians of theological purity offer more radical hope. Worse still, when such a faith is used to bestow theological sanctification on a single form of political life — even an attractive one like liberal democracy — the more it will be seen as collaborating with injustice when that political system fails. The dynamics of political theology seem to dictate that when liberalizing reformers try to conform to the present, they inspire a countervailing and far more passionate longing for redemption in the messianic future. That is what happened in Weimar Germany and is happening again in contemporary Islam.

In the end, though, what happens on the opposite shore will not be up to us. We have little reason to expect societies in the grip of a powerful political theology to follow our unusual path, which was opened up by a unique crisis within Christian civilization. This does not mean that those societies necessarily lack the wherewithal to create a decent and workable political order; it does mean that they will have to find the theological resources within their own traditions to make it happen.

Our challenge is different. We have made a choice that is at once simpler and harder: we have chosen to limit our politics to protecting individuals from the worst harms they can inflict on one another, to securing fundamental liberties and providing for their basic welfare, while leaving their spiritual destinies in their own hands. We have wagered that it is wiser to beware the forces unleashed by the Bible’s messianic promise than to try exploiting them for the public good. We have chosen to keep our politics unilluminated by divine revelation. All we have is our own lucidity, which we must train on a world where faith still inflames the minds of men.

Two Books on Brain Plasticity

I'm not sure why I haven't mentioned these books, both appearing earlier this year. In "Train Your Mind, Change Your Brain: How a New Science Reveals Our Extraordinary Potential to Transform Ourselves" Wall Street Journal science writer Sharon Begley gives an account that derives largely from a 2004 meeting at MIT in Cambridge Mass (which I also enjoyed attending) in which the Dali Lama, Buddhist monks, and prominent neuroscientists exchanged insight and information. The book mentions work with meditation and mind training, as well as new approaches in treating dyslexia, depression, mental deterioration on aging, etc., but it is not a how-to manual.

The book by Norman Doidge, "The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science" gives stories of numerous examples of neuroplasticity and rehabilitation among his own patients, as well as relating other case studies of recovery and conversations with neuroscientists.

What I totally do not get....a new book on consciousness

I've received four emails promoting a new book by B. Alan Wallace, a guy who has been the subject of two previous posts, one a positive review and abstracting of his book "The Attention Revolution," and the other more critical comments on a video presentation titled "Towards the first revolution in the mind sciences" he gave at a seminar for Google employees. That video presentation contains core ideas in his new book "Hidden Dimensions: The Unification of Physics and Consciousness (Columbia University Press, 2007)."

Below I give you the blurb on the book, and the problems I have with this are stated in the critical review just mentioned, some repeated below:

Bridging the gap between the world of science and the realm of the spiritual, B. Alan Wallace introduces a natural theory of human consciousness that has its roots in contemporary physics and Buddhism. Wallace’s "special theory of ontological relativity" suggests that mental phenomena are conditioned by the brain, but do not emerge from it. Rather, the entire natural world of mind and matter, subjects and objects, arises from a unitary dimension of reality that is more fundamental than these dualities, as proposed by Wolfgang Pauli and Carl Jung.

To test his hypothesis, Wallace employs the Buddhist meditative practice of samatha, refining one’s attention and metacognition, to create a kind of telescope to examine the space of the mind. Drawing on the work of the physicist John Wheeler, he then proposes a more general theory in which the participatory nature of reality is envisioned as a self-excited circuit. In comparing these ideas to the Buddhist theory known as the Middle Way philosophy, Wallace explores further aspects of his "general theory of ontological relativity," which can be investigated by means of vipasyana, or insight, meditation. Wallace then focuses on the theme of symmetry in reference to quantum cosmology and the “problem of frozen time,” relating these issues to the theory and practices of the Great Perfection school of Tibetan Buddhism. He concludes with a discussion of the general theme of complementarity as it relates to science and religion.

The theories of relativity and quantum mechanics were major achievements in the physical sciences, and the theory of evolution has had an equally deep impact on the life sciences. Yet rigorous scientific methods do not yet exist to observe mental phenomena, and naturalism has its limits for shedding light on the workings of the mind. A pioneer of modern consciousness research, Wallace offers a practical and revolutionary method for exploring the mind that combines the keenest insights of contemporary physicists and philosophers with the time-honored meditative traditions of Buddhism.

My previous response:

The problem I think is that his analogy with other scientific revolutions fails on the issue of universality and ability to reproduce basic introspective observations. Galileo's and Darwin's observations and measurements can be reproduced by anyone in any culture having appropriate equipment. In the period after William James' challenge and before the behaviorists' 50+ year death grip on progress in psychology a number of groups pursuing an introspective approach could not agree on many basic observations (Wallace commented on, but did not really address this issue in the discussion period). The introspective and meditative approaches associated with many different cultures and religions don't seem remotely close to yielding a unified introspective description of consciousness and our mental processes that transcends their cultural origins in the way that astronomy and biology do.

Still, I think that the Buddha was the first great human biologist in his astute descriptions of levels of human behavior that corresponds roughly to stages in the biological evolution of our own brains and behavior (see my "Beast Within" essay). The mutual reinforcement of ancient introspective and modern scientific traditions yields some robustness, and perhaps the prospect of an eventual union of materialistic and mentalistic perspectives. Perhaps this will yield the "consciousness meter," analogous to a telescope or microscope, than we are now lacking.

Flipping switches in the brain with light.

The Aug. 14 science section of the NYTimes (PDF here) notes a technique which I mentioned in a previous post: making brain cells susceptible to light activation by inserting a light sensitive ion channel in their membranes.

A first step is establishing that it is possible to tweak a brain circuit by remote control and observe the corresponding behavioral changes in freely moving lab animals. On a recent Sunday at Stanford, Dr. Deisseroth and Feng Zhang, a graduate student, hovered over a dark brown mouse placed inside a white plastic tub. Through standard gene-manipulating tricks, the rodent had been engineered to produce channelrhodopsin only in one particular kind of neuron found throughout the brain, to no apparent ill effect....Mr. Zhang had implanted a tiny metal tube into the right side of the mouse’s partly shaved head...Now he carefully threaded a translucent fiber-optic cable not much wider than a thick human hair into that tube, positioned over the area of the cerebral cortex that controls movement...(then).. adjusted a key on a nearby laser controller box, and the fiber-optic cable glowed with blue light. The mouse started skittering in a left-hand spin, like a dog chasing its tail....“Turn it off, and then you can see him stand up,” Dr. Deisseroth continued. “And now turn it back on, and you can see it’s circling.”..Because the brain lacks pain receptors, the mouse felt no discomfort from the fiber optic, the scientists said, although it looked a tad confused. Scientists have long known that using electrodes to gently zap one side of a mouse’s motor cortex will make it turn the opposite way. What is new here is that for the first time, researchers can perturb specific neuron types using light.....

Legend: Light stimulation every 200 milliseconds generates electrical activity, right, in an area of the brain associated with depression.

At Stanford, Dr. Deisseroth’s group has identified part of a brain circuit, in the hippocampus, that is underactive in rats, with some symptoms resembling depression. The neural circuit’s activity — and the animals’ — perked up after antidepressant treatment, in findings reported last week in the journal Science. Now the team is examining whether they can lift the rats’ low-energy behavior by using channelrhodopsin to rev up the sluggish neural zone...

The Stanford group has sent DNA copies of the “on” and “off” light-switch genes to more than 175 researchers eager to try them in all stripes of electrically excitable cells, from insulin-releasing pancreas cells to heart cells.

Imaging Depression

Thomas Insel writes a perspectives article in the Aug. 10 issue of Science (PDF here) on efforts to specify brain areas that show abnormal activity during depression. A clip from his article:

Neuroimaging studies of humans with major depressive disorder have largely pointed to prefrontal sites, especially implicating an area in the midline subgenual anterior cingulate cortex, often denoted as area 25 (see the figure. Not only does this region appear abnormal on structural and functional scans, but also it is enriched with the serotonin transporter, a target for many antidepressant drugs. Individuals inheriting a risk allele within the promoter of the serotonin transporter gene have reduced volume of area 25 and reduced functional coupling of this region to the amygdala, a subcortical region implicated in the regulation of emotion. An initial study of treatment-resistant depressed patients reports that deep brain stimulation adjacent to area 25 relieves the symptoms of major depressive disorder.

Male sexual behavior circuits in female brains...

A fascinating bit of work by Kimchi and Dulac shows that female mice missing a gene involved in pheromone detection show the same sexual behaviour as males. Their abstract:

In mice, pheromone detection is mediated by the vomeronasal organ and the main olfactory epithelium. Male mice that are deficient for Trpc2, an ion channel specifically expressed in VNO neurons and essential for VNO sensory transduction, are impaired in sex discrimination and male–male aggression. We report here that Trpc2-/- female mice show a reduction in female-specific behaviour, including maternal aggression and lactating behaviour. Strikingly, mutant females display unique characteristics of male sexual and courtship behaviours such as mounting, pelvic thrust, solicitation, anogenital olfactory investigation, and emission of complex ultrasonic vocalizations towards male and female conspecific mice. The same behavioural phenotype is observed after VNO surgical removal in adult animals, and is not accompanied by disruption of the oestrous cycle and sex hormone levels. These findings suggest that VNO-mediated pheromone inputs act in wild-type females to repress male behaviour and activate female behaviours. Moreover, they imply that functional neuronal circuits underlying male-specific behaviours exist in the normal female mouse brain.

There is some controversy over whether this result is unique to inbred laboratory mouse strains, so Dulac is now breeding wild mice with the Trpc2-mutant mice, to experiment with a 'wilder' version.

Happiness Tips

I enjoyed watching an interview of Tal Ben-Shahar on the John Stewart Daily News shows several days ago, discussing his new book "Happier." He has integrated threads of the positive psychology movement initiated largely by Martin Seligman (see my post on Seligman) to offer the most popular undergraduate course at Harvard. Although I usually have a gag reaction at most of the self-help stuff I see, I thought I would pass on some of the sane happiness tips from his website. And, a quick search at YouTube gets you his promotional video, also shown below.

* 1. Give yourself permission to be human. When we accept emotions — such as fear, sadness, or anxiety — as natural, we are more likely to overcome them. Rejecting our emotions, positive or negative, leads to frustration and unhappiness.

* 2. Happiness lies at the intersection between pleasure and meaning. Whether at work or at home, the goal is to engage in activities that are both personally significant and enjoyable. When this is not feasible, make sure you have happiness boosters, moments throughout the week that provide you with both pleasure and meaning.

* 3. Keep in mind that happiness is mostly dependent on our state of mind, not on our status or the state of our bank account. Barring extreme circumstances, our level of well being is determined by what we choose to focus on (the full or the empty part of the glass) and by our interpretation of external events. For example, do we view failure as catastrophic, or do we see it as a learning opportunity?

* 4. Simplify! We are, generally, too busy, trying to squeeze in more and more activities into less and less time. Quantity influences quality, and we compromise on our happiness by trying to do too much.

* 5. Remember the mind-body connection. What we do — or don't do — with our bodies influences our mind. Regular exercise, adequate sleep, and healthy eating habits lead to both physical and mental health.

* 6. Express gratitude, whenever possible. We too often take our lives for granted. Learn to appreciate and savor the wonderful things in life, from people to food, from nature to a smile.