The Kerfuffle over whether men and women's brains are different.

Nothing kicks up a firestorm in the Neuroscience blogosphere like talk of sex differences in brain architecture. Within days of PNAS's early December 2013 publication of what may be a landmark paper on the differing 'connectomes' (nerve fiber tracts connecting different brain areas) of 428 male and 521 female 8-22 year old humans, a storm of criticism of the work was bouncing around the internet, along with accusations of 'neurosexism'. (see, for example, here, here, here, and here.)

The critics make many points - 1. Men have bigger brains on average than women, possibly conflating results; 2. Maybe men and women move their heads differently while in the MRI machine; 3. The structural differences don't necessarily correlate with behavioral differences, and there are varying results on whether the structural results correlate with cognitive function tests. It is unfortunate that the authors of the study were spouting gender stereotypes...but...it seems to me that the objections are mainly nit-picking, the data are rather compelling on fundamental differences in sexual connectivity that arise from genetic/environmental/cultural factors during brain development. (There is no such thing as 'hard wiring'.):

The results establish that male brains are optimized for intrahemispheric and female brains for interhemispheric communication. The developmental trajectories of males and females separate at a young age, demonstrating wide differences during adolescence and adulthood...The brains of men exhibit a far smaller degree of interconnectedness, both within and across the hemispheres, than do those of women.

I decided to wait for the dust to settle a bit, and let the final publication appear, and sure enough in the same issue there is an essay commentary by Larry Cahill that argues essentially that the politically correct view in brain research has been to assume no significant difference between male and female brain, and to assume results obtained (mainly for male brains) apply also to female brains.  Mouse studies in particular have shown that this is not the case.

...we now know that sex influences—small to medium to large—are extremely widespread on brain function. The validity of the assumption that the sex of subjects cannot powerfully alter, negate, and even reverse findings (hence, conclusions) has been crushed under the weight of evidence proving that it can and regularly does and at every level of investigation down to genes, single neurons, and even ion channels...For neuroscientists cognizant of this striking development, the main challenge now is to better understand the dizzying plethora of sex influences being uncovered. Males and females appear to be two complex mosaics, similar in some respects, mildly to highly different in others

Here is Cahill's summary comment:

A comedian discussing men and women once described the male brain as a bunch of boxes that don’t touch one another and the female brain as a complex ball of interconnected wires. Amusing as the bit was, the analogies may be more apt than he could have known. The findings of Ingahalikar et al. do indeed point to a greater degree of modular function in the physical architecture of the male brain and of interconnectedness in physical architecture of the female brain. Given the size of the study, the consistency of the conclusions across various analytic approaches, and the seeming concordance of key findings with well-established literature addressing brain function, one cannot fairly accuse Ingalhalikar et al. of hyperbole when they claim that their findings “reveal fundamental sex differences in the architecture of the human brain.” Theirs is a landmark paper that should accelerate acceptance of the notion that, for those who want to understand how brains function, sex matters.

And here, finally, is the Ingalhalikar et al. abstract:

Sex differences in human behavior show adaptive complementarity: Males have better motor and spatial abilities, whereas females have superior memory and social cognition skills. Studies also show sex differences in human brains but do not explain this complementarity. In this work, we modeled the structural connectome using diffusion tensor imaging in a sample of 949 youths (aged 8–22 y, 428 males and 521 females) and discovered unique sex differences in brain connectivity during the course of development. Connection-wise statistical analysis, as well as analysis of regional and global network measures, presented a comprehensive description of network characteristics. In all supratentorial regions, males had greater within-hemispheric connectivity, as well as enhanced modularity and transitivity, whereas between-hemispheric connectivity and cross-module participation predominated in females. However, this effect was reversed in the cerebellar connections. Analysis of these changes developmentally demonstrated differences in trajectory between males and females mainly in adolescence and in adulthood. Overall, the results suggest that male brains are structured to facilitate connectivity between perception and coordinated action, whereas female brains are designed to facilitate communication between analytical and intuitive processing modes.

Bodily maps of emotions.

Nummenmaa and collaborators, from several universities in Finland, propose that our emotions are represented in our somatosensory system as culturally universal categorical somatotopic maps.

Emotions are often felt in the body, and somatosensory feedback has been proposed to trigger conscious emotional experiences. Here we reveal maps of bodily sensations associated with different emotions using a unique topographical self-report method. In five experiments, participants (n = 701) were shown two silhouettes of bodies alongside emotional words, stories, movies, or facial expressions. They were asked to color the bodily regions whose activity they felt increasing or decreasing while viewing each stimulus. Different emotions were consistently associated with statistically separable bodily sensation maps across experiments. These maps were concordant across West European and East Asian samples. Statistical classifiers distinguished emotion-specific activation maps accurately, confirming independence of topographies across emotions. We propose that emotions are represented in the somatosensory system as culturally universal categorical somatotopic maps. Perception of these emotion-triggered bodily changes may play a key role in generating consciously felt emotions.

Figure - Bodily topography of basic (Upper) and nonbasic (Lower) emotions associated with words. The body maps show regions whose activation increased (warm colors) or decreased (cool colors) when feeling each emotion.

The morning morality effect.

Here is an interesting tidbit from Kouchaki1 and Smith:

Are people more moral in the morning than in the afternoon? We propose that the normal, unremarkable experiences associated with everyday living can deplete one’s capacity to resist moral temptations. In a series of four experiments, both undergraduate students and a sample of U.S. adults engaged in less unethical behavior (e.g., less lying and cheating) on tasks performed in the morning than on the same tasks performed in the afternoon. This morning morality effect was mediated by decreases in moral awareness and self-control in the afternoon. Furthermore, the effect of time of day on unethical behavior was found to be stronger for people with a lower propensity to morally disengage. These findings highlight a simple yet pervasive factor (i.e., the time of day) that has important implications for moral behavior.

The milliseconds of a choice - Watching your mind when it matters.

This is actually a post about mindfulness, in reaction to Dan Hurley's article describing how contemporary applications of the ancient tradition of mindfulness meditation are being engaged in many more contexts than the initial emphasis on chilling out in the 1970s, and being employed for very practical purses such as mental resilience in a war zone. It seems like to me that we are approaching a well defined technology of brain control whose brain basis is understood in some detail. I've done numerous posts on behavioral and brain correlates of mindfulness meditation (enter 'meditation' or 'mindfulness' in MindBlog's search box in the left column). For example, only four weeks of a mindfulness meditation regime emphasizing relaxation of different body parts correlates with increases in white matter (nerve tract) efficiency. Improvements in cognitive performance, working memory, etc. have been claimed. A special issue of The journal Social Cognitive and Affective Neuroscience discusses issue in the research.

Full time mindfulness might be a bad idea, suppressing the mind wandering that facilitates bursts of creative insight. (During my vision research career, my most original ideas popped up when I was spacing out, once when I was riding a bike along a lakeshore path.) Many physicists and writers reports their best ideas happen when they are disengaged. It also appears that mindfulness may inhibit implicit learning in which habits and skill are acquired without conscious awareness.

Obviously knowing whether we are in an attentional or mind wandering (default, narrative) modes is useful (see here, and here), and this is where the title of this posts comes in. To note and distinguish our mind state is most effectively accomplished with a particular style of alertness or awareness that is functioning very soon (less than 200 milliseconds) after a new thought or sensory perception appears to us. This is a moment of fragility that offers a narrow time window of choice over whether our new brain activity will be either enhanced or diminished in favor of a more desired activity. This is precisely what is happening in mindfulness meditation that instructs a central focus of some sort (breathing, body relaxation, or whatever) to which one returns as soon as one notes that any other thoughts or distractions have popped into awareness. The ability to rapidly notice and attend to thoughts and emotions of these short time scales is enhanced by brain training regimes of the sort offered by BrainHq of positscience.com and others. I have found the exercises on this site, originated by Michael Merznich, to be the most useful.  It offers summaries of changes in brain speed, attention, memory, intelligence, navigation, etc. that result from performing the exercises - changes that can persist for years.

A book title that has been popping into my head for at least the last 15 years is "The 200 Millisecond Manager." (a riff on the title the popular book of the early 1980's by Blanchard and Johnson, "The One Minute Manager.") The gist of the argument would be that given in the "Guide" section of some 2005 writing, and actually in Chapter 12 of my book, Figure 12-7.

It might make the strident assertion that the most important thing that matters in regulating our thoughts, feelings, and actions is their first 100-200 msec in the brain, which is when the levers and pulleys are actually doing their thing. It would be a nuts and bolts approach to altering - or at least inhibiting - self limiting behaviors. It would suggest that a central trick is to avoid taking on on the ‘enormity of it all,’ and instead use a variety of techniques to get our awareness down to the normally invisible 100-200 msec time interval in which our actions are being programmed. Here we are talking mechanics during the time period is when all the limbic and other routines that result from life script, self image, temperament, etc., actually can start-up. The suggestion is that you can short circuit some of this process if you bring awareness to the level of observing the moments during which a reaction or behavior is becoming resident, and can sometimes say “I don’t think so, I think I'll do something else instead.”

"The 200 msec Manager" has gone through the ‘this could be a book’ cycle several times, the actual execution  bogging down as I actually got into description of the underlying science and techniques for expanding awareness. Also, I note the enormous number of books out there on meditation, relaxation, etc. that are all really addressing the same core processes in different ways.

Beauty at the ballot box.

From White et al.:

Why does beauty win out at the ballot box? Some researchers have posited that it occurs because people ascribe generally positive characteristics to physically attractive candidates. We propose an alternative explanation—that leadership preferences are related to functional disease-avoidance mechanisms. Because physical attractiveness is a cue to health, people concerned with disease should especially prefer physically attractive leaders. Using real-world voting data and laboratory-based experiments, we found support for this relationship. A first study revealed that congressional districts with elevated disease threats, physically attractive candidates are more likely to be elected. A second study found that experimentally activating disease concerns leads people to especially value physical attractiveness in leaders and a third study showed they prefer more physically attractive political candidates. In a final study, we demonstrated that these findings are related to leadership preferences, specifically, rather than preferences for physically attractive group members more generally. Together, these findings highlight the nuanced and functional nature of leadership preferences.

Signals from inside and outside our bodies in self consciousness

Olaf Blanke (whose work on projecting ourselves outside our bodies I've mentioned previously) and collaborators extend their studies on body perception and self consciousness to show that signals from both the inside and the outside of the body are fundamental in determining our self consciousness:

Prominent theories highlight the importance of bodily perception for self-consciousness, but it is currently not known whether bodily perception is based on interoceptive or exteroceptive signals or on integrated signals from these anatomically distinct systems. In the research reported here, we combined both types of signals by surreptitiously providing participants with visual exteroceptive information about their heartbeat: A real-time video image of a periodically illuminated silhouette outlined participants’ (projected, “virtual”) bodies and flashed in synchrony with their heartbeats. We investigated whether these “cardio-visual” signals could modulate bodily self-consciousness and tactile perception. We report two main findings. First, synchronous cardio-visual signals increased self-identification with and self-location toward the virtual body, and second, they altered the perception of tactile stimuli applied to participants’ backs so that touch was mislocalized toward the virtual body. We argue that the integration of signals from the inside and the outside of the human body is a fundamental neurobiological process underlying self-consciousness.

Experimental setup for the body conditions. Participants (a) stood with their backs facing a video camera placed 200 cm behind them (b). The video showing the participant’s body (his or her “virtual body”) was projected in real time onto a head-mounted display. An electrocardiogram was recorded, and R peaks were detected in real time (c), triggering a flashing silhouette outlining the participant’s virtual body (d). The display made it appear as though the virtual body was standing 200 cm in front of the participant (e). After each block, participants were passively displaced 150 cm backward to the camera and were instructed to walk back to the original position.

A reason for the power of prayer.

Friesea and Wänke find one source of the power of prayer that is not supernatural: it enhances self control by buffering self-control depletion, that is, protecting from breakdowns of will. In a sequential experimental paradigm, subjects were told to watch a humorous video but stifle emotional responses (this causes cognitive depletion) and then performed the stroop task, in which they indicated the ink color of words spelling various color, with the words being either consistent or inconsistent with their actual colors. Studies have shown that this task is harder after cognitive depletion. Both religious and non-religious who were asked to pray about a topic of their choosing for five minutes showed significantly better performance on the stroop task after emotion suppression, compared to participants who were simply asked to think about a topic of their choosing. The authors suggest that people might interpret prayer as a social interaction with a deity, with that social interaction enhancing cognitive resources. Other studies have found that social interaction enhances general cognitive functioning. Here is the Friesea and Wänke abstract:

The strength model of self-control has inspired large amounts of research and contributed to a deeper understanding of the temporal dynamics underlying self-control. Several studies have identified factors that can counteract self-control depletion, but relatively little is known about factors that can prevent depletion effects. Here we tested the hypothesis that a brief period of personal prayer would buffer self-control depletion effects. Participants either briefly prayed or thought freely before engaging (or not engaging) in an emotion suppression task. All participants completed a Stroop task subsequently. Individuals who had thought freely before suppressing emotions showed impaired Stroop performance compared to those who had not suppressed emotions. This effect did not occur in individuals who had prayed at the beginning of the study. These results are consistent with and contribute to a growing body of work attesting to the beneficial effects of praying on self-control.

Left spatial neglect goes with neglecting the “Left Side” of time.

An interesting observation from Saj et al.:

Previous research suggests that people construct mental time lines to represent and reason about time. However, is the ability to represent space truly necessary for representing events along a mental time line? Our results are the first to demonstrate that deficits in spatial representation (as a function of left hemispatial neglect) also result in deficits in representing events along the mental time line. Specifically, we show that patients with left hemispatial neglect have difficulty representing events that are associated with the past and, thus, fall to the left on the mental time line. These results demonstrate that representations of space and time share neural underpinnings and that representations of time have specific spatial properties (e.g., a left and a right side). Furthermore, it appears that intact spatial representations are necessary for at least some types of temporal representation.

How the brains of virtuosic pianists are different...

Because I'm a performing classical pianist (in fact, giving a concert on Feb. 9 in Fort Lauderdale, my snowbird roost from mid-October to mid_April), I always perk up when I come across articles showing how the brains of experienced pianists or other musicians are different from the brains of non-musicians. Candidi et al. make the interesting observation that the refined somatosensory and motor skills of musicians provide the brain with fine anticipatory, simulative error monitoring systems that are absent in non-pianist naive individuals.

Virtuosic musical performance requires fine sensorimotor skills and high predictive control of the fast finger movements that produce the intended sounds, and cannot be corrected once the notes have been played. The anticipatory nature of motor control in experts explains why musical performance is barely affected by auditory feedback. Using single-pulse transcranial magnetic stimulation, In a first experiment we provide evidence that, in expert pianists, the observation of a mute piano fingering error induces 1) a time-locked facilitation of hand corticospinal representation which occurred 300 and 700 ms but not 100 ms after error onset, and 2) a somatotopic corticospinal facilitation of the very same finger that commits the error. In a second experiment, we show that no corticospinal modulation is found in non-pianist naïve individuals who were experimentally trained to visually detect the observed fingering errors. This is the first evidence showing that the refined somatosensory and motor skills of musicians exceed the domain of individual motor control and may provide the brain with fine anticipatory, simulative error monitoring systems for the evaluation of others’ movements.

The social life of our genes - the devastating effects of social isolation

David Dobbs has done a broad and accessible review of how completely the expression of the genes regulating behavior are controlled by the social milieu, giving examples for bees, birds, fish, primates, and humans. Social conditions can change our gene expression with a rapidity, breadth, and depth previously overlooked. Humans, and other animals, most likely have this evolved capability because an organism that responds quickly to fast-changing social environments will more likely survive them. Dobbs points in particular to work by work by Steve Cole on social regulation of gene expression. Cole analyzed the relationship between social factors and human gene expression by surveying transcriptional profiles in white blood cells (leukocytes) from healthy older adults who differed in the extent to which they felt socially connected to others.

Among the 22,283 genes assayed, 209 showed systematically different levels of expression in people who reported feeling lonely and distant from others consistently over the course of 4 years (see Figure). These effects did not involve a random smattering of all human genes, but focally affected three specific groups of genes. Genes supporting the early “accelerator” phase of the immune response—inflammation—were selectively up-regulated; and two groups of genes involved in the subsequent “steering” of immune responses—genes involved in responses to viral infections (particularly Type I interferons), and genes involved in the production of antibodies by B lymphocytes—were down-regulated. These results provided a molecular framework for understanding why socially isolated individuals show heightened vulnerability to inflammation-driven cardiovascular diseases (i.e., excessive nonspecific immune activity) and impaired responses to viral infections and vaccines (i.e., insufficient immune responses to specific pathogens). A major clue about the psychological pathways mediating these effects came from the observation that differential gene-expression profiles were most strongly linked to a person's subjective sense of isolation rather than to their objective number of social contacts.

Figure: Gene expression in human immune cells in lonely and socially integrated people. Expression of 22,283 human gene transcripts was assayed in 10 million blood leukocytes sampled from each of 14 older adults who showed consistent differences over 4 years in their level of subjective social isolation. Two hundred nine gene transcripts showed at least 30% difference in average expression level between six people experiencing chronic social isolation and eight experiencing consistent social integration. In the heat-plot above, each row represents data from one of the 14 study participants, each column contains expression values for one of the 209 differentially active genes, and the coloring of each cell represents the relative level of that gene's expression in a given participant's leukocyte sample: Red = high expression, Black = intermediate expression, Green = low expression.

Social Darwinism isn't dead - the rich really do think they are different...

An engaging piece by Matthew Hutson in Slate points to work by Kraus and Keltner. Some clips:

...In 2012 the top 0.01 percent of households earned an average of $10.25 million, while the mean household income for the country overall was $51,000. Are top earners 200 times as smart as the rest of the field? Doubtful. Do they have the capacity to work 200 times more hours in the week? Even more doubtful.

..say you’re in that top 0.01 percent—or even the top 50 percent. Would you want to admit happenstance as a benefactor? Wouldn’t you rather believe that you earned your wealth, that you truly deserve it? Wouldn’t you like to think that any resources you inherited are rightfully yours, as the descendant of fundamentally exceptional people? .. you might even adjust your ideas about the power of genes. The lower classes are not merely unfortunate, according to the upper classes; they are genetically inferior.

Kraus and Keltner's work explores "social class essentialism" - the belief that surface differences can be explained by differences in fundamental identities. Studies have shown that

...people hold essentialist beliefs about generally biological categories such as gender, race, and sexuality, as well as about more cultural ones such as nationality, religion, and political orientation. Essentialism leads to stereotyping, prejudice, and a disinclination to mingle with outsiders.

Kraus and Keltner wanted to know if we see social class as an essential category. They found:

...that higher social class was associated with greater social class essentialism. This pattern remained even after controlling for political orientation as well as objective measures of a participant’s income and education level, indicating that it’s one’s sense of being above or below others, not one’s actual resources, that drives the result...the higher people perceived their social class to be, the more strongly they endorsed just-world beliefs (i.e. that the world is a fair place), and that this difference explained their increased social class essentialism: Apparently if you feel that you’re doing well, you want to believe success comes to those who deserve it, and therefore those of lower status must not deserve it.

There is a grain to truth to social class essentialism; the few studies on the subject estimate that income, educational attainment, and occupational status are perhaps at least 10 percent genetic (and maybe much more). ..But that’s a far cry from saying “It is possible to determine one’s social class by examining his or her genes.” Such a statement ignores the role of wealth inheritance, the social connections one shares with one’s parents, or the educational opportunities family money can buy—not to mention strokes of good or bad luck (that are not tied to karma).

Social class essentialism is basically inciting social Darwinism. This distortion of Darwin’s theory of evolution, in one interpretation, is the belief that only the fit survive and thrive—and, further, that this process should be accepted or even accelerated by public policy...It might also entail belief in survival of the fittest as a desired end, given the results linking it to reduced support for restorative interventions... It’s an example of the logical fallacy known as the “appeal to nature”—what is natural is good. (If that were true, technology and medicine would be moral abominations.)

Watching our brain remembering something.

This is kind of neat! Staresinaa et al. observe a part of our brain working at remembering something while we go on about our further activities unrelated to what we want to remember.

How is new information converted into a memory trace? Here, we used functional neuroimaging to assess what happens to representations of new events after we first experience them. We found that a particular part of the medial temporal lobe, a brain region known to be critical for intact memory, spontaneously reactivates these events even when we are engaged in unrelated activities. Indeed, the extent to which such automatic reactivation occurs seems directly related to later memory performance. This finding shows that we can now study the dynamics of memory processes for specific experiences during the “offline” periods that follow the initial learning phase.

Figure- Offline reactivation in the entorhinal cortex (ErC). (Left) Hand-drawn anatomical regions of interest (ROIs) shown for one participant. (Right) Reactivation of encoding representations is greater for later recalled (R) than forgotten (F) trials. Bars represent mean ± SE of the condition difference. *P = 0.013, one-tailed paired t test.

The "being happy" stress-out.

Oliver Burkeman (the author of “The Antidote: Happiness for People Who Can’t Stand Positive Thinking”) does an engaging article on how deliberate effort on the part of managers and other to generate fun,

...might have precisely the opposite effect, making people miserable and thus reaffirming one of the oldest observations about happiness: When you try too hard to obtain it, you’re almost guaranteed to fail.

Here are some further clips:

...corporations call upon a burgeoning industry of happiness consultants, who’ll construct a Gross Happiness Index for your workplace, then advise you on ways to boost it…Countless self-help bloggers offer tips for generating cheer among the cubicles…There’s nothing wrong with happiness at work. Enjoyable jobs are surely preferable to boring or unpleasant ones; moreover, studies suggest that happy employees are more productive ones. But it doesn’t follow that the path to this desirable state of affairs is through deliberate efforts.

...there’s evidence that this approach… can have precisely the opposite effect, making people miserable and thus reaffirming one of the oldest observations about happiness: When you try too hard to obtain it, you’re almost guaranteed to fail. the pressure to maintain a cheery facade in such workplaces can be stressful and exhausting in itself, a form of what the sociologist Arlie Russell Hochschild called “emotional labor.” In a 2011 study of workers at an Australian call center, where bosses championed the “3 Fs” (focus, fun and fulfillment), researchers found that many experienced the party atmosphere as a burden, not a boon.…

The problem here is an organizational version of the “paradox of hedonism,” best expressed by John Stuart Mill: “Ask yourself whether you are happy, and you cease to be so.” The attempt to impose happiness is self-sabotaging. Psychologists have shown that positive-thinking affirmations make people with low self-esteem feel worse; that patients with panic disorders can become more anxious when they try to relax; and that an ability to experience negative emotions, rather than struggling to exclude them, is crucial for mental health.

…managers should concentrate on creating the conditions in which a variety of personality types, from the excitable to the naturally downbeat, can flourish. That means giving employees as much autonomy as possible, and ensuring that people are treated evenhandedly. According to a recent Danish study, lack of fairness at work is a strong predictor of depression, and even heavy workloads don’t bring people down, provided their bosses are fair.

Oxytocin enhances brain function in children with autism.

Fascinating observations from Gordon et al, who find that that intranasal administration of oxytocin enhances activity in the brain for socially meaningful stimuli and attenuates its response to nonsocially meaningful stimuli in children with autism spectrum disorder (ASD), as measured via functional MRI. This raises the prospect of treatments that target the core social dysfunction in ASD, and might bring about long-term behavioral improvements.:

Following intranasal administration of oxytocin (OT), we measured, via functional MRI, changes in brain activity during judgments of socially (Eyes) and nonsocially (Vehicles) meaningful pictures in 17 children with high-functioning autism spectrum disorder (ASD). OT increased activity in the striatum, the middle frontal gyrus, the medial prefrontal cortex, the right orbitofrontal cortex, and the left superior temporal sulcus. In the striatum, nucleus accumbens, left posterior superior temporal sulcus, and left premotor cortex, OT increased activity during social judgments and decreased activity during nonsocial judgments. Changes in salivary OT concentrations from baseline to 30 min postadministration were positively associated with increased activity in the right amygdala and orbitofrontal cortex during social vs. nonsocial judgments. OT may thus selectively have an impact on salience and hedonic evaluations of socially meaningful stimuli in children with ASD, and thereby facilitate social attunement. These findings further the development of a neurophysiological systems-level understanding of mechanisms by which OT may enhance social functioning in children with ASD.

A neural prosthesis can restore sensory-motor function after brain damage.

Guggenmos et al. use a brain–machine–brain interfaces (BMBIs) to reconnect two active brain regions whose connections had severed by damage to the brain area between them:

Closed-loop systems, or brain–machine–brain interfaces (BMBIs), have not been widely developed for brain repair. In this study, we targeted spared motor and somatosensory regions of the rat brain after traumatic brain injury for establishment of a functional bridge using a battery-powered microdevice. The results show that by using discriminated action potentials as a trigger for stimulating a distant cortical location, rapid recovery of fine motor skills is facilitated. This study provides strong evidence that BMBIs can be used to bridge damaged neural pathways functionally and promote recovery after brain injury. Although this study is restricted to a rodent model of TBI, it is likely that the approach will also be applicable to other types of acquired brain injuries.

Figure: Model of neuroprosthetic treatment approach after brain injury. (A) Normal connectivity of M1 (motor cortex), S1 (somatosensory cortex), and PM (premotor cortex). Both M1 (CFA in rat) and PM (RFA in rat) send substantial outputs to the spinal cord via the corticospinal tract. Also, extensive reciprocal connections exist between M1 and PM, as well as between M1 and S1. (B) Effects of focal M1 injury on brain connectivity and the hypothetical effect of a BMBI to restore somatosensory-motor communication. An injury to M1, as might occur in stroke or brain trauma, results in a focal area of necrosis, as well as loss of M1 outputs to the spinal cord. Corticocortical communication between M1 and S1 (and between M1 and PM) is also disrupted, further contributing to functional impairment. Because the uninjured PM also contains corticospinal neurons, it might have the ability to serve in a vicarious role. The dotted line indicates enhanced functional connection between PM and S1 that we propose is established after treatment with a BMBI. (C) Location of target areas in rat cerebral cortex. A topographic map of the somatosensory representation in S1 is superimposed on the cortex.

My aversion to "selfies" and the demographics of social media.

The actor James Franco has done an interesting brief essay on the meaning of "selfies", photos of himself reporting what he is doing relayed via Instagram. (Tumblr, Facebook, Pinterest, Twitter, Snapchat, and others,  are other common routes for selfies.)

...the self-portrait is an easy target for charges of self-involvement, but, in a visual culture, the selfie quickly and easily shows, not tells, how you’re feeling, where you are, what you’re doing….I am actually turned off when I look at an account and don’t see any selfies, because I want to know whom I’m dealing with. In our age of social networking, the selfie is the new way to look someone right in the eye and say, “Hello, this is me.”…We all have different reasons for posting them, but, in the end, selfies are avatars: Mini-Me’s that we send out to give others a sense of who we are.

I feel a complete aversion to the idea of advertising my daily life by posting pictures of myself as I move through a day.  It seems a violation of my privacy, a threat to periods of solitude and being alone that I value, and I wonder if this is a character trait that is increasingly rare in the millennial generation, which seems to have a fear of being alone.   … and this prompted me to do a cursory survey of the demographics of the users of some of these sites. I am not surprised to find that at age 71 I am on the much older side of a generational gap in behavior. One quickly finds that 90% of the 150 million people who are active on instagram are under the age of 35, urban, with a significant skew towards women. Facebook (which owns instagram) users are clustered in the 25-34 and over 55 age range. A table reported from the Pew research center shows the fraction of internet users who use various social networking sites.

Cognitive Control - what you see depends on how you look.

Turk-Brown argues for a more expansive approach to understanding various kinds of non-invasive brain imaging data. I relay his abstract, and one figure describing how interactions between brain regions vary by cognitive state.

Noninvasive studies of human brain function hold great potential to unlock mysteries of the human mind. The complexity of data generated by such studies, however, has prompted various simplifying assumptions during analysis. Although this has enabled considerable progress, our current understanding is partly contingent upon these assumptions. An emerging approach embraces the complexity, accounting for the fact that neural representations are widely distributed, neural processes involve interactions between regions, interactions vary by cognitive state, and the space of interactions is massive. Because what you see depends on how you look, such unbiased approaches provide the greatest flexibility for discovery.

Fig. 2 Attentional modulation of functional connectivity. (A) The guided activation theory of cognitive control posits that prefrontal cortex (PFC) sends feedback to posterior cortex to switch connectivity between cortex and establish task-relevant pathways. (B) Such pathways exist in the visual cortex of nonhuman primates: V4 shows enhanced coherence with the area of V1 containing receptive fields for the attended target. (C) This mechanism also supports category-based selection in human visual cortex: V4 shows stronger background connectivity with the fusiform face area (FFA) when faces are attended and with the parahippocampal place area (PPA) when scenes are attended.

How our advanced capabilities may have come from separation of our primary brain areas.

Buckner and Krienen put forward the fascinating idea that our advanced human capabilities may be a spandrel (i.e. a byproduct of the evolution of some other characteristic, rather than a direct product of adaptive selection). They note that the striking increase of hominid brain size over the past three million years (from ~ 400cc in chimps to ~600-800cc in H. habilis to 1,500-1,800 in H. sapiens) has gone with the enlargement not of the size of primary sensory and motor regions of the brain, but instead with the association regions between them, as if the primary regions had become untethered from each other. These association regions might be to form new circuits as they mature later in development in a more plastic and adaptive way than the primary regions. Now, instead of an automatic and tightly coupled linkage between sensory areas and motor areas driving behavior, the association cortices can insert the computations required for making more complex decisions, retrieving memories, and reflecting.

Phylogeny of the cortical mantle.
Schematic depictions of the cortex of placental mammals are shown with the size and positions of several conserved areas. Two organizational features are apparent in the phylogenic tree. Across all species, the relative positions of the areas are preserved, suggesting they arise from an ancient developmental template, or Bauplan, that is conserved. Second, as the brain is enlarged in primates a greater percentage of the cortical mantle falls between the primary and secondary sensory systems. The insets at the top represent hypothetical estimates of the mammalian common ancestor and the primate common ancestor. Dark blue, primary visual area (V1); light blue, secondary visual area (V2); green, middle temporal (MT) visual area; yellow, primary auditory area (A1); red, primary somatosensory area (S1); orange, secondary somatosensory area (S2).

The Tethering Hypothesis:
Bottom: The developing cortical mantle of the estimated mammalian common ancestor is schematically displayed as a thick line with two representative signaling gradients, labeled Signal A (red) and Signal B (blue). These gradients are heuristic presentations of the signal gradients present in the embryonic telencephalon (Figure 6). In the ancestral mammal, the signaling gradients and extrinsic activity from the sensory systems placed strong constraints on most of the developing cortex. Intermediate zones existed, colored in white, but represented a small portion of the cortical mantle. The resulting cortical organization included multiple sensory–motor hierarchies that occupied most of the mantle and formed canonical networks. Top: Following massive evolutionary expansion of the cortical mantle, in the presence of the same core signaling gradients, most of the cortical mantle emerges that is distant from the combined constraints of signaling gradients and extrinsic sensory activity. This emergent zone is illustrated as the large white area in the expanded cortical mantle. Untethered from sensory hierarchies, these distributed in-between zones are hypothesized to wire to one another and emerge as association cortex. The tethering hypothesis, which at this point should be considered a speculation, offers one framework to explain how association networks evolved their prominence and came to possess circuit properties vital to human cognition. The tethering hypothesis awaits further support or falsification.

Your brain has many genomes.

Life used to be simple. We had one set of genes, found in all cells of the body. Skin cells, liver cells, and brain cells were different only because different subsets of those genes were expressed appropriate to each organ. Now, it is turning out that one organ, like the heart, may be governed by one set of genes (genome) while the brain may be run by a mosaic of other genomes generated by somatic mutations, (as opposed to germline mutations that are inherited and found in every body cell.) Psychiatric genetic studies generally have assumed mutations in red blood cells would also appear in the brain, but mutations unique to brain genomes have now been found.

Thomas Insel, who is head of the National Institute of Mental Health, has written a paper on this situation titled “The dark matter of psychiatric genetics.” Here is his abstract:

Although inherited DNA sequences have a well-demonstrated role in psychiatric disease risk, for even the most heritable mental disorders, monozygotic twins are discordant at a significant rate. The genetic variation associated with mental disorders has heretofore been based on the search for rare or common variation in blood cells. This search is based on the premise that every somatic cell shares an identical DNA sequence, so that variation found in lymphocytes should reflect variation present in brain cells. Evidence from the study of cancer cells, stem cells and now neurons demonstrate that this premise is false. Somatic mutation is common in human cells and has been implicated in a range of diseases beyond cancer. The exuberant proliferation of cortical precursors during fetal development provides a likely environment for somatic mutation in neuronal and glial lineages. Studies of rare neurodevelopmental disorders, such as hemimegencephaly, demonstrate somatic mutations in affected cortical cells that cannot be detected in unaffected parts of the brain or in peripheral cells. This perspective argues for the need to investigate somatic variation in the brain as an explanation of the discordance in monozygotic twins, a proximate cause of mental disorders in individuals with inherited risk, and a potential guide to novel treatment targets.

Cognitive benefits of music lessons?

I’ve done numerous posts on effects that early music training has on the brain. Adults with early music training in general show enhanced capabilities in sensory (auditory time resolution) and motor actives related to music generation. There also has been the claim that early music training also enhances cognitive development in other areas. Mehr et al have now done randomized trial studies that show no consistent evidence for nonmusical cognitive benefits of preschool music enrichment. Only one music curriculum was used, and it is possible that a trial with a different kind or intensity of training might yield different results.

Young children regularly engage in musical activities, but the effects of early music education on children's cognitive development are unknown. While some studies have found associations between musical training in childhood and later nonmusical cognitive outcomes, few randomized controlled trials (RCTs) have been employed to assess causal effects of music lessons on child cognition and no clear pattern of results has emerged. We conducted two RCTs with preschool children investigating the cognitive effects of a brief series of music classes, as compared to a similar but non-musical form of arts instruction (visual arts classes, Experiment 1) or to a no-treatment control (Experiment 2). Consistent with typical preschool arts enrichment programs, parents attended classes with their children, participating in a variety of developmentally appropriate arts activities. After six weeks of class, we assessed children's skills in four distinct cognitive areas in which older arts-trained students have been reported to excel: spatial-navigational reasoning, visual form analysis, numerical discrimination, and receptive vocabulary. We initially found that children from the music class showed greater spatial-navigational ability than did children from the visual arts class, while children from the visual arts class showed greater visual form analysis ability than children from the music class (Experiment 1). However, a partial replication attempt comparing music training to a no-treatment control failed to confirm these findings (Experiment 2), and the combined results of the two experiments were negative: overall, children provided with music classes performed no better than those with visual arts or no classes on any assessment. Our findings underscore the need for replication in RCTs, and suggest caution in interpreting the positive findings from past studies of cognitive effects of music instruction.