Wednesday, October 31, 2012

I R’ Us - a waking mashup

When I am going through the daily transition from the last bit of REM sleep to having an awake self I frequently find articles I have recently noted appear in mind in an associated cluster. Thus the title of this post, which tries to point to our delusion that each of us is a tidy "I" that is running its own show. The chunks that come together are:
1). A review by Ezenwa et al. as well as an excellent article by Michael Specter in The New Yorker ('Germs are Us') discuss the microbiome of bacteria, viruses, and fugi whose cells vastly outnumber our own and whose genes outnumber our own by least 100 times. These 'invaders' influence not only our behavior but also our physiology and resistance to disease. We are being managed by a much larger ensemble of creatures than the "I" that writes or reads these lines.
2). A piece by Paul summarizes the powerful effect that social factors and stereotypes can have on our performance. And finally,
3).Nick Bilton writes on how our social boundaries and privacy are being erased as people are watching and reporting on us on Twitter, Facebook, Foursquare, Path and an interminable list of other social networks. Our identities diffuse into the public sphere, and we don't get to choose what show we are going to be on...
The common thread here is the message that our lives are being run by a vast army of creatures, microscopic to human size, that we usually take to be external to our "I".

Tuesday, October 30, 2012

Mouse song: features similar to human and bird song.

A MindBlog reader has pointed out to me an interesting article by Arriaga et al. that notes that mice courtship ultrasonic sound has some anatomical features and limited learning abilities previously thought unique to humans and birds. Their abstract:
Humans and song-learning birds communicate acoustically using learned vocalizations. The characteristic features of this social communication behavior include vocal control by forebrain motor areas, a direct cortical projection to brainstem vocal motor neurons, and dependence on auditory feedback to develop and maintain learned vocalizations. These features have so far not been found in closely related primate and avian species that do not learn vocalizations. Male mice produce courtship ultrasonic vocalizations with acoustic features similar to songs of song-learning birds. However, it is assumed that mice lack a forebrain system for vocal modification and that their ultrasonic vocalizations are innate. Here we investigated the mouse song system and discovered that it includes a motor cortex region active during singing, that projects directly to brainstem vocal motor neurons and is necessary for keeping song more stereotyped and on pitch. We also discovered that male mice depend on auditory feedback to maintain some ultrasonic song features, and that sub-strains with differences in their songs can match each other's pitch when cross-housed under competitive social conditions. We conclude that male mice have some limited vocal modification abilities with at least some neuroanatomical features thought to be unique to humans and song-learning birds. To explain our findings, we propose a continuum hypothesis of vocal learning.

Monday, October 29, 2012

Brain correlates of switching consciousness on and off again

Kock points in Scientific American Mind to work by Långsjö et al. (open access), who image the neural core of consciousness. They performed MRI imaging of patients recovering from propofol, dexmedetomidine, or sevoflurane anesthesia. Here is their abstract, followed by a key figure from the paper:
One of the greatest challenges of modern neuroscience is to discover the neural mechanisms of consciousness and to explain how they produce the conscious state. We sought the underlying neural substrate of human consciousness by manipulating the level of consciousness in volunteers with anesthetic agents and visualizing the resultant changes in brain activity using regional cerebral blood flow imaging with positron emission tomography. Study design and methodology were chosen to dissociate the state-related changes in consciousness from the effects of the anesthetic drugs. We found the emergence of consciousness, as assessed with a motor response to a spoken command, to be associated with the activation of a core network involving subcortical and limbic regions that become functionally coupled with parts of frontal and inferior parietal cortices upon awakening from unconsciousness. The neural core of consciousness thus involves forebrain arousal acting to link motor intentions originating in posterior sensory integration regions with motor action control arising in more anterior brain regions. These findings reveal the clearest picture yet of the minimal neural correlates required for a conscious state to emerge.
Colored areas indicate the parts of the brain that first come online when patients emerge from consciousness after being anesthetized with one of two different agents. The three critical regions are the anterior cingulate cortex (a), the thalamus (b) and parts of the brain stem (c).

Saturday, October 27, 2012

A new study on implicit attitudes and voting..

Following my post on implicit attitudes and voting I have received an email from a group of collaborators doing further studies on the same issue. They need to recruit undecided voters and request that I post this note including the URL of their study in MindBlog.

Friday, October 26, 2012

Gender bias is alive and well in academic science.

Handelsman and collaborators do a rather clear study on how the academy works, showing that science faculties favor male students:
Despite efforts to recruit and retain more women, a stark gender disparity persists within academic science. Abundant research has demonstrated gender bias in many demographic groups, but has yet to experimentally investigate whether science faculty exhibit a bias against female students that could contribute to the gender disparity in academic science. In a randomized double-blind study (n = 127), science faculty from research-intensive universities rated the application materials of a student—who was randomly assigned either a male or female name—for a laboratory manager position. Faculty participants rated the male applicant as significantly more competent and hireable than the (identical) female applicant. These participants also selected a higher starting salary and offered more career mentoring to the male applicant. The gender of the faculty participants did not affect responses, such that female and male faculty were equally likely to exhibit bias against the female student. Mediation analyses indicated that the female student was less likely to be hired because she was viewed as less competent. We also assessed faculty participants’ preexisting subtle bias against women using a standard instrument and found that preexisting subtle bias against women played a moderating role, such that subtle bias against women was associated with less support for the female student, but was unrelated to reactions to the male student. These results suggest that interventions addressing faculty gender bias might advance the goal of increasing the participation of women in science.

Thursday, October 25, 2012

Resilience to stress replacing happiness as fashionable research topic


Wednesday, October 24, 2012

Mechanism of unconscious internal bias in our choices

What's actually happening when we make choices that do not seem to be justifiable on purely economic or logical grounds? Wimmer and Shohamy do some interesting work showing how the hippocampus can instill an unconscious bias in our valuations, whereby an object that is not highly valued on its own, increases in value when it becomes implicitly associated with a truly high-value object. As a consequence, we then end up preferring the associated object over a neutral object of equal objective value while not really knowing why. The abstract:
The details of the experiment are kind of neat. I pass on two figures:

Fig. 1 The task consists of three phases: association learning, reward learning, and decision-making. (A) In the association phase, participants were exposed to a series of pairs of pictures (S1 and S2 stimuli) while performing a cover task to detect “target” upside-down pictures. S1 stimuli were either face, scene, or body part pictures; S2 stimuli were circle images. (B) In the reward phase, participants learned through classical conditioning that half of the S2 stimuli were followed by a monetary reward (S2+), whereas the other S2 stimuli were followed by a neutral outcome (no reward, S2–). S1 stimuli never appeared in this stage. (C) In the decision phase, participants were asked to decide between two stimuli (both S1 or both S2) for a possible monetary win. No feedback was provided, and all gains were awarded at the end of the experiment. Decision bias was operationalized as the tendency to choose S1+ over S1– stimuli in this phase.

Fig. 3 Reactivation of category-specific visual areas during the first half of the reward phase is related to subsequent decision bias. (A) Example participant region of interest masks (derived from the association phase) for body, face, and scene S1 stimuli. Masks were applied to S2 presentations during the reward phase. (B) S2 presentation elicits activation in visual regions responsive to associated S1 stimuli when participants later exhibit decision bias. Error bars indicate ±SEM; a.u., arbitrary units.

Tuesday, October 23, 2012

Memory fading? Try some dopamine...

From Chowdhury et al. in the Journal of Neuroscience:
Activation of the hippocampus is required to encode memories for new events (or episodes). Observations from animal studies suggest that, for these memories to persist beyond four to six hours, a release of dopamine generated by strong hippocampal activation is needed. This predicts that dopaminergic enhancement should improve human episodic memory persistence also for events encoded with weak hippocampal activation. Here, using pharmacological functional MRI (fMRI) in an elderly population in which there is a loss of dopamine neurons as part of normal aging, we show this very effect. The dopamine precursor levodopa led to a dose-dependent (inverted U-shape) persistent episodic memory benefit for images of scenes when tested after six hours, independent of whether encoding-related hippocampal fMRI activity was weak or strong (U-shaped dose–response relationship). This lasting improvement even for weakly encoded events supports a role for dopamine in human episodic memory consolidation, albeit operating within a narrow dose range.

Monday, October 22, 2012

A revolution in understanding our genetics, personality, and disease.


Friday, October 19, 2012

Learning new information during sleep.

Arzi et al. do an ingenious experiment to show that we can do associative learning during our sleep. We can associate a sound with a pleasant or unpleasant odor and react, both while still asleep and after waking, with a deeper or shallower breath. This does not, however, represent the kind of 'sleep learning' long sought by students who unsuccessfully try to remember scientific or literary facts needed for an exam by playing a tape softly during sleep. Here is the abstract:

Thursday, October 18, 2012

The Neurochemistry of Storytelling.

Having in the previous post just made an ill-tempered dump on one kind of popularization, I decide to be inconsistent and now pass on this nice piece with a little less pizazz from the Brain Pickings Newsletter, on how storytelling can engage our brain neurochemistry associated with stress and empathy. It is a very effective and touching piece, and I recommend that you watch the video below:

Wednesday, October 17, 2012

Brain Showbiz...

Put me down as a curmudgeonly old fart, but I'm not getting a 'gee whiz' response to a recent promotional email asking for publicity on a rhythm and the brain project. It's cute, the graphics are kewl, but the science is out to lunch - it seems to me more like publicity seeking and self promotion masquerading as brain science.

Tuesday, October 16, 2012

Conscious awareness not required for our placebo or nocebo responses.

Interesting observations from Jensen et al. They first condition a placebo (beneficial) or nocebo (adverse) reponse to a thermal pain stimulus, and then find subliminal (non-conscious) presentation of the conditioning cues elicits the same responses. Their abstract:
The dominant theories of human placebo effects rely on a notion that consciously perceptible cues, such as verbal information or distinct stimuli in classical conditioning, provide signals that activate placebo effects. However, growing evidence suggest that behavior can be triggered by stimuli presented outside of conscious awareness. Here, we performed two experiments in which the responses to thermal pain stimuli were assessed. The first experiment assessed whether a conditioning paradigm, using clearly visible cues for high and low pain, could induce placebo and nocebo responses. The second experiment, in a separate group of subjects, assessed whether conditioned placebo and nocebo responses could be triggered in response to nonconscious (masked) exposures to the same cues. A total of 40 healthy volunteers (24 female, mean age 23 y) were investigated in a laboratory setting. Participants rated each pain stimulus on a numeric response scale, ranging from 0 = no pain to 100 = worst imaginable pain. Significant placebo and nocebo effects were found in both experiment 1 (using clearly visible stimuli) and experiment 2 (using nonconscious stimuli), indicating that the mechanisms responsible for placebo and nocebo effects can operate without conscious awareness of the triggering cues. This is a unique experimental verification of the influence of nonconscious conditioned stimuli on placebo/nocebo effects and the results challenge the exclusive role of awareness and conscious cognitions in placebo responses.

Monday, October 15, 2012

Clever crows! Now shown to reason about hidden causes.


Friday, October 12, 2012

Kids as little scientists - early academics can be misguided

A review article by Gopnik offers an interesting perspective:

Thursday, October 11, 2012

Opps! Sex does decrease human male lifespan.

Animal studies have suggested that castration increases lifespan in males, and now Korean researchers have examined genealogy records and lifespan of 81 Korean eunuchs to find that their average lifespan is ~14-19 years longer than that of non-castrated men of similar class. (I doubt this finding will lead to an uptick in voluntary male castrations, the trade off of minus fifteen years for what our male sex hormones make possible doesn’t seem so bad...) The abstract:

Wednesday, October 10, 2012

Followup on evolutionary psychology as ' just so stories'

A comment on my Sept. 28 post has passed on a number of excellent response to the book review I was noting in that post. I was remiss (lazy) in not taking to task one absurd contention of the reviewer, namely that "you don’t have to know about the evolution of an organ in order to understand it." (a third of my Biology of Mind Book argued the contrary.) After Jabr notes in his Scientific American comments several examples of how understanding the evolution of different brain areas has enhanced understanding and medical practice, he gives this nice analogy:
Studying the brain and mind in ignorance of its vast evolutionary tale does not make sense. It would be equivalent to an archaeologist discovering the remains of an enormous tapestry, slicing out a particular figure from the cloth and claiming that he could learn everything he needs to know by examining that figure in isolation. Even if the archaeologist described the figure in exquisite detail, taking it apart thread by thread and sewing it back together, he would remain willfully oblivious of the whole story. In the same way, disregarding the human brain’s history limits psychology and neuroscience to a paltry understanding of our brains and minds.
The comment also points to Kurzban and Gottschall as offering further commentary.

Also, let me note this comment on the Sept 28 post by Jim Birch:
I'm a little surprised by the animosity directed at evolutionary psychology. For me, it has provided revolutionary insights and understanding. In particular, the general notion that in biology, energy is not wasted, it is utilized adaptively. Under evolution, "adaptive" is not local in time and space but statistically selected over a period and range of the species' evolution.
This gives, or actually requires, a new way of interpreting any human behaviour: as statistically adaptive. And in doing so, it blasts away the incoherent mass of narrative explanations that have been conventionally applied. Our "craziest" tendencies like dying on Everest or blowing life savings on poker machines are no longer down to Freudian death wishes or moral failings (etc) but can be seen as adaptive behaviours operating badly, or even just out of context.
Of course, no one was around in the Pleistocene recording behaviours and survival rates so there's a need for speculation, modelling and indirect evidence. It is this that opens the field up to "just-so stories" charge. There is also the potential for use of selective evidence - to simplistically support preferred moral positions, eg, tooth-and-claw v. cooperative vision of "human nature". However, this is not a problem that is peculiar to evolutionary psychology, it's a perenial problem for science, especially new fields. No doubt the situation will improve as things develop and there's a lot of baby in the bathwater of evolutionary psychology.

Tuesday, October 09, 2012

Young children and adults: intrinsically motivated to see others helped

This interesting piece from Tomasello and collaborators:
Young children help other people, but it is not clear why. In the current study, we found that 2-year-old children’s sympathetic arousal, as measured by relative changes in pupil dilation, is similar when they themselves help a person and when they see that person being helped by a third party (and sympathetic arousal in both cases is different from that when the person is not being helped at all). These results demonstrate that the intrinsic motivation for young children’s helping behavior does not require that they perform the behavior themselves and thus “get credit” for it, but rather requires only that the other person be helped. Thus, from an early age, humans seem to have genuine concern for the welfare of others.
And, Rand et al. use economic games with adult subjects to demonstrate that cooperation is intuitive, because cooperative heuristics are developed in daily life where cooperation is typically advantageous. This data adds to Kahneman's recent summary of evidence that much of human decision-making is governed by fast and automatic intuitions, rather than by slow, effortful thinking (see Kahneman, D. Thinking, Fast and Slow, Allen Lane, 2011). The Rand et al. abstract

Monday, October 08, 2012

MRI of reading Jane Austen

Another totally annoying example of science by press release sans any reference to an original research article offers a glimpse at what looks like fascinating work, showing brain correlates of a kind of deep attention going with reading literature that is very different from the kind of deep attention that is focused on mastering a particular task.
A commentary by Alan Jacobs on this work makes a further point, that we might do well to exercise various parts of our minds just as we do well to exercise various parts of our bodies. Otherwise we could end up like Charles Darwin, who felt that over time he had lost certain mental functions:

Friday, October 05, 2012

Rethinking sleep - brief wakeful resting boosts new memories over the long term.

Two recent articles point out that the prevailing notion that an eight hour chunk of sleep is required for optimum health and function is a relatively recent invention that doesn't take into account the usefulness of many varieties of sleep. Randall notes historical and contemporary evidence that other patterns are useful, and here is an abstract from Dewar et al. on how wakeful rest enhances long term consolidation of new memories:

Thursday, October 04, 2012

Regulators of prosocial and empathetic behavior.

Two pieces in the September issue of Psychological Science deal with empathetic or prosocial behavior. Grant and Dutton make observations showing that prosocial behavior is boosted more by reflecting on giving than on receiving; and Lewis et al.'s experiments give a example of how stereotypes enhance empathetic accuracy.
Grant and Dutton:
Research shows that reflecting on benefits received can make people happier, but it is unclear whether or not such reflection makes them more helpful. Receiving benefits can promote prosocial behavior through reciprocity and positive affect, but these effects are often relationship-specific, short-lived, and complicated by ambivalent reactions. We propose that prosocial behavior is more likely when people reflect on being a benefactor to others, rather than a beneficiary. The experience of giving benefits may encourage prosocial behavior by increasing the salience and strength of one’s identity as a capable, caring contributor. In field and laboratory experiments, we found that participants who reflected about giving benefits voluntarily contributed more time to their university, and were more likely to donate money to natural-disaster victims, than were participants who reflected about receiving benefits. When it comes to reflection, giving may be more powerful than receiving as a driver of prosocial behavior.
Lewis et al.:
An ideal empathizer may attend to another person’s behavior in order to understand that person, but it is also possible that accurately understanding other people involves top-down strategies. We hypothesized that perceivers draw on stereotypes to infer other people’s thoughts and that stereotype use increases perceivers’ accuracy. In this study, perceivers (N = 161) inferred the thoughts of multiple targets. Inferences consistent with stereotypes for the targets’ group (new mothers) more accurately captured targets’ thoughts, particularly when actual thought content was also stereotypic. We also decomposed variance in empathic accuracy into thought, target, and perceiver variance. Although past research has frequently focused on variance between perceivers or targets (which assumes individual differences in the ability to understand other people or be understood, respectively), the current study showed that the most substantial variance was found within targets because of differences among thoughts.

Wednesday, October 03, 2012

Idle Minds - why are our brains so active when doing ‘nothing’?

Kerri Smith does a review on the resting or default activity of our brains, what is happening when we are not focused on anything in particular, but letting our minds just rest or wander at random: After initial observations in the mid-1990s showed that the brain never really takes a break,
...studies of the resting state in its own right began to emerge. A team led by Marcus Raichle characterized activity in one such network as the brain's default mode — what they considered its baseline setting. During tasks, default-mode activity actually dropped, coming back online when the brain was no longer focusing so intensely.
The default-mode network has been joined by dozens of other flavors of resting-state network — some of which resemble the circuitry that contributes to attention, vision, hearing or movement. They seem very similar across study participants but are also dynamic, changing over time.
One idea is that the brain is running several models of the world in the background, ready for one of them to turn into reality.
Raichle favors the idea that activity in the resting state helps the brain to stay organized. The connections between neurons are continually shifting as people age and learn, but humans maintain a sense of self throughout the upheaval. Spontaneous activity might play a part in maintaining that continuity. “Connections between neurons turn over in minutes, hours, days and weeks,...The structure of the brain will be different tomorrow but we will still remember who we are.” …the brain replays and consolidates new memories at any chance it gets — even when awake.
…perhaps the activity is part of the reshaping process, tweaking connections while we idle. Several teams have reported changes in resting connectivity after language and memory tasks and motor learning… suggesting that the brain is not only thinking about supper coming up, but it's also processing the recent past and converting some of that into long-term memories. The network changes are specific to the tasks performed.

Tuesday, October 02, 2012

Interpersonal closeness and brain social reward processing

I'm passing on a graphic from Vrticka's comments on recent work by Farei et al., who have observed brain activation patterns associated with sharing positive outcomes with a friends, that are also mirrored in high subjective ratings of excitement and high skin conductance responses during the same condition, reflecting increased biological arousal.

Illustration of the dynamic “push–pull” between social approach and aversion in the affective processing module of human social interaction. According to the phylogenetic perspective of social engagement and attachment proposed by Porges, human social functioning is determined by two opposite emotional brain systems representing positive (social approach; purple) versus negative (social aversion; blue) information. Whereas the social approach module mainly includes dopaminergic pathways (ventral tegmental area, striatum, ventral medial orbitofrontal cortex), as well as the pituitary/hypothalamus as the main site of oxytocin synthesis, the social aversion module operates through brain areas involved in fear/threat (amygdala), stress (hippocampus), disgust/empathy for pain/social rejection (insula and anterior cingulate cortex), and sadness (anterior temporal pole).
Here is the Farei et al. abstract:
Everyday goals and experiences are often shared with others who may hold different places within our social networks. We investigated whether the experience of sharing a reward differs with respect to social network. Twenty human participants played a card guessing game for shared monetary outcomes with three partners: a computer, a confederate (out of network), and a friend (in network). Participants subjectively rated the experience of sharing a reward more positively with their friends than the other partners. Neuroimaging results support participants' subjective reports, as ventral striatal BOLD responses were more robust when sharing monetary gains with a friend as compared to the confederate or computer, suggesting a higher value for sharing with an in-network partner. Interestingly, ratings of social closeness covaried with this activity, resulting in a significant partner × closeness interaction; exploratory analysis showed that only participants reporting higher levels of closeness demonstrated partner-related differences in striatal BOLD response. These results suggest that reward valuation in social contexts is sensitive to distinctions of social network, such that sharing positive experiences with in-network others may carry higher value.

Monday, October 01, 2012

Want to be unhappy? Trying to be happy will do it!

I'm finding the "Anxiety" topic in the Opinionator series at the NYTimes to be a real treat. This entry by British expatriate Ruth Whippman brings back memories of a my signing on several years ago to be a talking head neuroscience expert on the  California "Make Me Happy!" Radio Show (I don't think they were all that pleased with their dyspeptic guest!). Whippman notes the American obsession with, and anxiety over, being "happy", and contrasts this with the attitudes of more stoic Britishers:
Happiness in America has become the overachiever's ultimate trophy. A vicious trump card, it outranks professional achievement and social success, family, friendship and even love…this elusive MacGuffin is creating a nation of nervous wrecks. Despite being the richest nation on earth, the United States is, according to the World Health Organization, by a wide margin, also the most anxious, with nearly a third of Americans likely to suffer from an anxiety problem in their lifetime. America's precocious levels of anxiety are not just happening in spite of the great national happiness rat race, but also perhaps, because of it.
The British are generally uncomfortable around the subject, and as a rule, don't subscribe to the happy-ever-after. It's not that we don't want to be happy, it just seems somehow embarrassing to discuss it, and demeaning to chase it, like calling someone moments after a first date to ask them if they like you….Even the recent grand spectacle of the London 2012 Olympic Games told this tale. The opening ceremony, traditionally a sparklefest of perkiness, was, with its suffragist and trade unionists, mainly a celebration of dissent, or put less grandly, complaint…Our queen, despite the repeated presence of a stadium full of her subjects urging in song that she be both happy and glorious, could barely muster a smile, staring grimly through her eyeglasses and clutching her purse on her lap as if she might be mugged.
Cynicism is the British shtick. When happiness does come our way, it is entirely without effort, as unmeritocratic as a hereditary peerage. By contrast, in America, happiness is work. Intense, nail-biting work, slogged out in motivational seminars and therapy sessions, meditation retreats and airport bookstores. For the left there's yoga, for the right, there's Jesus. For no one is there respite…The people taking part in "happiness pursuits," as a rule, don't seem very happy…The happy person would be more likely to be off doing something fun, like sitting in the park drinking.
Happiness should be serendipitous, a by-product of a life well lived, and pursuing it in a vacuum doesn't really work. This is borne out by a series of slightly depressing statistics. The most likely customer of a self-help book is a person who has bought another self-help book in the last 18 months. The General Social Survey, a prominent data-based barometer of American society, shows little change in happiness levels since 1972, when such records began. Every year, with remarkable consistency, around 33 percent of Americans report that they are "very happy." It's a fair chunk, but a figure that remains surprisingly constant, untouched by the uptick in Eastern meditation or evangelical Christianity, by Tony Robbins or Gretchen Rubin or attachment parenting. For all the effort Americans are putting into happiness, they are not getting any happier. It is not surprising, then, that the search itself has become a source of anxiety.
So here's a bumper sticker: despite the glorious weather and spectacular landscape, the people of California are probably less happy and more anxious than the people of Grimsby. So they may as well stop trying so hard.