On continuing MindBlog - Drawing personal structure from sampling the digital stream.

The responses in comments and emails to my ‘scratching my head about mindblog’ post are telling me that my small contributions are valued, with some making it part of the ritual that structures their lives. So, I guess I should listen to that rather than fretting about adding to the digital stream that threatens to overwhelm us all.

We all want to understand how our show is run, what is going on with the little grey cells between our ears (and of course, we would like it run it better). We want to ‘see’ in addition to just ‘being.’ Indeed, this distinction is one of the most central ones I have been making through the course of over three thousand posts. It can be recast in numerous guises, such as being a moral agent in addition a moral patient or between third and first person self construals.

I feel like the recent disjunctive break in generating Deric’s MindBlog - occasioned by a two week return to my former world of vision research - has been a useful one for me. (I will mention, by the way, that I was gratified a the recent vision meeting I attended when several doctoral and postdoctoral students told me that they look back on their time in my laboratory as one of the best in their lives - a time when they were given structure and support, and also given freedom to grow the beginnings of their future independent professional selves.)

I’ve kept a journal since 1974, when I was into gestalt therapy, transactional analysis, and trips to Esalen to learn massage, attend workshops, and commune with the Monarch butterflies and whales of the Big Sur. That journal started to mark entries on psychology and mind with a tag (*mind), that I could search for. My reading on mind and brain grew out of the cellular neurobiology course I started with Julius Adler and then Tony Stretton in 1970, and it formed a parallel track alongside my vision research laboratory work that finally resulted in a new course, The Biology of Mind, in 1994, and the book “Biology of Mind” of 1999 that grew out of its lecture notes. A number of lectures and web essays in the early 2000’s led to the startup of this MindBlog in February of 2006. Thinking about this stuff is how I have structured my life for over 40 years, and I realize that giving that up would be the same as giving up my self.

So..... I guess MindBlog, in some form, isn’t going away.

Deric’s MindBlog spends time in the past...in the future?

The past:  I’ve been spending the past two weeks in a former life. I was in Seattle last week to attend the annual meeting of ARVO (Assoc. for Research in Vision and Opthalmology), at which my last postdoc, Vadim Arshavsky, was awarded the Proctor Prize.   The graphic in this post is from a lecture I just gave on Tuesday to the final seminar this term of the McPherson Eye Research Institute here at U.W., describing the contributions of my laboratory (from 1968 to 1998) to understanding how light changes into a nerve signal in our eyes. (The talk is posted here.)

The future:  I’m scratching my head about how (maybe whether?) to continue MindBlog.  It has had a good run since Feb. of 2006, and I'm kind of wondering if I should withdraw - as I did from the vision field - while I’m ahead, or at least cut back to less frequent, more thoughtful, posts…. I’m a bit dissatisfied that many of the posts are essentially expanded tweets, passing on the link and abstract of an article I find interesting.  I think this is lazy, but I do get ‘thank you’ emails for pointing out something that reader X is interested in.  A downside is that the time I take scanning journals and chaining myself to the daily post regime makes it difficult for me to settle into deeper development of a few topics.  It also competes with the increasing amount of time I am spending on classical piano performance. I will be curious to see whether these rambling comments elicit any responses from the current 2,500 subscribers to MindBlog’s RSS feed or ~1,100 twitter followers.     

MindBlog in Seattle this week - hiatus in posts

There will be a hiatus in MindBlog posts for awhile.

I'm spending this week at an ARVO (Association for Research in Vision and Opthalmology) meeting where a protege of mine, Vadim Arshavsky, who I brought to my lab from the former USSR for post-doctoral training, is being given the field's Proctor Award for work done (mainly after leaving my laboratory) on understanding how the nerve signal initiated by a flash of light in our eyes is rapidly turned off.

Riding other people's coattails.

Another interesting bit from Psychological Science:

Two laboratory experiments and one dyadic study of ongoing relationships of romantic partners examined how temporary and chronic deficits in self-control affect individuals’ evaluations of other people. We suggest that when individuals lack self-control resources, they value such resources in other people. Our results support this hypothesis: We found that individuals low (but not high) in self-control use information about other people’s self-control abilities when judging them, evaluating other people with high self-control more positively than those with low self-control. In one study, participants whose self-control was depleted preferred people with higher self-control, whereas nondepleted participants did not show this preference. In a second study, we conceptually replicated this effect while using a behavioral measure of trait self-control. Finally, in a third study we found individuals with low (but not high) self-control reported greater dependence on dating partners with high self-control than on those with low self-control. We theorize that individuals with low self-control may use interpersonal relationships to compensate for their lack of personal self-control resources.

Willpower and Abundance - The case for less.

I wanted to pass on some clips from Tim Wu's sane commentary in The New Republic on the recent Diamandis and Kotler book "Abundance: The Future Is Better Than You Think.":

“The future is better than you think” is the message of Peter Diamandis’s and Steven Kotler’s book. Despite a flat economy and intractable environmental problems, Diamandis and his journalist co-author are deeply optimistic about humanity’s prospects. “Technology,” they say, “has the potential to significantly raise the basic standards of living for every man, woman, and child on the planet.... Abundance for all is actually within our grasp.”

Optimism is a useful motivational tool, and I see no reason to argue with Diamandis about the benefits of maintaining a sunny disposition...The unhappy irony is that Diamandis prescribes a program of “more” exactly at a point when a century of similar projects have begun to turn on us. To be fair, his ideas are most pertinent to the poorer parts of the world, where many suffer terribly from a lack of the basics. But in the rich and semi-rich parts of the world, it is a different story. There we are starting to see just what happens when we reach surplus levels across many categories of human desire, and it isn’t pretty. The unfortunate fact is that extreme abundance—like extreme scarcity, but in different ways—can make humans miserable. Where the abundance project has been truly successful, it has created a new host of problems that are now hitting humanity…

The worldwide obesity epidemic is our most obvious example of this “flip” from problems of scarcity to problems of surplus…There is no single cause for obesity, but the sine qua non for it is plenty of cheap, high-calorie foods. And such foods, of course, are the byproduct of our marvelous technologies of abundance, many of them celebrated in Diamandis’s book. They are the byproducts of the “Green Revolution,” brilliant techniques in industrial farming and the genetic modification of crops. We have achieved abundance in food, and it is killing us.

Consider another problem with no precise historical equivalent: “information overload.”…phrases such as “Internet addiction” describe people who are literally unable to stop consuming information even though it is destroying their lives…many of us suffer from milder versions of information overload. Nicolas Carr, in The Shallows, made a persuasive case that the excessive availability of information has begun to re-program our brains, creating serious issues for memory and attention span. Where people were once bored, we now face too many entertainment choices, creating a strange misery aptly termed “the paradox of choice” by the psychologist Barry Schwartz. We have achieved the information abundance that our ancestors craved, and it is driving us insane.

This very idea that too much of what we want can be a bad thing is hard to accept…But in today’s richer world, if you are overweight, in debt, and overwhelmed, there is no one to blame but yourself. Go on a diet, stop watching cable, and pay off your credit card—that’s the answer. In short, we think of scarcity problems as real, and surplus problems as matters of self-control…That may account for the current popularity of books designed to help readers control themselves. The most interesting among them is Willpower: Rediscovering the Greatest Human Strength, by Roy Baumeister and John Tierney.

The book’s most profound sections describe a phenomenon that they call “ego depletion,” a state of mental exhaustion where bad decisions are made. It turns out that being forced to make constant decisions is what causes ego depletion. So if willpower is a muscle, making too many decisions in one day is the equivalent of blowing out your hamstrings with too many squats…they recommend avoiding situations that cause ego-depletion altogether. And here is where we find the link between Abundance and Willpower…Over the last century, mainly through the abundance project, we have created a world where avoiding constant decisions is nearly impossible. We have created environments that are designed to destroy our powers of self-control by creating constant choices among abundant options. [We have] a negative feedback loop: we have more than ever, and therefore need more self-control than ever, but the abundance we’ve created destroys our ability to resist. It is a setup that Sisyphus might have actually envied. 

…it is increasingly the duty of the technology industry and the technologists to take seriously the challenge of human overload, and to give it as much attention as the abundance project. It is the first great challenge for post-scarcity thinkers…So advanced are our technological powers that we will be increasingly trying to create access to abundance and to limit it at the same time. Sometimes we must create both the thesis and the antithesis to go in the right direction. We have spent the last century creating an abundance that exceeds any human scale, and now technologists must turn their powers to controlling our, or their, creation.  

Overearning

Here is an interesting study from Hsee et al on our tendency to keeping working to earn more than we need for happiness, at the expense of that happiness.

Their abstract:

High productivity and high earning rates brought about by modern technologies make it possible for people to work less and enjoy more, yet many continue to work assiduously to earn more. Do people overearn—forgo leisure to work and earn beyond their needs? This question is understudied, partly because in real life, determining the right amount of earning and defining overearning are difficult. In this research, we introduced a minimalistic paradigm that allows researchers to study overearning in a controlled laboratory setting. Using this paradigm, we found that individuals do overearn, even at the cost of happiness, and that overearning is a result of mindless accumulation—a tendency to work and earn until feeling tired rather than until having enough. Supporting the mindless-accumulation notion, our results show, first, that individuals work about the same amount regardless of earning rates and hence are more likely to overearn when earning rates are high than when they are low, and second, that prompting individuals to consider the consequences of their earnings or denying them excessive earnings can disrupt mindless accumulation and enhance happiness.

And, their description of the paradigm used:

Participants are tested individually while seated at a table in front of a computer and wearing a headset. The procedure consists of two consecutive phases, each lasting 5 min. In Phase I, the participant can relax and listen to music (mimicking leisure) or press a key to disrupt the music and listen to a noise (mimicking work). For every certain number of times the participant listens to the noise (e.g., 20 times), he or she earns 1 chocolate; the computer keeps track and shows how many chocolates the participant has earned. The participant can only earn (not eat) the chocolates in Phase I and can only eat (and not earn more of) the chocolates in Phase II. The participant does not need to eat all of the earned chocolates in Phase II, but if any remain, they must be left on the table at the end of the study. Participants learn about these provisions in advance and are informed that they can decide how many chocolates to earn in Phase I and how many to eat in Phase II, and that their only objective is to make themselves as happy as possible during the experiment.

Our paradigm simulates a microcosmic life with a fixed life span; in the first half, one chooses between leisure and labor (earning), and in the second half, one consumes one’s earnings and may not bequeath them to others. In designing the paradigm, our priority was minimalism and controllability rather than realism and external validity. The paradigm was inspired by social scientists’ approaches to investigating complex real-world issues, such as unselfish motives, using minimalistic simulations, such as the ultimatum game. These simulations involve contrived features—for example, players cannot learn each other’s identities and need not worry about reputations—but such features are important because they allow researchers to control for normative reasons for unselfish behaviors and test for pure, unselfish motives. Likewise, our paradigm also involves contrived features—for example, rewards are chocolates rather than money, and participants cannot take their rewards from the lab—but these features are crucial for us to control for normative reasons for overearning effects and test for pure overearning tendencies.

The slippery slope of fear

LeDoux makes some useful comments on confusion one encounters in studies of fear, especially involving the amygdala, a clip:

‘Fear’ is used scientifically in two ways, which causes confusion: it refers to conscious feelings and to behavioral and physiological responses...As long as the term ‘fear’ is used interchangeably to describe both feelings and brain/bodily responses elicited by threats, confusion will continue. Restricting the scientific use of the term ‘fear’ to its common meaning and using the less-loaded term, ‘threat-elicited defense responses’, for the brain/body responses yields a language that more accurately reflects the way the brain evolved and works, and allows the exploration of processes in animal brains that are relevant to human behavior and psychiatric disorders without assuming that the complex constellation of states that humans refer to by the term fear are also consciously experienced by other animals. This is not a denial of animal consciousness, but a call for researchers not to invoke animal consciousness to explain things that do not involve consciousness in humans.

Lessons learned from a Chaos and Comlexity seminar.

For ~ 15 years I have participated in the weekly Chaos and Complexity seminar at the Univ. of Wisconsin organized by physics professor Clint Sprott, and have given ~5 lectures to the group during that period.  I want to pass on this link to Sprott's summary comments  presented at the final meeting of the spring term on 5/7/2013. Here I would like to pass on his closing comments:

We have heard many speakers over the years make dire predictions, especially regarding the climate and the ecology, but I am more optimistic than most about our future for five fundamental reasons: 1) Negative feedback is at least as common as positive feedback, and it tends to regulate many processes. 2) Most nonlinearities are beneficial, putting inherent limits on the growth of deleterious effects. 3) Complex dynamical systems self-organize to optimize their fitness. 4) Chaotic systems are sensitive to small changes, making prediction difficult, but facilitating control. 5) Our knowledge and technology will continue to advance, meaning that new solutions to problems will be developed as they are needed or, more likely, soon thereafter in response to the need. Whether it's fusion reactors, geoengineering, vastly improved batteries, halting of the aging process, DNA cloning to restore extinct species, or some other game changer, things may get worse before they get better, but humans are enormously ingenious and adaptable and will rise to the challenge of averting disaster.

This is not a prediction that our problems will vanish or an argument for ignoring them. On the contrary, our choices and actions are the means by which society will reorganize to become even better in the decades to follow, albeit surely not a Utopia.

Teleological reasoning about nature: intentional design or relational perspectives?

Ojalehto et al. offer an interesting analysis of assumptions about our reasoning about natural phenomena. Some slightly edited clips from the abstract and paper:

According to the theory of ‘promiscuous teleology’, humans are naturally biased to (mistakenly) construe natural kinds as if they (like artifacts) were intentionally designed ‘for a purpose’ (i.e. clouds are 'for' raining). However, this theory introduces two paradoxes. First, if infants readily distinguish natural kinds from artifacts, as evidence suggests, why do school-aged children erroneously conflate this distinction? Second, if Western scientific education is required to overcome promiscuous teleological reasoning, how can one account for the ecological expertise of non-Western educated, indigenous people? We develop an alternative ‘relational-deictic’ interpretation, proposing that the teleological stance may not index a deep-rooted belief that nature was designed for a purpose, but instead may reflect an appreciation of the perspectival relations among living things and their environments.

A new relational-deictic framework can take into account a rich set of relations and perspectives among natural entities, permitting one to avoid cultural assumptions about the ‘right way’ to conceptualize nature, and identifying the claim for ‘intuitive theism’ as a culturally-infused stance. Kelemen writes that teleological reasoning is a ‘side-effect’ of people's natural inclination to ‘privilege intentional explanation’ and view ‘nature as an intentionally designed artifact.’ The relational-deictic framework outlined here offers a different interpretation: teleological reasoning reflects a tendency to think through perspectival relationships within (socio-ecological) webs of interdependency. On this view, the origins of teleological thinking are social and relational rather than individual and intentional. This has implications for ongoing debates about the primacy of social and relational theories in human development.

The relational-deictic interpretation opens new avenues for research into how people come to understand the natural world and their place within it. Teleological reasoning may not be immature or misguided. Instead, it may reflect young children's ecological perspective-taking abilities and serve as an entry-point for reasoning about socio-ecological systems of living things, rather than reasoning about isolated, abstracted, and essentialized individual kinds

Brain activity correlating with future antisocial activity.

From Aharoni et al.:

Identification of factors that predict recurrent antisocial behavior is integral to the social sciences, criminal justice procedures, and the effective treatment of high-risk individuals. Here we show that error-related brain activity elicited during performance of an inhibitory task prospectively predicted subsequent rearrest among adult offenders within 4 y of release (N = 96). The odds that an offender with relatively low anterior cingulate activity would be rearrested were approximately double that of an offender with high activity in this region, holding constant other observed risk factors. These results suggest a potential neurocognitive biomarker for persistent antisocial behavior.

A marker, fine, but as a guide to action?  Suggesting more post-incarceration therapeutic efforts with those having lower anterior cingulate activities?

Body posture modulates action perception.

From Zimmermann et al:

Recent studies have highlighted cognitive and neural similarities between planning and perceiving actions. Given that action planning involves a simulation of potential action plans that depends on the actor's body posture, we reasoned that perceiving actions may also be influenced by one's body posture. Here, we test whether and how this influence occurs by measuring behavioral and cerebral (fMRI) responses in human participants predicting goals of observed actions, while manipulating postural congruency between their own body posture and postures of the observed agents. Behaviorally, predicting action goals is facilitated when the body posture of the observer matches the posture achieved by the observed agent at the end of his action (action's goal posture). Cerebrally, this perceptual postural congruency effect modulates activity in a portion of the left intraparietal sulcus that has previously been shown to be involved in updating neural representations of one's own limb posture during action planning. This intraparietal area showed stronger responses when the goal posture of the observed action did not match the current body posture of the observer. These results add two novel elements to the notion that perceiving actions relies on the same predictive mechanism as planning actions. First, the predictions implemented by this mechanism are based on the current physical configuration of the body. Second, during both action planning and action observation, these predictions pertain to the goal state of the action.

Where our brains compute musical reward.

Yet another fascinating chunk from Zatorre and collaborators:

We used functional magnetic resonance imaging to investigate neural processes when music gains reward value the first time it is heard. The degree of activity in the mesolimbic striatal regions, especially the nucleus accumbens, during music listening was the best predictor of the amount listeners were willing to spend on previously unheard music in an auction paradigm. Importantly, the auditory cortices, amygdala, and ventromedial prefrontal regions showed increased activity during listening conditions requiring valuation, but did not predict reward value, which was instead predicted by increasing functional connectivity of these regions with the nucleus accumbens as the reward value increased. Thus, aesthetic rewards arise from the interaction between mesolimbic reward circuitry and cortical networks involved in perceptual analysis and valuation.

Quiet - the world of introverts.

I recently visited my year old grandson in Austin, TX., who turns out to be my opposite on Jerome Kagan's scale of temperamental introversion/extraversion. Like his mother, he is outgoing and gregarious, and wears me out very quickly with his intensity in play activities. Against this background I was struck by reading a book review by Judith Warner of Susan Cain's new book "Quiet", listed by the NY Times as one of the 10 major popular science books of the past year. Some clips from the review:

Too often denigrated and frequently overlooked in a society that’s held in thrall to an “Extrovert Ideal — the omnipresent belief that the ideal self is gregarious, alpha and comfortable in the spotlight,” Cain’s introverts are overwhelmed by the social demands thrust upon them. They’re also underwhelmed by the example set by the voluble, socially successful go-getters in their midst who “speak without thinking,” in the words of a Chinese software engineer whom Cain encounters in Cupertino, Calif.

Many of the self-avowed introverts she meets in the course of this book.. ape extroversion...some fake it well enough to make it, going along to get along in a country that rewards the out­going...Unchecked extroversion — a personality trait Cain ties to ebullience, excitability, dominance, risk-taking, thick skin, boldness and a tendency toward quick thinking and thoughtless action — has actually, she argues, come to pose a real menace of late. The outsize reward-seeking tendencies of the hopelessly ­outer-directed helped bring us the bank meltdown of 2008...she claims....it’s time to establish “a greater balance of power” between those who rush to speak and do and those who sit back and think. Introverts — who, according to Cain, can count among their many virtues the fact that “they’re relatively immune to the lures of wealth and fame” — must learn to “embrace the power of quiet.” And extroverts should learn to sit down and shut up.

Her accounts of introverted kids misunderstood and mishandled by their parents should give pause, for she rightly notes that introversion in children (often incorrectly viewed as shyness) is in some ways threatening to the adults around them. Indeed, in an age when kids are increasingly herded into classroom “pods” for group work, Cain’s insights into the stresses of nonstop socializing for some children are welcome; her advice that parents should choose to view their introverted offspring’s social style with understanding rather than fear is well worth hearing.

A...problem with Cain’s argument is her assumption that most introverts are actually suffering in their self-esteem. This may be true in the sorts of environments — Harvard Business School, corporate boardrooms, executive suites — that she knows best and appears to spend most of her time thinking about. Had she spent more time in other sorts of places, among other types of people — in research laboratories, for example, or among economists rather than businessmen and -women — she would undoubtedly have discovered a world of introverts quite contented with who they are, and who feel that the world has been good to them.

Free Will, continued - Prior unconscious brain activity predicts choices for abstract intentions!

I've been running a thread on free will and neuroscience in this blog, recently noting comments by Nahmias:

...As long as people understand that discoveries about how our brains work do not mean that what we think or try to do makes no difference to what happens, then their belief in free will is preserved. What matters to people is that we have the capacities for conscious deliberation and self-control that I’ve suggested we identify with free will.

...None of the evidence marshaled by neuroscientists and psychologists suggests that those neural processes involved in the conscious aspects of such complex, temporally extended decision-making are in fact causal dead ends. It would be almost unbelievable if such evidence turned up.

Almost unbelievable appears to have happened, with this from Soon et al.. Interestingly, they identified a partial spatial and temporal overlap of choice-predictive signals with activity in the default mode network I reviewed in this past Monday's post. The abstract:

Unconscious neural activity has been repeatedly shown to precede and potentially even influence subsequent free decisions. However, to date, such findings have been mostly restricted to simple motor choices, and despite considerable debate, there is no evidence that the outcome of more complex free decisions can be predicted from prior brain signals. Here, we show that the outcome of a free decision to either add or subtract numbers can already be decoded from neural activity in medial prefrontal and parietal cortex 4 s before the participant reports they are consciously making their choice. These choice-predictive signals co-occurred with the so-called default mode brain activity pattern that was still dominant at the time when the choice-predictive signals occurred. Our results suggest that unconscious preparation of free choices is not restricted to motor preparation. Instead, decisions at multiple scales of abstraction evolve from the dynamics of preceding brain activity.

And, a chunk from their discussion:

It is interesting that mental calculation, the more complex task, had less predictive lead time than a simple binary motor choice in our previous study. This could tentatively reflect a general limitation of unconscious processing in the sense that unconscious processes might be restricted in their ability to develop or stabilize complex representations such as abstract intentions. It is also worth noting that both studies showed the same dissociation between cortical regions that were predictive of the content versus the timing of the decision. This implies that the formation of an intention to act depends on interactions between the choice-predictive and time-predictive regions. The temporal profile of this interaction is likely to determine when the earliest choice-predictive information is available and might differ between tasks.

There was a partial spatial overlap between the choice-predictive brain regions and the DMN. Interestingly, the state of the DMN (default mode network) during the early preparatory phase still resembled that during off-task or “resting” periods. This lends further credit to the notion that the preparatory signals were not a result of conscious engagement with the task. Furthermore, the spatial and temporal overlap hints at a potential involvement of the DMN in unconscious choice preparation.

To summarize, we directly investigated the formation of spontaneous abstract intentions and showed that the brain may already start preparing for a voluntary action up to a few seconds before the decision enters into conscious awareness. Importantly, these results cannot be explained by motor preparation or general attentional mechanisms. We found that frontopolar and precuneus/posterior cingulate encoded the content of the upcoming decision, but not the timing. In contrast, the pre-SMA predicted the timing of the decision, but not the content.

Showing where moral intent is determined in our brains.

Interesting work from Koster-Hale et al:

Intentional harms are typically judged to be morally worse than accidental harms. Distinguishing between intentional harms and accidents depends on the capacity for mental state reasoning (i.e., reasoning about beliefs and intentions), which is supported by a group of brain regions including the right temporo-parietal junction (RTPJ). Prior research has found that interfering with activity in RTPJ can impair mental state reasoning for moral judgment and that high-functioning individuals with autism spectrum disorders make moral judgments based less on intent information than neurotypical participants. Three experiments, using multivoxel pattern analysis, find that (i) in neurotypical adults, the RTPJ shows reliable and distinct spatial patterns of responses across voxels for intentional vs. accidental harms, and (ii) individual differences in this neural pattern predict differences in participants’ moral judgments. These effects are specific to RTPJ. By contrast, (iii) this distinction was absent in adults with autism spectrum disorders. We conclude that multivoxel pattern analysis can detect features of mental state representations (e.g., intent), and that the corresponding neural patterns are behaviorally and clinically relevant.

Brain training games don't actually make you smarter.

Wow...after having done several posts uncritically passing on studies by Jaeggi and others claiming that games to improve working memory, such as the n-Back game, increase cognitive skills in other areas, a number of studies have failed to replicate these phenomena. Gareth Cook has done an interesting article on this in The New Yorker, suggesting that claims made by commercial software sites like Cogmen, Lumosity, and CogniFit are bogus.

Over the last year, however, the idea that working-memory training has broad benefits has crumbled. One group of psychologists, lead by a team at Georgia Tech, set out to replicate the Jaeggi findings, but with more careful controls and seventeen different cognitive-skills tests. Their subjects showed no evidence whatsoever for improvement in intelligence. They also identified a pattern of methodological problems with experiments showing positive results, like poor controls and a reliance on a single measure of cognitive improvement. This failed replication was recently published in one of psychology’s top journals, and another, by a group at Case Western Reserve University, has been published since.

The recent meta-analysis, led by Monica Melby-Lervåg, of the University of Oslo, and also published in a top journal, is even more damning. Some studies are more convincing than others, because they include more subjects and show a larger effect. Melby-Lervåg’s paper laboriously accounts for this, incorporating what Jaeggi, Klingberg, and everyone else had reported. The meta-analysis found that the training isn’t doing anyone much good. If anything, the scientific literature tends to overstate effects, because teams that find nothing tend not to publish their papers. (This is known as the “filedrawer” effect.) A null result from meta-analysis, published in a top journal, sends a shudder through the spine of all but the truest of believers. In the meantime, a separate paper by some of the Georgia Tech scientists looked specifically at Cogmed’s training, which has been subjected to more scientific scrutiny than any other program. “The claims made by Cogmed,” they wrote, “are largely unsubstantiated.”

Older brains - just as much nerve firing, but scrambled connections?

A group of colleagues at Imperial College London and Tsinghua University in Beijing have fitted glass windows on the skulls of old and young mice. Contrary to expectation they observe that older mice have more firing points than younger ones, but they are more erratic in their activity than in younger mice, with high turnover rates and wavering firing strengths. The older mice also performed less well on a memory test. The suggestion then is that the mental decline seen in aging may be due more do disorderly wiring than to loss of nerve cells. Their abstract:

Aging is a major risk factor for many neurological diseases and is associated with mild cognitive decline. Previous studies suggest that aging is accompanied by reduced synapse number and synaptic plasticity in specific brain regions. However, most studies, to date, used either postmortem or ex vivo preparations and lacked key in vivo evidence. Thus, whether neuronal arbors and synaptic structures remain dynamic in the intact aged brain and whether specific synaptic deficits arise during aging remains unknown. Here we used in vivo two-photon imaging and a unique analysis method to rigorously measure and track the size and location of axonal boutons in aged mice. Unexpectedly, the aged cortex shows circuit-specific increased rates of axonal bouton formation, elimination, and destabilization. Compared with the young adult brain, large (i.e., strong) boutons show 10-fold higher rates of destabilization and 20-fold higher turnover in the aged cortex. Size fluctuations of persistent boutons, believed to encode long-term memories, also are larger in the aged brain, whereas bouton size and density are not affected. Our data uncover a striking and unexpected increase in axonal bouton dynamics in the aged cortex. The increased turnover and destabilization rates of large boutons indicate that learning and memory deficits in the aged brain arise not through an inability to form new synapses but rather through decreased synaptic tenacity. Overall our study suggests that increased synaptic structural dynamics in specific cortical circuits may be a mechanism for agerelated cognitive decline.

A review - Mindfulness meditation and our brain's default versus attentional networks.

I've been doing some homework on potential topics to work up into a lecture, one of them being brain correlates of various meditative, attentional, or default mode states. The vocabulary used is sometimes contradictory between papers, but two categories emerge. One uses terms for thought like default, narrative focus, phenomenal, social reasoning, theory of mind, baseline setting, self referential, introspective, and stimulus independent. The contrasting descriptors are attentional, direct experience, experiential focus, task positive network, physical cause/effect reasoning.

This cooks down roughly to distinguishing between brain networks whose primary activity occurs during internal narrative focus versus those activated during direct attentional experience.

In reviewing previous mindblog posts on the default network I come up with a partial bibliography of reviews and experiments, and thought some readers might find it useful, a list in no particular order, with brief notes:

Reciprocal repression (mutual inhibition) between networks - nice graphics  - some muddying of definitions

Relationship of this mutual inhibition to mindfulness meditation , which notes Farb et al., 2007

Review (NYTimes) on power of concentration - mindfulness training causing increased connectivity in attentional and default networks. 

Review with graphics of MRI of default network activated by autobiographical memory, envisioning future, theory of mind, moral decision making. 

Tierney - virtues of a wandering mind.  (context, larger agenda, creativity)

Review of varieties of resting state activity

Change between operating systems during eyeblink.

Different components of default mode active in different kinds of memory.

Mental time travel and default network.

Synchronization of both modes between individuals.

Default network can be realized by multiple architectures (split brain patients).

Default network as underpinning of cerebral ‘connectome‘  - good graphic.

Development of human default network from being sparsely functionally connected at 7-9  years.







Default mode in Chimps and Monkeys

Association of default network with midline structures.

Why old folks more easy lose their way,

Wiener et al. make observations that shed light on why older people have more difficulty finding their car in a shopping mall's large parking lot if they exit the mall by a different door than they used to enter it (or follow directions involving an intersection if they approach the intersection from a different direction than the one used for learning them.) From their introduction:

Everyday navigation can be based on different strategies. The hippocampus plays a key role in cognitive map or place strategies that rely on allocentric processing, whereas the parietal cortex and striatal circuits are involved in route or response strategies...To test the hypothesis that cognitive aging not only results in a shift away from allocentric strategies but in a specific preference for beacon-based strategies, we developed a novel experimental paradigm: participants first learned a route along a number of intersections and were then asked to rejoin the original route approaching the intersections from different directions. Trials in which participants approached the intersections from a direction different from that during training (see Fig. 1) allowed us (1) to compare the use and adoption of route-learning strategies between young and older participants and (2) to test for specific preferences for beacon-based strategies in older participants.

The abstract:

Efficient spatial navigation requires not only accurate spatial knowledge but also the selection of appropriate strategies. Using a novel paradigm that allowed us to distinguish between beacon, associative cue, and place strategies, we investigated the effects of cognitive aging on the selection and adoption of navigation strategies in humans. Participants were required to rejoin a previously learned route encountered from an unfamiliar direction. Successful performance required the use of an allocentric place strategy, which was increasingly observed in young participants over six experimental sessions. In contrast, older participants, who were able to recall the route when approaching intersections from the same direction as during encoding, failed to use the correct place strategy when approaching intersections from novel directions. Instead, they continuously used a beacon strategy and showed no evidence of changing their behavior across the six sessions. Given that this bias was already apparent in the first experimental session, the inability to adopt the correct place strategy is not related to an inability to switch from a firmly established response strategy to an allocentric place strategy. Rather, and in line with previous research, age-related deficits in allocentric processing result in shifts in preferred navigation strategies and an overall bias for response strategies. The specific preference for a beacon strategy is discussed in the context of a possible dissociation between beacon-based and associative-cue-based response learning in the striatum, with the latter being more sensitive to age-related changes.

Defining when a visual stimulus become conscious to us.

Llinás and collaborators do a nice dissection of our conscious versus unconscious visual processing and note the timing (240 milliseconds) of a brain signal that correlates with our conscious awareness of a stimulus. (This is the same time epoch that I evoke in the "millisecond manager" term I use in several of my essays in the left column of this blog - a period during which we can note the onset of a visual or emotional perception before further action or interpretation begins.)

At perceptual threshold, some stimuli are available for conscious access whereas others are not. Such threshold inputs are useful tools for investigating the events that separate conscious awareness from unconscious stimulus processing. Here, viewing unmasked, threshold-duration images was combined with recording magnetoencephalography to quantify differences among perceptual states, ranging from no awareness to ambiguity to robust perception. A four-choice scale was used to assess awareness: “didn’t see” (no awareness), “couldn’t identify” (awareness without identification), “unsure” (awareness with low certainty identification), and “sure” (awareness with high certainty identification). Stimulus-evoked neuromagnetic signals were grouped according to behavioral response choices. Three main cortical responses were elicited. The earliest response, peaking at ∼100 ms after stimulus presentation, showed no significant correlation with stimulus perception. A late response (∼290 ms) showed moderate correlation with stimulus awareness but could not adequately differentiate conscious access from its absence. By contrast, an intermediate response peaking at ∼240 ms was observed only for trials in which stimuli were consciously detected. That this signal was similar for all conditions in which awareness was reported is consistent with the hypothesis that conscious visual access is relatively sharply demarcated.