Cortical thickness, MRI, and early Alzheimer's diagnosis

Alongside today's brief post on diet and aging, I thought I would pass on the links to two open access articles in the neurology journal "Brain." The first deals with early diagnosis of Alzheimer's disease using cortical thickness, and the second uses automated MRI measurements to identify individuals with mild cognitive impairment and Alzheimer's disease. (And, I suppose this is a good post in which to act on a request that I provide a link to Caring.com, "a website dedicated to helping people take care of their aging parents and other loved ones.")

Thursday morning Grieg, a Berceuse

I just looked up what a Berceuse is.... it's a lullaby, or soothing composition... This version would have to be considered a fairly robust rendering of the style.

Positive self statements: power for some, peril for others

Wood et al. offer an interesting article in Psychological Science. They present experiments showing that positive self-statements have the potential to make one feel worse if they lie outside one's latitude of acceptance, are self-discrepant and thereby highlight one's failures to meet one's standards, and arouse self-verification motives. Positive self-statements are especially likely to backfire for the very people they are meant to benefit: people with low self-esteem. Such people, by definition, see themselves as failing to meet standards in more domains or in more important domains than do people with high self-esteem. Moreover, self-verification motives should bias people with low self-esteem to reject positive self-statements, but encourage people with high self-esteem to accept them. Here is their abstract:

Positive self-statements are widely believed to boost mood and self-esteem, yet their effectiveness has not been demonstrated. We examined the contrary prediction that positive self-statements can be ineffective or even harmful. A survey study confirmed that people often use positive self-statements and believe them to be effective. Two experiments showed that among participants with low self-esteem, those who repeated a positive self-statement ("I'm a lovable person") or who focused on how that statement was true felt worse than those who did not repeat the statement or who focused on how it was both true and not true. Among participants with high self-esteem, those who repeated the statement or focused on how it was true felt better than those who did not, but to a limited degree. Repeating positive self-statements may benefit certain people, but backfire for the very people who "need" them the most.

Masturbation in the animal kingdom

An interesting piece by Engber from Slate Magazine (The article even includes a link to a YouTube gallery on the subject!):

The recent finding that masturbation improves the quality of human sperm supports the notion that it's an evolved trait and not merely a byproduct of our physiology. According to a branch of evolutionary theory called "sperm competition" that developed in the late-1960s, natural selection can produce just such a change in reproductive behavior. The theory focuses on polyandrous species—i.e., those in which a single female takes multiple partners and the sperm from several potential fathers might end up competing to fertilize the same egg. Under those conditions, the relative quality of male ejaculate very clearly determines whose genes are passed on to the next generation.

So....this is how my cat is manipulating me

If you are a cat person, check out this interesting bit from Gisela Telis (it is open access for the new few weeks). She discusses a new study that reports that our feline friends modify their signature sound when seeking food, adding a higher-frequency element that exploits our sensitivity to infant wails-- thus making it harder to ignore. The article has some sound clips of the effect.

Rapamycin - a midlife longevity drug?

From the Nature 'Editor's Summary' of the paper by Harrison et al.

The antitumour drug rapamycin targets TOR, a kinase that is part of the PI3K–AKT–mTOR cascade, involved in regulating protein translation, cell growth and autophagy. Reducing TOR function is known to extend the life of yeast, worms and flies. Now experiments replicated in three different laboratories demonstrate that rapamycin, fed to male and female mice in a dose that substantially inhibits TOR signalling, can extend their median and maximal lifespan by up to 14%. This life extension was observed in mice fed rapamycin from 270 days of age and also at a late stage in their life, from age 600 days. These findings point to the TOR pathway as a critical point in the control of ageing in mammals and in the pathogenesis of late-life illnesses.

The brain sets fatigue.

Reynolds reviews work showing that fatigue clearly involves more than muscles - the brain also determines how far and hard we can exercise. For example, if the brain's reward center is tricked into thinking more energy is on the way (by swishing a sugar drink in the mouth but not swallowing it, for example), endurance is increased.

To Sleep, Perchance to Analyze

Pogue writes on a neat new sleep monitor that plots and reports back your periods of light sleep, REM sleep, and deep sleep - and then prompts you to note the effects coffee, booze, etc.

Insightful problem solving in birds.

An exchange of letters in PNAS as followup to the subject of the July 3 post on tool use in birds, in which the birds spontaneously use a series of tools to obtain a reward. Lind et al. question whether insight (internal mental modeling of possible problem solutions) or shaping (through successive reinforcement of behaviors) was involved. Authors Bird and Emery respond:

...our study found that rooks not only learned to obtain food by dropping a stone into a tube to collapse a platform, but that they were able to spontaneously choose the correct size and shape tool when presented with subsequent transfer tests and spontaneously solve a completely new task, whereby they had to lift a bucket by using a novel hook tool and manufacture a hook tool from a piece of wire. While we agree that the question of animal “insight” is a complex one in light of studies on chimpanzees and pigeons, we find shaping an unsatisfactory explanation for the spontaneous choice of the correct tool and the bending of the wire. We do not dispute the argument that initial acquisition of stone dropping was brought about through shaping, however, because shaping requires one or more stimulus/behaviour–reward pairings, a novel behaviour such as hook manufacture cannot simply be a case of shaping.

Lost in the internet cloud.

Cautionary sentiments about the idea of moving all of our programs and data from our personal computers to the internet 'cloud.' In the absence of rigid safeguards (which probably won't happen) the erosion of our personal power, autonomy, and privacy will be really scary.

Last week Amazon apparently conveyed a publisher’s change-of-heart to owners of its Kindle e-book reader: some purchasers of Orwell’s “1984” found it removed from their devices, with nothing to show for their purchase other than a refund. (Orwell would be amused.)

Worse, data stored online has less privacy protection both in practice and under the law. A hacker recently guessed the password to the personal e-mail account of a Twitter employee, and was thus able to extract the employee’s Google password. That in turn compromised a trove of Twitter’s corporate documents stored too conveniently in the cloud. Before, the bad guys usually needed to get their hands on people’s computers to see their secrets; in today’s cloud all you need is a password.

Thanks in part to the Patriot Act, the federal government has been able to demand some details of your online activities from service providers — and not to tell you about it. There have been thousands of such requests lodged since the law was passed, and the F.B.I.’s own audits have shown that there can be plenty of overreach — perhaps wholly inadvertent — in requests like these.

Erotica

Pretty mild stuff, by today's standards, but reasonably sensual for Grieg's time - Lyrical Piece Op 43 No 5 - Erotica

The possibility of impossible cultures.

Marc Hauser offers an essay in the 9 July issue of Nature, in which he suggests points of contact between work in the generative tradition of linguistics (Chomsky, etc.) and evolutionary developmental biology research on animal forms. Just as a developing animal form faces a massive range of possible variation:

...children are born with the capacity to acquire a wide range of possible languages, as opposed to specific languages such as English, Korean or French. This implies that a child is equipped with an abstract acquisition device, allowing the 'growth' of many different languages. Furthermore, as the child's acquisition device generates a space of possible languages, something internal or external to the device creates a space of impossible languages — forms that are never entertained by the child because they are poorly designed for acquisition and externalization in linguistic communication.

...in the same way that biologists speak of morphospaces — n-dimensional volumes that define the range of existing and potential morphological variation — linguists can speak of 'linguaspaces'. These are n-dimensional environments that constrain the set of possible languages and therefore, by definition, establish the set of impossible languages. What is necessary, therefore, is to establish the set of parameters that allow the range of variation and place constraints on its overall form.

...a point of contact concerns how the internal language system ultimately forms an acquired and externalizable language. If, as discussed earlier, the acquisition device constrains the range of possible languages by providing a set of options, then the role of environmental input is to favour, and thus select, certain options over others. This selective perspective, although uncommon in the mind sciences, aligns more closely with other work in biology, including studies of the immune system, the development of animal forms, the wiring of neurons and the acquisition of bird song. For example, songbirds have evolved brains with a set of developmental options for creating variation in song-relevant acoustic forms. Depending on the environment, certain note types are selected and are then reproduced in particular orders to create population-specific dialects — and so it is for language acquisition by humans. When a child is exposed to a particular linguistic environment, the relevant linguistic input or experience fixes the available options to create an externalizable language that is comprehensible to those who will care for and compete with the child.

Research in the generative tradition of linguistics suggests therefore that, like the variety of animal forms, the sense of unbounded variation in linguistic form is illusory, concealing a suite of universally held, biologically instantiated mechanisms for generating variation, allowing acquisition and constraining the space of possible languages. Although biologists have long sensed the close connection between the generative properties of language and generative biological systems, including the immune system, microbial diversity and proteonomics (the study of protein function and expression) relatively few students of the mind sciences have acknowledged such connections with other domains of human knowledge.

Heuser suggests that only humans have evolved four computational capacities, constituting a phylogenetic mind gap between humans and other animals:

Generative computation Recursive and combinatorial operations provide the only known mechanisms for generating an almost limitless variety of meaningful expressions, whether mathematical, linguistic, musical or moral. Recursion is an iterative operation, in which a rule is called up repeatedly to create new expressions, be they embedded phrases within a sentence, new musical scores with repeating themes, or tools within tools (for example, a Swiss army knife). Each expression has a unique interpretation or function depending on the arrangement of the elements. By contrast, combinatorial operations allow discrete elements to be unified and ordered, thus creating new ideas, which could be expressed as novel words (Walkman from walk and man) or novel musical forms.

Mental symbols Humans readily, without instruction, convert sensory experiences and abstract thoughts into externalized symbols, either as words or images. This capacity cuts across domains of knowledge and sensory experience, enabling humans to express beliefs in sentences, to depict particular melodies with explicit notations, and to provide logos indicating when to turn off the highway for a hamburger or a coffee.

Promiscuous interfaces Humans have unique creative capacities and problem-solving abilities, which stem from the capacity to combine representations promiscuously from different domains of knowledge. For instance, humans can combine the concepts of number, belief, causality and harm in deciding that it is sometimes morally obligatory to harm one person to save the lives of many.

Abstract thought Some thoughts derive from direct sensory experiences: for example, thinking of red items such as cherries and blood requires experience with these, as opposed to non-red objects such as celery and bone. But many human thoughts are abstract, with no explicit or even necessary sensory connection. These include concepts such as infinity, grammatical categories such as nouns and verbs, and ethical judgments such as permissible and forbidden.



Figure - Promiscuous interfaces between different domains of knowledge. An example of deciding whether taking one life is justified if the action saves many other lives. A representation of an action (a finger pulling a trigger) interfaces with a representation of death as a potential consequence, which in turn interfaces with a system of numerical representation that evaluates whether the number of lives killed exceeds the number saved. This then interfaces with a moral evaluative system that judges the permissibility of the initial action, which then interfaces with the human linguistic system to deliver the judgement "forbidden".

The generative mechanisms that underpin so much of human mental life acquire their expressive power because the recursive and combinatorial operations can functionally 'grab' the outputs of different modular systems or domains of knowledge. This capacity for promiscuously creating interfaces between domains is almost absent in animals. Thus, although both human and animal brains are characterized by modular functions and mechanisms, the modular outputs are typically restricted to a single functional problem in animals but are broadly accessible in humans. Non-human animals therefore show a form of myopic intelligence, designed to solve one problem with exquisite efficiency. For example, although honeybees have a symbolic dance that indicates the distance, direction and quantity of food, this communication system is largely restricted to food despite the intricate social lives of bees. Although meerkat adults teach their pups how to kill scorpion prey by providing them with age-appropriate opportunities for handling and dismembering, teaching does not occur in any other context. Although plovers use a deceptive display to lure predators away from their nest of eggs, they do not deceive in any other situation. And although chimpanzees use the direction of another's eyes to guide strategic competition, they are far less skilled at using another's eyes to guide cooperation. By contrast, in humans, neither language, teaching, deception, or the use of seeing to infer knowing are restricted to a single context.

The evolution of misbelief

Below I paste in the abstract (and here is the PDF) of a forthcoming article in Brain and Behavioral Science by McKay and Dennett that examines possible evolutionary rationales for mistaken beliefs, bizarre delusions, instances of self-deception, etc. Of the range of potential candidates for evolved misbelief, they conclude that, among those surveyed, only positive illusions meet their criteria.

From an evolutionary standpoint, a default presumption is that true beliefs are adaptive and misbeliefs maladaptive. But if humans are biologically engineered to appraise the world accurately and to form true beliefs, how are we to explain the routine exceptions to this rule? How can we account for mistaken beliefs, bizarre delusions and instances of self-deception? We explore this question in some detail. We begin by articulating a distinction between two general types of misbelief: those resulting from a breakdown in the normal functioning of the belief formation system (e.g. delusions) and those arising in the normal course of that systems operations (e.g. beliefs based on incomplete or inaccurate information). The former are instances of biological dysfunction or pathology, reflecting culpable limitations of evolutionary design. Although the latter category includes undesirable (but tolerable) by-products of forgivably limited design, our quarry is a contentious subclass of this category: misbeliefs best conceived as design features. Such misbeliefs, unlike occasional lucky falsehoods, would have been systematically adaptive in the evolutionary past. Such misbeliefs, furthermore, would not be reducible to judicious but doxastically noncommittal - action policies. Finally, such misbeliefs would have been adaptive in themselves, constituting more than mere by-products of adaptively biased misbelief-producing systems. We explore a range of potential candidates for evolved misbelief, and conclude that, of those surveyed, only positive illusions meet our criteria.

EEG prediction of lapses in attention.

O'Connell et al. show that EEG signals can predict a forthcoming lapse in attention 20 seconds before it occurs. Could this prove useful for a task (like flying an airplane or operating complex but boring equipment) in which constant attention is required?

Feminize yourself by drinking bottled water....

Kristof does a piece on how the phthalates used in plastic manufacture, found now in our water supply and leached from many plastic bottle products, can nudge the development of humans and other animals towards feminization.

Melancholy...

Here's a haunting piece: from Grieg's Lyric Pieces, Op 47 No 5 - Melancholy
(I enjoy sitting down at the end of an afternoon and playing these brief Grieg pieces, and it takes only a modest effort to record them, using Apple's Garage Band and iMovie applications.)

A sixth sense...

A prosthesis that immerses you in the data world, described by Pattie Maes in a TED lecture.

Obamology

From the Random Samples section of the July 10 issue of Science:

Obamology

Hey, they never did this with George W. Bush! The American Sociological Association, meeting in San Francisco, California, in August, will be examining the presidency in-depth in sessions held under the heading "The Sociological Significance of President Barack Obama."

* Plenary Session: "Why Obama Won (and What that Says About Democracy and Change in America)"
* Presidential Panel: "A Defining Moment? Youth, Power and the Obama Phenomenon"
* Presidential Panel: "Through the Lens of Gender, Race, Sexuality and Class: The Obama Family and the American Dream"
* Thematic Session: "Understanding Democratic Renewal: The Movement to Elect Barack Obama"
* Thematic Session: "The Future of Community Organizing During an Obama Presidency"
* Thematic Session: "Asian-American Movements, Identities, and Politics: A New Racial Project in the Obama Years?"
* Open Forum: "Does the Obama Administration Need a Social Science Scholars Council?"

Narrowing of intersensory speech perception in infancy

From Pons et al.:

The conventional view is that perceptual/cognitive development is an incremental process of acquisition. Several striking findings have revealed, however, that the sensitivity to non-native languages, faces, vocalizations, and music that is present early in life declines as infants acquire experience with native perceptual inputs. In the language domain, the decline in sensitivity is reflected in a process of perceptual narrowing that is thought to play a critical role during the acquisition of a native-language phonological system. Here, we provide evidence that such a decline also occurs in infant response to multisensory speech. We found that infant intersensory response to a non-native phonetic contrast narrows between 6 and 11 months of age, suggesting that the perceptual system becomes increasingly more tuned to key native-language audiovisual correspondences. Our findings lend support to the notion that perceptual narrowing is a domain-general as well as a pan-sensory developmental process.

Racial group membership modulates empathic brain responses.

From Xu et al.:

The pain matrix including the anterior cingulate cortex (ACC) mediates not only first person pain experience but also empathy for others' pain. It remains unknown, however, whether empathic neural responses of the pain matrix are modulated by racial in-group/out-group relationship. Using functional magnetic resonance imaging we demonstrate that, whereas painful stimulations applied to racial in-group faces induced increased activations in the ACC and inferior frontal/insula cortex in both Caucasians and Chinese, the empathic neural response in the ACC decreased significantly when participants viewed faces of other races. Our findings uncover neural mechanisms of an empathic bias toward racial in-group members.


Figure - a, Illustration of Caucasian faces receiving painful and non-painful stimuli. b, Illustration of Chinese faces receiving painful and non-painful stimuli. c, Contrast values of the parameter estimates of signal intensity in the ACC and the frontal cortex that differentiated painful and non-painful stimuli in Caucasians. d, Contrast values of the parameter estimates of signal intensity in the ACC and the frontal cortex that differentiated painful and non-painful stimuli in Chinese. e, Correlation between ACC empathic neural responses to racial in-group and out-group members. X and Y axes respectively indicate ACC empathic responses to racial in-group and racial out-group members indexed in contrast values of painful versus non-painful stimulation. f, Increased activations in the ACC and the frontal/insula cortex shown in whole-brain statistical parametric mapping analyses when participants perceived racial in-group faces. The upper figures show the results from Caucasian subjects and the lower figures show the results from Chinese subjects.