Cognitive changes caused by single exposure to a placebo

Given the mention of placebo responses in today's other post on acupuncture, I thought I would pass on this interesting bit in Neuropsychologia from Morton et al., showing that the cognitive effects of a single placebo intervention can persist for six weeks:

Placebo has been shown to be a powerful analgesic with corresponding reduction in the activation of the pain matrix in the brain. However, the response to placebo treatment is highly variable. It is unclear how anticipatory and pain-evoked potentials are affected by the treatment and how reproducible the response is. Laser stimulation was used to induce moderate pain in healthy volunteers. We induced placebo analgesia by conditioning subjects to expect pain reduction by applying a sham anaesthetic cream on one arm in conjunction with a reduced laser stimulus. Pain ratings were assessed before, during and after treatment. Using electroencephalography (EEG) we measured anticipatory neural responses and pain-evoked potentials to laser heat to determine how expectation of analgesia affected the response to a placebo manipulation. This was a reproducibility study and as such the experimental procedure was repeated after a minimum gap of 2 weeks. Significant reductions in pain-evoked potentials were shown after treatment. The anticipatory responses did not change after treatment for the control and sham-treatment groups in the first session but were significantly lower in the repeat session relative to the first session in the sham-treatment group only. A significant correlation was found between the reduction in state anxiety in the repeat session relative to the first and the reduction in the anticipatory response in the sham-treatment group. Receiving a placebo treatment appears to cause a lasting change in the cognitive processing of pain for at least 6 weeks. This cognitive change may be facilitated by a change in state anxiety.

Our brains on the internet - smarter, dumber, neither?

As part of my re-entry catching up with accumulated articles, I want to point out some contrasting takes on how gadgets, the internet, our modern pace, multi-tasking and attention span, etc. are influencing our brains:
Richtel describes a number of experiments demonstrating how multitasking can diminish the ability to focus on or switch between tasks

While many people say multitasking makes them more productive, research shows otherwise. Heavy multitaskers actually have more trouble focusing and shutting out irrelevant information...and they experience more stress...even after the multitasking ends, fractured thinking and lack of focus persist.

Jonah Lehrer reviews "The Shallows," a new book by Nicholas Carr on the internet and the brain. Carr takes a dire view of what the internet is doing to our brains, but Lehrer counters:

There is little doubt that the Internet is changing our brain. Everything changes our brain. What Carr neglects to mention, however, is that the preponderance of scientific evidence suggests that the Internet and related technologies are actually good for the mind. For instance, a comprehensive 2009 review of studies published on the cognitive effects of video games found that gaming led to significant improvements in performance on various cognitive tasks,...Carr's argument also breaks down when it comes to idle Web surfing. A 2009 study by neuroscientists at the University of California, Los Angeles, found that performing Google searches led to increased activity in the dorsolateral prefrontal cortex, at least when compared with reading a "book-like text." Interestingly, this brain area underlies the precise talents, like selective attention and deliberate analysis, that Carr says have vanished in the age of the Internet. Google, in other words, isn't making us stupid -- it's exercising the very mental muscles that make us smarter.

Pinker offers a sanguine and sane assessment:

New forms of media have always caused moral panics...such panics often fail basic reality checks...If electronic media were hazardous to intelligence, the quality of science would be plummeting. Yet discoveries are multiplying like fruit flies, and progress is dizzying. Other activities in the life of the mind, like philosophy, history and cultural criticism, are likewise flourishing.

...the effects of experience are highly specific to the experiences themselves. If you train people to do one thing (recognize shapes, solve math puzzles, find hidden words), they get better at doing that thing, but almost nothing else. Music doesn’t make you better at math, conjugating Latin doesn’t make you more logical, brain-training games don’t make you smarter...The effects of consuming electronic media are also likely to be far more limited than the panic implies. Media critics write as if the brain takes on the qualities of whatever it consumes, the informational equivalent of “you are what you eat.” As with primitive peoples who believe that eating fierce animals will make them fierce, they assume that watching quick cuts in rock videos turns your mental life into quick cuts or that reading bullet points and Twitter postings turns your thoughts into bullet points and Twitter postings.

...to encourage intellectual depth, don’t rail at PowerPoint or Google. It’s not as if habits of deep reflection, thorough research and rigorous reasoning ever came naturally to people. They must be acquired in special institutions, which we call universities, and maintained with constant upkeep, which we call analysis, criticism and debate. They are not granted by propping a heavy encyclopedia on your lap, nor are they taken away by efficient access to information on the Internet.

The new media have caught on for a reason. Knowledge is increasing exponentially; human brainpower and waking hours are not. Fortunately, the Internet and information technologies are helping us manage, search and retrieve our collective intellectual output at different scales, from Twitter and previews to e-books and online encyclopedias. Far from making us stupid, these technologies are the only things that will keep us smart.

Believing is seeing.

Langer et al. do experiments showing that vision can be improved by manipulating our mind-set:

.... In Study 1, participants were primed with the mind-set that pilots have excellent vision. Vision improved for participants who experientially became pilots (by flying a realistic flight simulator) compared with control participants (who performed the same task in an ostensibly broken flight simulator). Participants in an eye-exercise condition (primed with the mind-set that improvement occurs with practice) and a motivation condition (primed with the mind-set “try and you will succeed”) demonstrated visual improvement relative to the control group. In Study 2, participants were primed with the mind-set that athletes have better vision than nonathletes. Controlling for arousal, doing jumping jacks resulted in greater visual acuity than skipping (perceived to be a less athletic activity than jumping jacks). Study 3 took advantage of the mind-set primed by the traditional eye chart: Because letters get progressively smaller on successive lines, people expect that they will be able to read the first few lines only. When participants viewed a reversed chart and a shifted chart, they were able to see letters they could not see before. Thus, mind-set manipulation can counteract physiological limits imposed on vision.

MindBlog back in Madison - the anterior insula rests from risk alertness

I'm finally back in my University of Wisconsin office, after a month of mainly being on the road, and I'm very much looking forward to settling in to have more time to read and face the  list of accumulated articles that might be the subjects of blog posts.  No matter how comfortable I think I am feeling while traveling, I still am surprised on the return to familiar settings as I watch the body relax to reveal a stored up tiredness, indicating how much energy was being put into the alertness and vigilance - being poised for the unexpected in foreign settings.

It would appear that my being more alert to risks associated with travel was, according to Mohr et al.,  strenuously exercising my anterior insula:

In our everyday life, we often have to make decisions with risky consequences, such as choosing a restaurant for dinner or choosing a form of retirement saving. To date, however, little is known about how the brain processes risk. Recent conceptualizations of risky decision making highlight that it is generally associated with emotions but do not specify how emotions are implicated in risk processing. Moreover, little is known about risk processing in non-choice situations and how potential losses influence risk processing. Here we used quantitative meta-analyses of functional magnetic resonance imaging experiments on risk processing in the brain to investigate (1) how risk processing is influenced by emotions, (2) how it differs between choice and non-choice situations, and (3) how it changes when losses are possible. By showing that, over a range of experiments and paradigms, risk is consistently represented in the anterior insula, a brain region known to process aversive emotions such as anxiety, disappointment, or regret, we provide evidence that risk processing is influenced by emotions. Furthermore, our results show risk-related activity in the dorsolateral prefrontal cortex and the parietal cortex in choice situations but not in situations in which no choice is involved or a choice has already been made. The anterior insula was predominantly active in the presence of potential losses, indicating that potential losses modulate risk processing.

Observing disease symptoms causes a more vigorous immune response

We know that social status, positive versus negative affect, etc. can influence immune system robustness. Now Schaller et al. show that the mere observation of photographs depicting symptoms of infectious disease can boost the subsequent elevation of proinflammatory cytokines released by white blood cells in response to a bacterial stimulus. The effect was specific to the perception of disease-connoting social cues; it did not occur in response to a different category of stress-inducing interpersonal threat. The abstract and a few clips:

An experiment (N = 28) tested the hypothesis that the mere visual perception of disease-connoting cues promotes a more aggressive immune response. Participants were exposed either to photographs depicting symptoms of infectious disease or to photographs depicting guns. After incubation with a model bacterial stimulus, participants’ white blood cells produced higher levels of the proinflammatory cytokine interleukin-6 (IL-6) in the infectious-disease condition, compared with the control (guns) condition. These results provide the first empirical evidence that visual perception of other people’s symptoms may cause the immune system to respond more aggressively to infection.

This linkage may have been adaptive in ancestral ecologies, as individuals characterized by perception-facilitated immune responses would have had reduced likelihood of succumbing to pathogenic infections...People are sensitive to visual stimuli connoting the potential presence of infectious pathogens in others. These stimuli include anomalous morphological and behavioral characteristics (e.g., skin discolorations, sneezing) that suggest infection with disease-causing microorganisms. When perceived, these stimuli trigger psychological responses—such as disgust and the activation of aversive cognitions into working memory—that inhibit interpersonal contact.

You are how you eat - fast food and impatience

Here is a gem from the May issue of Psychological Science, offered by Zhong and DeVoe at the University of Toronto:

Based on recent advancements in the behavioral priming literature, three experiments investigated how incidental exposure to fast food can induce impatient behaviors and choices outside of the eating domain. We found that even an unconscious exposure to fast-food symbols can automatically increase participants’ reading speed when they are under no time pressure and that thinking about fast food increases preferences for time-saving products while there are potentially many other product dimensions to consider. More strikingly, we found that mere exposure to fast-food symbols reduced people’s willingness to save and led them to prefer immediate gain over greater future return, ultimately harming their economic interest. Thus, the way people eat has far-reaching (often unconscious) influences on behaviors and choices unrelated to eating.

"Vital Exhaustion"

Benedict Carey discusses how the term "Nervous Breakdown," popular in 1900 before yielding to number of supposedly more scientific diagnoses, has mutated to what psychiatrists in Europe have been diagnosing as “burnout syndrome,” the signs of which include “vital exhaustion.” A paper published last year defined three types: “frenetic,” “underchallenged,” and “worn out.” "Nervous breakdown" has begun to fade from use, and the same fate may or may not await "burnout syndrome".

Austin pictures

This is my last day in Austin Texas, where, after attending a 50th high school reunion, I have been revisiting scenes of my childhood.  One of the most beautiful is Hamilton's Pool, formed in a box canyon on a creek that runs into the Pedernales River about 23 miles west of Austin.  I have put a few photos from the trip on my Picassa photo page. 

Testosterone decreases trust.

Fascinating observations from Bos et al., who tested the effect of testosterone in regulating womens' rating of the trustworthiness of a series of men’s faces shown in photographs. It is essentially an antidote to oxytocin, which has been shown to increase judgments of trustworthiness. Their abstract:

Trust plays an important role in the formation and maintenance of human social relationships. But trusting others is associated with a cost, given the prevalence of cheaters and deceivers in human society. Recent research has shown that the peptide hormone oxytocin increases trust in humans. However, oxytocin also makes individuals susceptible to betrayal, because under influence of oxytocin, subjects perseverate in giving trust to others they know are untrustworthy. Testosterone, a steroid hormone associated with competition and dominance, is often viewed as an inhibitor of sociality, and may have antagonistic properties with oxytocin. The following experiment tests this possibility in a placebo-controlled, within-subjects design involving the administration of testosterone to 24 female subjects. We show that compared with the placebo, testosterone significantly decreases interpersonal trust, and, as further analyses established, this effect is determined by those who give trust easily. We suggest that testosterone adaptively increases social vigilance in these trusting individuals to better prepare them for competition over status and valued resources. In conclusion, our data provide unique insights into the hormonal regulation of human sociality by showing that testosterone downregulates interpersonal trust in an adaptive manner.

Also, check out this article by Nicholas Wade in the NYTimes discussing this work and comments on its relevance to understanding human evolution.

Neural processing of risk.

Mohr et al. show that, over a range of experiments and paradigms, risk is consistently represented in the anterior insula, a brain region known to process aversive emotions such as anxiety, disappointment, or regret. This provides further evidence that risk processing is influenced by emotions.

In our everyday life, we often have to make decisions with risky consequences, such as choosing a restaurant for dinner or choosing a form of retirement saving. To date, however, little is known about how the brain processes risk. Recent conceptualizations of risky decision making highlight that it is generally associated with emotions but do not specify how emotions are implicated in risk processing. Moreover, little is known about risk processing in non-choice situations and how potential losses influence risk processing. Here we used quantitative meta-analyses of functional magnetic resonance imaging experiments on risk processing in the brain to investigate (1) how risk processing is influenced by emotions, (2) how it differs between choice and non-choice situations, and (3) how it changes when losses are possible. By showing that, over a range of experiments and paradigms, risk is consistently represented in the anterior insula, a brain region known to process aversive emotions such as anxiety, disappointment, or regret, we provide evidence that risk processing is influenced by emotions. Furthermore, our results show risk-related activity in the dorsolateral prefrontal cortex and the parietal cortex in choice situations but not in situations in which no choice is involved or a choice has already been made. The anterior insula was predominantly active in the presence of potential losses, indicating that potential losses modulate risk processing.

More on clever crows and complex cognition.

Taylor et al have done some beautiful experiments clearly demonstrating complex cognition in New Caledonian crows, proving that these birds are capable to thinking through their actions, not simply learning through association a series of behaviors and combining them. You really should watch the video in the review by Telis. From that review:

...Taylor trained seven wild crows to associate a short stick with ineffectiveness; the crows failed to obtain their out-of-reach food with the stick and eventually began to ignore or reject it. Then they were divided into two groups, an innovation group and a training group. The training group learned six activities—such as how to use a short stick to extract a long stick from a toolbox—that together could help them get meat with long and short tools. The innovation group wasn’t taught how to use a short stick to extract a long stick from the toolbox, but did learn other techniques.

When tasked with reaching a snack in a hole using a short stick on a string and a longer stick trapped in a toolbox, all of the crows pulled it off. The three birds in the training group linked the behaviors they had learned into a new behavior. They freed the short stick from the string, used it to dislodge the long stick, and used the long stick to obtain their food. And all four crows in the innovation group figured out the sequence on their own. One crow in the innovation group stared at the setup for less than 2 minutes and then performed the whole trial correctly on her very first attempt.

The Taylor et al. abstract:

Apes, corvids and parrots all show high rates of behavioural innovation in the wild. However, it is unclear whether this innovative behaviour is underpinned by cognition more complex than simple learning mechanisms. To investigate this question we presented New Caledonian crows with a novel three-stage metatool problem. The task involved three distinct stages: (i) obtaining a short stick by pulling up a string, (ii) using the short stick as a metatool to extract a long stick from a toolbox, and finally (iii) using the long stick to extract food from a hole. Crows with previous experience of the behaviours in stages 1–3 linked them into a novel sequence to solve the problem on the first trial. Crows with experience of only using string and tools to access food also successfully solved the problem. This innovative use of established behaviours in novel contexts was not based on resurgence, chaining and conditional reinforcement. Instead, the performance was consistent with the transfer of an abstract, causal rule: ‘out-of-reach objects can be accessed using a tool’. This suggests that high innovation rates in the wild may reflect complex cognitive abilities that supplement basic learning mechanisms.

Older is happier

Many diminutions come with aging,  but decreasing happiness is not apparently among them. Bakalar notes studies by Stone et al. showing, to the contrary, that by almost any measure, people get happier as they get older, for reasons that are not clear. Clips from Bakalar's summary:

On the global measure, people start out at age 18 feeling pretty good about themselves, and then, apparently, life begins to throw curve balls. They feel worse and worse until they hit 50. At that point, there is a sharp reversal, and people keep getting happier as they age. By the time they are 85, they are even more satisfied with themselves than they were at 18.

In measuring immediate well-being — yesterday’s emotional state — the researchers found that stress declines from age 22 onward, reaching its lowest point at 85. Worry stays fairly steady until 50, then sharply drops off. Anger decreases steadily from 18 on, and sadness rises to a peak at 50, declines to 73, then rises slightly again to 85. Enjoyment and happiness have similar curves: they both decrease gradually until we hit 50, rise steadily for the next 25 years, and then decline very slightly at the end, but they never again reach the low point of our early 50s.

...we can expect to be happier in our early 80s than we were in our 20s...and it’s not being driven predominantly by things that happen in life. It’s something very deep and quite human that seems to be driving this.

Keep Austin Weird

The title of this post is the unofficial motto of Austin Texas, where I am spending this week.  One of the things I enjoy most is its funky coffee houses,  all with high speed wireless internet, and copious outlets to plug in your laptop.

Washing away postdecisional dissonance

An interesting tidbit from Lee and Schwartz:

Hand washing removes more than dirt—it also removes the guilt of past misdeeds, weakens the urge to engage in compensatory behavior, and attenuates the impact of disgust on moral judgment. These findings are usually conceptualized in terms of a purity-morality metaphor that links physical and moral cleanliness; however, they may also reflect that washing more generally removes traces of the past by metaphorically wiping the slate clean. If so, washing one’s hands may lessen the influence of past behaviors that have no moral implications at all. We test this possibility in a choice situation. Freely choosing between two similarly attractive options (e.g., Paris or Rome for vacation) arouses cognitive dissonance, an aversive psychological state resulting from conflicting cognitions. People reduce dissonance by perceiving the chosen alternative as more attractive and the rejected alternative as less attractive after choice, thereby justifying their decision.

The authors tested whether hand washing reduces this classic postdecisional dissonance effect (the need to justify a recent choice) by designing a ranking and choice experiment in which participants, after making a choice, were subsequently asked to evaluate a soap - some with actual hand washing and some without. Their finding:

...indicate that the psychological impact of physical cleansing extends beyond the moral domain. Much as washing can cleanse us from traces of past immoral behavior, it can also cleanse us from traces of past decisions, reducing the need to justify them. This observation is not captured by the purity-morality metaphor and highlights the need for a better understanding of the processes that mediate the psychological impact of physical cleansing. To further constrain the range of plausible candidate explanations, future research may test whether the observed "clean slate" effect is limited to past acts that may threaten one’s self-view (e.g., moral transgressions and potentially poor choices) or also extends to past behaviors with positive implications.

Brunch at Fonda San Miquel in Austin

A picture from yesterday's birthday brunch for my son, now 36 years old, at my favorite Mexican gourmet restaurant in Austin Texas.  Shown from left to right are my partner Len Walker, my son Jon Bownds, Deric (me), daughter-in-law Shana Merlin, and old family friend Martha Leipziger. 

Prozac reverses maturation of some brain cells

Here is some intriguing work from Kobayashi et al. showing that fluoxetine (Prozac) indices a dematuration of hippocampus dentate gyrus cells that reinstates synaptic plasticity that is reduced with development, thereby potentially causing beneficial effects on the adult brain. (These cells are key in learning and memory processes). Their results suggest that the state of neuronal maturation, including aberrant maturation, might be controlled or corrected in adults, a unique approach to treating neuronal dysfunctions associated with neurodevelopmental disorders. Some clips from the abstract:

Serotonergic antidepressant drugs have been commonly used to treat mood and anxiety disorders, and increasing evidence suggests potential use of these drugs beyond current antidepressant therapeutics. Facilitation of adult neurogenesis in the hippocampal dentate gyrus has been suggested to be a candidate mechanism of action of antidepressant drugs, but this mechanism may be only one of the broad effects of antidepressants. Here we show a distinct unique action of the serotonergic antidepressant fluoxetine in transforming the phenotype of mature dentate granule cells. Chronic treatments of adult mice with fluoxetine strongly reduced expression of the mature granule cell marker calbindin. The fluoxetine treatment induced active somatic membrane properties resembling immature granule cells and markedly reduced synaptic facilitation that characterizes the mature dentate-to-CA3 signal transmission. These changes cannot be explained simply by an increase in newly generated immature neurons, but best characterized as “dematuration” of mature granule cells...Our results suggest that serotonergic antidepressants can reverse the established state of neuronal maturation in the adult hippocampus...Such reversal of neuronal maturation could affect proper functioning of the mature hippocampal circuit, but may also cause some beneficial effects by reinstating neuronal functions that are lost during development.

Six Famous Geniuses You Didn't Know Were Perverts

Another random curious piece. 

MindBlog in Austin Texas

Having just returned from Istanbul last Friday, I travel again - this time with my partner Len Walker to Austin Texas to attend the 50th reunion of Austin High School Alumni. I will be vacationing here through next week.   Being in Austin requires adapting the digestive system to gargantuan servings of TexMex dishes. 

Aging brains are less able to recover from the effects of stress

It is well documented that aging reduces the effectiveness of our prefrontal cortex in mediating cognitive processing and decision making, including working memory and flexible use of mental strategies. Bloss, McEwen et al. have now conducted studies that suggest that one reason for this decline may be that aging reduces the ability of prefrontal cortex to recover from stress-induced damage. Their abstract:

Neuronal networks in the prefrontal cortex mediate the highest levels of cognitive processing and decision making, and the capacity to perform these functions is among the cognitive features most vulnerable to aging. Despite much research, the neurobiological basis of age-related compromised prefrontal function remains elusive. Many investigators have hypothesized that exposure to stress may accelerate cognitive aging, though few studies have directly tested this hypothesis and even fewer have investigated a neuronal basis for such effects. It is known that in young animals, stress causes morphological remodeling of prefrontal pyramidal neurons that is reversible. The present studies sought to determine whether age influences the reversibility of stress-induced morphological plasticity in rat prefrontal neurons. We hypothesized that neocortical structural resilience is compromised in normal aging. To directly test this hypothesis we used a well characterized chronic restraint stress paradigm, with an additional group allowed to recover from the stress paradigm, in 3-, 12-, and 20-month-old male rats. In young animals, stress induced reductions of apical dendritic length and branch number, which were reversed with recovery; in contrast, middle-aged and aged rats failed to show reversible morphological remodeling when subjected to the same stress and recovery paradigm. The data presented here provide evidence that aging is accompanied by selective impairments in long-term neocortical morphological plasticity.

Michelangelo as brain anatomist

Check out this Andrew Sullivan post.