Neuroanthropology

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Archive for the ‘Neural plasticity’ Category

Psychiatry affects human psychology: e.g., ‘bipolar’ children

Posted by gregdowney on July 24, 2008

Prof. Joseph Biederman, MD

Prof. Joseph Biederman, MD

Although I really enjoy psychology, like many anthropologists, I feel a deep ambivalence about some contemporary psychological theory and research.

Some of these problems are trivial and tendentious, to be honest, more the effects of pushing our own disciplinary preferences in the way research is presented or semiotic hair-splitting in theoretical terms than substantive concerns. But there are some more profound issues, touched on in recent posts like Daniel’s Neurotosh, Neurodosh and Neurodash and my post, Bench and couch: genetics and psychiatry. Ironically, I was reminded of one of the more serious issues while reading a piece a few weeks ago by psychologist and psychologist-sceptic Bruce Levine on Alternet, The Science of Happiness: Is It All Bullshit?

In a meandering way, this post is a reflection on one of anthropology’s consistent criticisms of psychology; the often unacknowledged role of psychiatry in shaping psyches. That is, the difficulty of studying a phenomenon when one is helping to create it and one’s theories influence your subjects’ accounts. When psychology is successful in breaking through into popular awareness, it becomes entangled with its subject, a kind of folk theory operating in the same space that psychologists seek to study. So this post is a kind of neuroanthropological reflection on clinical psychology as both research enterprise and world-making project, and the way the two come into conflict.

Specifically, Daniel’s post on Neurotosh and Levine’s story of John Stewart confronting Harvard happiness researcher, Prof. Tal Ben-Shahar, reminded me of the recent scandal surrounding psychiatrist Prof. Joseph Biederman. Biederman took large unreported consulting fees from pharmaceutical companies who manufactured anti-psychotic medicines while he was simultaneously encouraging psychiatrists to diagnose children with bipolar disorder, and then to prescribe their young patients anti-psychotic medicines. Senator Charles E. Grassley (R-Iowa) held hearings on the financial conflicts of interest as reported in The New York Times in Researchers Fail to Reveal Full Drug Pay, by Gardiner Harris and Benedict Carey. (For an earlier critical article, see the Boston Globe piece, Backlash on bipolar diagnoses in children.)

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Posted in Neural plasticity, Psychological anthropology, general, Medical anthropology, Mental Illness | Tagged: , , | 4 Comments »

The Cultural Brain in Five Flavors

Posted by dlende on July 11, 2008

By Daniel Lende

Next week is the Critical Neurosciences workshop, where I will help lead a discussion of the cultural brain. So I better figure out what I want to say!

Thinking about it yesterday, I came up with this. Rather than one “cultural brain” and lots of arguing about what that means, I will argue that we have five distinct varieties of the cultural brain to consider.

Each flavor deals with a different sort of problem at the intersection of human culture and neuroscience. I will outline these different intersections below, and provide links to our posts to give further depth.

Here are our five flavors:

-The Symbolic Brain: Culture, meaning and the brain combined
-The Inequality Brain: Bad outcomes through society, power, and the brain
-The Theory Brain: Neuroscience impacts social science theory
-The Brain Transformed: Social science impacts brain theory
-The Critical Brain: Taking down bad brain justifications and examining the cultural uses of the brain

The Symbolic Brain

The symbolic brain represents the increasing convergence of work in anthropology and in neuroscience on questions of meaning, symbolism, subjective experience, and behavior. To take an example from my own work, understanding compulsive drug use has required that I examine how processes of attention and behavioral involvement are altered by consistent drug use and how people interpret their own use, from the reasons they had to use to what the experience of use represents to them.

In many ways, this work focuses on a central problem raised but not resolved by Clifford Geertz when he wrote that we should treat human behavior as “symbolic action—action, which, like phonation in speech, pigment in painting, line in writing, or sonance in music, signifies (1973: 9).” Today, rather than reducing that significance to either a cultural pattern or a brain function (both determinist approaches), people interested in the cultural brain are looking for synergies between different domains of research.

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Posted in Neural plasticity, Psychological anthropology, Cultural theory, general, Human variation, Brain Mechanisms | 7 Comments »

Cabbies’ brains

Posted by gregdowney on July 3, 2008

The BBC has a nice piece covering the continuing research of Prof. Eleanor Maguire (Wellcome Institute of Neurology, University College London) on the distinctive development of the hippocampus in the brains of London taxi drivers: Taxi drivers’ brains ‘grow’ on the job. Prof. Maguire’s research in this area is pretty extensive (see publication list). She’s found a great naturally occurring experiment in the brains of cabbies who have to navigate London’s notoriously byzantine downtown streets.

As the BBC report describes, driving a cab in London is difficult and demands a well-developed knowledge of urban geography:

In order to drive a traditional black cab in London drivers have to gain “the knowledge” – an intimate acquaintance with the myriad of streets in a six-mile radius of Charing Cross.

It can take around three years of hard training, and three-quarters of those who embark on the course drop out, according to Malcolm Linskey, manager of London taxi school Knowledge Point. “There are 400 prescribed runs which you can be examined on but in reality, you can be asked to join any two points,” he told BBC News Online.

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Posted in Brain imaging, Brain Mechanisms, general, Human variation, Learning, Neural plasticity, Skill acquisition | Tagged: , , , , , , | 8 Comments »

Cultural Aspects of PTSD, Part II: Narrative and Healing

Posted by epfinley on June 22, 2008

Bremner et al. 2000.  MRI showing decreased hippocampal volume in Vietnam veterans diagnosed with PTSD.

Narrative and memory are interwoven in our consciousness, and thus explorations into trauma from both humanities and social science perspectives almost invariably discuss narrative in one form or another. An ongoing debate within psychological research, for example, ponders whether the coherence of trauma stories is correlated to the amount of emotional distress associated with a given traumatic memory. It is hypothesized that the greater the distress, the less organized the narrative. If this were the case, we might expect that the coherence with which an individual is able to talk about the trauma would increase as the memory is processed and resolved, a finding for which we have some evidence.

We do know – when it comes to Post-Traumatic Stress Disorder (PTSD) – that narrative matters. As I wrote in an earlier post, the most effective therapies yet proven for reducing PTSD symptoms are the exposure therapies, particularly Prolonged Exposure (PE) therapy. These therapies are more effective for reducing the full range of PTSD symptoms than any pharmaceutical yet identified. And the crux of these therapies rests on telling the story of the trauma, sometimes over and over again. This simple practice, this process of speaking, has been reliably demonstrated to result in an improvement of PTSD symptoms for many patients.

But for all its clinical benefit, this extraordinary observation tells us very little about the mechanisms of psychic healing after trauma. Instead, it points to a growing body of evidence that suggests it is not just narrative that matters in PTSD, but, more intriguingly, that it is the type of narrative that matters. Unstructured psychodynamic therapies, for example, have not been demonstrated to lessen the severity of PTSD, even among patients who continue in therapy for years. And yet certain ways of narrating memory do make a difference, and this phenomenon once again points to a role for anthropologists and other culturally-minded researchers in exploring the cultural-emotional-physiological-environmental interactions at play in post-traumatic processing.

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Posted in Brain imaging, general, Language, Neural plasticity, Psychological anthropology, Stress | 9 Comments »

Monkeys and robots teaming up — worried?

Posted by gregdowney on May 29, 2008

As Daniel discussed in January in Monkey Makes Robot Walk!, a number of researchers are working on brain-machine interfaces by attaching prostheses to monkeys. Science Daily carries a new story, Mind Over Matter: Monkey Feeds Itself Using Its Brain, about a University of Pittsburgh School of Medicine experiment in which a monkey successfully used a human-like prosthetic limb to feed itself. As the Science Daily story reports:

Using this technology, monkeys in the Schwartz lab are able to move a robotic arm to feed themselves marshmallows and chunks of fruit while their own arms are restrained. Computer software interprets signals picked up by probes the width of a human hair. The probes are inserted into neuronal pathways in the monkey’s motor cortex, a brain region where voluntary movement originates as electrical impulses. The neurons’ collective activity is then evaluated using software programmed with a mathematic algorithm and then sent to the arm, which carries out the actions the monkey intended to perform with its own limb. Movements are fluid and natural, and evidence shows that the monkeys come to regard the robotic device as part of their own bodies.

According to the team, this is the ‘first’ example of the ‘use of cortical signals to control a multi-jointed prosthetic device for direct real-time interaction with the physical environment (‘embodiment’)’ (from the abstract to the Nature article) (I’m always dubious about such ‘firsts,’ especially as this team has been announcing work on this project since at least 2004; but the research is still fascinating even if not a ‘first’).

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Posted in Animals, Embodiment, Neural plasticity, Skill acquisition | Leave a Comment »

Rats’ visual systems made plastic by anti-depressants

Posted by gregdowney on April 17, 2008

Blogging on Peer-Reviewed ResearchMy mind raced for potential titles to a post when I read the recent report from Science, ‘The Antidepressant Fluoxetine Restores Plasticity in the Adult Visual Cortex,’ by a team headed by José Fernando Maya Vetencourt (abstract), but I’ve opted to be demure, rather than go with some of my other options (like ‘Anti-depressants the “Cocoon” pool for brain?’ or something similarly outrageous).

The research team investigated wither fluoxetine, a selective serotonin reuptake inhibitor (SSRI), could restore plasticity in the visual system of adult rats. They chose fluoxetine because long-term regimens of the drug promote neurogenesis and synaptogenesis in the hippocampus and increased activity of neurotrophin brain-derived neurotrophic factor (BDNF) and its primary receptor, TrkB (close paraphrase to the original article). These effects have been shown essential to the drug’s effect; block one of these processes, and the anti-depressant doesn’t work nearly as well. In order to test plasticity, the team studied how rats responded to monocular deprivation — covering one eye — both the initial shift in ocular dominance and then the recovery of visual function after long-term monocular deprivation. In general, the fluoxetine-treated rats responded in exaggerated fashion to both conditions, suggesting that plasticity was greater with long-term administration of the drug. From the abstract:

We found that chronic administration of fluoxetine reinstates ocular dominance plasticity in adulthood and promotes the recovery of visual functions in adult amblyopic animals, as tested electrophysiologically and behaviorally. These effects were accompanied by reduced intracortical inhibition and increased expression of brain-derived neurotrophic factor in the visual cortex. Cortical administration of diazepam prevented the effects induced by fluoxetine, indicating that the reduction of intracortical inhibition promotes visual cortical plasticity in the adult. Our results suggest a potential clinical application for fluoxetine in amblyopia as well as new mechanisms for the therapeutic effects of antidepressants and for the pathophysiology of mood disorders.

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Posted in Animals, Brain Mechanisms, Emotion, Medical anthropology, Mental Illness, Neural plasticity, Stress | 1 Comment »

Doidge on The Brain That Changes Itself

Posted by gregdowney on April 10, 2008

Dr. Norman Doidge has a short column on his own book, The Brain That Changes Itself, over at Science Blog. His book is extremely good, but it’s funny, when you read the column, it sounds like a science ‘travel log,’ as if he went on a long brain science roadtrip. It seems to be a leitmotif in a lot of recent popular science book; traveling around, meeting scientists, having a bit of a chat, getting a bit of personal back story as well as a chance to talk about their research. Or am I the only one who feels this way?

One of the commenters on the Science Blog says something about a book of ‘anecdotal evidence,’ which I think is pretty ignorant. Anyone who regularly reads neuropathology knows that ‘anecdotal evidence’ of human brain injury is not just typical, it’s essential. Singular cases can have an enormous impact on our knowledge of how the brain works by causing such distinctive disruptions of function. Where would we be in brain sciences with Phineas Gage, the folks Oliver Sachs writes about, and this unlucky brotherhood?

Check out Doidge’s column — and his book gets a strong recommendation as well.

Posted in general, Links, Neural plasticity | 3 Comments »

Smell, fear and sensory learning

Posted by gregdowney on March 29, 2008

Blogging on Peer-Reviewed ResearchWen Li, James D. Howard, Todd B. Parrish, and Jay A. Gottfried have a fascinating article in the most recent edition of Science, ‘Aversive Learning Enhances Perceptual and Cortical Discrimination of Indiscriminable Odor Cues.’ The researchers trained subjects to discern between the aroma of chemicals that initially were indistinguishable using electric shocks (!) coupled with one of the two aromas. The research is a great example of perceptual learning, a form of neural enculturation that I think is absolutely essential to understanding cultural difference but little appreciated in anthropology.

Subjects in the experiment were given a test of their ability to discern between very closely related chemicals: ‘On each trial, subjects smelled sets of three bottles (two containing one odorant, the third containing its chiral opposite) and selected the odd stimulus.’ Before the training, subjects selected the odd odor out 33% of the time — no better than random. After the repeated association of one chemical with shocks, subjects’ ability to discriminate the smells improved markedly, showing that negative reinforcement training could ‘enhance perceptual discriminability between initially indistinguishable odors.’ Moreover, the neural representation of the smells changed, as found with fMRI.

From their abstract:

We combined multivariate functional magnetic resonance imaging with olfactory psychophysics to show that initially indistinguishable odor enantiomers (mirror-image molecules) become discriminable after aversive conditioning, paralleling the spatial divergence of ensemble activity patterns in primary olfactory (piriform) cortex. Our findings indicate that aversive learning induces piriform plasticity with corresponding gains in odor enantiomer discrimination, underscoring the capacity of fear conditioning to update perceptual representation of predictive cues, over and above its well-recognized role in the acquisition of conditioned responses. That completely indiscriminable sensations can be transformed into discriminable percepts further accentuates the potency of associative learning to enhance sensory cue perception and support adaptive behavior.

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Posted in Cognitive anthropology, Human variation, Neural plasticity, Perception and the senses | 1 Comment »

The history of mind-altering mechanisms

Posted by gregdowney on March 16, 2008

Katherine MacKinnon of St. Louis University just dropped me a line to point out a recent book review in The New York Times, I Feel Good, by Alexander Star. Star reviews the book, On Deep History and the Brain, by Daniel Lord Smail (University of California Press). Amazon raters are giving it 4.5 stars at the moment, if you want to check it out through the bookseller. Normally, I’d trust Daniel to write our best stuff about ‘mind-altering’ chemicals of all sorts, but this book review just set me to thinking, so I thought I’d put my own two cents in.

Smail wants to tell the story of humanity as a series of ‘self-modifications of our mental states,’ according to the reviewer Star:

We want to alter our own moods and feelings, and the rise of man from hunter-gatherer and farmer to office worker and video-game adept is the story of the ever proliferating devices — from coffee and tobacco to religious rites and romance novels — we’ve acquired to do so. Humans, Smail writes, have invented “a dizzying array of practices that stimulate the production and circulation of our own chemical messengers,” and those devices have become more plentiful with time. We make our own history, albeit with neurotransmitters not of our choosing.

Smail is really a historian, but his venture into a kind of neuro-history shows the robustness of the emerging awareness that the brain is shaped by what humans do. Star points out that most ‘macro-history’ these days — long, sweeping accounts of human evolution and what is sometimes called something prosaic like the ‘rise and fall of civilizations’ — is not being written by historians, but rather by folks like Jared Diamond. In contrast, Smail is a medieval historian.

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Posted in Addiction, Animals, Cultural theory, Emotion, Evolution, Food & Eating, Neural plasticity | Leave a Comment »

Brainy muscles

Posted by gregdowney on February 28, 2008

A recent story in The New York Times by Gina Kolata, one of my favorite science writers, highlights one reason why I think neuroanthropology has to be broader than ‘cognitive anthropology’ was in the 1980s and 1990s (and why ‘cognitive science’ itself has really expanded with the more recent wave of thinking about embodied cognition). In an article on whether or not weight training is really good for athletes, titled Does Weight Lifting Make a Better Athlete?, I think Kolata does a much better job presenting the case for the efficacy of weight training than the arguments against it. Even several of the physiologists and trainers who Kolata suggests are less than rapt with weight training make comments that are more specifically about weight training done badly than against the practice as a whole; they criticize poor form, badly designed programs, and even not working hard enough, hardly criticisms of the overall efficacy of weight training.

Most of the athletes and other experts seem to me to be pretty strongly in favor of weight training, and I have no doubt that there’s good reason. Most athletic training has been radically transformed with the advent of weight training, and approaches that have come out of weight training (such as targeting specific muscle groups and working different parts of the body to failure) are also applied even in non-weight training exercises, such as selective sprinting, whole body exercises, and the like. Some of my research on capoeira, no-holds-barred fighting (or MMA), and other forms of wresting training suggest that actually training with ‘weights’ — barbells, dumbbells, and the like — can be less than ideal, but most of the modifications that this research suggests are consistent with the theory and practice of weight training, even if they expand the activities involved (body weight exercises, whole body dynamic lifting, jumping, etc.).

But one of the few critics says something that I found extremely interesting, and it resonated with some of the stuff I’ve been writing in my sports-related manuscript (hopefully a book soon) about how neural plasticity affects athletic performance. Specifically, Dr. Patrick O’Connor, a University of Georgia exercise scientist, says that ‘a sport like rowing, swimming or running requires specific muscles and nerve-firing patterns that may best be developed by actually doing the sport.’ A sport like ‘rowing, swimming or running’ that ‘requires specific muscles and nerve-firing patterns…’ hmmmm? So that would be like, what, every sport?

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Posted in Embodiment, general, Neural plasticity, Skill acquisition, Sport, Uncategorized | 1 Comment »

 
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