+ Autism Science Moving “Stunningly Fast”

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From an article in USA TODAY by Liz Szabo, we learn that the quest to unravel the mystery of autism has become more urgent.  Autism is more widely diagnosed; today the condition is affecting one in 88 children (Centers for Disease Control and Prevention).

Researchers feel that for the first time they are making progress  in understanding the autistic brain.  Thanks to work with real autistic children, scientists are getting a glimpse of what might go wrong in early development, according to researcher Sarah Paterson, developmental psychologist at Children’s Hospital in Philadelphia.

And Kevin Pelphrey, associate professor of child psychiatry at the Yale School of Medicine’s Child Study Center, says the latest research gives him hope for therapies, even therapies that can reshape children’s brains.  ”Treatment can have effects even very late.  It’s not a lost cause at all.”

Much of the progress is a result of parents who have pushed for funding that is now bearing fruit.

Technological advances in imaging, stem cell research, gene sequencing and computing have opened doors.  Robert Schultz, director of the Center for Autism Research at Children’s Hospital, says that in only a few years, it will be cheaper to sequence an autistic child’s genetic blueprint than to perform an intensive, one-on-one behavioral examination.

Many Problems, Not Just One

Autism is now commonly regarded not as a single condition but as a puzzle with multiple pieces, and none of them appear to fit together to form a recognizable picture.  The condition seems to be a group of related disorders with similar symptoms but different causes.

Thomas Insel, director of the National Institutes of Mental Health, says that if you’re looking at an autistic child’s whole brain, “you would be amazed at how normal their brains look.”  So doctors are zooming in deep.  They’re looking at the “wiring” between brain regions and the spaces between cells, where chemical messages are sent.

Other researchers have “created” brain cells in the lab: they transform ordinary skin from autistic children into stem cells and then coaxing them to morph again into neurons.  This approach allows doctors to examine the microscopic spaces between brain cells, called synapses, the place where chemical messages are sent.

Ricardo Dolmetsch, associate professor of neurobiology at Stanford, says “This is the very beginning of a revolution.”

sole source is Liz Szabo’s article at www.usatoday.com on April 8, 2012.

Orton-Gillingham tutoring in Columbus OH:  Adrienne Edwards 614-579-6021 or email aedwardstutor@columbus.rr.com.

+ Signs of Dyslexia Show Up Before Reading: Study

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According to Andrea Facoetti, assistant professor of psychology at the University of Padova who co-authored research into the matter, dyslexia cannot be considered a language problem any more.

An ABC article by Mikaela Conley explains that dyslexia is a developmental reading disorder that occurs when the brain does not properly recognize and process certain symbols.

Facoetti says it has been widely “accepted that reading disorders arise from a spoken language problem, [but] results demonstrate the critical role played by visual attention in learning to read.”

Dyslexia, the most common cause of reading and writing difficulties in the US, may affect up to 15 per cent of the population, according to the National Institutes of Health.

Facoetti and colleagues followed 96 Italian children for three years, between kindergarten and third grade.  What they observed was that the children who had difficulty identifying certain symbols within patterns and sentences had a harder time reading later on.

Results indicate that the ability to filter out and identify such information is crucial in isolating single letters or syllables before the written words are translated in corresponding speech sounds, says Facoetti.

For this reason the authors feel that treatment for dyslexia should be changed to take this information into account.

Says Facoetti,

The possibility to dramatically reduce the reading disorder would have a great impact in improving the children’s quality of life and in decreasing governmental costs.

It must be noted that Stefanie Hines, director of the Center for Human Development at Beaumont Children’s Hospital in Michigan, feels that, interesting as the findings are, they might not easily translate to US children.  The orthography — the relationship between sounds and spelling — is more complicated in English than in Italian.

I would caution that the study was conducted on Italian children.  The prevalence of dyslexia in Italy is lower than in the US.

source: The LD Source <lda@multibriefs.com> and http://www.abcnews.com 

Orton-Gillingham tutoring in Columbus OH:  Adrienne Edwards  614-579-6021 or email aedwardstutor@columbus.rr.com 

+ MIT: Dyslexia Independent of IQ

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A brain imaging study at MIT suggests that reading difficulties are the same regardless of overall intelligence – and that more children could benefit from support in school, according to Emily Finn of the MIT news office .

About 5 to 10 percent of American children are diagnosed as dyslexic.  Historically, the label has been assigned to kids who are bright, even verbally articulate, but who struggle with reading — in short whose high IQs mismatch their low reading scores.  On the other hand, reading troubles in children with low IQs have traditionally been considered a byproduct of their general cognitive limitations, not a reading disorder in particular.

But a new brain-imaging study challenges this understanding of dyslexia.  According to John D.E. Gabrieli, MIT’s Grover Hermann Professor of Health Sciences and Technology and Cognitive Neuroscience, who is one of the researchers,

We found that children who are poor readers have the same brain difficulty in processing the sounds of language whether they have a high or low IQ.  Reading difficulty is independent of other cognitive abilities.

Gabrieli  performed the research with Fumiko Hoeft and colleagues at the Stanford University School of Medicine, Charles Hulme at York University in the U.K., and Susan Whitfield-Gabrieli, also at MIT.

The study will be published in the journal Psychological Science, and may change how educators diagnose dyslexia, opening up reading support to more children who could benefit from it.

Rhyming

Rhymes are an effective way to probe dyslexics’ reading performance, since dyslexia is thought to entail difficulty connecting written words to sounds.

One hundred thirty-one children, from 7 to 17 years of age, were given a simple reading test and an IQ measure.  Each child was assigned to one of three groups: typical readers with typical IQs’ poor readers with typical IQs, and poor readers with low IQs.

All were shown pairs of words and asked to judge whether the words rhymed.

For some of the pairs, researchers used words that rhyme but don’t share the same final letters — such as “bait” and “gate,” or “night” and “bite.”  In those cases, rhyme could not be inferred simply from spelling.

Using functional magnetic resonance imaging (fMRI), researchers observed the activity in the brain regions known to be important for reading.

Results showed that neural activity in the two groups of poor readers was indistinguishable. 

“The brain patterns could not have been more similar, whether the child had a high or low IQ,” says Gabrieli.  Poor readers of all IQ levels showed significantly less brain activity in the six observed areas than typical readers. 

This suggests that reading difficulty is due to the same underlying neural mechanism — regardless of general cognitive ability. 

Currently, according to Gabrieli, many public school systems still require that a child have an otherwise normal IQ in order to receive a diagnosis of dyslexia and then appropriate intervention.  These findings could have an important impact on such an approach.

Essentially, the present thought is that the label “dyslexic” is reserved for children with a reading difficulty that can’t be explained by anything else.

The new study suggests that even children with low IQ scores might benefit from specific dyslexia intervention.

Gabrieli says he hopes the new results will encourage educators to offer reading support to more struggling students.  He stresses the importance of diagnosing dyslexia and other behavioral disorders sooner, rather than later.

Now,  you basically diagnose dyslexia when a child seems miserable in school.  Maybe you could intervene before they ever get that way.

Sole source: online article by Emily Finn:  http://web.mit.edu/newsoffice/2011/dyslexia-iq-0923.html?utm_source=Twitter&utm_campaign=LDOnLine.org

tutoring in Columbus OH:  Adrienne Edwards  614-579-6021  or email aedwardstutor@columbus.rr.com

+ Memory Implant Improves Memory in Rats

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In a study reported on by Benedict Carey in the NY Times, scientists have designed a brain implant that restored lost memory function in laboratory rats.  It also strengthened recall of new information.

The research marks a crucial first step in the development of neuroprosthetic devices which might repair deficits in patients suffering from dementia, stroke or brain injury.

Be aware, however, that use of the implant in humans is still a long way off.

The implant research was led by Sam A. Deadwyler, a scientist at Wake forest.  In a series of experiments, the researchers trained rats to remember which of two identical levers to press to receive water.  First, the animals saw one of the two levers appear and then were distracted.  They then had to remember to press the other lever to be rewarded.

Repeated training on this task taught the rats the general rule, but in each trial, the animal had to remember which lever appeared first and use that information to inform the subsequent choice. 

The rats were implanted with a tiny array of electrodes in two neighboring pieces of the hippocampus, the brain structure which is crucial for forming new memories in both rats and humans.

The two slivers of tissue are called CA1 and CA3.  They communicate with each other as the brain learns, and stores, information.  The device transmitted these exchanges to a computer.

To test the effect of the implant, researchers used a drug to shut down the activity of CA1.  Without CA1 online, rats could not remember which lever to push in order to get their water.

They remembered their rule — push the opposite lever from the one that first appeared — but they couldn’t remember which they had seen first.

So researchers, who had recorded the appropriate CA1 signal, simply replayed it (like a melody on a player piano) and the animals remembered.

The implant acted as if it were CA1, at least for this one task. 

“Turn the switch on, the animal has the memory; turn it off and they don’t: that’s exactly how it worked,” says the lead author of the study, Theodore W. Berger, professor of engineering at USC.

It is being published by The Journal of Neural Engineering.  Co-authors were Robert E. Hampson and Anushka Goonawardena, along with Dr. Deadwyler of Wake Forest , Dong Song and and Vasilis Z. Marmarelis of USC.

In rats that did not receive the drug, new memories faded by about 40 percent after a long distraction period.  But if the researchers amplified the corresponding CA1 signals using the implant, the memories eroded only about 10 percent in that time.

With wireless technology and computer chips, say the authors, the system could easily be fitted for human use.  But there are a number of technical and theoretical obstacles.

One problem is that the implant must first record a memory trace before playing it back or amplifying it.  But in patients with significant memory problems, those signals may be too weak.

Another is that human memory, a rich, diverse neural process, involves many other brain areas, not just CA3 and CA1.  Implants in those areas will be limited.

Nevertheless, some restored memories such as “Where is the bathroom? Where are the pots and pans stored? — could make a big difference in the lives of a dementia patient.

Says Dr. Berger, “If you’re caring for someone in the house, for example, it might be enough to keep the person out of the nursing home.”

For the article, the sole source for this post, visit http://www.nytimes.com/2011/06/17/science/17memory.html?scp=3&sq=Benedict%20Carey&st=cse

tutoring in Columbus OH:  Adrienne Edwards  614-579-6021  or email  aedwardstutor@columbus.rr.com

+ Abstract Ideas: Some Brain Calisthenics Helps

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In an article in Science Times, by Benedict Carey, we learn that   cognitive scientists are making the case for  strengthening “perceptual” learning. 

This is what might be called “gut instinct,” the instantaneous grasp of a problem like that of a ballplayer who can “read” pitches early or the chessmaster who “sees” the best move.  They believe it can be trained into being.

At New Roads School in Santa Monica California, students are using an online program that prompts them to match graphs to equations, dozens and dozens of them, and fast — often before they have time to work out the correct answer.

An equation will appear on the screen and below it three graphs (or a graph with three equations below).  A student clicks on one and the screen flashes to tell herwhether she’s right or wrong and immediately jumps to the next problem.  Says junior Wynn Haimer,

I’m much better at it.  In the beginning it was difficult, having to work so quickly; but you sort of get used to it, and in the end it’s more intuitive.  It becomes more effortless.

 For years curricula have stressed a top-down instruction for topics like math and science.  Learn the rules first — the theorems, the order of operations, Newton’s laws — and then work on solving some problems.  This method turns top-down strategies on their head.

A small group of cognitive scientists argues that the brain is a pattern-recognition machine.  They say that when focussed properly, it can quickly deepen an individual’s grasp of a principle.  New studies are suggesting this is true.

Read Carey’s article at http://www.nytimes.com/2011/06/07/health/07learn.html?_r=1&scp=3&sq=Benedict%20Carey&st=cse

tutoring in Columbus OH: Adrienne Edwards  614-579-6021  or email aedwardstutor@columbus.rr.com.

+ Reading Practice Strengthens Brain “Highways”

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A study detailed in the journal Neuron reports that intensive reading programs can produce measurable changes in the structure of a child’s brain.

The study also found that several different improved the integrity of fibers that carry information from one part of the brain to another, according to a PBS article by Jon Hamilton in December 2009.

According to Marcel Just, director of the Center for Cognitive Brain Imaging at Carnegie Mellon University in Pittsburgh, “That helped areas of the brain work together.” 

Coordination is important because reading involves many separate parts of the brain.

Some parts recognize letters.  Others apply knowledge about vocabulary and syntax.  And still others decide what it all means.  The brain relies on high-speed  “highways” that carry information back and forth to synchronize all these operations.

When those highways can’t handle the traffic, the brain can’t make sense of the text on a page or screen.  The researchers, Just and Timothy Keller, wondered whether that might be one of the reasons a lot of children struggle to read.

Using a special MRI, they looked at the brains of several dozen children between the ages of 8 to 12.  Some were poor readers and some had typical reading skills. 

 The scans allowed scientists to study the network of fibers that carries information around the brain.  That network is found in the brain’s white matter.

What they found was that children with poor reading skills had “lower structure quality” in the white matter than typical readers.  

The Study

During the following school year, the scientists enrolled some of the poor readers in programs that provided a total of 100 hours of intensive remedial instruction.  The children practiced reading words and sentences over and over again.

After they were finished, a second set of MRI scans showed that the training had changed “not just their reading ability but the tissues in their brain,” according to Just.  The integrity of their white matter improved, while the white matter of children in standard classes was unchanged.

And in addition, says Just, “The amount of improvement in the white matter in an individual was correlated with that individual’s improvement in his reading ability.”

These findings add to evidence that learning involves more than just the gray matter that was known to process and store information.

A researcher in the Child Health and Human Development group at the National Institutes of Health, Doug Fields, says that it is becoming clear that white matter is also critical for learning.  And this has led to a shift in the way many scientists view the brain.

Other studies have shown that white matter changes when people learn to juggle or play a musical instrument, according to Fields.  And white matter also seems to be involved in everything from psychiatric illness to mathematical ability to autism.  Says Fields:

“Really, the more we look, the more we find.”

sole source: NPR article by Jon Hamilton, December 9, 2009.   http://www.npr.org

tutoring in Columbus OH:   Adrienne Edwards   614-579-6021   or email  aedwardstutor@columbus.rr.com

+ Mixed-Handedness Linked to ADHD

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From an article by John Gever at MedPage Today:

An online report in Pediatrics details findings that indicate that ambidextrous 5-year-olds are more likely to develop attention deficit-hyperactivity disorder symptoms later on, compared with right- and left-handed children.

The authors feel that brain morphology and neural circuitry associated with handedness also affects cognitive and behavioral function. 

The study was done by a team of Swedish researchers led by Alina Rodriguez, PhD, of Uppsala University in Sweden.

This was a longitudinal study of 7,871 children, born in 1986, in northern Finland.   There were 87 mixed-handed children, 632 left-handed, with the remainder right-handed.

 Rodriquez and her colleagues found that when these children were tested at age 8, teachers were about twice as likely to find hyperactivity in the mixed-handed children, as compared with those who were right-handed.

In addition, the learning and behavioral problems persisted into adolescence.

Similar increases were found in rates of teacher assessments of probable psychiatric disturbance and in overall school performance (as well as parental reports of language problems) in ambidextrous children.

Evaluated at age 16, those children classed as mixed-handed were more than three times as likely to suffer inattention or a combination of inattention and hyperactivity-impulsivity, relative to right-handed 16-year-olds.

And self-reported problems in Finnish language and math classes were also significantly more common in the mixed-handed young people.

Note: these effects were NOT seen in left-handed children.

The authors write that

“Mixed-handedness can be used as a marker of risk for difficulties and warrants additional evaluation.”

 Rodriquez and colleagues say results support the hypothesis that brain abnormalities stemming from before birth underlie what they called “atypical lateralization” and subsequent learning and behavior problems.

They add that recent neuropsychological work related to patterns of brain organization and function corroborates the findings.

They cite research indicating that ADHD is associated with left-side motor deficits, apart from hand preference, as well as reduced attention to visual stimuli on the left versus the right side.

These observations suggest weaker right hemisphere function.

Other studies have suggested that neural transmission can be assymetric between hemispheres.

They write

“These studies together highlight the possible interconnection among mixed-handedness, neurotransmitter dysfunction in the right hemisphere, and ADHD symptoms.”

The study was funded by the Academy of Finland, Sigrid Julius Foundation, Thula Institute, University of Oulu, Finland, and the National Institute of Mental Health.  Rodriquez was also supported by VINMER, with no potential conflicts of interest reported.

sole source: article at http://www.medpagetoday.com artile by John Gever on 1/25/2010.

tutoring in Columbus OH:   Adrienne Edwards   614-579-6021  or email  aedwardstutor@columbus.rr.com.

+ Reading Remediation Rewires a Child’s Brain

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Scientists at Carnegie Mellon University have uncovered the first evidence that intensive instruction to improve reading skills in children causes the brain to physically rewire itself. 

Timothy Keller and Marcel Just found that new white matter is created, which improves communication within the brain. 

Reporting in the journal Neuron, the researchers report that brain imaging of children within the ages of 8 and 10 showed that the quality of white matter — which is the brain tissue that carries signals between areas of grey matter (where information is processed) –improved substantially after the children received 100 hours of remedial training.

After the training, imaging indicated that the capability of the white matter to transmit signals efficiently had increased; and in addition,  the testing showed that the children could read better.

Says D. O. Hebb, Professor of Psychology and director of Carnegie Mellon’s Center for Cognitive Brain Imaging (CCBI), “Showing that it’s possible to rewired a brain’s white matter has important implications for treating reading disabilities and other developmental disorders, including autism.”

And Dr. Thomas R. Insel, director of the National Institute of Mental Health, agrees:

We have known that behavioral training can enhance brain function.  The exciting breakthrough here is detecting changes in brain connectivity with behavioral treatment. 

This finding with reading deficits suggests an exciting new approach to be tested in the treatment of mental disorders, which increasingly appear to be due to problems in specific brain circuits.

The study by Keller and Just was designed to discover what it is that physically changes in the brains of poor readers who make the transition to good reading.

They scanned the brains of 72 children before and after they went through a six-month remedial instruction program.

Using diffusion tensor imaging (DTI), a new brain imaging technique that tracks water movement in order to reveal the microscopic structure of white matter, Keller and Just found a brain change that involved the white matter cabling that wires different parts of the brain together.

Keller is a CCBI research scientist and author of the first developmental study of compromised what matter in autism. 

“Water molecules that are inside nerve fibers tend to move or diffuse parallel to the nerve fibers,” he says.   “To track the nerve fibers, the scanner senses areas in which many water molecules are moving along in the same direction and produces a road-map of the brain’s wiring.”

Previous studies had shown that both children and adults with reading difficulty displayed areas of compromised white matter. 

This new study shows that 100 hours of intensive reading instruction improved cheldren’s reading skills and also increased the quality of the compromised white matter to normal levels.

More precisely, the DTI imaging illustrated that the consistency of water diffusion had increased in this region, indicating an improvement in the integrity of white matter tracts.

Says Just,

The improved integrity essentially increases communication bandwidth between the two brain areas that the white matter connects, by a factor of 10. 

This opens a new era of being able to see the brain wiring change when an effective instructional treatment is applied.  It lets us see educational interventions from a new perspective.

Directly Related to the Amount of Increase in Phonological Decoding Ability

Keller and Just also found that the amount of change in diffusion among the treated group was directly related to the amount of increase in phonological decoding ability.

The children who showed the most white matter change also showed the most improvement in reading ability — confirming the link between brain tissue alteration and reading progress.

According to additional analyses, the change resulted from a decrease in the movement of water perpendicular to the main axes of the underlying white matter fibers, a finding consistent with increased myelin content in the region.

The authors caution that further research will be necessary to uncover the precise mechanism for the change in white matter.

Some previous findings indicate a role for electrical activity alon axons in promoting the formation of myelin around them, providing a plausible physiological basis for intensive practice and instruction increasing the efficiency of communication among brain areas.

Just says

We’re excited about these results.  The indication that behavioral intervention can improve both cognitive performance and the microstructure of white matter tracts is a breakthrough for treating and understanding development problems.

source: http://www.sciencedaily.com article on December 9, 2009.  Journal Reference: Timothy A. Keller, Marcel Adam Just.  Altering Cortical Connectivity: Remediation-Induced Changes in the White Matter of Poor Readers.  Neuron, 2009; 64 (5): 624-631 DOI: 10.1016/j.neuron.2009.10.018  

…  tutoring in Columbus OH:  Adrienne Edwards   614-579-6021   or email  aedwardstutor@columbus.rr.com

+ Light at Night May Link to Depression

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Researchers at Ohio State University have produced a study that may link depression to light at night, according to an article in Science Daily.

Researchers found that when mice were housed in a lighted room 24 hours a day, they exhibited more depressive symptoms than did similar mice who had normal light-dark cycles.

However, some mice were housed in constant light but had an escape option: a dark opaque tube they could go into.  They showed less evidence of depressive symptoms than the constant-light mice.

Says Laura Folken, lead author of the study and a graduate student in psychology at OSU, “The ability to escape light seemed to quell the depressive effects.  But constant light, with no chance of escape, increased depressive symptoms.”

Results suggest that more attention needs to be focused on how artificial lighting affects emotional health in humans. 

Co-author Randy Nelson, professor of neuroscience and psychology at Ohio State says

The increasing rate of depressive disorders in humans corresponds with the increasing use of light at night in modern society.  Many people are now exposed to unnatural light cycles, and that may have real consequences for our health.

The researchers presented the work October 21 in Chicago at the meeting of the Society for Neuroscience; it will appear in the December 28, 2009 issue of the journal Behavioral Brain Research.

“This is important for people who work night shifts, and for children and others who watch TV late into the night, disrupting their usual light-dark cycle,” says Fonken.

And there are many other practical implications, says Nelson.  Intensive care units are brightly lit all night long, which might add to the patients’ problems.

source: www.sciencedaily.com article on 10/21/09; journal reference is Laura K Fonken, M Sima Finy, James C Walton, Zachary M Weil, Joanna L Workman, Jessica Ross, Randy J Nelson, “Influence of light at night on murine anxiety- and depressive-like  responses.”  Behavioral Brain Research, 2009; 205 (2): 349 DOI: 10.1016/j.bbr.2009.07.001

tutoring in Columbus OH:   Adrienne Edwards   614-579-6021   or email  aedwardstutor@columbus.rr.com

+ Chronic Stress-Loops in Brain Change Behavior

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In an article in the NY Times, Natalie Angier writes that chronic stress changes the brain, but relaxation can change it back.

In the journal Science this summer, Nuno Sousa of the Life and Health Sciences Research Institute in Portugal says he and his colleagues found that rats, if chronically stressed, lost their elastic rat cunning – they instead fell back on familiar routines and rote responses.  They would, for example, compulsively press a bar for food pellets they had no intention of eating.

Brain Changes

In addition, the rats’ behavioral oddnesses were reflected by a pair of complementary changes in their underlying neural circuitry.

On the one hand, regions of the brain associated with executive decision making and goal-directed behaviors had shriveled.  Conversely, brain sectors linked to habit formation had bloomed.

In other words, rats were now cognitively disposed to keep doing the same things over and over, to “run laps in the same dead-end rat race rather than seek a pipeline to greener sewers,” writes Angier.  And Dr Sousa says,

“Behaviors become habitual faster in stressed animals than in the controls, and worse, the stressed animals can’t shift back to goal-directed behaviors when that would be the better approach.”

A neurobiologist who studies stress at Stanford, Robert Sapolsky, says

“This is a great model for understanding why we end up in a rut, and then dig ourselves deeper and deeper into that rut.”

In fact, continues Sapolsky, humans are lousy at recognizing when their normal coping mechanisms aren’t working.  We usually try it five more times, when it would have been better to try something new.

While perseverance is an admirable trait — is indeed essential for success in life — if it’s taken too far it becomes “perseveration.”  Perseveration is  uncontrollable repetition.  Taken to extremes, it simply seems perverse.

Dr Sapolsky is the author of “Why Zebras Don’t Get Ulcers.” 

“If  I were to try to break into the world of modern dance, after the first few rejections the logical response might be, practice even more.  But after the 12,000th rejection, maybe I should realize this isn’t a viable career option.”

But It Can Be Reversed

Luckily, it appears that stress-induced changes in behavior and brain can be reversed.  

After four weeks’ vacation in a supportive setting free of bullies, Tasers and dunking in water, the formerly stressed rats looked just like the controls.  They were able to innovate, discriminate and refrain from obsessive behavior.

Atrophied synaptic connections in the decisive regions of the prefrontal cortex resprouted, while the overgrown dendritic vines of the habit-prone sensorimotor striatum retreated.

Says Bruce McEwen, head of the neuroendocrinology lab at Rockefeller University, the new findings offer a particularly elegant demonstration of a principle that researchers have just begun to grasp.

“The brain is a very resilient and plastic organ.  Dendrites and synapses retract and reform, and reversible remondeling can occur throughout life.”

We associate stress with the split-second pace of our wired society.  But the body’s stress response is one of our oldest attributes.  Its basic architecture, with its linked network of neural and endocrine organs that spit out stimulatory and inhibitory hormones and other factors as needed, looks pretty much the same in a human as it does in a goldfish or a red-spotted newt.

Our stress response is itself dynamic.  It was essential for maneuvering through a dynamic world.  We had to dodge predators and chase down prey; we swung through trees; we fought off disease. 

As we go about our days, says McEwen, the biochemical mediators of the stress response rise and fall, flutter and flare.  “Cortisol and adrenaline go up and down.  Our inflammatory cytokines go up and down.”

The target organs of stress hormones likewise “dance to the beat ,” writes Angier.  The heart races and slows, the intestines constrict and relax.  This system of so-called allostasis, of maintaining control through constant change, stands in contrast to the mechanisms of homeostasis that keep the pH level and oxygen concentration in the blood within a narrow and invariant range.

But the dynamism of a person’s stress response makes it vulnerable to disruption, especially when the system is treated too roughly and not according to instructions.

In most animals, a serious threat provokes activation of the stimulatory, sympathetic, “fight or flight” side of the stress response.  But when the danger has passed, the calming parasympathetic circuitry tamps everything back down to baseline flickering.

Humans, however, have a brain that can think too much, that can extract phantom threats on a daily and sometimes hourly basis.  Over time such constant hyperactivation of the stress response can unbalance the entire feedback loop.

Reactions which would be desirable in limited, targeted quantities become hazardous in “promiscuous excess,”  writes Angier.  You need a spike in blood pressure if you’re going to run, to speedily deliver oxygen to your muscles.  But chronically elevated blood pressure is a source of mutiple medical miseries.

We might ask, why should the stressed brain be prone to habit formation? 

Perhaps — to help shunt as many behaviors as possible over to automatic pilot, so we can focus on the crisis at hand.

sole source: NY Times article by Natalie Angier on 8/18/09.  www.nytimes.com   

tutoring in columbus OH:   Adrienne Edwards   614-579-6021   or email  aedwards tutor@columbus.rr.com