How does your brain know where your hand has to go to pick up
a cup of coffee and successfully bring this to your mouth? By converting all of
the information into coordinates of the eye discovered Dutch researcher Sabine
Beurze. Unravelling those calculations will make it possible to more accurately
control arm prostheses.
Babies learn to pick things up or put things
down without knocking everything over. How the brain combines information about
the position of your arms with the information that comes in through your eyes
was largely unknown. Beurze allowed study subjects to perform tests in an MRI
scanner. These revealed that our brains convert all of the information into a
single calculation system: that of our eyes.
Two regions in the brain were found to be
involved in the movement: the posterior parietal cortex and the dorsal premotor
cortex. The brain uses the same regions for the planning of eye movements.Sabine Beurze examined for the first time how
people convert different information flows into a system to control movement.
Up until now, most of the research had been done on apes. The results of
Beurze's research might contribute to an improved control of arm prostheses.
Although prostheses that can be controlled by the brain are currently under
development, these are still prone to errors. Understanding which calculations
the brain performs to control movement will make it possible to further perfect
these arm prostheses. The results also provide hope for people with a motor
impairment.
JULY 2010
Music Training Boosts
Learning
A data-driven review by Northwestern
University researchers that will be published July 20 in Nature Reviews
Neuroscience pulls together converging research from the
scientific literature linking musical training to learning that spills over to
skills including language, speech, memory, attention and even vocal emotion.
The explosion of research in recent years
focusing on the effects of music training on the nervous system, including the
studies in the review, have strong implications for education, said Nina Kraus,
lead author of the Nature perspective, the Hugh Knowles Professor of
Communication Sciences and Neurobiology and director of Northwestern's Auditory
Neuroscience Laboratory.
The studies covered in the Northwestern review
offer a model of neuroplasticity, Kraus said. The research strongly suggests
that the neural connections made during musical training also prime the brain
for other aspects of human communication.
An active engagement with musical sounds not
only enhances neuroplasticity, she said, but also enables the nervous system to
provide the stable scaffolding of meaningful patterns so important to learning.
"The brain is unable to process all of
the available sensory information from second to second, and thus must
selectively enhance what is relevant," Kraus said. Playing an instrument
primes the brain to choose what is relevant in a complex process that may
involve reading or remembering a score, timing issues and coordination with
other musicians.
"A musician's brain selectively enhances
information-bearing elements in sound," Kraus said. "In a beautiful
interrelationship between sensory and cognitive processes, the nervous system
makes associations between complex sounds and what they mean." The
efficient sound-to-meaning connections are important not only for music but for
other aspects of communication, she said.
The Nature article reviews literature showing,
for example, that musicians are more successful than non-musicians in learning
to incorporate sound patterns for a new language into words. Children who are
musically trained show stronger neural activation to pitch changes in speech
and have a better vocabulary and reading ability than children who did not
receive music training.
And musicians trained to hear sounds embedded
in a rich network of melodies and harmonies are primed to understand speech in
a noisy background. They exhibit both enhanced cognitive and sensory abilities
that give them a distinct advantage for processing speech in challenging
listening environments compared with non-musicians.
The research review, the Northwestern
researchers conclude, argues for serious investing of resources in music
training in schools accompanied with rigorous examinations of the effects of
such instruction on listening, learning, memory, attention and literacy skills.
"The effect of music training suggests that, akin
to physical exercise and its impact on body fitness, music is a resource that
tones the brain for auditory fitness and thus requires society to re-examine
the role of music in shaping individual development, " the researchers
conclude.
JUNE 2010
Brain Structure Corresponds
to Personality
Psychologists have worked out that all
personality traits can be divided into five factors, commonly called the Big
Five: conscientiousness, extraversion, neuroticism, agreeableness, and
openness/intellect. Colin DeYoung at the University of Minnesota and colleagues
wanted to know if these personality factors correlated with the size of
structures in the brain.
For the study, 116 volunteers answered a
questionnaire to describe their personality, then had a brain imaging test that
measured the relative size of different parts of the brain. A computer program
was used to warp each brain image so that the relative sizes of different structures
could be compared. Several links were found between the size of certain brain
regions and personality. The research appears in Psychological Science,
a journal of the Association for Psychological Science.
For example, "Everybody, I think, has a
common sense of what extraversion is -- someone who is talkative, outgoing,
brash," says DeYoung. "They get more pleasure out of things like
social interaction, amusement parks, or really just about anything, and they're
also more motivated to seek reward, which is part of why they're more
assertive." That quest for reward is thought to be a leading factor in
extraversion. Earlier studies had found parts of the brain that are active in
considering rewards. So DeYoung and his colleagues reasoned that those regions
should be bigger in people who are more extraverted. Indeed, they found that
one of those regions, the medial orbitofrontal cortex -- it's just above and
behind the eyes -- was significantly larger in study subjects with a lot of
extraversion.
The study found similar associations for
conscientiousness, which is associated with planning; neuroticism, a tendency
to experience negative emotions that is associated with sensitivity to threat
and punishment; and agreeableness, which relates to parts of the brain that
allow us to understand each other's emotions, intentions, and mental states.
Only openness/intellect didn't associate clearly with any of the predicted
brain structures.
"This starts to indicate that we can
actually find the biological systems that are responsible for these patterns of
complex behavior and experience that make people individuals," says
DeYoung. He points out, though, that this doesn't mean that your personality is
fixed from birth; the brain grows and changes as it grows. Experiences change
the brain as it develops, and those changes in the brain can change
personality.
MAY 2010
Protein Regulates Enzyme
Linked to Alzheimer's Disease
Researchers at Tufts University School of
Medicine have zeroed in on a protein that may play a role in the progression of
Alzheimer's disease. The team found that increasing levels of the protein
(called GGA3) prevented the accumulation of an enzyme linked to Alzheimer's.
People with Alzheimer's disease typically have
higher levels of an enzyme called BACE1 in their brains. BACE1 produces a toxin
that researchers have pinpointed as a cause of Alzheimer's, and now,
researchers have found a way to prevent BACE1 from accumulating in the brain.
"We have identified the protein that
takes this enzyme to the cell's garbage disposal for removal. Increasing levels
of the protein allows more of the enzyme to be eliminated, possibly preventing
the high levels seen in people with Alzheimer's disease," said senior
author Giuseppina Tesco, MD, PhD, assistant professor in the department of
neuroscience at Tufts University School of Medicine (TUSM).
Tesco and colleagues previously discovered
that levels of the GGA3 protein were significantly lower in the brains of
Alzheimer's patients than those free of the disease. In the current in vitro
study, the team also found, unexpectedly, that the GGA3 protein must bind with
the regulatory protein ubiquitin in order to lower enzyme levels.
"This insight advances our understanding
of the molecular mechanisms of Alzheimer's disease. We hope that our approach
will lead to new therapies that treat and prevent Alzheimer's, which currently
affects as many as 5.1 million Americans," said Tesco. Tesco is also a
member of the neuroscience program faculty at the Sackler School of Graduate
Biomedical Sciences at Tufts, leading the Alzheimer's disease research
laboratory.
APRIL 2010
Regular Exercise Improves Learning
Regular exercise speeds learning and improves
blood flow to the brain, according to a new study led by researchers from the
University of Pittsburgh School of Medicine that is the first to examine these
relationships in a non-human primate model.
While there is ample evidence of the beneficial
effects of exercise on cognition in other animal models, such as the rat, it
has been unclear whether the same holds true for people, said senior author
Judy L. Cameron, Ph.D., a psychiatry professor at Pitt School of Medicine and a
senior scientist at the Oregon National Primate Research Center at Oregon
Health and Science University. Testing the hypothesis in monkeys can provide
information that is more comparable to human physiology.
"We found that monkeys who exercised regularly at
an intensity that would improve fitness in middle-aged people learned to do
tests of cognitive function faster and had greater blood volume in the brain's
motor cortex than their sedentary counterparts," Dr. Cameron said.
"This suggests people who exercise are getting similar benefits."
MARCH 2010
Discovery In Elderly People With Super-sharp
Memory
In a presentation given at the National
Meeting of the American Chemical Society (ACS) in San Fransisco March 23,
Changiz Geula, Ph.D. and colleagues described their discovery of elderly people
with super-sharp memory -- so-called "super-aged" individuals -- who
somehow escaped formation of brain "tangles." The tangles consist of
an abnormal form of a protein called "tau" that damages and
eventually kills nerve cells. Named for their snarled, knotted appearance under
a microscope, tangles increase with advancing age and peak in people with
Alzheimer's disease.
"This discovery is very exciting,"
said Geula, principal investigator of the Northwestern University Super Aging
Project and a professor of neuroscience at the Cognitive Neurology and
Alzheimer's Disease Center. "It is the first study of its kind and its
implications are vast. We always assumed that the accumulation of tangles is a
progressive phenomenon throughout the normal aging process. Healthy people
develop moderate numbers of tangles, with the most severe cases linked to
Alzheimer's disease. But now we have evidence that some individuals are immune
to tangle formation. The evidence also supports the notion that the presence of
tangles may influence cognitive performance. Individuals with the fewest
tangles perform at superior levels. Those with more appear to be normal for
their age."
The findings are based on examination of the
nine brains from super-aged individuals. Subjects who volunteer for this study
get a battery of memory and other tests and agree to donate their brains for
examination after death. They are considered 'super- aged' because of their
high performance on the tests. The tests include memory exercises to evaluate
their ability to recall facts after being told a story or their ability to
remember a list of more than a dozen words and recall those words sometime
later. The super-aged individuals recruited for study so far are all more than
80 years old, but they performed the memory tasks at the level of 50-year-olds.
The scientists are recruiting more volunteers for the study, with the goal of
eventually including about 50 people.
Geula pointed out that previous studies tended
to focus on what goes wrong with the brain as people age. It established that
tangles and other deposits termed plaques accumulate at higher levels in the
brains of people with Alzheimer's Disease. Geula said the new study is unique
in its focus on what's right with the brains of older people. It seeks insights
into what lifestyle, genetic[s?], or other factors may protect super-aged
individuals from the age-related memory loss that affects most other people.
The scientists found that super-aged people
appear to fall into two subgroups: Those who are almost immune to tangle
formation and those that have few tangles.
"One group of super-aged seems to dodge
tangle formation," Geula explained. "Their brains are virtually
clean, which doesn't happen in normal-aged individuals. The other group seems
to get tangles but it's less than or equal to the amount in the normal elderly.
But for some reason, they seem to be protected against its effects."
The next step, Geula said, involves
determining why one subgroup is immune to tangle formation and the other seems
to be immune to its effects. Environment, lifestyle, and genetics may be key
factors.
Emory University neuroscientist Lori Marino
will speak on the anatomical basis of dolphin intelligence at the American
Association for the Advancement of Science conference in San Diego, on Feb. 21,
2010.
"Many modern dolphin brains are
significantly larger than our own and second in mass to the human brain when
corrected for body size," Marino says.
A leading expert in the neuroanatomy of
dolphins and whales, Marino will appear as part of a panel discussing these
findings and their ethical and policy implications.
Some dolphin brains exhibit features
correlated with complex intelligence, she says, including a large expanse of
neocortical volume that is more convoluted than our own, extensive insular and
cingulated regions, and highly differentiated cellular regions.
"Dolphins are sophisticated, self-aware,
highly intelligent beings with individual personalities, autonomy and an inner
life. They are vulnerable to tremendous suffering and psychological trauma,"
Marino says.
The growing industry of capturing and
confining dolphins to perform in marine parks or to swim with tourists at
resorts needs to be reconsidered, she says.
"Our current knowledge of dolphin brain
complexity and intelligence suggests that these practices are potentially
psychologically harmful to dolphins and present a misinformed picture of their
natural intellectual capacities," Marino says.
Marino worked on a 2001 study that showed that
dolphins can recognize themselves in a mirror -- a finding that indicates
self-awareness similar to that seen in higher primates and elephants.
JANUARY 2010
Cell Phone May Protect Against Alzheimer's Disease
A new study in mice provides the first evidence that long-term
exposure to electromagnetic waves associated with cell phone use may actually
protect against, and even reverse, Alzheimer's disease. The study, led by
University of South Florida researchers at the Florida Alzheimer's Disease
Research Center was published January 6 in the Journal of Alzheimer's
Disease.
The researchers showed that exposing old Alzheimer's mice to
electromagnetic waves generated by cell phones erased brain deposits of the
harmful protein beta-amyloid, in addition to preventing the protein's build-up
in younger Alzheimer's mice. The sticky brain plaques formed by the abnormal
accumulation of beta amyloid are a hallmark of Alzheimer's disease. Most
treatments against Alzheimer's try to target beta-amyloid.
The highly-controlled study allowed researchers to isolate the effects
of cell phone exposure on memory from other lifestyle factors such as diet and
exercise. It involved 96 mice, most of which were genetically altered to
develop beta-amyloid plaques and memory problems mimicking Alzheimer's disease
as they aged. Some mice were non-demented, without any genetic predisposition
for Alzheimer's, so researchers could test the effects of electromagnetic waves
on normal memory as well.
Both the Alzheimer's and normal mice were exposed to the
electromagnetic field generated by standard cell phone use for two 1-hour
periods each day for seven to nine months. The mice didn't wear tiny headsets
or have scientists holding cell phones up to their ears; instead, their cages
were arranged around a centrally-located antenna generating the cell phone
signal. Each animal was housed the same distance from the antenna and exposed
to electromagnetic waves typically emitted by a cell phone pressed up against a
human head.
If cell phone exposure was started when the genetically-programmed
mice were young adults -- before signs of memory impairment were apparent --
their cognitive ability was protected. In fact, the Alzheimer's mice performed
as well on tests measuring memory and thinking skills as aged mice without
dementia. If older Alzheimer's mice already exhibiting memory problems were
exposed to the electromagnetic waves, their memory impairment disappeared.
Months of cell phone exposure even boosted the memories of normal mice to
above-normal levels. The memory benefits of cell phone exposure took months to
show up, suggesting that a similar effect in humans would take years if cell
phone-level electromagnetic exposure was provided.
The researchers were particularly surprised to discover that months of
cell phone exposure actually boosted the memory of non-demented (normal mice)
to above-normal levels. They suspect that the main reason for this improvement
involves the ability of electromagnetic exposure to increase brain activity,
promoting greater blood flow and increased energy metabolism in the brain.
"Our study provides evidence that long-term cell phone use is not harmful
to brain," Dr. Cao said. "To the contrary, the electromagnetic waves
emitted by cell phones could actually improve normal memory and be an effective
therapy against memory impairment."
DECEMBER 2009
Antidepressants May Change Personality Individuals taking a medication to treat depressionmay experience changes in their personality separate from the alleviation of
depressive symptoms, according to a report in the December issue of Archives of
General Psychiatry, one of the JAMA/Archives journals.
Two personality traits, neuroticism and extraversion, have been related to
depression risk, according to background information in the article.
Individuals who are neurotic tend to experience negative emotions and emotional
instability, whereas extraversion refers not only to socially outgoing behavior
but also to dominance and a tendency to experience positive emotions. Both
traits have been linked to the brain's serotonin system, which is also targeted
by the class of antidepressants known as selective serotonin reuptake
inhibitors (SSRIs).
Tony Z. Tang, Ph.D., of Northwestern University, Evanston, Ill., and colleagues
studied the effects of one particular SSRI, paroxetine, in a placebo-controlled
trial involving 240 adults with major depressive disorder. A total of 120
participants were randomly assigned to take paroxetine, 60 to undergo cognitive
therapy and 60 to take placebo for 12 months. Their personalities and
depressive symptoms were assessed before, during and after treatment.
All participants experienced improvement in their symptoms of depression.
However, even after controlling for these improvements, individuals taking
paroxetine experienced a significantly greater decrease in neuroticism and
increase in extraversion than those receiving cognitive therapy or placebo.
"Patients taking paroxetine reported 6.8 times as much change on
neuroticism and 3.5 times as much change on extraversion as placebo patients
matched for depression improvement," the authors write.
NOVEMBER 2009
Cannabinoids Could Help Post-traumatic Stress Disorder Patients
The study, carried out at the Learning and
Memory Lab in the University of Haifa’s Department of Psychology by research
student Eti Ganon-Elazar under the supervision of Dr. Irit Akirav, was
published in the Journal of Neuroscience.
In most cases, the result of experiencing a
traumatic event (a car accident or terror attack) is the appearance of
medical and psychological symptoms that affect various functions, but which
pass. However, some 10%-30% of people who experience a traumatic event develop
post-traumatic stress disorder, a condition in which the patient continues to
suffer stress symptoms for months and even years after the traumatic event.
Symptoms include reawakened trauma, avoidance of anything that could recall the
trauma, and psychological and physiological disturbances. One of the problems
in the course of treating trauma patients is that a person is frequently
exposed to additional stress, which hinders the patient's overcoming the
trauma.
The researchers used a synthetic form of
marijuana, which has similar properties to the natural plant, and they chose to
use a rat model, which presents similar physiological responses to stress to
that of humans.
The first stage of the research examined how
long it took for the rats to overcome a traumatic experience, without any
intervention. A cell colored white on one side and black on the other was
prepared. The rats were placed in the white area, and as soon as they moved
over to the black area, which they prefer, they received a light electric
shock. Each day they were brought to the cell and placed back in the white
area. Immediately following exposure to the traumatic experience, the rats
would not move to the black area voluntarily, but a few days later after not
receiving further electric shocks in the black area, they learned that it is
safe again and moved there without hesitation.
Next, the researchers introduced an element of
stress. A second group of rats were placed on a small, elevated platform after
receiving the electric shock, which added stress to the traumatic experience.
These rats abstained from returning to the black area in the cell for much
longer, which shows that the exposure to additional stress does indeed hinder
the process of overcoming trauma.
The third stage of the research examined yet
another group of rats. These were exposed to the traumatic and additional
stress events, but just before being elevated on the platform received an
injection of synthetic marijuana in the amygdala area of the brain -- a
specific area known to be connected to emotive memory. These rats agreed to
enter the black area after the same amount of time as the first group --
showing that the synthetic marijuana cancelled out the symptoms of stress.
Refining the results of this study, the researchers then administered marijuana
injections at different points in time on additional groups of rats, and found
that regardless of when exactly the injection was administered, it prevented
the surfacing of stress symptoms.
Dr. Akirav and Ganon-Elazar also examined
hormonal changes in the course of the experiment and found that synthetic
marijuana prevents increased release of the stress hormone that the body
produces in response to stress.
According to Dr. Akirav, the results of this
study show that cannabinoids can play an important role in stress-related
disorders. "The results of our research should encourage psychiatric
investigation into the use of cannabinoids in post-traumatic stress
patients," she concludes.
OCTOBER 2009
Chimpanzees Help Each Other On
Request
A new study by researchers at the Primate Research
Institute (PRI) and the Wildlife Research Center (WRC) of Kyoto University
shows that chimpanzees altruistically help conspecifics, even in the absence of
direct personal gain or immediate reciprocation, although the chimpanzees were
much more likely to help each other upon request than voluntarily.
Shinya Yamamoto and colleagues studied six pairs of
chimpanzees (three mother-offspring pairs and three non-kin adult pairs) in two
different experiments, designed to test whether the chimpanzees would transfer
a tool to a conspecific even if doing so would bring no immediate benefit to
themselves. In each case, two chimpanzees would be situated in two adjacent,
transparent booths, either in a straw-use situation where the chimpanzee would
need access to a straw to be able to drink the juice box available to it, or in
a stick-use situation where the chimpanzee would need access to a stick to drag
a juice reward back into the booth.
In the first experiment, the two chimpanzees would
have access to the opposite tool needed to obtain the reward in their booth—the
chimpanzee that needed the straw would have access to the stick and vice-versa.
In the second experiment, the mother-offspring pairs were tested in a situation
where there was no opportunity for reciprocation because each individual was
assigned a fixed role—giver or recipient—for 24 trials (one week's worth)
before the roles were reversed.
The researchers found that the chimpanzees did
spontaneously transfer tools in order to help their partner. This tool transfer
occurred predominantly after the partner had actively solicited help (by poking
its arm through a hole in the booth, for example, or by clapping), even when there
was no hope of reciprocation from the partner (as in experiment 2) and even
when the two animals were unrelated.
"Communicative interactions play an important
role in altruism in chimpanzees," said Dr Yamamoto. "While humans may
help others without being solicited, the chimpanzees rarely voluntarily offered
an effective tool to a struggling partner. Indeed, simple observation of
another's failed attempts did not elicit voluntary helping in
chimpanzees."
Helping upon request may be a more economical and effective
strategy. Altruistic behaviour by definition produces no direct immediate
benefit to the actor; making a request is a clear indicator to the actor that
the recipient requires help, minimizing the risk to the actor of unnecessarily
behaving altruistically. In this sense, "help upon request" is an
ideal strategy since the helping is always helpful and not wasted. This type of
altruism may have initially driven the prevalence and development of altruism
during human evolution.
SEPTEMBER 2009
Crying Can Strengthen Relationships
New analysis by Dr. Oren Hasson of Tel Aviv University
shows that tears still signal physiological distress, but they also function as
an evolution-based mechanism to bring people closer together.
"Crying is a highly evolved behavior,"
explains Dr. Hasson. "Tears give clues and reliable information about
submission, needs and social attachments between one another. My research is
trying to answer what the evolutionary reasons are for having emotional tears.
"My analysis suggests that by blurring vision,
tears lower defences and reliably function as signals of submission, a cry for
help, and even in a mutual display of attachment and as a group display of
cohesion," he reports.
His research, published recently in Evolutionary
Psychology, investigates the different kinds of tears we shed — tears of joy,
sadness and grief — as well as the authenticity or sincerity of the tears.
Crying, Dr. Hasson says, has unique benefits among friends and others in our
various communities.
Crying enhances attachments and friendships, says Dr.
Hasson, but taboos are still there in certain cases. In some cultures,
societies or circumstances, the expression of emotions is received as a
weakness and the production of tears is suppressed. For example, it is rarely acceptable
to cry in front of your boss at work — especially if you are a man, he says.
Multiple studies across cultures show that crying
helps us bond with our families, loved ones and allies, Dr. Hasson says. By
blurring vision, tears reliably signal your vulnerability and that you love
someone, a good evolutionary strategy to emotionally bind people closer to you.
"Of course," Dr. Hasson adds, "the
efficacy of this evolutionary behavior always depends on who you're with when
you cry those buckets of tears, and it probably won't be effective in places,
like at work, when emotions should be hidden."
Dr. Hasson, a marriage therapist, uses his conclusions
in his clinic. "It is important to legitimize emotional tears in
relationships," he says. "Too often, women who cry feel ashamed,
silly or weak, when in reality they are simply connected with their feelings,
and want sympathy and hugs from their partners."
AUGUST 2009
The brain predicts the consequences of eye movement
even before the eyes take in a new scene
The study, "Looking ahead: The perceived
direction of gaze shifts before the eyes move," published in the
Association for Research in Vision and Ophthalmology's peer-reviewed Journal
of Vision, asked subjects to shift their eyes to a clock with a fast-moving hand
and report the time on the clock when their eyes landed on it. The average
reported time was 39 milliseconds before the actual time. As a control task,
the clock moved instead of the eyes, and the reported arrival times averaged 27
milliseconds after the actual time.
"We've revealed a moment in time when things are
not perceived as they actually are," said lead researcher Amelia Hunt,
PhD, of the University of Aberdeen's School of Psychology. "These findings
serve as a reminder that every aspect of our experience is constructed by our
brains."
The report suggests that the prediction is a result of
remapping, where neurons involved in visual perception become active or dormant
to help the brain maintain a stable visual environment despite the constant
shift of images on the retina.
PSYCHOLOGY READERS NEWS