Posts tagged psychology
Articles and news from the latest research reports.
Depressed people have a more accurate perception of time
People with mild depression underestimate their talents. However, new research carried out researchers at the University of Limerick and the University of Hertfordshire shows that depressed people are more accurate when it comes to time estimation than their happier peers.
Depressed people often appear to distort the facts and view their lives more negatively than non-depressed people. Feelings of helplessness, hopelessness and worthlessness and of being out of control are some of the main symptoms of depression. For these people time seems to pass slowly and they will often use phrases such as “time seems to drag” to describe their experiences and their life. However, depressed people sometimes have a more accurate perception of reality than their happier friends and family who often look at life through rose-tinted glasses and hope for the best.
Dr Rachel Msetfi, senior lecturer in psychology, University of Limerick and one of the studies authors, said: “We found that depressed people tended to be more accurate when estimating time whereas non-depressed people tended to be less accurate. This finding, along with some of our other work, suggests that depression leads to more attention paid to time passing. Sometimes this might lead to a phenomenon known as ‘depressive realism’, though on other occasions time might seem to be moving more slowly than usual.”
In the study, volunteers, who were classified as mildly depressed or non-depressed, made estimates of the length of different time intervals of between two and sixty-five seconds. Overall, those volunteers who were mildly–depressed were more accurate in their time estimations.
Dr Msetfi noted that: “Time is a very important part of everyday experience, it flies when we are having fun or enjoying ourselves. One of the commonest experiences of depression is that people feel that time passes slowly and sometimes painfully. Our findings may help to shed a little light on how people with depression can be treated. People with depression are often encouraged to check themselves against reality, but maybe this timing skill can be harnessed to help in the treatment of mildly-depressed people. These findings may also link to successful mindfulness based treatments for depression which focus on encouraging present moment awareness.”
The paper, “Time perception and depressive realism: Judgement type, psychophysical functions and bias”, is published in PLOS ONE.
(Source: ul.ie)
Human Brains Are Hardwired for Empathy, Friendship, Study Shows
Perhaps one of the most defining features of humanity is our capacity for empathy – the ability to put ourselves in others’ shoes. A new University of Virginia study strongly suggests that we are hardwired to empathize because we closely associate people who are close to us – friends, spouses, lovers – with our very selves.
“With familiarity, other people become part of ourselves,” said James Coan, a U.Va. psychology professor in the College of Arts & Sciences who used functional magnetic resonance imaging brain scans to find that people closely correlate people to whom they are attached to themselves. The study appears in the August issue of the journal Social Cognitive and Affective Neuroscience.
“Our self comes to include the people we feel close to,” Coan said.
In other words, our self-identity is largely based on whom we know and empathize with.
Coan and his U.Va. colleagues conducted the study with 22 young adult participants who underwent fMRI scans of their brains during experiments to monitor brain activity while under threat of receiving mild electrical shocks to themselves or to a friend or stranger.
The researchers found, as they expected, that regions of the brain responsible for threat response – the anterior insula, putamen and supramarginal gyrus – became active under threat of shock to the self. In the case of threat of shock to a stranger, the brain in those regions displayed little activity. However when the threat of shock was to a friend, the brain activity of the participant became essentially identical to the activity displayed under threat to the self.
“The correlation between self and friend was remarkably similar,” Coan said. “The finding shows the brain’s remarkable capacity to model self to others; that people close to us become a part of ourselves, and that is not just metaphor or poetry, it’s very real. Literally we are under threat when a friend is under threat. But not so when a stranger is under threat.”
Coan said this likely is because humans need to have friends and allies who they can side with and see as being the same as themselves. And as people spend more time together, they become more similar.
“It’s essentially a breakdown of self and other; our self comes to include the people we become close to,” Coan said. “If a friend is under threat, it becomes the same as if we ourselves are under threat. We can understand the pain or difficulty they may be going through in the same way we understand our own pain.”
This likely is the source of empathy, and part of the evolutionary process, Coan reasons.
“A threat to ourselves is a threat to our resources,” he said. “Threats can take things away from us. But when we develop friendships, people we can trust and rely on who in essence become we, then our resources are expanded, we gain. Your goal becomes my goal. It’s a part of our survivability.”
People need friends, Coan added, like “one hand needs another to clap.”
Brain circuit can tune anxiety
New findings may help neuroscientists pinpoint better targets for antianxiety treatments.
Anxiety disorders, which include posttraumatic stress disorder, social phobias and obsessive-compulsive disorder, affect 40 million American adults in a given year. Currently available treatments, such as antianxiety drugs, are not always effective and have unwanted side effects.
To develop better treatments, a more specific understanding of the brain circuits that produce anxiety is necessary, says Kay Tye, an assistant professor of brain and cognitive sciences and member of MIT’s Picower Institute for Learning and Memory.
“The targets that current antianxiety drugs are acting on are very nonspecific. We don’t actually know what the targets are for modulating anxiety-related behavior,” Tye says.
In a step toward uncovering better targets, Tye and her colleagues have discovered a communication pathway between two brain structures — the amygdala and the ventral hippocampus — that appears to control anxiety levels. By turning the volume of this communication up and down in mice, the researchers were able to boost and reduce anxiety levels.
Lead authors of the paper, which appears in the Aug. 21 issue of Neuron, are technical assistant Ada Felix-Ortiz and postdoc Anna Beyeler. Other authors are former research assistant Changwoo Seo, summer student Christopher Leppla and research scientist Craig Wildes.
Measuring anxiety
Both the hippocampus, which is necessary for memory formation, and the amygdala, which is involved in memory and emotion processing, have previously been implicated in anxiety. However, it was unknown how the two interact.
To study those interactions, the researchers turned to optogenetics, which allows them to engineer neurons to turn their electrical activity on or off in response to light. For this study, the researchers modified a set of neurons in the basolateral amygdala (BLA); these neurons send long projections to cells of the ventral hippocampus.
The researchers tested the mice’s anxiety levels by measuring how much time they were willing to spend in a situation that normally makes them anxious. Mice are naturally anxious in open spaces where they are easy targets for predators, so when placed in such an area, they tend to stay near the edges.
When the researchers activated the connection between cells in the amygdala and the hippocampus, the mice spent more time at the edges of an enclosure, suggesting they felt anxious. When the researchers shut off this pathway, the mice became more adventurous and willing to explore open spaces. However, when these mice had this pathway turned back on, they scampered back to the security of the edges.
Complex interactions
In a study published in 2011, Tye found that activating a different subset of neurons in the amygdala had the opposite effect on anxiety as the neurons studied in the new paper, suggesting that anxiety can be modulated by many different converging inputs.
“Neurons that look virtually indistinguishable from each other in a single region can project to different regions and these different projections can have totally opposite effects on anxiety,” Tye says. “Anxiety is such an important trait for survival, so it makes sense that you want some redundancy in the system. You want a couple of different avenues to modulate anxiety.”
The Neuron study contributes significantly to scientists’ understanding of the roles of the amygdala and hippocampus in anxiety and offers directions for seeking new drug targets, says Joshua Gordon, an associate professor of psychiatry at Columbia University.
“The study specifies a particular connection in the brain as being important for anxiety. One could imagine, then, identifying components of the machinery of that connection — synaptic proteins or ion channels, for example — that are particularly important for amygdala-hippocampal connectivity. If such specific components could be identified, they would be potential targets for novel antianxiety drugs,” says Gordon, who was not part of the research team.
In future studies, the MIT team plans to investigate the effects of the amygdala on other targets in the hippocampus and the prefrontal cortex, which has also been implicated in anxiety. Deciphering these circuits could be an important step toward finding better drugs to help treat anxiety.
Schizophrenia symptoms linked to faulty ‘switch’ in brain
Scientists at The University of Nottingham have shown that psychotic symptoms experienced by people with schizophrenia could be caused by a faulty ‘switch’ within the brain.
In a study published today in the leading journal Neuron, they have demonstrated that the severity of symptoms such as delusions and hallucinations which are typical in patients with the psychiatric disorder is caused by a disconnection between two important regions in the brain — the insula and the lateral frontal cortex.
The breakthrough, say the academics, could form the basis for better, more targeted treatments for schizophrenia with fewer side effects.
The four-year study, led by Professor Peter Liddle and Dr Lena Palaniyappan in the University’s Division of Psychiatry and based in the Institute of Mental Health, centred on the insula region, a segregated ‘island’ buried deep within the brain, which is responsible for seamless switching between inner and outer world.
"Powerful explanation"
Dr Lena Palaniyappan, a Wellcome Trust Research Fellow, said: “In our daily life, we constantly switch between our inner, private world and the outer, objective world. This switching action is enabled by the connections between the insula and frontal cortex. This switch process appears to be disrupted in patients with schizophrenia. This could explain why internal thoughts sometime appear as external objective reality, experienced as voices or hallucinations in this condition. This could also explain the difficulties in ‘internalising’ external material pleasures (e.g. enjoying a musical tune or social events) that result in emotional blunting in patients with psychosis. Our observation offers a powerful mechanistic explanation for the formation of psychotic symptoms.”
Several brain regions are engaged when we are lost in thought or, for example, remembering a past event. However, when interrupted by a loud noise or another person speaking we are able to switch to using our frontal cortex area of the brain, which processes this external information. With a disruption in the connections from the insula, such switching may not be possible.
Compromised brain function
The Nottingham scientists used functional MRI (fMRI) imaging to compare the brains of 35 healthy volunteers with those of 38 schizophrenic patients. The results showed that whereas the majority of healthy patients were able to make this switch between regions, the patients with schizophrenia were less likely to shift to using their frontal cortex.
The insular and frontal cortex form a sensitive ‘salience’ loop within the brain — the insular should stimulate the frontal cortex while in turn the frontal cortex should inhibit the insula — but in patients with schizophrenia this system was found to be seriously compromised.
The results suggest that detecting the lack of a positive influence from the insula to the frontal cortex using fMRI could have a high degree of predictive value in identifying patients with schizophrenia.
The results of the study offer vital information for the development of more effective treatments for the condition.
Schizophrenia is one of the most common serious mental health conditions affecting around 1 in 100 people. Its onset occurs most commonly in a patient’s late teens or early 20s which can have devastating consequences for their future.
Genetic and environmental triggers
Scientists remain unsure what causes schizophrenia but believe it could be a combination of a genetic predisposition to the condition combined with environmental factors. Drug use is known to be a key trigger – people who use cannabis, or stimulant drugs, are three to four times more likely to go on to develop recurrent psychotic symptoms.
It is also believed that underdevelopment of the brain in the womb caused by complications in the mother’s pregnancy and in early childhood linked to issues such as malnutrition could play a key part. Previous observations from this research group have also uncovered the presence of unusually smooth folding patterns of the brain over the insula region in patients, suggesting an impairment in the normal development of this structure in schizophrenia.
At present, treatment involves a combination of antipsychotic medications, psychological therapies and social interventions. Currently, only one in five patients with schizophrenia achieve complete recovery and many patients who develop the condition in the long-term struggle to find a treatment that is 100 per cent effective in managing their condition.
Antipsychotic drugs, though effective in a number of patients, have poor acceptance rates due to the side effect burden meaning that many patients stop taking them in the longer run, leading to recurrence of disabling symptoms.
Researchers in Nottingham are also looking at a technique called TMS – transcranial magnetic stimulation — which uses a powerful magnetic pulse to stimulate the brain regions that are malfunctioning.
Compassion-based therapy
Despite the fact that the insular region is buried so deeply within the brain that TMS would usually be ineffective, the results of the Nottingham study suggest that the loop between the insular and the frontal cortex could be exploited for TMS– if a pulse is delivered to the frontal lobe it could stimulate the insula and reset the ‘switch’.
Other future treatment options could include the use of a compassion-based meditation therapy called mindfulness, which may have the potential to ‘reset’ the switching function of the insula and can promote physical changes within the brain. Meditation over a long period of time has been shown to increase the folding patterns within the insula area of the brain. These ideas are in its early stages at present, but may deliver more focussed treatment approaches in the longer term.
Why Some Remember Dreams, Others Don’t
People who tend to remember their dreams also respond more strongly than others to hearing their name when they’re awake, new research suggests.
Everyone dreams during sleep, but not everyone recalls the mental escapade the next day, and scientists aren’t sure why some people remember more than others.
To find out, researchers used electroencephalography to record the electrical activity in the brains of 36 people while the participants listened to background tunes, and occasionally heard their own first name. The brain measurements were taken during wakefulness and sleep. Half of the participants were called high recallers, because they reported remembering their dreams almost every day, whereas the other half, low recallers, said they only remembered their dreams once or twice a month.
When asleep, both groups showed similar changes in brain activity in response to hearing their names, which were played quietly enough not to wake them.
However, when awake, high recallers showed a more sustained decrease in a brain wave called the alpha wave when they heard their names, compared with the low recallers.
"It was quite surprising to see a difference between the groups during wakefulness," said study researcher Perrine Ruby, neuroscientist at Lyon Neuroscience Research Center in France.
The difference could reflect variations in the brains of high and low recallers that could have a role in how they dream, too, Ruby said.
Who remembers their dreams
A well-established theory suggests that a decrease in the alpha wave is a sign that brain regions are being inhibited from responding to outside stimuli. Studies show that when people hear a sudden sound or open their eyes, and more brain regions become active, the alpha wave is reduced.
In the study, as predicted, both groups showed a decrease in the alpha wave when they heard their names while awake. But high recallers showed a more prolonged decrease, which may be a sign their brains became more widely activated when they heard their names.
In other words, high recallers may engage more brain regions when processing sounds while awake, compared with low recallers, the researchers said.
While people are asleep, the alpha wave behaves in the opposite way —it increases when a sudden sound is heard. Scientists aren’t certain why this happens, but one idea is that it protects the brain from being interrupted by sounds during sleep, Ruby said.
Indeed, the study participants showed an increase in the alpha wave in response to sounds during sleep, and there was no difference between the groups.
One possibility to explain the lack of difference, the researchers said, could be that perhaps high recallers had a larger increase in alpha waves, but it was so high that they woke up.
Time spent awake, during the night
The researchers saw that high recallers awoke more frequently during the night. They were awake, on average, for 30 minutes during the night, whereas low recallers were awake for 14 minutes. However, Ruby said “both figures are in the normal range, it’s not that there’s something wrong with either group.”
Altogether, the results suggest the brain of high recallers may be more reactive to stimuli such as sounds, which could make them wake up more easily. It is more likely a person would remember their dreams if they are awakened immediately after one, Ruby said.
However, waking up at night can account for only a part of the differences people show in remembering dreams. “There’s still much more to understand,” she said.
The study is published online (Aug. 13) in the journal Frontiers in Psychology.
Female frogs prefer males who can multitask
From frogs to humans, selecting a mate is complicated. Females of many species judge suitors based on many indicators of health or parenting potential. But it can be difficult for males to produce multiple signals that demonstrate these qualities simultaneously.
In a study of gray tree frogs, a team of University of Minnesota researchers discovered that females prefer males whose calls reflect the ability to multitask effectively. In this species (Hyla chrysoscelis) males produce “trilled” mating calls that consist of a string of pulses.
Typical calls can range in duration from 20-40 pulses per call and occur between 5-15 calls per minute. Males face a trade-off between call duration and call rate, but females preferred calls that are longer and more frequent, which is no simple task.
The findings were published in August issue of Animal Behavior.
"It’s kind of like singing and dancing at the same time," says Jessica Ward, a postdoctoral researcher who is lead author for the study. Ward works in the laboratory of Mark Bee, a professor in the College of Biological Sciences’ Department of Ecology, Evolution and Behavior.
The study supports the multitasking hypothesis, which suggests that females prefer males who can do two or more hard-to-do things at the same time because these are especially good quality males, Ward says. The hypothesis, which explores how multiple signals produced by males influence female behavior, is a new area of interest in animal behavior research.
By listening to recordings of 1,000 calls, Ward and colleagues learned that males are indeed forced to trade off call duration and call rate. That is, males that produce relatively longer calls only do so at relatively slower rates.
"It’s easy to imagine that we humans might also prefer multitasking partners, such as someone who can successfully earn a good income, cook dinner, manage the finances and get the kids to soccer practice on time."
The study was carried out in connection with Bee’s research goal, which is understanding how female frogs are able to distinguish individual mating calls from a large chorus of males. By comparison, humans, especially as we age, lose the ability to distinguish individual voices in a crowd. This phenomenon, called the “cocktail party” problem, is often the first sign of a diminishing ability to hear. Understanding how frogs hear could lead to improved hearing aids.
(Source: www1.umn.edu)
Autistic kids who best peers at math show different brain organization
Children with autism and average IQs consistently demonstrated superior math skills compared with nonautistic children in the same IQ range, according to a study by researchers at the Stanford University School of Medicine and Lucile Packard Children’s Hospital.
“There appears to be a unique pattern of brain organization that underlies superior problem-solving abilities in children with autism,” said Vinod Menon, PhD, professor of psychiatry and behavioral sciences and a member of the Child Health Research Institute at Packard Children’s.
The autistic children’s enhanced math abilities were tied to patterns of activation in a particular area of their brains — an area normally associated with recognizing faces and visual objects.
Menon is senior author of the study, published online Aug. 17 in Biological Psychiatry. Postdoctoral scholar Teresa luculano, PhD, is the lead author.
Children with autism have difficulty with social interactions, especially interpreting nonverbal cues in face-to-face conversations. They often engage in repetitive behaviors and have a restricted range of interests.
But in addition to such deficits, children with autism sometimes exhibit exceptional skills or talents, known as savant abilities. For example, some can instantly recall the day of the week of any calendar date within a particular range of years — for example, that May 21, 1982, was a Friday. And some display superior mathematical skills.
“Remembering calendar dates is probably not going to help you with academic and professional success,” Menon said. “But being able to solve numerical problems and developing good mathematical skills could make a big difference in the life of a child with autism.”
The idea that people with autism could employ such skills in jobs, and get satisfaction from doing so, has been gaining ground in recent years.
The participants in the study were 36 children, ages 7 to 12. Half had been diagnosed with autism. The other half was the control group. Each group had 14 boys and four girls. (Autism disproportionately affects boys.) All participants had IQs in the normal range and showed normal verbal and reading skills on standardized tests administered as part of the recruitment process for the study. But on the standardized math tests that were administered, the children with autism outperformed children in the control group.
After the math test, researchers interviewed the children to assess which types of problem-solving strategies each had used: Simply remembering an answer they already knew; counting on their fingers or in their heads; or breaking the problem down into components — a comparatively sophisticated method called decomposition. The children with autism displayed greater use of decomposition strategies, suggesting that more analytic strategies, rather than rote memory, were the source of their enhanced abilities.
Then, the children worked on solving math problems while their brain activity was measured in an MRI scanner, in which they had to lie down and remain still. The brain scans of the autistic children revealed an unusual pattern of activity in the ventral temporal occipital cortex, an area specialized for processing visual objects, including faces.
“Our findings suggest that altered patterns of brain organization in areas typically devoted to face processing may underlie the ability of children with autism to develop specialized skills in numerical problem solving,” Iuculano said.
“These findings not only empirically confirm that high-functioning children with autism have especially strong number-problem-solving abilities, but show that this cognitive strength in math is based on different patterns of functional brain organization,” said Carl Feinstein, MD, director of the Center for Autism and Related Disorders at Packard Children’s and professor of psychiatry and behavioral sciences at the School of Medicine. He was not involved in the study.
Menon added that previous research “has focused almost exclusively on weaknesses in children with autism. Our study supports the idea that the atypical brain development in autism can lead, not just to deficits, but also to some remarkable cognitive strengths. We think this can be reassuring to parents.”
The research team is now gathering data from a larger group of children with autism to learn more about individual differences in their mathematical abilities. Menon emphasized that not all children with autism have superior math abilities, and that understanding the neural basis of variations in problem-solving abilities is an important topic for future research.
(Image: Corbis)
Remembering to Remember Supported by Two Distinct Brain Processes
You plan on shopping for groceries later and you tell yourself that you have to remember to take the grocery bags with you when you leave the house. Lo and behold, you reach the check-out counter and you realize you’ve forgotten the bags.
Remembering to remember — whether it’s grocery bags, appointments, or taking medications — is essential to our everyday lives. New research sheds light on two distinct brain processes that underlie this type of memory, known as prospective memory.
The research is published in Psychological Science, a journal of the Association for Psychological Science.
To investigate how prospective memory is processed in the brain, psychological scientist Mark McDaniel of Washington University in St. Louis and colleagues had participants lie in an fMRI scanner and asked them to press one of two buttons to indicate whether a word that popped up on a screen was a member of a designated category. In addition to this ongoing activity, participants were asked to try to remember to press a third button whenever a special target popped up. The task was designed to tap into participants’ prospective memory, or their ability to remember to take certain actions in response to specific future events.
When McDaniel and colleagues analyzed the fMRI data, they observed that two distinct brain activation patterns emerged when participants made the correct button press for a special target.
When the special target was not relevant to the ongoing activity — such as a syllable like “tor” — participants seemed to rely on top-down brain processes supported by the prefrontal cortex. In order to answer correctly when the special syllable flashed up on the screen, the participants had to sustain their attention and monitor for the special syllable throughout the entire task. In the grocery bag scenario, this would be like remembering to bring the grocery bags by constantly reminding yourself that you can’t forget them.
When the special target was integral to the ongoing activity—such as a whole word, like “table” — participants recruited a different set of brain regions, and they didn’t show sustained activation in these regions. The findings suggest that remembering what to do when the special target was a whole word didn’t require the same type of top-down monitoring. Instead, the target word seemed to act as an environmental cue that prompted participants to make the appropriate response – like reminding yourself to bring the grocery bags by leaving them near the front door.
“These findings suggest that people could make use of several different strategies to accomplish prospective memory tasks,” says McDaniel.
McDaniel and colleagues are continuing their research on prospective memory, examining how this phenomenon might change with age.
(Image: Shutterstock)
Imaging in mental health and improving the diagnostic process
What are some of the most troubling numbers in mental health? Six to 10 — the number of years it can take to properly diagnose a mental health condition. Dr. Elizabeth Osuch, a Researcher at Lawson Health Research Institute and a Psychiatrist at London Health Sciences Centre and the Department of Psychiatry at Western University, is helping to end misdiagnosis by looking for a ‘biomarker’ in the brain that will help diagnose and treat two commonly misdiagnosed disorders.
Major Depressive Disorder (MDD), otherwise known as Unipolar Disorder, and Bipolar Disorder (BD) are two common disorders. Currently, diagnosis is made by patient observation and verbal history. Mistakes are not uncommon, and patients can find themselves going from doctor to doctor receiving improper diagnoses and prescribed medications to little effect.
Dr. Osuch looked to identify a ‘biomarker’ in the brain which could help optimize the diagnostic process. She examined youth who were diagnosed with either MDD or BD (15 patients in each group) and imaged their brains with an MRI to see if there was a region of the brain which corresponded with the bipolarity index (BI). The BI is a diagnostic tool which encompasses varying degrees of bipolar disorder, identifying symptoms and behavior in order to place a patient on the spectrum.
What she found was the activation of the putamen correlated positively with BD. This is the region of the brain that controls motor skills, and has a strong link to reinforcement and reward. This speaks directly to the symptoms of bipolar disorder. “The identification of the putamen in our positive correlation may indicate a potential trait marker for the symptoms of mania in bipolar disorder,” states Dr. Osuch.
In order to reach this conclusion, the study approached mental health research from a different angle. “The unique aspect of this research is that, instead of dividing the patients by psychiatric diagnoses of bipolar disorder and unipolar depression, we correlated their functional brain images with a measure of bipolarity which spans across a spectrum of diagnoses.” Dr. Osuch explains, “This approach can help to uncover a ‘biomarker’ for bipolarity, independent of the current mood symptoms or mood state of the patient.”
Moving forward Dr. Osuch will repeat the study with more patients, seeking to prove that the activation of the putamen is the start of a trend in large numbers of patients. The hope is that one day there could be a definitive biological marker which could help differentiate the two disorders, leading to a faster diagnosis and optimal care.
In using a co-relative approach, a novel method in the field, Dr. Osuch uncovered results in patients that extend beyond verbal history and observation. These results may go on to change the way mental health is diagnosed, and subsequently treated, worldwide.
Researchers Debunk Myth of “Right-brain” and “Left-brain”Personality Traits
Newly released research findings from University of Utah neuroscientists assert that there is no evidence within brain imaging that indicates some people are right-brained or left-brained.
Chances are, you’ve heard the label of being a “right-brained” or “left-brained” thinker. Logical, detail-oriented and analytical? That’s left-brained behavior. Creative, thoughtful and subjective? Your brain’s right side functions stronger —or so long-held assumptions suggest.
But newly released research findings from University of Utah neuroscientists assert that there is no evidence within brain imaging that indicates some people are right-brained or left-brained.
For years in popular culture, the terms left-brained and right-brained have come to refer to personality types, with an assumption that some people use the right side of their brain more, while some use the left side more.
Following a two-year study, University of Utah researchers have debunked that myth through identifying specific networks in the left and right brain that process lateralized functions. Lateralization of brain function means that there are certain mental processes that are mainly specialized to one of the brain’s left or right hemispheres. During the course of the study, researchers analyzed resting brain scans of 1,011 people between the ages of seven and 29. In each person, they studied functional lateralization of the brain measured for thousands of brain regions —finding no relationship that individuals preferentially use their left -brain network or right- brain network more often.
“It’s absolutely true that some brain functions occur in one or the other side of the brain. Language tends to be on the left, attention more on the right. But people don’t tend to have a stronger left- or right-sided brain network. It seems to be determined more connection by connection, ” said Jeff Anderson, M.D., Ph.D., lead author of the study, which is formally titled “An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging.” It is published in the journal PLOS ONE this month.
Researchers obtained brain scans for the population they studied from a database called INDI, the International Neuroimaging Data-Sharing Initiative. The participants’ scans were taken during a functional connectivity MRI analysis, meaning a participant laid in a scanner for 5 to 10 minutes while their resting brain activity was analyzed.
By viewing brain activity, scientists can correlate brain activity in one region of the brain compared to another. In the study, researchers broke up the brain into 7,000 regions and examined which regions of the brain were more lateralized. They looked for connections — or all of the possible combinations of brain regions — and added up the number of connections for each brain region that was left- lateralized or right-lateralized. They discovered patterns in brain imaging for why a brain connection might be strongly left- or right-lateralized, said Jared Nielsen, a graduate student in neuroscience who carried out the study as part of his coursework.
“If you have a connection that is strongly left- lateralized, it relates to other strongly lateralized connection only if both sets of connections have a brain region in common,” said Nielsen.
Results of the study are groundbreaking, as they may change the way people think about the old right-brain versus left-brain theory, he said.
“Everyone should understand the personality types associated with the terminology ‘left-brained’ and ‘right-brained’ and how they relate to him or her personally; however, we just don’t see patterns where the whole left-brain network is more connected or the whole right-brain network is more connected in some people. It may be that personality types have nothing to do with one hemisphere being more active, stronger, or more connected,” said Nielsen.