Are our brains physically shaped by life experiences?

Can external life experiences – such as exposure to violence, childhood abuse or bullying – change the physical properties of our brains? What about depictions of violence in the media – such as on TV or in video games?

 

Last month, Medical News Today investigated what the adult health consequences – both psychological and physical – of childhood bullying may be. Among the adverse effects linked with a history of being bullied, our feature briefly touched on some intriguing findings concerning physiological changes linked to bullying.

These included a 2014 study into the long-term health effects of bullying that posited bullying as a kind of “toxicstress,” measurable by abnormal levels of C-reactive protein, which last into adulthood.

However, other studies have gone further – assessing the physiological impact that not only physical, but verbal bullying may have on brain development.

The notion that an experience external to the body – not something we have ingested, that has been affected by disease or damaged through physical injury – can measurably change the physical properties of an organ as intrinsic to our functioning as the brain is revelatory. But can we prove cause and effect?

Tracy Vaillancourt, a psychologist at the University of Ottawa, Canada, who has conducted a range of studies into the emotional and psychological effects of bullying – as well as the neurobiological impact of bullying – finds it frustrating the media, public and policy makers are more inclined to pay attention to research on the subject if researchers can demonstrate biological damage.

“When I show that something is biological, it makes headlines,” she told The Boston Globe. “For some reason I think humans are more compelled to believe biological evidence than someone saying, ‘Oh I’m depressed. I don’t feel good about this.’ I’m hoping that that is a policy changer.”

Bullying and the brain

In a 2008 study, Vaillancourt found that while bullied boys have higher levels of the stress hormone cortisol than their non-bullied peers, bullied girls have much lower levels of cortisol compared with their peers.

Abnormalities in the corpus callosum might explain some of the cognitive impairments associated with people who have been bullied – poor memory, attention and concentration.

She also found that bullied teens score less well on tests of verbal memory than their peers, suggesting that the abnormal cortisol levels may be killing neurons in the hippocampus, leading to memory problems.

As part of an ongoing, long-term study, Vaillancourt has been following teenagers – some of whom have a history of being bullied by their peers – and assessing their cognitive functioning every 6 months. Vaillancourt is also using magnetic resonance imaging (MRI) to scan the brains of the teens for evidence of damage to the hippocampus.

In a previous study, neuroscientist Martin Teicher scanned the brains of 63 young adults, as part of a study into verbal victimization.

Teicher found that, among the subjects who reported being the victims of verbal bullying, there were abnormalities in the corpus callosum. This region of the brain consists of a bundle of fibers connecting the brain’s left and right hemispheres and is known to be important in visual processing and memory.

The neurons in the corpus callosums of the bullied subjects were found to have less of the myelin coating that boosts communication between brain cells.

It has been suggested that these brain abnormalities might make it difficult for victims to process what is happening around them and respond appropriately.

It might also explain some of the cognitive impairments associated with being bullied – poor memory, attention and concentration – and could even contribute to the anxiety, depression and suicidal thoughts experienced by many victims.

Reduced grey matter in people maltreated as children

The impact of childhood maltreatment, more generally, on neurobiology has been explored in several studies. Previously, the results of neuroimaging studies in abused children have been considered to be inconsistent.

The researchers found that the participants who had been exposed to maltreatment exhibited significantly smaller volumes of grey matter in several brain regions.

However, in June of this year, an international study published in the American Journal of Psychiatry claimed to have strong evidence of an association between childhood maltreatment – defined by the World Health Organization (WHO) as physical or emotional ill-treatment, sexual abuse, neglect or exploitation resulting in harm to the child’s health, survival, development or dignity – and volume of cerebral grey matter.

“Childhood maltreatment acts as a severe stressor that produces a cascade of physiological and neurobiological changes that lead to enduring alterations in the brain structure,” says author Joaquim Radua.

Radua’s study used a neuroimaging technique called voxel based morphometric (VBM) to compare the brains of 56 children and 275 adults who had a history of childhood maltreatment with 56 children and 306 adults who had no history of maltreatment.

The researchers found that the participants who had been exposed to maltreatment exhibited significantly smaller volumes of grey matter in several brain regions.

“Deficits in the right orbitofrontal-temporal-limbic and left inferior frontal regions remained in a subgroup analysis of unmedicated participants, indicating that these abnormalities were not related to medication but to maltreatment,” says Radua.

In addition, abnormalities in grey matter volume in the left post-central gyrus were only found in adults who had been exposed to maltreatment as children. The most consistent grey matter abnormalities in victims of maltreatment were found in the ventrolateral prefrontal and limbic-temporal regions, which show signs of late development.

As with Teicher’s findings of myelin deficits among bullied teens, Radua’s team believes that this late development following maltreatment could explain why people with a history of child abuse sometimes exhibit cognitive impairment.

Children exposed to family violence show same brain activity as soldiers in combat

A 2011 study from researchers at University College London in the UK was the first to use functional MRI (fMRI) to investigate the neurobiological impact of physical abuse and domestic violence on children.

Startlingly, the study demonstrated that children exposed to family violence have the same patterns of brain activity as soldiers exposed to combat.

In the study, the brain scans of 20 children who had been exposed to documented violence – and had all been referred to social services – at home were compared with 23 matched peers who had not been exposed to violence in their families. The average age of the participants was 12 years old.

While in the scanner, the children were shown pictures of male and female faces exhibiting sad, calm or angry expressions – the children were not required to identify the emotion, but simply whether the face was male or female.

However, when the children were shown the angry faces, the fMRI scans registered increased activity in the anterior insula and amygdala of children that had been exposed to violence. Both of these brain regions are associated with threat detection, and previous studies of combat veterans have shown the same heightened activation in the anterior insula and amygdala.

What this suggests, said the researchers, is that both maltreated children and soldiers have adapted to be “hyper-aware” of danger in their environment.

However, both of the hyper-activated brain regions are also associated with anxiety disorders, so this might explain why abused children have an increased risk of anxiety problems in later life. As lead author Dr. Eamon McCrory explained:

“All the children studied were healthy and none were suffering from a mental health problem. What we have shown is that exposure to family violence is associated with altered brain functioning in the absence of psychiatric symptoms and that these alterations may represent an underlying neural risk factor. We suggest these changes may be adaptive for the child in the short term but may increase longer term risk.”

However, exposure to violence in the family or at school are not the only experiences that neuroscientists have suggested may influence brain development. The effects of exposure to violence on TV and in video games on brain development has been a recurring area of interest.

White matter and violence on TV

This year, a study from the Indiana University School of Medicine found that young adult men who watch more violence on TV exhibit less mature brain development and poorer executive functioning – the ability to make decisions, reason and solve problems – than peers who watch less violent TV shows.

While the amount of TV viewing overall was not found to be linked to performance on executive function tests undertaken by the study participants – 65 healthy males with normal IQs, aged 18-29 – viewing of violent TV was.

“We found that the more violent TV viewing a participant reported, the worse they performed on tasks of attention and cognitive control,” said author Tom A. Hummer, PhD.

What is more, when Hummer’s team looked at MRI scans of participants who watched a lot of violent TV, they found physiological abnormalities:

“When we looked at the brain scans of young men with higher violent television exposure, there was less volume of white matter connecting the frontal and parietal lobes, which can be a sign of less maturity in brain development.”

White matter insulates nerves that connect different brain regions. Some of these connections – such as between the frontal and parietal lobes – are believed to be important for executive functioning.

Normally, the amount of white matter in the brain increases, gradually making more connections, up until about the age of 30.

Although Hummer’s study excluded regular players of video games – to avoid confounding evidence on the relationship of white matter volume and TV violence – a 2011 study looked specifically at the influence of violent video games on the brain.

After a week without playing the shooting game, the adverse changes to the executive regions of the brain in the study subjects were shown to diminish.

In this study, 22 healthy men aged 18-29 who were not regular players of violent video games were randomized into two groups. One group was required to play a shooting game for 10 hours at home for 1 week but instructed not to play at all the second week. The second group did not play any violent video games throughout the 2-week period.

All of the participants underwent fMRI at the beginning of the study, with follow-up sessions after the first and second weeks.

The researchers reported that after 1 week of playing the shooting game, participants exhibited less activation in the left inferior frontal lobe during an “emotional interference task” and less activation in the anterior cingulate cortex during a “cognitive inhibition counting task,” compared with their results at the start of the study and the results of the control group.

“These brain regions are important for controlling emotion and aggressive behavior,” said author Dr. Yang Wang, from the Indiana University School of Medicine in Indianapolis.

However, after a week without playing the shooting game, these changes to the executive regions of the brain were shown to diminish.

Proving cause and effect is challenging

Although Dr. Wang’s study demonstrates a specific change in brain activity that occurs following exposure to violence (in video game form), in many of the other studies this spotlight feature has looked at, it is difficult to prove cause and effect.

For instance, in the violent TV study, the researchers were unable to prove whether it was because of the violent TV that study participants had lower volumes of white matter, or whether the participants responded favorably to the violent TV because they had lower volumes of white matter.

As author Tom Hummer explained, additional research is needed:

“With this study we could not isolate whether people with poor executive function are drawn to programs with more violence or if the content of the TV viewing is responsible for affecting the brain’s development over a period of time.”

“There is still much that neuroscientists need to sort out,” admitted science writer Emily Anthes, in an article on the relationship of bullying and neurobiology. “It remains difficult to thoroughly disentangle cause and effect: it’s possible, for instance, that kids with certain hormonal levels or brain characteristics are more likely, for whatever reason, to be bullied in the first place.”

This question has perhaps been more extensively investigated in animal models than in human subjects. For instance, a recent study looking at the interaction of sleep and learning found that sleeping after a learning task promoted the growth of dendritic spines – connectors that pass information between synapses – in the brains of mice.

Even more interestingly, mice that learned to run forward on a spinning rod in the learning task exhibited spines growing on different dendritic branches to another group of mice that learned to run backward on the rod.

Other studies in rats have found that, following exposure to intimidation by a larger rat, the production of neurons is damaged in the brains of bullied rats. In a 2007 paper published in The Journal of Neuroscience, the researchers reported that an unusually high percentage of neurons in the bullied rats would die before maturing.

But further research is required before scientists can say whether results such as these might apply to humans.

As complex and mysterious an organ as the human brain is, neuroscientists hope that the results of their studies will provide new targets for possible interventions in patients whose mental health problems may be related to victimization or exposure to violence, whether as children or adults.

Written by David McNamee

http://www.medicalnewstoday.com/articles/284341.php

 

 

What kinds of exercise can boost long-term memory?

Think that improving your memory is all brain training and omega-3 supplements? Think again. A new study from researchers at Georgia Institute of Technology in Atlanta suggests that working out at the gym for as little as 20 minutes can improve long-term memory.

 

Previous studies have shown that memory may be improved by several months of aerobic exercises, such as running, cycling or swimming. However, the findings of the new study – published in the journal Acta Psychologica – demonstrate that a similar memory boost can be achieved in a much shorter period.

“Our study indicates that people don’t have to dedicate large amounts of time to give their brain a boost,” says Lisa Weinberg, the Georgia Tech graduate student who led the project.

As well as looking at aerobic exercise, Weinberg’s team also examined how resistance exercise – weightlifting, push-ups and sit-ups – might affect memory.

The team recruited 46 participants (29 women and 17 men), who were randomly assigned into two groups. For the first part of the experiment, all participants viewed a series of 90 images on a computer screen.

These images were split evenly been photographs that had been classed “positive,” “neutral,” and “negative.” These ranged from pictures of children playing on a waterslide, to photographs of clocks, to images of mutilated bodies. The participants were asked to try and remember as many of them as they could.

Next, the participants were randomized into “active” and “passive” groups and seated at leg extension resistance exercise machines.

The active group were told to extend and contract each leg 50 times, at their personal maximum effort. The passive group were told to simply sit in the chair and allow the machine to move their legs.

The blood pressure and heart rate of the participants were monitored, and saliva samples were collected.

‘Active’ group showed improved recall of images

Two days later, the participants were again shown the original 90 images they had seen previously, but this time they were mixed in with 90 new photos that the participants had not seen before.

The researchers found about 50% of the original photos were recalled by the passive group, while the active group remembered about 60% of the images.

All of the participants were better at recalling the positive and negative images than the neutral images, but this was even more true for the active participants. The researchers suggest that this is because people are more likely to remember emotional experiences following short-term stress.

The team believes their results are consistent with previous research in a rodent model that found stress responses result in releases of norepinephrine – a hormone that may improve memory.

Analyzing the saliva from the participants, the team found that the active group showed increased levels of alpha amylase in their saliva – a marker of norepinephrine.

Audrey Duarte, an associate professor in the School of Psychology at Georgia Tech, describes the results:

“Even without doing expensive fMRI scans, our results give us an idea of what areas of the brain might be supporting these exercise-induced memory benefits. The findings are encouraging because they are consistent with rodent literature that pinpoints exactly the parts of the brain that play a role in stress-induced memory benefits caused by exercise.”

The Georgia Tech study looked at weight exercises, but Weinberg says that other forms of resistance exercise – such as squats or knee bends – would most likely produce similar results. She explains the study in the video below.

Previously, Medical News Today has reported on studies finding that exercise may ward off Alzheimer’s and Parkinson’s, and that caffeine may boost long-term memory.

Written by David McNamee

Copyright: Medical News Today

http://www.medicalnewstoday.com/articles/283473.php

 

An hour of after-school exercise linked to better cognitive functioning

New study finds that at least 60 minutes of physical activity after school every day is not only beneficial for children’s physical health, but it may also improve their cognitive functioning.

 

The research team, led by Prof. Charles Hillman of the University of Illinois at Urbana-Champaign, publish their findings in the journal Pediatrics.

The US Department of Health and Human Services recommend that children and adolescents aged 6-17 years engage in at least 60 minutes of physical activity a day. But last year, a survey of high school students found that only 29% had met this recommendation within the last 7 days.

Studies have shown that regular physical activity in childhood and adolescence can have numerous benefits for immediate and later-life health. It can help build healthy bones and muscles, help control weight and even improve cholesterol levels and blood pressure.

But increasingly, studies are showing the positive effects physical activity can have on children’s brain function. In a 2012 study, for example, researchers found that just 20 minutes of exercise a day may boost academic performance in children with attention-deficit hyperactivity disorder (ADHD).

And last year, Medical News Today reported on research from Kings College London in the UK, which found that regular exercise as a child may improve cognitive functioning later in life.

In this latest study, Prof. Hillman and his team found that children who took part in at least an hour of exercise after school showed improvements in attention, were better able to avoid distractions and had a greater ability to switch between cognitive tasks, compared with children who did not take part in the program.

Children enrolled to FITKids program for 9 months

The researchers enrolled 221 children aged 7-9 years to their 9-month study. Half of the children were randomly assigned to an exercise program called FITKids, while the other half were placed on a waiting list to act as controls.

Based on the CATCH program launched by the National Institutes of Health in the 1980s with the aim of boosting physical activity among school children, FITKids involved the children engaging in a minimum of 60 minutes of moderate-to-vigorous physical activity every day after school.

“Those in the exercise group received a structured intervention that was designed for the way kids like to move,” says Prof. Hillman. “They performed short bouts of exercise interspersed with rest over a 2-hour period.”

The children wore heart monitors and pedometers during exercise, and both the exercise group and control group underwent brain imaging and cognitive testing at study baseline and at the end of the study.

Exercise program ‘improved children’s attentional inhibition, cognitive flexibility’

The researchers were not surprised to find that, compared with children in the control group, those in the exercise group showed a significant increase in fitness during the study period.

However, they also found that the children in the exercise group demonstrated improvements in “attentional inhibition” – the ability to block out distractions and focus on tasks – compared with the control group. They also had better “cognitive flexibility,” meaning they could move between intellectual tasks without compromising accuracy and speed.

“Kids in the intervention group improved two-fold compared to the wait-list kids in terms of their accuracy on cognitive tasks,” adds Prof. Hillman. “And we found widespread changes in brain function, which relate to the allocation of attention during cognitive tasks and cognitive processing speed. These changes were significantly greater than those exhibited by the wait-list kids.”

The researchers note that the overall improvements in cognitive functioning seen among the exercise group were also associated with increased attendance to the program.

Commenting on their findings, the team says:

“The [FITKids] intervention enhanced cognitive performance and brain function during tasks requiring greater executive control. These findings demonstrate a causal effect of a physical activity program on executive control, and provide support for physical activity for improving childhood cognition and brain health.”

Prof. Hillman notes that improved cognitive functioning among the children in the exercise program could be down to the social interaction that such programs incorporate:

“The fact is that kids are social beings; they perform physical activity in a social environment,” he says. “A big reason why kids participate in a structured sports environment is because they find it fun and they make new friends. And this intervention was designed to meet those needs as well.”

It is not only children’s brains that may benefit from physical activity. MNT recently reported on a study claiming thataerobic exercise in older adults may protect brain function, while another study suggests yoga may boost the cognitive ability of sedentary seniors.

http://www.medicalnewstoday.com/articles/283169.php

 

 

Advanced calculations performed by neurons in human skin

Neurons in human skin perform advanced calculations, previously believed that only the brain could perform. This is according to a study from Umea University in Sweden published in the journal Nature Neuroscience.

A fundamental characteristic of neurons that extend into the skin and record touch, so-called first-order neurons in the tactile system, is that they branch in the skin so that each neuron reports touch from many highly-sensitive zones on the skin.

According to researchers at the Department of Integrative Medical Biology, IMB, Umeå University, this branching allows first-order tactile neurons not only to send signals to the brain that something has touched the skin, but also process geometric data about the object touching the skin.

“Our work has shown that two types of first-order tactile neurons that supply the sensitive skin at our fingertips not only signal information about when and how intensely an object is touched, but also information about the touched object’s shape,” says Andrew Pruszynski, who is one of the researchers behind the study.

The study also shows that the sensitivity of individual neurons to the shape of an object depends on the layout of the neuron’s highly-sensitive zones in the skin.

“Perhaps the most surprising result of our study is that these peripheral neurons, which are engaged when a fingertip examines an object, perform the same type of calculations done by neurons in the cerebral cortex. Somewhat simplified, it means that our touch experiences are already processed by neurons in the skin before they reach the brain for further processing,” says Andrew Pruszynski.

http://www.medicalnewstoday.com/releases/281921.php

 

 

Risks of long-term aspirin use ‘outweighed by cancer benefits’

Past research has linked long-term aspirin use to adverse side effects, such as internal bleeding. But according to a new study, the benefits of longstanding aspirin therapy outweigh such risks; it can significantly reduce the risk of major cancers of the digestive tract, including stomach, bowel and esophageal cancers.

 

The research team, led by Prof. Jack Cuzick, head of the Centre for Cancer Prevention at the Queen Mary University of London in the UK, recently published their findings in the journal Annals of Oncology.

Aspirin, also known as acetlylsalicylic acid (ASA), is a salicylate drug commonly used to reduce minor aches and pains, inflammation and fever. In long-term low doses, the drug is also used as an antiplatelet for patients at high risk of heart attackand stroke.

There has been much debate surrounding the benefits of long-term aspirin therapy. Previous studies have suggested it can reduce risk of ovarian cancer and improve colon cancer survival, while others claim it can cause harm, with one study suggesting it increases the risk of age-related macular degeneration.

In this latest research, Prof. Cuzick and his team set out to determine whether the health benefits of continued aspirin use outweigh the risks.

Taking daily aspirin ‘important for reducing cancer risk’

To reach their findings, the team conducted an analysis of all available evidence from an array of studies looking at the beneficial and harmful effects of aspirin use.

The researchers estimated that if individuals aged 50-65 took a daily 75-100 mg dose of aspirin for 5-10 years, the number of bowel cancer cases could be reduced by 35% and deaths by 40%, while rates of stomach and esophageal cancers could be cut by 30% and deaths by 35-50%.

Overall, they estimate that daily aspirin use for 5-10 years could provide a 9% reduction in the number of cancers, strokes and heart attacks in men, and a 7% reduction in women. Over a 20-year period, they estimate the number of deaths from all causes could be reduced by 4%. No benefits were found until individuals used aspirin for a minimum of 3 years.

But the researchers note that continued aspirin use does increase the risk of bleeding in the digestive tract. They found that individuals aged 60 who took aspirin daily for 10 years increased their risk of gastrointestinal bleeding by 1.4%, from 2.2% to 3.6%. However, they note that this is only likely to be life-threatening in around 5% of people.

“The risk of bleeding depends on a number of known factors which people need to be aware of before starting regular aspirin, and it would be advisable to consult with a doctor before embarking on daily medication,” notes Prof. Cuzick.

In addition, they found that continuing aspirin use increased the risk of peptic ulcer by 30-60%.

But despite these side effects, Prof. Cuzick believes that long-term aspirin therapy could be vital to cancer prevention:

“It has long been known that aspirin – one of the cheapest and most common drugs on the market – can protect against certain types of cancer. But until our study, where we analyzed all the available evidence, it was unclear whether the pros of taking aspirin outweighed the cons.

Whilst there are some serious side effects that can’t be ignored, taking aspirin daily looks to be the most important thing we can do to reduce cancer after stopping smoking and reducing obesity, and will probably be much easier to implement.”

The team notes that further research is warranted to better pinpoint those who are most likely to benefit from long-term aspirin use and who is at highest risk of gastrointestinal bleeding.

Earlier this year, Medical News Today reported on a consumer update from the US Food and Drug Administration (FDA), stating that while daily low-dose aspirin use can prevent heart attack or stroke for those who have already had one, there is insufficient evidence to support its use for prevention of first-time heart attack or stroke.

Written by Honor Whiteman

 

Study explains why some brain tumors are more common in men

Some brain tumors, such as glioblastomas – the most common and invasive brain tumors in humans – are more prevalent in men than women and are often more harmful, but the reasons behind this have been unclear. Now, researchers from Washington University in St. Louis, MO, may have shed some light on the issue.

In a study published in The Journal of Clinical Investigation, the researchers reveal that a protein associated with reduced cancer risk – retinoblastoma protein (RB) – is much less active in the brain cells of men than women.

Dr. Joshua Rubin and colleagues began their research by conducting a series of experiments on a cell model of glioblastoma. This involved exposing male and female brain cells to a tumor growth factor and a number of genetic alterations.

From this, the team confirmed that tumors grow faster and more frequently from male brain cells than they do from female brain cells.

To try and determine the mechanisms behind this, the researchers analyzed three genes – neurofibromin, p53 and RB – that normally lower tumor development by curbing cell division and survival. The researchers note that in many cancers, these particular genes are disabled or mutated.

Disabling RB protein increased cancer susceptibility

Dr. Rubin and colleagues found that, compared with female brain cells, the RB protein was significantly more likely to be inactivated in male brain cells.

Furthermore, they found that disabling the RB protein in female brain cells caused them to be just as susceptible to cancer than the male brain cells.

Dr. Rubin says these findings may have important implications for treating patients with brain tumors and identifying those at risk:

“This is the first time anyone ever has identified a sex-linked difference that affects tumor risk and is intrinsic to cells, and that’s very exciting.

These results suggest we need to go back and look at multiple pathways linked to cancer, checking for sex differences. Sex-based distinctions at the level of the cell may not only influence cancer risk but also the effectiveness of treatments.”

He adds that as well as brain tumors, there are other cancers – such as some liver cancers – that are more common in men than women.

“Knowing more about why cancer rates differ between males and females will help us understand basic mechanisms in cancer, seek more effective therapies and perform more informative clinical trials.”

Should clinical data be reviewed by gender?

RB is currently being evaluated as a drug target in clinical trials. Researchers are attempting to trigger the anti-tumor effects of the protein in the hope it will prolong survival of cancer patients.

But Dr. Rubin says the team’s findings should prompt the researchers of these trials – and those involved in other trials – to look at data in a different way.

“In clinical trials, we typically examine data from male and female patients together, and that could be masking positive or negative responses that are limited to one sex,” he explains. “At the very least, we should think about analyzing data for males and females separately in clinical trials.”

Last month, Medical News Today reported on a study published in Nature Communications, which claimed to reveal one reason why glioblastomas spread so rapidly. The team found that the cancer cells hijack and feed off the brain’s blood vessels, weakening the blood-brain barrier.

Written by Honor Whiteman

http://www.medicalnewstoday.com/articles/280516.php

 

Immune cell discovered that plays neuroprotective role in the brain

A type of immune cell widely believed to exacerbate chronic adult brain diseases, such as Alzheimer’s disease and multiple sclerosis (MS), can actually protect the brain from traumatic brain injury (TBI) and may slow the progression of neurodegenerative diseases, according to Cleveland Clinic research published in the online journal Nature Communications.

The research team, led by Bruce Trapp, PhD, Chair of the Department of Neurosciences at Cleveland Clinic’s Lerner Research Institute, found that microglia can help synchronize brain firing, which protects the brain from TBI and may help alleviate chronic neurological diseases. They provided the most detailed study and visual evidence of the mechanisms involved in that protection.

“Our findings suggest the innate immune system helps protect the brain after injury or during chronic disease, and this role should be further studied,” Dr. Trapp said. “We could potentially harness the protective role of microglia to improve prognosis for patients with TBI and delay the progression of Alzheimer’s disease, MS, and stroke. The methods we developed will help us further understand mechanisms of neuroprotection.”

Microglias are primary responders to the brain after injury or during illness. While researchers have long believed that activated microglia cause harmful inflammation that destroys healthy brain cells, some speculate a more protective role. Dr. Trapp’s team used an advanced technique called 3D electron microscopy to visualize the activation of microglia and subsequent events in animal models.

They found that when chemically activated, microglia migrate to inhibitory synapses, connections between brain cells that slow the firing of impulses. They dislodge the synapse (called “synaptic stripping”), thereby increasing neuronal firing and leading to a cascade of events that enhance survival of brain cells.

Trapp is internationally known for his work on mechanisms of neurodegeneration and repair in multiple sclerosis. His past research has included investigation of the cause of neurological disability in MS patients, cellular mechanisms of brain repair in neurodegenerative diseases, and the molecular biology of myelination in the central and peripheral nervous systems.

http://www.medicalnewstoday.com/releases/280008.php

 

 

Regeneration of retinal ganglion cell axons and gene therapy

Because the adult mammalian central nervous system has only limited intrinsic capacity to regenerate connections after injury, due to factors both intrinsic and extrinsic to the mature neuron, therapies are required to support the survival of injured neurons and to promote the long-distance regrowth of axons back to their original target structures.

The retina and optic nerve are part of the CNS and this system is much used in experiments designed to test new ways of promoting regeneration after injury.

Testing of therapies designed to improve RGCs viability also has direct clinical relevance because there is loss of these centrally projecting neurons in many ophthalmic diseases.

Many different approaches are being trialed, targeting different receptor systems and/or different signaling pathways, some aimed at enhancing intrinsic growth capacity in injured RGCs, others aimed at reducing the impact of factors external to the neuron that suppress/restrict the regenerative response.

An approach increasingly of interest involves the use of modified, replication-deficient viral vectors to introduce appropriate genes into injured cells in the visual pathway (gene therapy).

In the perspective article written by Prof Alan Harvey, from School of Anatomy, Physiology and Human Biology, The University of Western Australia, he summarized recent gene therapy research from his laboratory, using the rodent visual system as an experimental model, which is aimed at improving both the viability and regenerative capacity of injured adult RGCs.

These perspectives were published in Neural Regeneration Research (Vol. 9, No. 3, 2014).

http://www.medicalnewstoday.com/releases/279274.php

 

Picture courtesy of www.rndsystems.com

 

 

 

Taste metaphors emotionally engage the brain

So accustomed are we to metaphors related to taste that when we hear a kind smile described as “sweet,” or a resentful comment as “bitter,” we most likely don’t even think of those words as metaphors. But while it may seem to our ears that “sweet” by any other name means the same thing, new research shows that taste-related words actually engage the emotional centers of the brain more than literal words with the same meaning.

Researchers from Princeton University and the Free University of Berlin report in the Journal of Cognitive Neuroscience the first study to experimentally show that the brain processes these everyday metaphors differently than literal language. In the study, participants read 37 sentences that included common metaphors based on taste while the researchers recorded their brain activity. Each taste-related word was then swapped with a literal counterpart so that, for instance, “She looked at him sweetly” became “She looked at him kindly.”

The researchers found that the sentences containing words that invoked taste activated areas known to be associated with emotional processing, such as the amygdala, as well as the areas known as the gustatory cortices that allow for the physical act of tasting. Interestingly, the metaphorical and literal words only resulted in brain activity related to emotion when part of a sentence, but stimulated the gustatory cortices both in sentences and as stand-alone words.

Metaphorical sentences may spark increased brain activity in emotion-related regions because they allude to physical experiences, said co-author Adele Goldberg, a Princeton professor of linguistics in the Council of the Humanities. Human language frequently uses physical sensations or objects to refer to abstract domains such as time, understanding or emotion, Goldberg said. For instance, people liken love to a number of afflictions including being “sick” or shot through the heart with an arrow. Similarly, “sweet” has a much clearer physical component than “kind.” The new research suggests that these associations go beyond just being descriptive to engage our brains on an emotional level and potentially amplify the impact of the sentence, Goldberg said.

“You begin to realize when you look at metaphors how common they are in helping us understand abstract domains,” Goldberg said. “It could be that we are more engaged with abstract concepts when we use metaphorical language that ties into physical experiences.”

If metaphors in general elicit an emotional response from the brain that is similar to that caused by taste-related metaphors, then that could mean that figurative language presents a “rhetorical advantage” when communicating with others, explained co-author Francesca Citron, a postdoctoral researcher of psycholinguistics at the Free University’s Languages of Emotion research center.

“Figurative language may be more effective in communication and may facilitate processes such as affiliation, persuasion and support,” Citron said. “Further, as a reader or listener, one should be wary of being overly influenced by metaphorical language.”

Colloquially, metaphors seem to be employed precisely to evoke an emotional reaction, yet the actual emotional effect of figurative phrases on the person hearing them has not before been deeply explored, said Benjamin Bergen, an associate professor of cognitive science at the University of California-San Diego who studies language comprehension, and metaphorical language and thought.

“There’s a lot of research on the conceptual effects of metaphors, such as how they allow people to think about new or abstract concepts in terms of concrete things they’re familiar with. But there’s very little work on the emotional impact of metaphor,” said Bergen, who had no role in the research but is familiar with it.

“Emotional impact seems to be one of the main reasons people use metaphors to begin with. For instance, a senator might describe a bill as ‘job-killing’ to evoke an emotional reaction,” he said. “These results suggest that using certain metaphorical expressions induces more of an emotional reaction than saying the same thing literally. Those expressions that have this property are likely to have the effects on reasoning, inference, judgment and decision-making that emotion is known to have.”

The brain areas that taste-related words did not stimulate are also an important outcome of the study, Citron said. Existing research on metaphors and neural processing has shown that figurative language generally requires more brainpower than literal language, Citron and Goldberg wrote. But these bursts of neural activity have been related to higher-order processing from thinking through an unfamiliar metaphor.

The brain activity Citron and Goldberg observed did not correlate with this process. In order to create the metaphorical- and literal-sentence stimuli, they had a group of people separate from the study participants rate sentences for familiarity, apparent arousal, imageability – which is how easily a phrase can be imagined in the reader’s mind – and how positive or negative each sentence was interpreted as being. The metaphorical and literal sentences were equal on all of these factors. In addition, each metaphorical phrase and its literal counterpart were rated as being highly similar in meaning.

These steps helped to ensure that the metaphorical and literal sentences were equally as easy to comprehend. Thus, the brain activity the researchers recorded was not likely to be in response to any additional difficulty study participants had in understanding the metaphors.

“It is important to rule out possible effects of familiarity, since less familiar items may require more processing resources to be understood and elicit enhanced brain responses in several brain regions,” Citron said.

Researchers from Princeton University and the Free University of Berlin found that taste-related metaphors such as ‘sweet’ actually engage the emotional centers of the brain more than literal words such as ‘kind’ that have the same meaning. Sentences containing words that invoked taste activated areas in the lateral orbitofrontal cortex (a) and frontal operculum (b) known as the gustatory cortices that allow for the physical act of tasting. Taste-related metaphors also stimulated brain regions known to be associated with emotional processing, such as the left hippocampus, parahippocampal gyrun and amygdala (c). The colors indicate the level of activation prompted by metaphorical sentences in comparison to literal sentences with 8 signifying the greatest amount of neural activity.

Credit: Image courtesy of Adele Goldberg, Council of the Humanities

http://www.medicalnewstoday.com/releases/278824.php

 

 

 

 

 

Neuroendocrine cancer halted by chemo-radionuclide therapy

Advanced cancer of the neuroendocrine system can lead to dismal prognoses, but a novel therapy is packing a punch by uniting powerful radionuclide treatment and chemotherapydrugs, revealed researchers at the Society of Nuclear Medicine and Molecular Imaging’s 2014 Annual Meeting.

The research findings show that the experimental therapy led to stabilization or regression of patients’ cancer in about 70 percent of cases a year after completion of the treatment, now called peptide receptor chemo-radionuclide therapy (PRCRT). The therapy is just catching on across Europe and Australia and now in U.S. clinical trials.

“Results of this study suggest that PRCRT is a highly effective treatment option for patients with progressive NETs with high somatostatin receptor expression,” explained Grace Kong, MBBS, principal investigator for this study conducted at the Centre for Cancer Imaging, Peter MacCallum Cancer Centre in Melbourne, Australia.

Neuroendocrine tumors (NETs) are those that develop within a multiplicity of organs throughout the body that have nerve cells and interact with the endocrine system through chemical signaling made possible with various hormones. These tumors usually develop along the intestines and lungs, but they can also be found in the pancreas and many other sites, although rarely. For this study, researchers observed patients who had undergone at least three courses of treatment with Lutetium-177 DOTA-Octreotate, which is prescribed for inoperable patients with NETs expressing somatostatin hormone receptors. This study included a high proportion of grade two disease, which is more aggressive and associated with adverse prognosis. Researchers added a radio-sensitizing chemotherapy for 63 out of the 68 patients in the study.

All of these steps together produced encouraging responses in a majority of subjects, with 72 percent survival at two years. More than half of patients were still alive past the five-year mark after therapy.

“The high objective response and long median survival even in patients with more aggressive tumor biology warrant further studies comparing it with other targeted therapies recently approved, despite much lower response rates,” Kong added.

 

http://www.medicalnewstoday.com/releases/278056.php