Posts Tagged brain

[NEWS] New Virtual Reality Therapy game could offer relief for patients with chronic pain, mobility issues

News-MedicalA Virtual Reality Therapy game (iVRT) which could introduce relief for patients suffering from chronic pain and mobility issues has been developed by a team of UK researchers.

Dr Andrew Wilson and colleagues from Birmingham City University built the CRPS app in collaboration with clinical staff at Sandwell and West Birmingham Hospitals NHS Trust for a new way to tackle complex regional pain syndrome and to aid people living with musculoskeletal conditions.

Using a head mounted display and controllers, the team created an immersive and interactive game which mimics the processes used in traditional ‘mirror therapy’ treatment. Within the game, players are consciously and subconsciously encouraged to stretch, move and position the limbs that are affected by their conditions.

Mirror therapy is a medical exercise intervention where a mirror is used to create areflective illusion that encourages patient’s brain to move their limb more freely. This intervention is often used by occupational therapists and physiotherapists to treat CRPS patients who have experienced a stroke. This treatment has proven to be successful exercises are often deemed routine and mundane by patients, which contributes to decline in the completion of therapy.

Work around the CRPS project, which could have major implications for other patient rehabilitation programmes worldwide when fully realised, was presented at the 12th European Conference on Game Based Learning (ECGBL) in France late last year.

Dr Wilson, who leads Birmingham City University’s contribution to a European research study into how virtual reality games can encourage more physical activity, and how movement science in virtual worlds can be used for both rehabilitation and treatment adherence, explained, “The first part of the CRPS project was to examine the feasibility of being able to create a game which reflects the rehabilitation exercises that the clinical teams use on the ground to reduce pain and improve mobility in specific patients.”

“By making the game enjoyable and playable we hope family members will play too and in doing so encourage the patient to continue with their rehabilitation. Our early research has shown that in healthy volunteers both regular and casual gamers enjoyed the game which is promising in terms of our theory surrounding how we may support treatment adherence by exploiting involvement of family and friends in the therapy processes.”

The CRPS project was realized through collaborative working between City Hospital, Birmingham, and staff at the School of Computing and Digital Technology, and was developed following research around the provision of a 3D virtual reality ophthalmoscopy trainer.

Andrea Quadling, Senior Occupational Therapist at Sandwell Hospital, said “The concept of using virtual reality to treat complex pain conditions is exciting, appealing and shows a lot of potential. This software has the potential to be very helpful in offering additional treatment options for people who suffer with CRPS.”

via New Virtual Reality Therapy game could offer relief for patients with chronic pain, mobility issues

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[NEWS] Pill that reverses brain damage could be on the horizon

 

Researchers at the University of Pennsylvania have made important progress in designing a drug that could recover brain function in cases of severe brain damage due to injury or diseases such as Alzheimer’s.

brain cellsVitaly Sosnovskiy | Shutterstock

The work builds on a previous study where the team managed to convert human fetal glial cells called astrocytes into functional neurons. However, that required using a combination of nine molecules – too many for the formula to be translated into a clinically useful solution.

As reported in the journal Stem Cell Reports, the team has now successfully streamlined the process so that only four molecules are needed – an achievement that could lead to pill for repairing brain damage.

We identified the most efficient chemical formula among the hundreds of drug combinations that we tested. By using four molecules that modulate four critical signaling pathways in human astrocytes, we can efficiently turn human astrocytes — as many as 70 percent — into functional neurons.”

Jiu-Chao Yin, Study Author

The researchers report that the new neurons survived for more than seven months in the laboratory environment and that they functioned like normal brain cells, forming networks and communicating with one another using chemical and electrical signaling.

“The most significant advantage of the new approach is that a pill containing small molecules could be distributed widely in the world, even reaching rural areas without advanced hospital systems,” says Chen.

“My ultimate dream is to develop a simple drug delivery system, like a pill, that can help stroke and Alzheimer’s patients around the world to regenerate new neurons and restore their lost learning and memory capabilities,” he continued.

Now, the years of effort the team has put into simplifying the drug formula has finally paid off and taken the researchers a step closer towards realizing that dream.

via Pill that reverses brain damage could be on the horizon

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[WEB SITE] The Benefits of Playing Music Help Your Brain More Than Any Other Activity

Learning an instrument has showed an increase resilience to any age-related decline in hearing.

The brain-training is big business. For companies like BrainHQ, Luminosity, and Cogmed, it’s actually a multimillion dollar business that is expected to surpass $3 billion by 2020. But, do the actually benefit your brain?

 

Research doesn’t believe so. In fact, the the University of Illinois determined that there’s little or no evidence that these games improve anything more than the specific tasks being trained. Luminosity was even fined $2 million for false claims.

So, if these brain games don’t work, then what will keep your brain sharp? The answer? Learning to play a musical instrument.

Why Being a Musician Is Good For Your Brain

Science has shown that musical training can change brain structure and function for the better. It can also improve long-term memory and lead to better brain development for those who start at a young age.

Furthermore, musicians tend to be more mentally alert, according to new research from a University of Montreal study.

 

“The more we know about the impact of music on really basic sensory processes, the more we can apply musical training to individuals who might have slower reaction times,” said lead researcher Simon Landry.

 

“As people get older, for example, we know their reaction times get slower. So if we know that playing a musical instrument increases reaction times, then maybe playing an instrument will be helpful for them.”

 

Previously, Landry found that musicians have faster auditory, tactile, and audio-tactile reaction times. Musicians also have an altered statistical use of multi-sensory information. This means that they’re better at integrating the inputs from various senses.

 

“Music probably does something unique,” explains neuropsychologist Catherine Loveday of the University of Westminster. “It stimulates the brain in a very powerful way, because of our emotional connection with it.”

 

Unlike brain-games, playing an instrument is a rich and complex experience. This is because it’s integrating information from senses like vision, hearing, and touch, along with fine movements. This can result long-lasting changes in the brain. This can also be applicable in the business world.

Changes in the Brain

Brains scans have been able to identify the difference in brain structure between musicians and non-musicians. Most notably, the corpus callosum, a massive bundle of nerve fibres connecting the two sides of the brain, is larger in musicians. Also, the areas involving movement, hearing, and visuospatial abilities appear to be larger in professional keyboard players.

 

Initially, these studies couldn’t determine if these differences were caused by musical training of if anatomical differences predispose some to become musicians. Ultimately, longitudinal studies showed that children who do 14 months of musical training displayed more powerful structural and functional brain changes.

 

These studies prove that learning a musical instrument increases grey matter volume in various brain regions, It also strengthens the long-range connections between them. Additional research shows that musical training can enhance verbal memory, spatial reasoning, and literacy skills.

Long Lasting Benefits For Musicians

Brain scanning studies have found that the anatomical change in musicians’ brains is related to the age when training began. It shouldn’t be surprising, but learning at a younger age causes the most drastic changes.

 

Interestingly, even brief periods of musical training can have long-lasting benefits. A 2013 study found that even those with moderate musical training preserved sharp processing of speech sounds. It was also able to increase resilience to any age-related decline in hearing.

 

Researchers also believe that playing music helps speech processing and learning in children with dyslexia. Furthermore, learning to play an instrument as a child can protect the brain against dementia.

“Music reaches parts of the brain that other things can’t,” says Loveday. “It’s a strong cognitive stimulus that grows the brain in a way that nothing else does, and the evidence that musical training enhances things like working memory and language is very robust.”

Other Ways Learning an Instrument Strengthens Your Brain

Guess what? We’re still not done. Here are eight additional ways that learning an instrument strengthens your brain.

 

1. Strengthens bonds with others. This shouldn’t be surprising. Think about your favorite band. They can only make a record when they have contact, coordination, and cooperation with each other.

 

2. Strengthens memory and reading skills. The Auditory Neuroscience Laboratory at Northwestern University states that this is because music and reading are related via common neural and cognitive mechanisms.

 

3. Playing music makes you happy. McMaster University discovered that babies who took interactive music classes displayed better early communication skills. They also smiled more.

 

4. Musicians can process multiple things at once. As mentioned above, this is because playing music forces you to process multiple senses at once. This can lead superior multisensory skills.

 

5. Musical increases blood flow in your brain. Studies have found that short bursts of musical training increase the blood flow to the left hemisphere of the brain. That can be helpful when you need a burst of energy. Skip the energy drink and jam for 30 minutes.

6. Music helps the brain recover. Motor control improved in everyday activities with stroke patients.

7. Music reduces stress and depression. A study of cancer patients found that listening and playing music reduced anxiety. Another study revealed that music therapy lowered levels of depression and anxiety.

 

8. Musical training strengthens the brain’s’ executive function. Executive function covers critical tasks like processing and retaining information, controlling behavior, making, and problem-solving. If strengthened, you can boost your ability to live. Musical training can improve and strengthen executive functioning in both children and adults.

 

And, wrap-up, check out this awesome short animation from TED-Ed on how playing an instrument benefits your brain.

 

via The Benefits of Playing Music Help Your Brain More Than Any Other Activity | Inc.com

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[BLOG POST] 7 principles of neuroscience every coach and therapist should know – Your Brain Health

What does neuroscience have to do with coaching and therapy?

Short answer: EVERYTHING!

If you’re a coach or therapist, your job is to facilitate change in your client’s

  • thinking (beliefs and attitudes)
  • emotions (more mindfulness and resilience)
  • behaviour (new healthy habits).

Coaching builds the mental skills needed to support lasting change. Skills such as:

  • mindfulness
  • self-awareness
  • motivation
  • resilience
  • optimism
  • critical thinking
  • stress management

Health and wellness coaching, in particular, are emerging as powerful interventions to help people initiate and maintain sustainable change.

And we have academic research to support this claim: check out a list of RCTs in table 2 of this paper).

How can neuroscience more deeply inform coaching and therapy?

Back in the mid-1990s when I was an undergrad, the core text of my neuroscience curriculum was ‘Principles of Neural Science’ by Eric Kandel, James Schwartz and Thomas Jessell. Kandel won the 2000 Nobel Prize in Physiology or Medicine for his research on memory storage in neurons.

A few years before his Nobel, Kandel wrote a paper A new intellectual framework for psychiatry’. The paper explained how neuroscience can provide a new view of mental health and wellbeing.

Based on Kandel’s paper, researchers at the Yale School of Medicine proposed seven principles of brain-based therapy for psychiatrists, psychologists and therapists. The principles have been translated intopractical applications for health & wellness, business, and life coaches. 

One fundamental principle is,

“All mental processes, even the most complex psychological processes, derive from the operation of the brain.”

And another is:

“Insofar as psychotherapy or counseling is effective . . . it presumably does so through learning, by producing changes in gene expression that alter the strength of synaptic connections.”

That is, human interactions and experience influence how the brain works.

This concept of brain change is now well established in neuroscience and is often referred to as neuroplasticity. Ample neuroscience research supports the idea that our brains remain adaptable (or plastic) throughout our lifespan.

Here is a summary of Kandel, Cappas and colleagues thoughts on how neuroscience can be applied to therapy and coaching…

Seven principles of neuroscience every coach should know.

1. Both nature and nurture win.

Both genetics and the environment interact in the brain to shape our brains and influence behaviour.

Therapy or coaching can be thought of as a strategic and purposeful ‘environmental tool’ to facilitate change and may be an effective means of shaping neural pathways.

2.  Experiences transform the brain.

The areas of our brain associated with emotions and memories such as the pre-frontal cortex, the amygdala, and the hippocampus are not hard-wired (they are ‘plastic’).

Research suggests each of us constructs emotions from a diversity of sources: our physiological state, by our reactions to the ‘outside’ environment, experiences and learning, and our culture and upbringing.

3.  Memories are imperfect.

Our memories are never a perfect account of what happened. Memories are re-written each time when we recall them depending on how, when and where we retrieve the memory.

For example, a question, photograph or a particular scent can interact with a memory resulting in it being modified as it is recalled.

With increasing life experience we weave narratives into their memories.  Autobiographical memories that tell the story of our lives are always undergoing revision precisely because our sense of self is too.

Consciously or not, we use imagination to reinvent our past, and with it, our present and future.

4. Emotion underlies memory formation.

Memories and emotions are interconnected neural processes.

The amygdala, which plays a role in emotional arousal, mediate neurotransmitters essential for memory consolidation. Emotional arousal has the capacity to activate the amygdala, which in turn modulates the storage of memory.

 

5. Relationships are the foundation for change 

Relationships in childhood AND adulthood have the power to elicit positive change.

Sometimes it takes the love, care or attention of just one person to help another change for the better.

The therapeutic relationship has the capacity to help clients modify neural systems and enhance emotional regulation.

6. Imagining and doing are the same to the brain.

Mental imagery or visualisation not only activates the same brain regions as the actual behaviour but also can speed up the learning of a new skill.

Envisioning a different life may as successfully invoke change as the actual experience.

7. We don’t always know what our brain is ‘thinking’.

Unconscious processes exert great influence on our thoughts, feelings, and actions.

The brain can process nonverbal and unconscious information, and information processed unconsciously can still influence therapeutic and other relationships. It’s possible to react to unconscious perceptions without consciously understanding the reaction.

 

via 7 principles of neuroscience every coach and therapist should know – Your Brain Health

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[WEB SITE] Long Term Depression Permanently Changes the Brain

Long-lasting cases of depression may need to be treated differently than newer cases.

Chelsea Gohd February 27th 2018

Depression Inflammation

New research from the Centre for Addiction and Mental Health (CAMH) in Toronto has revealed something remarkable about mental illness: years of persistent depression-caused inflammation permanently and physically alter the brain. This may dramatically affect how we understand mental illness and how it progresses over time.

In a study published in The Lancet Psychiatry, researchers found that those who had untreated depression for over a decade had significantly more inflammation in their brains, when compared to those with untreated clinical depression for less than a decade. This work jumps off of senior author Jeff Meyer’s previous work, in which he found the first concrete evidence that those with clinical depression experience inflammation of the brain.

This study went even further, proving for the first time that long-term depression can cause extensive and permanent changes in the brain. Dr. Meyer thinks that this study could be used to create treatments for different stages in depression. This is important because now it is clear that treating depression immediately after diagnosis should be significantly different than treatment after 10 years with the illness.

Improving Understanding

Once a doctor and patient find a treatments for depression that works for the patient, treatment typically remains static throughout the course of the patient’s life. Taking this new study into account, this might not be the most effective method.

A PET image of a slice of human brain, showing areas of blue and red coloring. This method was used to measure depression-caused inflammation in this study.
A PET image of a slice of human brain. Image Credit: Jens Maus

This study examined a total of 25 patients who have had depression for over a decade, 25 who had the illness for less time, and 30 people without clinical depression as a control group. The researchers measured depression-caused inflammation using positron emission tomography (PET), which can pick out the protein markers, called TSPO, that the brain immune cells produce due to inflammation. Those with long-lasting depression had about 30 percent higher levels of TSPO when compared to those with shorter periods of depression, as well as higher levels than the control group.

Many misunderstand mental illness to be entirely separate from physical symptoms, but this study shows just how severe those symptoms can be. These findings could spark similar studies with other mental illnesses.

It is even possible that depression might now be treated as a degenerative disease, as it affects the brain progressively over time: “Greater inflammation in the brain is a common response with degenerative brain diseases as they progress, such as with Alzheimer’s disease and Parkinson’s disease,” Meyer said in a press release.

 

via Long Term Depression Permanently Changes the Brain

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[BLOG POST] Antidepressants help us understand why we get fatigued during exercise

In general, the term ‘fatigue’ is used to describe any exercise-induced decline in the ability of a muscle to generate force. To identify the causes of fatigue, it is common to examine two divisions of the body that might be affected during exercise. The central component of fatigue includes the many nerves that travel throughout the brain to the spinal cord. The peripheral component predominantly reflects elements in the muscle itself. If there is a problem with either of these components, the ability to contract a muscle might be compromised. For many years, there has been suggestion that central fatigue is heavily influenced by neurotransmitters that get released in the central nervous system (such as dopamine and serotonin). However, little research has been performed in this area.

Serotonin is a chemical that can improve mood, and increasing the amount of serotonin that circulates in the brain is a common therapy for depression. However, serotonin also plays a vital role in activating neurons in the spinal cord which tell the muscle to contract. With the correct amount of serotonin release, a muscle will activate efficiently. However, if too much serotonin is released, there is a possibility that the muscle will rapidly fatigue. Recent animal studies indicate that moderate amounts of serotonin release, which are common during exercise, can promote muscle contractions (Cotel et al. 2013). However, massive serotonin release, which may occur with very large bouts of exercise, could further exacerbate the already fatigued muscle (Perrier et al. 2018).

Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed antidepressants. These medications keep serotonin levels high in the central nervous system by stopping the chemical from being reabsorbed by nerves (reuptake inhibition). Instead of using SSRIs to relieve symptoms of depression, we used them in our recent study (Kavanagh et al. 2019) to elevate serotonin in the central nervous system, and then determine if characteristics of fatigue are enhanced when serotonin is elevated. We performed three experiments that used maximal voluntary contractions of the biceps muscle to cause fatigue in healthy young individuals. Our main goal was to determine if excessive serotonin limits the amount of exercise that can be performed, and then determine which central or peripheral component was compromised by excessive serotonin.

WHAT DID WE FIND?

Given that SSRIs influence neurotransmitters in the central nervous system, it was not surprising that peripheral fatigue was unaltered by the medication. However, central fatigue was influenced with enhanced serotonin. The time that a maximum voluntary contraction could be held was reduced with enhanced serotonin, whereby the ability of the central nervous system to drive the muscle was compromised by 2-5%. We further explored the location of dysfunction and found that the neurons in the spinal cord that activate the muscle were 4-18% less excitable when fatiguing contractions were performed in the presence of enhanced serotonin.

SIGNIFICANCE AND IMPLICATIONS

The central nervous system is diverse, and the fatigue that is experienced during exercise is not just restricted to the brain. Instead, the spinal cord plays an integral role in activating muscles, and mechanisms of fatigue also occur in these lower, often overlooked, neural circuits. This is the first study to provide evidence that serotonin released onto the motoneurones contributes to central fatigue in humans.

PUBLICATION REFERENCE

Kavanagh JJ, McFarland AJ, Taylor JL. Enhanced availability of serotonin increases activation of unfatigued muscle but exacerbates central fatigue during prolonged sustained contractions. J Physiol. 597:319-332, 2019.

If you cannot access the paper, please click here to request a copy.

KEY REFERENCES

Cotel F, Exley R, Cragg SJ, Perrier JF. Serotonin spillover onto the axon initial segment of motoneurons induces central fatigue by inhibiting action potential initiation. Proc Natl Acad Sci U S A. 110:4774-4779, 2013.

Perrier JF, Rasmussen HB, Jørgensen LK, Berg RW. Intense activity of the raphe spinal pathway depresses motor activity via a serotonin dependent mechanism. Front Neural Circuits. 11:111, 2018.

AUTHOR BIO

Associate Professor Justin Kavanagh is a researcher and lecturer at Griffith University. His team explores how the central nervous system controls voluntary and involuntary movement, and he has particular interests in understanding how medications can be used to study mechanisms of human movement.

via Antidepressants help us understand why we get fatigued during exercise – Motor Impairment

 

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[WEB SITE] Restoring the function of arms that have been disconnected from the brain

Advances in the control of prosthetic arms, or even exoskeletal arms, continue to amaze. Yet someone with a severe neck injury doesn’t need any such device since the greatest arm they could imagine is sitting right there hanging off their shoulder — but unable to perform. Efforts to control an artificial arm may seem impotent to these folks, when a bridge spanning just a couple centimeters of scar tissue in the spinal column can not even be made. A way forward is now taking shape at Case Western University in Ohio. Researchers there are gearing up to combine the Braingate cortical chip developed at Brown University with their own Functional Electric Stimulation (FES) platform.

It has long been known that electrical stimulation can directly control muscles. The problem is that it is fairly inaccurate, and can be painful or damaging. Stimulating the nerves directly using precisely positioned arrays is a much better approach. One group of Case Western researchers recently demonstrated a remarkable device called a nerve cuff electrode that can be placed around small segments of nerve. They used the cuff to provide an interface for sending data from sensors in the hand back to the brain using sensory nerves in the arm. With FES, the same kind of cuff electrode can also be used to stimulate nerves going the other direction, in other words, to the muscles.

Arm Muscles

The difficulty in such a scheme, is that even if the motor nerves can be physically separated from the sensory nerves and traced to specific muscles, the exact stimulation sequences needed to make a proper movement are hard to find. To achieve this, another group at Case Western has developed a detailed simulation of how different muscles work together to control the arm and hand. Their model consists of 138 muscle elements distributed over 29 muscles, which act on 11 joints. The operational procedure is for the patient to watch the image of the virtual arm while they naturally generate neural commands that the BrainGate chip picks up to move the arm. (In practice, this means trying to make the virtual arm touch a red spot to make it turn green.) Currently in clinical trials, the Braingate2 chip has an array of 96 hair-thin electrodes that is used to stimulate a small region of motor cortex.

The trick here is not just to find any sequence that gets the arm from point A to point B, but to find sequences similar to those that real arms actually use in particular tasks. This is important because each muscle has not only a limited contraction range, but also a limited range where it can actually deliver significant force, and generate feedback signals about those forces. When muscles contract they obviously change shape, but less obvious perhaps, is that their shape at any given moment affects how the other muscles leverage the joints they work. Just as important is the effect of the opposing muscles that control counter movements.

ArmSim

Few movements that we make, even low-force movements, consist of pure contractions of the active muscle and pure inhibition of the opposing muscle. In actuality, muscle units on both sides can be firing in alternating bursts to quickly ratchet joint angles open, particularly when the vector of end-point movement is oblique to the axes of individual arm segments. In other words, even in a simple movement like a bench press, both the biceps and triceps generate forces alternately at various points in the lift, despite the fact that the weight rises uniformly in the upward direction.

If artificial methods of control are going to be used for flesh-and-blood systems, particularly ones that have been idle for some time, overstimulation (or mis-stimulation) when lifting anything even slightly heavy is something to be guarded against. Many sports injuries, such as those in older people performing unfamiliar moves, happen not because they reach too far or too hard, but because their nervous system is not sufficiently practiced to be able to protect the muscle.

While no model for limb movement can be perfect, for the majority of everyday tasks, close may be good enough. The eventual plan is that the patient and the control algorithm will learn together in tandem so that the training screen will not be needed at all. At that point, we might say that Case Western will have a pretty slick interface to offer.

via Restoring the function of arms that have been disconnected from the brain – ExtremeTech

 

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[WEB SITE] Half the brain encodes both arm movements

October 8, 2018, Society for Neuroscience
Half the brain encodes both arm movements

Patients implanted with electrocorticography arrays completed a 3D center-out reaching task. Electrode locations were based upon the clinical requirements of each patient and were localized to an atlas brain for display (A). B. Patients were seated in the semi-recumbent position and completed reaching movements from the center to the corners of a 50cm physical cube based upon cues from LED lights located at each target while hand positions and ECoG signals were simultaneously recorded. Each patient was implanted with electrodes in a single cortical hemisphere and performed the task with the arm contralateral (C) and ipsilateral (D) to the electrode array in separate recording sessions. Credit: Bundy et al., JNeuros(2018)

Individual arm movements are represented by neural activity in both the left and right hemispheres of the brain, according to a study of epilepsy patients published in JNeurosci. This finding suggests the unaffected hemisphere in stroke could be harnessed to restore limb function on the same side of the body by controlling a brain-computer interface.

The right side of the brain is understood to control the left side of the body, and vice versa. Recent evidence, however, supports a connection between the same side of the brain and body during .

Eric Leuthardt, David Bundy, and colleagues explored brain activity during such ipsilateral movements during a reaching task in four  whose condition enabled invasive monitoring of their brains through implanted electrodes. Using a machine learning algorithm, the researchers demonstrate successful decoding of speed, velocity, and position information of both left and right arm movements regardless of the location of the electrodes.

In addition to advancing our understanding of how the brain controls the body, these results could inform the development of more effective rehabilitation strategies following brain injury.

Half the brain encodes both arm movements

In the study a patient implanted with electrodes only on the left side of the brain was asked to make movements to 8 targets in 3D space with both their right and left arms. Using recordings from these electrodes, the authors were able to predict the hand speed, direction, and position for both arms showing that movements of both arms are encoded on one side of the brain. Credit: David Bundy and Eric Leuthardt

 Explore further: New research on the brain’s backup motor systems could open door to novel stroke therapies

More information: Unilateral, Three-dimensional Arm Movement Kinematics are Encoded in Ipsilateral Human Cortex, JNeurosci (2018). DOI: 10.1523/JNEUROSCI.0015-18.2018

via Half the brain encodes both arm movements

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[WEB SITE] Neuroscientists unravel how two different types of brain plasticity work on synapses

 

The brain’s crucial function is to allow organisms to learn and adapt to their surroundings. It does this by literally changing the connections, or synapses, between neurons, strengthening meaningful patterns of neural activity in order to store information. The existence of this process – brain plasticity – has been known for some time.

But actually, there are two different types of brain plasticity at work on synapses. One is “Hebbian plasticity”; it is the one which effectively allows for the recording of information in the synapses, named after pioneering neuroscientist Donald Hebb. The other, more recently discovered, is “homeostatic synaptic plasticity” (HSP), and, like other “homeostatic” processes in the body such as maintaining a constant body temperature, its purpose is to keep things stable. In this case, HSP ensures that the brain doesn’t build up too much activity (as is the case in epilepsy) or become too quiet (as can happen when you lose synapses in Alzheimer’s Disease).

However, little is known about how these two types of plasticity actually interact in the brain. Now, a team of neuroscientists at the Champalimaud Centre for the Unknown, in Lisbon, Portugal, has begun to unravel the fundamental processes that happen in the synapse when the two mechanisms overlap. Their results were published in the journal iScience.

“In theory, the two types of plasticity act as opposing forces”, says Anna Hobbiss, first author of the new study, which was led by Inbal Israely. “Hebbian plasticity reacts to activity at the synapses by inciting them to get stronger while HSP reacts to it by making them weaker. We wanted to understand, on a cellular and molecular level, how the synapse deals with these two forces when they are present at the same time.”

In so doing, the authors have surprisingly shown that, contrary to what might be expected, HSP facilitates Hebbian plasticity, and thus influences memory formation and learning. This means that these two types of plasticity “may actually not be such distinct processes, but instead work together at the same synapses”, says Israely.

The team’s goal was to determine the changes in size of minute structures called dendritic spines, which are the “receiving end” of the synapse. The size of these spines changes to reflect the strength of the synaptic connection.

For this, they studied cells from the mouse hippocampus, a part of the brain which is crucial for learning. In their experiments, they blocked activity in the cells by introducing a potent neurotoxin called tetrodotoxin, thus simulating the loss of input to a certain part of the brain (“think about a person suddenly becoming blind, which leads to loss of input from the eyes to the brain”, says Hobbiss).

Forty eight hours later, they mimicked a small recovery of activity at only one synapse by releasing a few molecules of a neurotransmitter called glutamate on single spines of single neurons. This was possible thanks to a very high resolution, state-of-the-art laser technology, called two-photon microscopy, which allowed the scientists to very precisely visualize and target individual dendritic spines.

As this process evolved, the team closely watched what was happening to the spines – and they saw various anatomical changes. First, the silencing of all neural activity made the spines grow in size. “The spines are like little microphones, which, when there is silence, ramp up the ‘volume’ to try and catch even the faintest noise”, Hobbiss explains.

The scientists then activated individual spines with pulses of glutamate and watched them for two hours. One of the things they thought could happen was that the size of the spines would not grow further, since they had already turned up their ‘volume’ as far is it would go. But the opposite happened: the spines grew even more, with the smaller spines showing the biggest growth.

Finally, the authors also saw growth in neighboring spines, even though the experiment only targeted one spine. “We found that after a lack of activity, other spines in the vicinity also grew, further enhancing the cell’s sensitivity to restored neural transmission”, says Hobbiss. “The cells become more sensitive, more susceptible to encode information. It is as though the ‘gain’ has been turned up”, she adds.

“The fact that neighboring spines grew together with an active spine signifies that homeostatic plasticity changes one of the hallmark features of information storage, which is that plasticity is limited to the site of information entry”, Israely explains. “So, in this sense, the different plasticity mechanisms which are at work in the neuron can cooperate to change which and how many inputs respond to a stimulus. I think this is an exciting finding of our study.”

Taken together, these results show that homeostatic plasticity can actually rev up Hebbian plasticity, the type required for storing information. “Our work adds a piece to the puzzle of how the brain performs one of its fundamental tasks: being able to encode information while still keeping a stable level of activity”, concludes Hobbiss.

The misregulation of homeostatic plasticity – the stabilizing one – has started to be implicated in human health, specifically neurodevelopmental disorders such as Fragile X syndrome and Rett syndrome as well as neurodegenerative ones such as Alzheimer’s Disease. “Perhaps this balance is what allows us to be able to learn new information while retaining stability of that knowledge over a lifetime”, says Israely.

 

via Neuroscientists unravel how two different types of brain plasticity work on synapses

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[Factsheet] Understanding TBI: Part 2 – Brain injury impact on individuals functioning – Model Systems Knowledge Translation Center (MSKTC)

Father teaching child with blocks

Written by Thomas Novack, PhD and Tamara Bushnik, PhD in collaboration with the MSKTC

 

A traumatic brain injury interferes with the way the brain normally works. When nerve cells in the brain are damaged, they can no longer send information to each other in the normal way. This causes changes in the person’s behavior and abilities. The injury may cause different problems, depending upon which parts of the brain were damaged most.

There are three general types of problems that can happen after TBI: physical, cognitive and emotional/ behavioral problems. It is impossible to tell early on which specific problems a person will have after a TBI. Problems typically improve as the person recovers, but this may take weeks or months. With some severe injuries changes can take many years.

Structure and function of the brain

The brain is the control center for all human activity, including vital processes (breathing and moving) as well as thinking, judgment, and emotional reactions. Understanding how different parts of the brain work helps us understand how injury affects a person’s abilities and behaviors.

Left vs. Right Brain

  • The brain is divided into two halves (hemispheres). The left half controls movement and sensation in the right side of the body, and the right half controls movement and sensation in the left side. Thus, damage to the right side of the brain may cause movement problems or weakness on the body’s left side.
  • For most people, the left half of the brain is responsible for verbal and logical functions including language (listening, reading, speaking, and writing), thought and memory involving words.
  • The right half is responsible for nonverbal and intuitive functions such as putting bits of information together to make up an entire picture, recognizing oral and visual patterns and designs (music and art), and expressing and understanding emotions.

Brain Areas & Associated Functions

The brain is made up of six parts that can be injured in a head injury. The effect of a brain injury is partially determined by the location of the injury. Sometimes only a single area is affected, but in most cases of TBI multiple areas have been injured. When all areas of the brain are affected, the injury can be very severe.

Image of Brain with Lobe Information

Six parts Functions
Brain Stem
  • Breathing
  • Heart Rate
  • Swallowing
  • Reflexes for seeing and hearing
  • Controls sweating, blood pressure, digestion, temperature
  • Affects level of alertness
  • Ability to sleep
  • Sense of balance
Cerebellum
  • Coordination of voluntary movement
  • Balance and equilibrium
  • Some memory for reflex motor acts
Frontal Lobe
  • How we know what we are doing within our environment
  • How we initiate activity in response to our environment
  • Judgments we make about what occurs in our daily activities
  • Controls our emotional response
  • Controls our expressive language
  • Assigns meaning to the words we choose
  • Involves word associations
  • Memory for habits and motor activities
  • Flexibility of thought, planning and organizing
  • Understanding abstract concepts
  • Reasoning and problem solving
Parietal Lobe
  • Visual attention
  • Touch perception
  • Goal directed voluntary movements
  • Manipulation of objects
  • Integration of different senses
Occipital Lobes
  • Vision
Temporal Lobes
  • Hearing ability
  • Memory aquisition
  • Some visual perceptions such as face recognition and object identification
  • Categorization of objects
  • Understanding or processing verbal information
  • Emotion

Physical Problems

Most people with TBI are able to walk and use their hands within 6-12 months after injury. In most cases, the physical difficulties do not prevent a return to independent living, including work and driving.

In the long term the TBI may reduce coordination or produce weakness and problems with balance. For example, a person with TBI may have difficulty playing sports as well as they did before the injury. They also may not be able to maintain activity for very long due to fatigue.

Cognitive (Thinking) Problems

  • Individuals with a moderate-to-severe brain injury often have problems in basic cognitive (thinking) skills such as paying attention, concentrating, and remembering new information and events.
  • They may think slowly, speak slowly and solve problems slowly.
  • They may become confused easily when normal routines are changed or when things become too noisy or hectic around them.
  • They may stick to a task too long, being unable to switch to different task when having difficulties.
  • On the other hand, they may jump at the first solution they see without thinking it through.
  • They may have speech and language problems, such as trouble finding the right word or understanding others.
  • After brain injury, a person may have trouble with all the complex cognitive activities necessary to be independent and competent in our complex world. The brain processes large amounts of complex information all the time that allows us to function independently in our daily lives. This activity is called executive function because it means being the executive or being in charge of one’s own life.

Emotional/Behavioral Problems

Behavioral and emotional difficulties are common and can be the result of several causes:

  • First, the changes can come directly from damage to brain tissue. This is especially true for injuries to the frontal lobe, which controls emotion and behavior.
  • Second, cognitive problems may lead to emotional changes or make them worse. For example, a person who cannot pay attention well enough to follow a conversation may become very frustrated and upset in those situations.
  • Third, it is understandable for people with TBI to have strong emotional reactions to the major life changes that are caused by the injury. For example, loss of job and income, changes in family roles, and needing supervision for the first time in one’s adult life can cause frustration and depression.

Brain injury can bring on disturbing new behaviors or change a person’s personality. This is very distressing to both the person with the TBI and the family. These behaviors may include:

  • Restlessness
  • Acting more dependent on others
  • Emotional or mood swings
  • Lack of motivation
  • Irritability
  • Aggression
  • Lethargy
  • Acting inappropriately in different situations
  • Lack of self-awareness. Injured individuals may be unaware that they have changed or have problems. This can be due to the brain damage itself or to a denial of what’s really going on in order to avoid fully facing the seriousness of their condition.

Fortunately, with rehabilitation training, therapy and other supports, the person can learn to manage these emotional and behavioral problems.

Disclaimer

This information is not meant to replace the advice from a medical professional. You should consult your health care provider regarding specific medical concerns or treatment.

Source

Our health information content is based on research evidence whenever available and represents the consensus of expert opinion of the TBI Model Systems directors.

Our health information content is based on research evidence and/or professional consensus and has been reviewed and approved by an editorial team of experts from the TBI Model Systems.

Authorship

Understanding TBI was developed by Thomas Novack, PhD and Tamara Bushnik, PhD in collaboration with the Model System Knowledge Translation Center. Portions of this document were adapted from materials developed by the University of Alabama TBIMS, Baylor Institute for Rehabilitation, New York TBIMS, Mayo Clinic TBIMS, Moss TBIMS, and from Picking up the pieces after TBI: A guide for Family Members, by Angelle M. Sander, PhD, Baylor College of Medicine (2002).

via Understanding TBI: Part 2 – Brain injury impact on individuals functioning | Model Systems Knowledge Translation Center (MSKTC)

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