Category: Neurology

Categories : NeurologyTags :

Visual Cortex Stimulation Boosts Brain-computer Interface

On By ModernMedia
Deep brain stimulation illustration. Credit: NIH

Brain-computer interfaces, or BCIs, promise life-changing benefits for people suffering from a range of neurological conditions, but implementation is for both the invasive and noninvasive methods is challenging. Researchers led by Bin He at Carnegie Mellon University used an innovative electroencephalogram (EEG) wearable. They successfully integrated a novel focused ultrasound stimulation to realise bidirectional BCI that both encodes and decodes brain waves using machine learning in a study with 25 human subjects.

This work, published in Nature Communications, opens up a new avenue to significantly enhance not only the signal quality, but also, overall nonivasive BCI performance by stimulating targeted neural circuits.

Noninvasive BCI is lauded for its merits of being cheap, safe, and virtually applicable to everyone, but because signals are recorded over the scalp versus inside the brain, low signal quality presents some limitations. The He group is exploring ways to improve the effectiveness of noninvasive BCIs and, over time, has used deep learning approaches to decode what an individual was thinking and then facilitate control of a cursor or robotic arm.

In their latest research, the He group demonstrated that through precision noninvasive neuromodulation using focused ultrasound, the performance of a BCI could be improved for communication.

“This paper reports a breakthrough in noninvasive BCIs by integrating a novel focused ultrasound stimulation to realise bidirectional BCI functionality,” explained Bin He, professor of biomedical engineering at Carnegie Mellon University. “Using a communication prosthetic, 25 human subjects spelled out phrases like ‘Carnegie Mellon’ using a BCI speller. Our findings showed that the addition of focused ultrasound neuromodulation significantly boosted the performance of EEG-based BCI. It also elevated theta neural oscillation that enhanced attention and led to enhanced BCI performance.”

For context, a BCI speller is a 6×6 visual motion aide containing the entire alphabet that is commonly used by nonspeakers to communicate. In He’s study, subjects donned an EEG cap and just by looking at the letters, were able to generate EEG signals to spell the desired words. When a focused ultrasound beam was applied externally to the V5 area (part of the visual cortex) of the brain, the performance of the noninvasive BCI greatly improved among subjects. The neuromodulation-integrated BCI actively altered the engagement of neural circuits to maximize the BCI performance, compared to previous uses, which consisted of pure processing and decoding recorded signals.

Following this discovery, the He lab is further investigating the merits and applications of focused ultrasound neuromodulation to the brain, beyond the visual system, to enhance noninvasive BCIs. They also aim to develop more compact-focused ultrasound neuromodulation device for better integration with EEG-based BCIs, and to integrate AI to continue to enhance the overall system performance.

“This is my lifelong interest, and I will never give up,” emphasized He. “Working to improve noninvasive technology is difficult, but I strongly believe that if we can find a way to make it work, everyone will benefit. I will keep working, and someday, noninvasive lifesaving technology will be available for every household.

Source: College of Engineering, Carnegie Mellon University

Categories : Injury & Trauma NeurologyTags :

Scarring after Spinal Cord Injury is More Complex than Previously Thought

On By ModernMedia
Fibrotic scar 14d after spinal cord injury, red – Col1a1+ perivascular fibroblast derived cells Photo: Daniel Holl

New research has found that scar formation after spinal cord injuries is more complex than previously thought. Scientists at Karolinska Institutet have identified two types of perivascular cells as key contributors to scar tissue, which hinders nerve regeneration and functional recovery. These findings, published in Natural Neuroscience, are also relevant for other brain and spinal cord injuries and could lead to targeted therapies for reducing scarring and improving outcomes.

The central nervous system (CNS) has very limited healing abilities. Injuries or autoimmune diseases like multiple sclerosis often lead to permanent functional deficits. 

Regardless of the injury’s cause, the body responds by forming a boundary around the damaged tissue, which eventually becomes permanent scar tissue. 

Two contributing cell types

While scar tissue seals the damaged area, it also prevents functional repair. After spinal cord injuries, scar tissue blocks the regeneration of nerve fibers that connect the brain with the body, resulting in paralysis after severe injuries.

The research team led by Christian Göritz at Karolinska Institutet has made significant progress in understanding how scar tissue forms in the CNS. The group now identified two distinct types of perivascular cells, which line different parts of blood vessels, as the major contributors to fibrotic scar tissue after spinal cord injury. Depending on the lesion’s location, the two identified cell types contribute differently.

“We found that damage to the spinal cord activates perivascular cells close to the damaged area and induces the generation of myofibroblasts, which consequently form persistent scar tissue,” explains first author Daniel Holl, researcher at the Department of Cell and Molecular Biology.

By examining the process of scar formation in detail, the researchers hope to identify specific therapeutic targets to control fibrotic scarring.

Categories : NeurologyTags :

Brain’s Structure Hangs in ‘a Delicate Balance’

On By ModernMedia
Photo by Fakurian Design on Unsplash

When a magnet is heated up, it reaches a critical point where it becomes demagnetisated. Called “criticality,” this point of high complexity is reached when a physical object is transitioning smoothly from one phase into the next.

Now, a new Northwestern University study has discovered that the brain’s structural features reside in the vicinity of a similar critical point – either at or close to a structural phase transition. Surprisingly, these results are consistent across brains from humans, mice and fruit flies, which suggests the finding might be universal. Although the researchers don’t know what phases the brain’s structure is transitioning between, they say this new information could enable new designs for computational models of the brain’s complexity and emergent phenomena.

The research was published in Communications Physics.

“The human brain is one of the most complex systems known, and many properties of the details governing its structure are not yet understood,” said Northwestern’s István Kovács, the study’s senior author. “Several other researchers have studied brain criticality in terms of neuron dynamics. But we are looking at criticality at the structural level in order to ultimately understand how this underpins the complexity of brain dynamics. That has been a missing piece for how we think about the brain’s complexity. Unlike in a computer where any software can run on the same hardware, in the brain the dynamics and the hardware are strongly related.”

“The structure of the brain at the cellular level appears to be near a phase transition,” said Northwestern’s Helen Ansell, the paper’s first author. “An everyday example of this is when ice melts into water. It’s still water molecules, but they are undergoing a transition from solid to liquid. We certainly are not saying that the brain is near melting. In fact, we don’t have a way of knowing what two phases the brain could be transitioning between. Because if it were on either side of the critical point, it wouldn’t be a brain.”

While researchers have long studied brain dynamics using functional magnetic resonance imaging (fMRI) and electroencephalograms (EEG), advances in neuroscience have only recently provided massive datasets for the brain’s cellular structure. These data opened possibilities for Kovács and his team to apply statistical physics techniques to measure the physical structure of neurons.

For the new study, Kovács and Ansell analysed publicly available data from 3D brain reconstructions from humans, fruit flies and mice. By examining the brain at nanoscale resolution, the researchers found the samples showcased hallmarks of physical properties associated with criticality.

One such property is the well-known, fractal-like structure of neurons. This nontrivial fractal-dimension is an example of a set of observables, called “critical exponents,” that emerge when a system is close to a phase transition.

Brain cells are arranged in a fractal-like statistical pattern at different scales. When zoomed in, the fractal shapes are “self-similar,” meaning that smaller parts of the sample resemble the whole sample. The sizes of various neuron segments observed also are diverse, which provides another clue. According to Kovács, self-similarity, long-range correlations and broad size distributions are all signatures of a critical state, where features are neither too organised nor too random. These observations lead to a set of critical exponents that characterise these structural features.

“These are things we see in all critical systems in physics,” Kovács said. “It seems the brain is in a delicate balance between two phases.”

Kovács and Ansell were amazed to find that all brain samples studied – from humans, mice and fruit flies – have consistent critical exponents across organisms, meaning they share the same quantitative features of criticality. The underlying, compatible structures among organisms hint that a universal governing principle might be at play. Their new findings potentially could help explain why brains from different creatures share some of the same fundamental principles.

“Initially, these structures look quite different – a whole fly brain is roughly the size of a small human neuron,” Ansell said. “But then we found emerging properties that are surprisingly similar.”

“Among the many characteristics that are very different across organisms, we relied on the suggestions of statistical physics to check which measures are potentially universal, such as critical exponents. Indeed, those are consistent across organisms,” Kovács said. “As an even deeper sign of criticality, the obtained critical exponents are not independent – from any three, we can calculate the rest, as dictated by statistical physics. This finding opens the way to formulating simple physical models to capture statistical patterns of the brain structure. Such models are useful inputs for dynamical brain models and can be inspirational for artificial neural network architectures.”

Next, the researchers plan to apply their techniques to emerging new datasets, including larger sections of the brain and more organisms. They aim to find if the universality will still apply.

Source:: Northwestern University

Categories : NeurologyTags :

Fruit Fly Study Shows Role of Age and Sex-related Head Injury Outcomes in Females

On By ModernMedia
Photo by Fakurian Design on Unsplash

A new study has discovered that even very mild, non-lethal head injuries early in life can lead to neurodegenerative conditions later in life upon ageing. Using fruit flies as a model, the researchers found that chronic immune suppression after mating might make female fruit flies susceptible to delayed brain deterioration following early-life head injuries, which may lead to insights for humans.

The study, published as a Reviewed Preprint in eLife, is described by the editors as fundamental work that advances our understanding of how sex-dependent responses to traumatic brain injury occurs. The work, by a team at Emory University provides what they call compelling results showing the immune and reproductive pathways that may contribute to these differences.

Environmental insults, including mild head trauma, significantly increase the risk of neurodegeneration later in life. However, identifying a causative connection between early-life exposure to mild head trauma and late-life emergence of neurodegeneration is challenging, and it remains unclear as to how sex and age compound the outcomes.

“With their short lives, fruit flies allow scientists to track brain-injury-related changes across their entire lifespan,” says lead author Changtian Ye, a graduate student in the Emory Neuroscience Program, and a member of senior author James Zheng’s lab, at the Emory University School of Medicine. “We recently developed a fruit fly model of mild traumatic brain injury that allows us to deliver mild headfirst impacts and then track what happens in male and female flies from the moment of injury to the occurrence of brain impairments later in life.”

Using their model, Ye and colleagues monitored the impact of mild traumatic brain injury on the flies’ behaviour. Whilst injury initially caused minimal acute deficits in the flies, it led to more profound brain-associated behavioural deficits and degeneration later in life, and these conditions worsened with age. Additionally, they were disproportionately elevated in females, affecting their climbing speed and ability, and leading them to have more damaged brain tissue than their male counterparts.

The researchers also found that female flies that had mated had worse outcomes than unmated (virgin) flies. They identified a protein called ‘sex peptide’ – which is transferred to the female reproductive tract through semen during mating – as a key player in making these flies more susceptible to the harmful effects of brain injury.

“Our analysis of the flies’ RNA data suggested that the chronic suppression of innate immune defence networks in mated females exposed to sex peptide makes them disproportionately vulnerable to neurodegeneration after mild head trauma,” Ye explains.

Together, the findings support the idea that a head injury can pose a major threat for brain health, even if it is mild, and that females can be disproportionately affected. The authors say that additional studies are now needed to determine if similar processes occur in other species.

“Our work establishes a causal relationship between early head trauma and late-life neurodegeneration, emphasising sex differences in injury response and the impact of age during and after injury,” concludes senior author James Zheng, Principle Investigator at the Zheng Lab, Emory University School of Medicine. “It will be interesting to understand if this relationship occurs in other organisms, and to dissect the genetic components and molecular players involved in the sex-different development of neurodegenerative conditions following mild head trauma.”

Source: eLife

Categories : Mental Health NeurologyTags :

Researchers Offer New Understanding of Antidepressant Mechanism

On By ModernMedia

Evidence suggests serotonin-boosting actions relieve depression by restoring normal communication and connections in the brain

Photo by Sydney Sims on Unsplash

Researchers at the University of Colorado Anschutz Medical Campus have established a new framework for understanding how classic antidepressants work in treating major depressive disorder (MDD), reemphasising their importance and aiming to reframe clinical conversation around their role in treatment.

The nature of the dysfunction at the root of MDD has been under investigation for decades. Classic antidepressants, such as SSRIs (selective serotonin reuptake inhibitors, such as fluoxetine) cause an elevation in serotonin levels, a key neurotransmitter. This observation led to the idea that antidepressants work because they restore a chemical imbalance, such as a lack of serotonin.

But subsequent years of research showed no significant decrease in serotonin in people with depression. While experts have moved away from this hypothesis due to lack of concrete evidence, this has led to a shift in public opinion on the effectiveness of these medications.

Antidepressants, such as SSRIs and serotonin and norepinephrine reuptake inhibitors (SNRIs), are still effective in alleviating depressive episodes in many patients, however. In a paper published in Molecular Psychiatry, researchers outline a new framework for understanding how antidepressants are efficacious in treating MDD. This framework helps clarify how antidepressants like SSRIs can still be helpful, even if MDD isn’t caused by a lack of serotonin.

Evidence points to a communication problem

“The best evidence of changes in the brain in people suffering from MDD is that some brain regions are not communicating with each other normally,” said Scott Thompson, PhD, professor in the Department of Psychiatry and senior author. “When the parts of the brain responsible for reward, happiness, mood, self-esteem, even problem-solving in some cases, are not communicating with each other properly, then they can’t do their jobs properly,” Thompson said.

“There is good evidence that antidepressants that increase serotonin, like SSRIs, all work by restoring the strength of the connections between these regions of the brain. So do novel therapeutics such as esketamine and psychedelics. This form of neuroplasticity helps release brain circuits from being ‘stuck’ in a pathological state, ultimately leading to a restoration of healthy brain function,” Thompson said.  

Thompson and colleagues liken this theory to a car running off the road and getting stuck in a ditch, requiring the help of a tow truck to pull the car out of its stuck state, allowing it to move freely down the road again. Researchers are hoping healthcare providers will use their examples to bolster conversations with apprehensive patients about these treatments, helping them better understand their condition and how to treat it.

Study aims to reshape the conversation

“We are hoping this framework provides clinicians new ways to communicate the way these treatments work in combating MDD,” said C. Neill Epperson, MD, co-author of the paper and professor of the Department of Psychiatry at the CU School of Medicine.

“Much of the public conversation around the effectiveness of antidepressants, and the role serotonin plays in diagnosis and treatment, has been negative and largely dangerous,” Epperson said. “While MDD is a heterogenous disorder with no one-fits-all solution, it is important to emphasise that if treatments or medications are working for you, then they are lifesaving. Understanding how these medications promote neuroplasticity can help strengthen that message.”

Source: CU Anschutz Medical Campus

Categories : Neurology PaediatricsTags :

Poor Sleep, Social Media Use and Adolescents’ Developing Brains

On By ModernMedia
Photo by Steinar Engeland on Unsplash

A new study to be presented at the SLEEP 2024 annual meeting found a distinct relationship between sleep duration, social media usage, and brain activation across brain regions that are key for executive control and reward processing.

Results show a correlation between shorter sleep duration and greater social media usage in teens. The analysis points to involvement of areas within the frontolimbic brain regions, such as the inferior and middle frontal gyri, in these relationships. The inferior frontal gyrus, key in inhibitory control, may play a crucial role in how adolescents regulate their engagement with rewarding stimuli such as social media. The middle frontal gyrus, involved in executive functions and critical in assessing and responding to rewards, is essential in managing decisions related to the balancing of immediate rewards from social media with other priorities like sleep. These results suggest a nuanced interaction between specific brain regions during adolescence and their influence on behaviour and sleep in the context of digital media usage.

“As these young brains undergo significant changes, our findings suggest that poor sleep and high social media engagement could potentially alter neural reward sensitivity,” said Orsolya Kiss, who has a doctorate in cognitive psychology and is a research scientist at SRI International. “This intricate interplay shows that both digital engagement and sleep quality significantly influence brain activity, with clear implications for adolescent brain development.”

This study involved data from 6516 adolescents, aged 10–14 years, from the Adolescent Brain Cognitive Development Study. Participants answered questionnaires about sleep duration and recreational social media use. Brain activities were analysed from functional MRI scans during the monetary incentive delay task, targeting regions associated with reward processing. The study used three different sets of models and switched predictors and outcomes each time. Results were adjusted for age, COVID-19 pandemic timing, and socio-demographic characteristics.

Kiss noted that these results provide new insights into how two significant aspects of modern adolescent life, social media usage and sleep duration, interact and impact brain development.

“Understanding the specific brain regions involved in these interactions helps us identify potential risks and benefits associated with digital engagement and sleep habits,” Kiss said. “This knowledge is especially important as it could guide the development of more precise, evidence-based interventions aimed at promoting healthier habits.”

The American Academy of Sleep Medicine recommends that teenagers 13 to 18 years of age should sleep 8 to 10 hours on a regular basis. The AASM also encourages adolescents to disconnect from all electronic devices at least 30 minutes to an hour before bedtime.

Source: American Academy of Sleep Medicine

Categories : NeurologyTags :

Is Your Coffee ‘Not Hot’ or Cold’? Observing How the Brain Processes Negated Adjectives

On By ModernMedia
Image: Pixabay CC0

Negating an adjective by placing ‘not’ in front of it affects the way our brains interpret its meaning, mitigating but not entirely inverting our interpretation of its definition. In a study published May 30th in the open-access journal PLOS Biology, Arianna Zuanazzi at New York University, US, and colleagues offer insight into how the brain represents changes of meaning over time and offer new methods for further linguistic research.

The way the brain processes negated adjectives – ‘not bad’ or ‘not good’ – is not understood. Previous studies suggest that negated phrases are processed more slowly and with more errors than their affirmative counterparts. Cutting-edge artificial neural networks appear to be largely insensitive to the contextual impacts of negation, leading many researchers to wonder how negation operates.

In lab-based experiments, 78 participants were asked to read affirmative or negated adjective phrases, good/bad, not good/not bad, happy/sad, not happy/not sad etc. on a screen and rate their meaning on a scale of one (really really bad/really really sad) to ten (really really good/really really happy). Answers took longer for negated adjectives and interpreted meaning was more varied. Cursor tracking showed that people are slower to interpret them, first understanding them to be affirmative before modifying towards their opposite meaning.

In a second experiment, participants rated affirmative or negated phrases on a scale. Meanwhile, magnetic fields generated by the electrical activity of their brains were captured by magnetoencephalography (MEG). Zuanazzi and colleagues again saw slower reaction times for negated adjectives. The brain activity shows that initial interpretations and early neural representations of negated adjectives are similar to that of affirmative adjectives, but are weakened, backing up the previous suggestion of a mitigated effect.

The analysis contributes to the debate as to how negation operates. The ability to characterize the subtle changes of linguistic meaning through negation in the brain using imaging methods could help to tease apart understanding of other linguistic processes beyond the sum of the processing of individual word meanings.

The authors add, “The study of negation offers a compelling linguistic framework to understand how the human brain builds meaning through combinatoric processes. Our time-resolved behavioural and neurophysiological data show that, in a sentence like ‘your coffee is not hot’, negation (‘not’) mitigates rather than inverts the representations of a scalar adjective (‘hot’). In other words, negation reduces the temperature of your coffee, though it does not make it cold.”

Provided by PLOS

Categories : NeurologyTags :

Brain Damage Reveals Part of the Brain Necessary for Helping Others

On By ModernMedia
Photo by Pexels on Pixabay

Our willingness to help others is governed by a specific brain region pinpointed by researchers in a study of patients with brain damage to that region.

Learning about where in the brain ‘helping’ decisions are made is important for understanding how people might be motivated to tackle large global challenges, such as climate change, infectious disease and international conflict. It is also essential for finding new approaches to treating disorders of social interactions.

The study, published in Nature Human Behaviour, was carried out by researchers at the University of Birmingham and the University of Oxford, and shows for the first time how a region called the ventromedial prefrontal cortex (vmPFC) has a critical role in helping, or ‘prosocial’ behaviours.

Lead author Professor Patricia Lockwood said: “Prosocial behaviours are essential for addressing global challenges. Yet helping others is often effortful and humans are averse to effort. Understanding how effortful helping decisions are processed in the brain is extremely important.”

In the study, the researchers focused on the vmPFC, a region located right at the front of the brain, which is known to be important for decision-making and other executive functions. Previous studies using magnetic resonance imaging (MRI scanning) have linked the vmPFC to choices that involve a trade-off between the rewards available and the effort required to obtain rewards. However, these techniques cannot show whether a part of the brain is essential for these functions.

Three groups of participants were recruited for the study. 25 patients had vmPFC damage, 15 patients had damage elsewhere in the brain, and 40 people were healthy age and gender-matched control participants. These groups allowed the researchers to test the impact of damage to vmPFC specifically.

Each participant attended an experiment where they met another person anonymously. They then completed a decision-making task that measured how willing they were to exert physical effort (squeezing a grip force device) to earn rewards (bonus money) for themselves and for the other person.

By enabling participants to meet – but not see – the person they were ‘working’ for in advance, researchers were able to convey the sense that participants’ efforts would have real consequences, but hide any information about the other person that could affect decision-making.

Each choice the participants made varied in how much bonus money for them or the other person was available, and how much force they would have to exert to obtain the reward. This allowed the researchers to measure the impact of reward and effort separately, and to use advanced mathematical modelling to precisely quantify people’s motivation.

The results of the study clearly showed that the vmPFC was necessary for motivation to help others. Patients with vmPFC damage were less willing to choose to help others, exerted less force on even after they did decide to help, and earned less money to help others compared to the control groups.

In a further step, the researchers used a technique called lesion symptom mapping which enabled them to identify even more specific subregions of the vmPFC where damage made people particularly antisocial and unwilling to exert effort for the other person. Surprisingly, damage to a nearby but different subregion made people relatively more willing to help.

Co-lead author Dr Jo Cutler said: “As well as better understanding prosocial motivation, this study could also help us to develop new treatments for clinical disorders such as psychopathy, where understanding the underlying neural mechanisms can give us new insights into how to treat these conditions.”

“This region of the brain is particularly interesting because we know that it undergoes late development in teenagers, and also changes as we get older,” added Professor Lockwood. “It will be really interesting to see whether this area of the brain can also be influenced by education – can we learn to be better at helping others?”

Source: University of Birmingham

Categories : NeurologyTags :

New Non-invasive Brain Stimulation may One Day Treat Addiction, Depression and OCD

On By ModernMedia
Source: CC0

Neurological disorders, such as addiction, depression, and obsessive-compulsive disorder (OCD), affect millions of people worldwide and are often characterised by complex pathologies involving multiple brain regions and circuits. These conditions are notoriously difficult to treat due to the intricate and poorly understood nature of brain functions and the challenge of delivering therapies to deep brain structures without invasive procedures.

In the rapidly evolving field of neuroscience, non-invasive brain stimulation enables the understanding and treating a myriad of neurological and psychiatric conditions, free of surgery or implants. Researchers, led by Friedhelm Hummel, who holds the Defitchech Chair of Clinical Neuroengineering at EPFL’s School of Life Sciences, and postdoc Pierre Vassiliadis, are pioneering a new approach in the field.

Their research, which is described in Nature Human Behaviour, makes use of transcranial Temporal Interference Electric Stimulation (tTIS). The approach specifically targets deep brain regions serving as control centres of several important cognitive functions and involved in different neurological and psychiatric pathologies.

“Invasive deep brain stimulation (DBS) has already successfully been applied to the deeply seated neural control centers in order to curb addiction and treat Parkinson, OCD or depression,” says Hummel. “The key difference with our approach is that it is non-invasive, meaning that we use low-level electrical stimulation on the scalp to target these regions.”

The innovative technique is based on the concept of temporal interference, initially explored in rodent models, and now successfully translated to human applications by the EPFL team. In this experiment, one pair of electrodes is set to a frequency of 2000Hz, while another is set to 2080Hz. Thanks to detailed computational models of the brain structure, the electrodes are specifically positioned on the scalp to ensure that their signals intersect in the target region.

It is at this juncture that the magic of interference occurs: the slight frequency disparity of 80Hz between the two currents becomes the effective stimulation frequency within the target zone. The brilliance of this method lies in its selectivity; the high base frequencies (eg, 2000Hz) do not stimulate neural activity directly, leaving the intervening brain tissue unaffected and focusing the effect solely on the targeted region.

The focus of this latest research is the human striatum, a key player in reward and reinforcement mechanisms. “We’re examining how reinforcement learning, essentially how we learn through rewards, can be influenced by targeting specific brain frequencies,” says Vassiliadis. By applying stimulation of the striatum at 80Hz, the team found they could disrupt its normal functioning, directly affecting the learning process.

The therapeutic potential of their work is immense, particularly for conditions like addiction, apathy and depression, where reward mechanisms play a crucial role. “In addiction, for example, people tend to over-approach rewards. Our method could help reduce this pathological overemphasis,” Vassiliadis, who is also a researcher at UCLouvain’s Institute of Neuroscience, points out.

Vassiliadis, lead author of the paper, a medical doctor with a joint PhD, describes tTIS as using two pairs of electrodes attached to the scalp to apply weak electrical fields inside the brain. “Up until now, we couldn’t specifically target these regions with non-invasive techniques, as the low-level electrical fields would stimulate all the regions between the skull and the deeper zones – rendering any treatments ineffective. This approach allows us to selectively stimulate deep brain regions that are important in neuropsychiatric disorders,” he explains.

Furthermore, the team is exploring how different stimulation patterns can not only disrupt but also potentially enhance brain functions. “This first step was to prove the hypothesis of 80Hz affecting the striatum, and we did it by disrupting it’s functioning. Our research also shows promise in improving motor behaviour and increasing striatum activity, particularly in older adults with reduced learning abilities,” Vassiliadis adds.

Hummel, a trained neurologist, sees this technology as the beginning of a new chapter in brain stimulation, offering personalised treatment with less invasive methods. “We’re looking at a non-invasive approach that allows us to experiment and personalise treatment for deep brain stimulation in the early stages,” he says. Another key advantage of tTIS is its minimal side effects. Most participants in their studies reported only mild sensations on the skin, making it a highly tolerable and patient-friendly approach.

Hummel and Vassiliadis are optimistic about the impact of their research. They envision a future where non-invasive neuromodulation therapies could be readily available in hospitals, offering a cost-effective and expansive treatment scope.

Original written by Michael David Mitchell. The original text of this story is licensed under Creative Commons CC BY-SA 4.0. Edited for style and length.

Source: Ecole Polytechnique Fédérale de Lausanne

Categories : NeurologyTags :

Differences in Cortical Development Seen for Autistic Boys and Girls

On By ModernMedia
Photo by Ben Wicks on Unsplash

A new study led by UC Davis researchers finds widespread differences in brain development between autistic boys and girls ages 2-13. The study, published recently in Molecular Psychiatry, found sex-specific changes in the thickness of the brain’s cortex, or outer layer.

The findings are notable because so few studies have addressed cortical development in autistic girls, who are diagnosed with autism less often than males. Nearly four males are diagnosed with autism for every one female.

“It is clear that this sex bias is due, in part, to underdiagnosis of autism in females,” said Christine Wu Nordahl, a professor in the Department of Psychiatry and Behavioral Sciences and the UC Davis MIND Institute and a senior author on the paper.

“But this study suggests that differences in diagnosis are not the full story – biological differences also exist.”

The cortex is made up of distinct layers comprised of millions of neurons. Until about age 2, the cortex rapidly thickens as new neurons are created. After this peak, the outer cortical layer thins. Previous studies have found that this thinning process is different in autistic children than non-autistic children, but whether autistic boys and girls share the same differences had not been examined.

“It’s important to learn more about how sex differences in brain development may interact with autistic development and lead to different developmental outcomes in boys and girls,” explained Derek Andrews, lead author on the study and an assistant project scientist in the Department of Psychiatry and Behavioral Sciences and at the MIND Institute.

A changing cortex in childhood

The research team studied the brain scans of 290 autistic children – 202 males and 88 females, and 139 non-autistic, typically developing individuals – 79 males and 60 females.

All participants were in the MIND Institute’s Autism Phenome Project (APP), one of the largest longitudinal autism studies in the world.

The project includes the Girls with Autism Imaging of Neurodevelopment (GAIN) study, launched to increase the number of females represented in research.

The researchers took MRI scans at up to four time periods between the ages of 2 and 13.

They found that at age 3, autistic girls had a thicker cortex than non-autistic girls of the same age, comprising about 9% of the total cortical surface. Differences in autistic males when compared to non-autistic males of the same age were much less widespread.

In addition, when compared to males, autistic females had faster rates of cortical thinning into middle childhood. The cortical differences were present across multiple neural networks.

“We found differences in the brain associated with autism across nearly all networks in the brain,” Andrews said.

He noted that it was a surprise at first that the differences were greatest at younger ages. Because autistic girls had a more rapid rate of cortical thinning, by middle childhood, the differences between autistic males and females were much less pronounced.

“We typically think of sex differences as being larger after puberty. However, brain development around the ages of 2-4 is highly dynamic, so small changes in timing of development between the sexes could result in large differences that then converge later,” Andrews explained.

The importance of long-term studies of both sexes

These findings make it clear that longitudinal studies that include both sexes are necessary, Nordahl said.

“If we had only looked at boys at age 3, we may have concluded that there were no differences. If we had both boys and girls, but only investigated differences at 11 years of age, we may have concluded that there were very few sex differences in the cortex. We needed to follow both boys and girls across development to see the full picture,” she explained.

This was why Nordahl, who now directs the APP, launched the GAIN study in 2014. “The APP had a wonderfully large sample of about 150 autistic boys, but only about 30 autistic girls. This was too few autistic girls to really examine how they might be similar or different to boys, so we worked to increase the representation of autistic females in our research,” she said.

GAIN is unique, and Andrews said he hopes other researchers will follow suit in including more autistic girls in autism research. “Autistic females represent about 20% of the autistic population. Any successful effort to understand autism will need to include autistic females.”

Source: University of California – Davis Health