It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Friday, September 22, 2023
Why are the brain's nerve cells organized into modules?
IMAGE: A SCHEMATIC ILLUSTRATION OF THE EXPERIMENTAL SETUP.view more
CREDIT: F. PAUL SPITZNER
Scientists have found that the outer cortex of the mammalian brain is able to maintain control over all the external inputs it receives because of how its nerve networks are organized into interconnected but independently functioning 'modules.' The finding was the result of a unique experimental system that grew neurons, the functional elements of the brain, on microfabricated glass surfaces. Computational models then described the experimental observations. The work, by an international team of researchers led by Hideaki Yamamoto from Tohoku University and Jordi Soriano from the University of Barcelona, was published in the journal Science Advances.
The cortex is the outer layer of the brain that contains a large number of neurons responsible for functions such as sensory perception, motor control, and higher-order computation. "Neuronal networks, like those in the mammalian cortex, need to be able to segregate inputs from specialised circuits, and to integrate inputs from multiple circuits," says Yamamoto. But it has not been clear how the cortex is able to support these two very different processing paradigms.
To study this, the researchers guided cortical neurons to form a network containing multiple sub-groups, or modules. The lab-grown neurons were engineered to express light-sensitive proteins so they could be stimulated using a specific wavelength of light.
The team found that the more well-formed modular networks had large responses to localised light stimulation, while those with less 'modularity' responded to all stimulus in an excessively synchronised way.
For this effect to happen, the applied light stimulation was delivered to different parts of the network at different times, to mimic the real-life inputs to the cortex from subcortical parts of the brain. However, when the overall excitability of the entire network was raised simultaneously, by increasing potassium concentration across the entire network, this did trigger a synchronous, coordinated activity response across the entirety of the networks.
"This balance between locally segregated activity and globally integrated activity is thought to be important for the brain to be able to expand its capacity for information representation with limited resources," explains Yamamoto.
The discovery not only helps scientists understand the interplay between structure and function of the mammalian brain but can also help improve the development of artificial neural networks for use in machine learning research.
Children whose mothers had a higher exposure to certain phthalates during pregnancy tend to show smaller total gray matter in their brains at age 10. This is one of the main conclusions of a study led by the NYU Grossman School of Medicine and the Barcelona Institute for Global Health (ISGlobal), a centre supported by the "la Caixa" Foundation, and published in Molecular Psychiatry.
The study also found that maternal exposure to plasticizers during pregnancy is associated with lower child IQ at age 14, which confirmed the results of two previous study on the topic. Moreover, the research team observed that this relationship between exposure to certain phthalates and lower child IQ is partially influenced by total gray matter volumes. In other words: exposure to plasticizers before birth could lead to smaller total gray matter in childhood, which in turn could be related to a lower IQ.
Finally, the results showed an association between gestational exposure to plasticizers and smaller white matter volumes in girls.
Phthalates, a group of chemicals of concern
Phthalates are a group of chemicals which are ubiquitously used as plasticizers and solvents in a wide range of commercial products, such as personal care products, food packaging or vinyl flooring. Previous studies have shown that certain phthalates are associated with less optimal cognitive function, social development, and motor skills as well as behavioral problems in children.
In order to provide new evidences, the authors used data from 775 mother-child pairs from Generation R, a pediatric neuroimaging cohort based in Rotterdam (The Netherlands). Phthalate exposure of mothers was assessed using urine samples collected during pregnancy. Since phthalates are difficult to detect due to their rapid decay in the human body, the analysis of the samples focused on detecting phthalate metabolites, the breakdown products generated as the consequence of the presence phthalates.
Brain volumetric measures of children were taken using MRI scans at age 10. Lastly, children's IQ was assessed via standard tests performed when children were 14 years old.
Results
The statistical analysis revealed an association between higher gestational concentrations of monoethyl phthalate (mEP) and smaller total gray matter volumes in offspring at age 10. mEP is a metabolite, or breakdown product, of diethyl phthalate, a compound used to make plastics more flexible and in cosmetic products.
Higher maternal concentrations in urine during pregnancy of monoisobutyl phthalic acid (mIBP), a metabolite of diisobutyl phthalate (DIBP), were associated with smaller white matter only in girls. DIBP is also used as a plasticizer.
Gray matter is the tissue that contains most of the brain's neuronal cell bodies and help us process information and govern our muscles. This part of the brain is essential in our ability to learn and retain information, speak, move or process sensation and perceptions.
In turn, white matter is a brain tissue that acts as a communication network between the different gray matter areas and between our brain and the rest of our body.
Lower IQ at age 14
In 2020 and 2021, the Generation R Study reported that maternal prenatal urinary concentrations of phthalates were associated with lower non-verbal IQ at age 6 years. After showing that the association persists at age 14, the authors state that "the impact of phthalate exposure on the brain and child cognition continues into adolescence".
The new study estimates that 18% of the total effect of phthalate exposure in pregnancy on children’s IQ could be explained by changes in gray matter volumes in both boys and girls. In girls, the association between gestational exposure to mIBP and lower IQ was found to be due to smaller cerebral white matter in a proportion of 76%.
Small differences at individual level
"Even though the observed differences in volumetric measures and IQ scores were small at individual level, it is the wide picture what shows reasons for concern because of the widespread exposure to phthalates and poor regulations, which lead to a high public health impact", says Mònica Guxens, ISGlobal researcher and last author of the study.
"In the light of scientific evidences on their health effects, countries such as the US or regions such as the EU have increased the regulations of this ubiquitous compounds. However, the use of new compounds to replace the regulated ones leads to a persistence of the global impact of prenatal exposure to phthalates", says Akhgar Ghassabian, researcher at the NYU School of Medicine.
Reference
Ghassabian A, van den Dries M, Trasande L, Lamballais S, Spaan S, Martinez-Moral MP, Kannan K, Jaddoe VWV, Engel SM, Pronk A, White T, Tiemeier H, Guxens M. Prenatal exposure to common plasticizers: a longitudinal study on phthalates, brain volumetric measures, and IQ in youth. Mol Psychiatry. 2023 Aug 29. doi: 10.1038/s41380-023-02225-6. Epub ahead of print. PMID: 37644173.
Phthalates are a group of chemicals used to make plastics more durable. They are often called plasticizers. Some phthalates are used to help dissolve other ...
Which population of humans is at a greater health risk to phthalate exposure? Children under the age of three are more at risk from phthalates because of their ...
Mar 10, 2021 ... A: These chemicals—generally referred to as “phthalates”—are a family of compounds that has been widely used for well over 50 years. They have ...
The indicators focus on three important phthalates: di-2-ethylhexyl phthalate (DEHP), dibutyl phthalate (DBP), and butyl benzyl phthalate (BBzP). These three ...
DGIST successfully concludes 2023 specialist training program in fragrance industry
DGIST (DAEGU GYEONGBUK INSTITUTE OF SCIENCE AND TECHNOLOGY)
DGIST (President Kuk Young) celebrated the graduation of 23 outstanding local talents, poised for success in the global fragrance industry, during the "French Fragrance Industry Specialist Training Completion Ceremony" held on August 19.
□ As part of the "Southern District Total Beauty Manufacturing and Service Specialist Training and Youth Entrepreneurship Vitalization Program" and the "University-Centered Research Center Support Program," DGIST conducted a four-day "Fragrance Industry Specialist Training Program" from August 16 to nurture experts who can excel in the global fragrance industry.
□ The program was modeled after the globally renowned "Fragrance Industry Specialist Training Program" in France. It covered topics such as fragrance marketing, basic chemistry related to fragrant substances, and foundational neuroscience related to olfaction. To offer more specialized training, the course featured guest lectures by Professor Jeremy Tobin, the driving force behind the fragrance industry training program at the University of Nice Sophia Antipolis, and Dr. Jerome Golebiewski, a French fragrance industry expert, generating considerable interest among the participants.
□ During the completion ceremony on the 19th, the program attendees shared their thoughts and reflections, expressing their strong aspirations to continue their endeavors in the fragrance industry.
□ Moon Che-il, Director of the DGIST Convergence Research Advanced Centre for Olfaction, remarked, "We anticipate that young, aspiring entrepreneurs will gain hands-on experience through this training program, ranging from the basics of scent science to commercialization. We expect them to surmount technological barriers of advanced fragrance-producing countries and emerge as world-class talents. Alongside the development of this program into a top-tier curriculum, our center will actively aid in overcoming these technological barriers by regularly introducing technologies and mentoring local enterprises, thus contributing to youth employment in Daegu and strengthening the capabilities of local SMEs."
□ This program aimed to stimulate the local industry by equipping specialists in the “total beauty” industry, which fits seamlessly with the industrial landscape of Daegu. It was supported by Daegu City and the National Research Foundation of Korea.
Over 50s with ADHD ‘overlooked’ for diagnosis and treatment, say experts
Doctors urgently need better international guidance on treating attention deficit hyperactivity disorder (ADHD) in the over 50s, conclude world-leading experts reviewing current research on this increasing issue globally.
Published in the peer-reviewed journal Expert Review of Neurotherapeutics, the team’s findings highlight a ‘striking’ gap in knowledge about older people as existing guidelines focus on children and young adults.
“Our analysis concludes that better approaches are urgently required to screen and diagnose people aged from around age 50 to 55,” says lead author Dr Maja Dobrosavljevic from the University of Orebro, in Sweden.
“As we gain deeper insights into the challenges faced by older adults living with ADHD, a comprehensive and tailored approach is crucial for their well-being.
“We therefore urge the medical community, researchers, and policymakers to collaborate in refining diagnostic criteria, treatment guidelines, and research initiatives that are inclusive of all age groups affected by ADHD.”
Estimated to affect around 2.5% of adults, ADHD runs in families.
Symptoms include being impulsive, hyperactive, and having poor focus, attention, and organisational skills.
The neurodevelopmental disorder can persist throughout life and have a negative impact on education, job prospects and social interaction. Stimulants such as methylphenidate are the most commonly-used medication for ADHD.
The team of authors includes Chair of the European ADHD Guidelines Group Samuele Cortese, who is a Professor of Child and Adolescent Psychiatry at the University of Southampton, and Henrik Larsson, a Professor of psychiatric epidemiology at Orebro Univeristy.
They reviewed almost 100 studies. Of these, 44 were papers on the prevalence, health outcomes, diagnosis, and treatment efficacy/safety, as well as clinical guidelines/consensus statements providing recommendations on clinical diagnosis and treatment of ADHD in older adults.
The team then assessed the current diagnostic criteria according to the Diagnostic and Statistical Manual of Mental Disorders (DSM), and the World Health Organisation’s International Classification of Diseases (ICD). Other aspects were also evaluated such as how useful current criteria are for diagnosing older adults.
“Our results show no studies have observed people over a long time period into older age. Research has instead focused on retrospective assessment of childhood symptoms, and this can be unreliable because of age-related memory issues,” says Professor Larsson, whose expertise lie in how genes and environment influence mental health problems across the life span.
“Essentially, this means that more trials are needed into the safety and efficacy of current ADHD medication, including the maximum recommended doses, used to treat this age group – who are at increased risk of other health conditions such as heart problems.”
Professor Larsson added: “Doctors should be assessing the physical health of an older person with ADHD before prescribing drug treatment.
“Diagnostic criteria have shifted towards a ‘wider inclusion’ of adults who previously would have remained undiagnosed.
“Yet, still, there is no specific consideration of how ADHD presents in older adults.
“Another issue is that screening tools validated for ADHD in older adults are not specific enough to recognize the condition in the over 50s. Only those with the most severe ADHD would be picked up.”
The team’s analysis also adds further weight to conclusions that ADHD is linked with mental health issues, increased death rates, and illness such as cardiovascular disease and dementia.
However, diagnosis remains an issue for this age group.
The research concludes that one of the main challenges for clinicians is that some medical conditions among older adults have similar clinical presentations as ADHD such as menopause-related memory decline.
On this basis, the researchers recommend that doctors take into account distinctive clues to distinguish ADHD from age-related mild cognitive impairment (MCI). People with ADHD typically report childhood symptoms whereas MCI has a more abrupt onset, they point out.
The authors do concede that future editions of the DSM and ICD are expected to address current gaps in the definition of ADHD for older adults, and that more data will become available.
They suggest that classification for older adults should include diagnoses that differentiate between ADHD and conditions with similar symptoms.
A new type of regulation is needed to support and encourage organisations to comply with equality and human rights law because enforcement alone is ineffective, a new study says.
The introduction of the Public Sector Equality Duty and the Human Rights Act were intended to establish an equality and human rights culture within public authorities. The research highlights how this culture has failed to take hold.
An alternative is needed to the current model of regulation (the enforcement pyramid) under which penalties increasingly progress until noncompliers comply. The study says the current model cannot recognise innovation, good practice or the reasons why organisations struggle to comply. Some organisations may lack confidence or feel overwhelmed rather than intentionally choosing not to follow the rules.
Dr David Barrett, from the University of Exeter Law School, analysed original empirical data and interviewed individuals within regulators and inspectorates and ombudsmen. He found firms are implementing the duty in three ways: strong implementation (where individuals make the most of the resources they have and drive ever deeper implementation), mixed implementation (where individuals oscillate between deeper and perfunctory implementation), and weak implementation (where individuals avoid taking meaningful action due to feeling overwhelmed and in need of rescue).
Dr Barrett said: “Equality and human rights laws require organisations to adjust and reconfigure themselves to mainstream the values of equality and human rights. This requires a model of enforcement that assists organisations, builds capabilities and ultimately sanctions organisations if they fail to comply.
“Ever severe punishment is unlikely to secure meaningful mainstreaming and instead is likely to result in minimal and perfunctory performance. What is needed is encouragement and support, but this cannot be adequately provided by the current enforcement pyramid.”
The study recommends there should be a “strength-based” pyramid, which would work alongside the enforcement based pyramid. This would involve increasing incentives in the form of education and persuasion, validation and encouragement, grants and awards, that would hopefully work to incentivise individuals and their organisations to embed equality and human rights ever deeper into the organisation.
Dr Barrett found a significant barrier to implementation is the finite number of resources - including money, staff and time. Even where staff had more interest in equality and human rights, time was still a significant constraint. Most staff have knowledge of the sector that they oversee rather than equality and human rights, meaning that it is difficult to integrate these norms into the work of the organisation.
Confidence was an important issue in relation to staff and often deterred staff from taking action. The majority of interviewees operated outside the top leadership of the organisation, and many spoke of the challenges imposed by the senior leadership.
The study recommends, as part of a strength-based system, organisations could apply either singularly or collectively (for example a network) for grants to further the implementation of equality and human rights. Eligibility requirements could be established to incentivise moving up the pyramid.
Organisations that had particularly excelled in equality and human rights could apply to be accredited. Awards could also be given to individual implementers to recognise and encourage innovation.
You’re looking at a truck. You’re with a young child and he follows your gaze. He’s interested in the object you’re looking at without you pointing at it. This is called joint attention and it is one of the primary ways children learn to connect words with objects and acquire language.
Lack of joint attention is a core feature of autism. Until now, it was thought that stimulating joint attention in people with autism would help them express themselves verbally. But a meta-analysis of 71 studies on autism challenges this assumption and suggests that people with autism spectrum disorders may acquire language differently.
The study – by Laurent Mottron, a professor in the Department of Psychiatry and Addiction at Université de Montréal and a psychiatrist at the Hôpital en santé mentale Rivière-des-Prairies of the CIUSSS du Nord-de-l’Île-de-Montréal; Mikhail Kissine, a professor of linguistics at Université Libre de Bruxelles; and Ariane St-Denis, a medical student at McGill University – is published in Neuroscience & Biobehavioral Reviews.
The authors looked at all studies of joint attention and language in children with autism since 1994.
They then selected all those that reported a clear measure of structural language using metrics such as vocabulary size, and excluded those that measured only communication skills.
In neurotypical individuals, social interaction plays an essential role in language development. “It makes sense to assume, therefore, that the ability to establish a shared attentional frame may increase the opportunities for autistic children to attend to linguistic stimuli and engage in communicative experiences,” the authors of the study write.
However, their meta-analysis did not find significant language gains from interventions aimed at promoting social communication in people with autism.
“Linking language outcomes to joint attention in autism is somewhat paradoxical, as the significant proportion of autistic children who become verbal still have a diagnosis of autism, a core component of which is, precisely, atypically low joint attention,” they observe. For example, children with Asperger’s develop impressive language skills without developing comparable social skills.
Of the 71 studies, only 28 reported a correlation between stimulation of joint attention in young children with autism and development of simple vocabulary.
“These studies do show that joint attention is associated with a very simple vocabulary of less than five words, but they cannot predict whether the child will be able to express himself correctly at age 7 or 8,” Mottron notes. Twenty-five other studies show no correlation between joint attention and vocabulary development in children with autism.
It is possible that people with autism learn language differently, without social interaction, he adds. “For example, in immigrant populations whose native language is not English, children with autism learn English by looking at digital tablets and never learn to speak their parents’ language."
If some children with autism are less sensitive to the human voice than to the written word, this could open up new avenues for intervention, Mottron says. “In this case, we should redirect autistic children towards exposure to non-communicative language, in addition to talking to them."
The study therefore opens the door to new ways of addressing neurodiversity.
The research was led by Jaroslav Klokočník, professor emeritus at the Astronomical Institute of the Czech Academy of Sciences. Gunther Kletetschka, associate research professor at the University of Alaska Fairbanks Geophysical Institute, is among the three co-authors. Kletetschka is also affiliated with Charles University in the Czech Republic.
“A lot of people are excited about water on Mars because there may be life forms that once existed on Mars or maybe exist today in some bacterial form,” Kletetschka said. “We can use this gravity approach to look for water on Mars, because we have done it already on Earth.
“In an area of northern Africa, for example, this gravity approach found a shoreline of a long-ago lake, and its finding was consistent with the archaeological evidence indicating a shoreline of that lake,” he said.
The authors write that analyzing the gravity aspects of Mars to better understand the planet improves upon prior approaches. They note that it can “provide complete information with a better insight of the celestial body, applicable in geology, geophysics, hydrology, glaciology and other disciplines.”
The work by Kletetschka and colleagues differs from the traditional approach of mapping a surface based on gravity anomalies alone.
Gravity anomalies are areas of greater or weaker gravitational force exerted by a planetary body’s surface features. A mountain would exert a greater gravitational force because it has a higher concentration of mass than would be expected on a planet without surface features. Ocean basins and trenches would have less gravitational force.
In their Mars research, the authors used a process developed by Klokočník that analyzes gravity aspects calculated from gravity anomaly measurements. Gravity aspects are mathematical products that characterize the gravity anomalies.
Klokočník used that approach to confirm earlier research about the existence of extensive paleolakes or paleoriver systems under the Saharan sands on Earth. His 2017 research paper also suggested a part of the Grand Egyptian Sand Sea as another candidate for a paleolake.
The gravity aspects method has also been used in a comparison of Earth’s geographic features to those of the cloud-shrouded Venus. That research is described in a July 2023 paper in the journal Scientific Reports in which Kletetschka is a co-author.
CONTACTS:
• Gunther Kletetschka, University of Alaska Fairbanks Geophysical Institute, 907-474-7090, gkletetschka@alaska.edu.
• Rod Boyce, University of Alaska Fairbanks Geophysical Institute, 907-474-7185, rcboyce@alaska.edu
UNIVERSITY OF ILLINOIS GRAINGER COLLEGE OF ENGINEERING
IMAGE: THIS GRAPHIC ILLUSTRATES THE PRODUCTION PATHWAYS FOR THE KEY ENERGY CARRIERS THAT EMERGED IN ANSELL’S RESEARCHview more
CREDIT: THE GRAINGER COLLEGE OF ENGINEERING AT UNIVERSITY OF ILLINOIS URBANA-CHAMPAIGN
Scientists and industry leaders worldwide are looking for answers on how to make aviation sustainable by 2050 and choosing a viable sustainable fuel is a major sticking point. Phil Ansell, aerospace engineer at the University of Illinois Urbana-Champaign, took a full inventory of the options to make a data-driven assessment about how they stack up in comparison. He reviewed over 300 research projects from across different sectors, not just aerospace, to synthesize the ideas and draw conclusions to help direct the dialogue about sustainable aviation toward a permanent solution.
Ansell said several key energy carriers emerged, including bio jet fuel pathways for synthetic kerosene, power-to-liquid pathways for synthetic kerosene, liquid hydrogen, ammonia, liquid natural gas, ethanol, methanol, and battery electric systems. Ansell compared each of them to conventional fossil-derived aviation turbine fuel.
For each of the alternate fuels Ansell addressed factors such as how their material properties impact aircraft performance and fuel handling, emissions, cost and scalability, and resource and land requirements, as well as social impacts, which can be difficult to measure.
“Let's face it, if we want to do this at scale, we need all three pillars of the environmental, economic, and societal contributions, to make that energy carrier sustainable, and every stakeholder in the value chain sees the challenges differently,” Ansell said. “Because the production and infrastructure costs required to adopt an alternative fuel source are significant, people think we can only pick one, the biggest contenders being bio jet fuel and hydrogen,” Ansell said. “But the choice doesn’t have to be mutually exclusive. For example, we can use hydrogen to produce synthetic aviation fuels like the power-to-liquid pathway or use biomass to produce hydrogen.”
Ansell admitted this is not what he typically studies, but his research and teaching areas in aircraft design and aerodynamics must consider where the energy will come from to make flight possible. So, for any fuel associated with a bio aspect Ansell had to look at the stresses it might create for crops.
“I leaned on a lot of the observations from the community, especially for the land use change question,” he said. “It is so driven case by case. Making a broad assessment doesn't do it justice, because land use changes depend on their location.”
Ansell said he has been working with hydrogen for several years and battery/electric systems before that, so he needed to remain objective and all the data to drive the conclusion.
“About eight years ago, I realized that battery systems are a pie-in-the-sky solution. The technology challenge is insurmountable. The weight and volume required for batteries is too difficult to close. I think my biases were from the fact that I've been studying hydrogen for a long time, and I think it has real potential. That’s one of the conclusions I arrived at from the data, and I think I would have learned that independently.”
Ansell said hydrogen presents infrastructural and integration challenges, unique to the aircraft platform and unique to the cryogenic handling of fuel on aircraft.
“The technological challenges of hydrogen are very solvable. And I can say that with confidence because we’ve done it as a society.” He referred to Tupolev 155, a commercial scale aircraft which was flown by the former Soviet Union with liquid hydrogen in the 1980s on a relevant airframe. Even earlier experimental studies were conducted by NASA. “It will take a bit longer to implement at scale, but it’s doable.”
In the study, Ansell examined numerous options to produce biofuel from just about anything, from municipal waste to seaweed and algae.
“Basically, anything that you can burn, create energy from, decompose, can be turned into a jet fuel. We’ve already been using corn to produce ethanol. But if you were to take corn, ferment it, then turn that ethanol into jet fuel, you now have lost the ability to feed people or animals that corn. This is one of the challenges of all first-generation biofuels.”
He said people are trying to use the stover, the parts of a corn plant left on the ground after harvesting to make fuel. Corn stover is full of sugar but it’s difficult to extract.
Why is an aerospace engineer studying feedstocks?
“I want to be able to know enough to interact with scientists who are tackling these options,” Ansell said. “And it’s important that the aviation community understands where the challenges exist. We need to draw the lines between the aircraft as a system, the aircraft operating in an airspace, and how that connects with energy. With a goal of net zero CO2 by 2050, I want the aviation community to recognize how big of a task this is.
“As a society, we are often attentive to challenges that are right in front of us, with limited foresight to plan for the future. So even as it pertains to the greenhouse gas effect, we still don't have an appreciation for the long-term sense of the damage that produces. We have other immediate concerns to spend money on. But without that foresight, we are going to struggle and regret decisions not to make investments and not to take seriously these aviation sustainability challenges when we still had time.”Again, Ansell stressed that it might not need to be a one-fuel-fits-all solution. In fact, countries may need different strategies, different rates of implementation, and adoption of renewables, based on their own resources. For example, Denmark doesn’t have as much land as the U.S. and so is making great use of offshore wind turbine platforms.
“Maybe we should play to our strengths. The U.S. has one of the world's largest agricultural sectors in the world. We may have more land than Europe that can be allocated to feedstock development, which can be used for a variety of bio-jet fuels or hydrogen production pathways. In contrast, Europe has an extensive network of clean energy, and as such is doing a lot of work in electrolytic hydrogen production.
The study, “Review of sustainable energy carriers for aviation: Benefits, challenges, and future viability,” by Phillip J. Ansell, appears in the journal Progress in Aerospace Sciences. DOI: 10.1016/j.paerosci.2023.100919
