Amnesia caused by sleep deprivation could be reversed with existing drugs

Researchers used drugs for erectile dysfunction and asthma to restore memories in mice

FEDERATION OF EUROPEAN NEUROSCIENCE SOCIETIES

 

IMAGE: 

RESEARCHER DR ROBBERT HAVEKES

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CREDIT: FENS FORUM / ROBBERT HAVEKES

Vienna, Austria: The loss of social memories caused by sleep deprivation could potentially be reversed using currently available drugs, according to a study in mice presented today (Friday) at the Federation of European Neuroscience Societies (FENS) Forum 2024. [1]

Lack of sleep is known to affect the brain, including memory, in mice and in humans, but research is beginning to show that these memories are not lost, they are just ‘hidden’ in the brain and difficult to retrieve.

The new research shows that access to these otherwise hidden social memories can be restored in mice with a drug currently used to treat asthma and chronic obstructive pulmonary disease. The team of researchers have also shown that another drug currently used to treat erectile dysfunction can restore access to spatial memories. Researchers say these spatial memories in mice are akin to humans remembering where they put their keys the night before, whereas the social memories could be compared with remembering a new person you met.

The research was presented by Dr Robbert Havekes from the University of Groningen in the Netherlands. He said: “Ever since starting as a PhD student, many years ago, I have been intrigued by the observation that even a single period of sleep deprivation can have a major impact on memory processes and the brain as a whole. The early work published years ago helped us identify some of the molecular mechanisms that mediate amnesia.

“By manipulating these pathways specifically in the hippocampus, we have been able to make memory processes resilient to the negative impact of sleep deprivation. In our new studies, we have examined whether we could reverse amnesia even days after the initial learning event and period of sleep deprivation.”

The new studies, presented at the FENS Forum and funded by the Air Force Office of Scientific Research (AFOSR), were conducted by Dr Havekes’ PhD students Adithya Sarma and Camilla Paraciani, who will also be presenting their work as poster presentations.

To study social memories in the lab, the researchers gave mice the opportunity to choose between interacting with a mouse they have never encountered before or a sibling from their own cage. Under normal circumstances, the mice prefer interacting with the new mouse over their litter-mate that they already know. Given the same choice the next day, mice will interact to a similar extent with both their litter-mate and the mouse they met the day before as both mice are now considered familiar.

However, if the mice are sleep-deprived after their first encounter then the next day they still prefer to interact with the new mouse as if they never met it before. These findings suggest that they simply cannot recall their previous encounter.

The team found they were able to permanently restore these hidden social memories, first using a technique called optogenetic engram technology. This technique allows them to identify neurons in the brain that together form a memory (known as a memory engram) for a specific experience and alter those neurons so they can be reactivated by light. Researchers can then use light to reactivate this specific group of neurons resulting in the recall of the specific experience (in this case a social memory).

They were also able to restore the mice’s social memories by treating them with roflumilast, a type of anti-inflammatory drug, approved by the US Food and Drug Administration, that is used to treat chronic obstructive pulmonary disease. Dr Havekes says this finding is particularly interesting as it provides a stepping stone towards studies of sleep deprivation and memory in humans, and he is now collaborating with another research group that is embarking on human studies.

In parallel, the same researchers have investigated the loss of spatial memory caused by sleep deprivation by studying mice’s abilities to learn and remember the location of individual objects. A brief period of sleep deprivation following training meant the mice could not recall the original locations of the object and so they did not notice when an object was moved to a new location during a test.

As with the social memories, access to these spatial memories could be restored by treating the mice with another drug, vardenafil, that is currently used to treat erectile dysfunction. This is a second drug that is approved by the US Food and Drug Administration that the researchers have successfully used to reverse amnesia in mice.

Dr Havekes said: “We have been able to show that sleep deprivation leads to amnesia in the case of specific spatial and social recognition memories. This amnesia can be reversed days later after the initial learning experience and sleep deprivation episode using drugs already approved for human consumption. We now want to focus on understanding what processes are at the core of these accessible and inaccessible memories. In the long term, we hope that these fundamental studies will help pave the way for studies in humans aimed at reversing forgetfulness by restoring access to otherwise inaccessible information in the brain.”

Professor Richard Roche is chair of the FENS Forum communication committee and Deputy Head of the Department of Psychology at Maynooth University, Maynooth, County Kildare, Ireland, and was not involved in the research. He said: “This research shows that social and spatial memories seemingly lost through sleep-deprivation can be recovered. Although these studies were carried out in mice, they suggest that it may be possible to recover people’s lost social and spatial memories using certain drug treatments that are already approved for human use. There are many situations where people cannot get the amount of sleep they need, so this area of research has obvious potential. However, it will take time and a lot more work to move this research from mice into humans.”

memory engram cells 

image of memory engram cells visualized in the brain

CREDIT

FENS Forum / Robbert Havekes

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METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

 

Researchers discover how nerve cells in bat brains respond to their environment and social interactions with other bats

First study of social groups of wild bats in a laboratory ‘bat cave’

FEDERATION OF EUROPEAN NEUROSCIENCE SOCIETIES

 

IMAGE: 

WILD EGYPTIAN FRUIT BAT IN FLIGHT

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CREDIT: WEIZMANN INSTITUTE OF SCIENCE, REHOVOT, ISRAEL

Vienna, Austria: Researchers have found that nerve cells in the hippocampus region of the brain encode complex information on numerous characteristics of other individuals in the same social group.

 

The work, which is being carried out in bats, is the first to show this in a large, mixed-sex group of wild, social animals, and is important because it sheds light on how the brain operates and generates thinking processes and behaviour.

 

Professor Nachum Ulanovsky, Head of the Center for Learning, Memory and Cognition at the Weizmann Institute of Science, Rehovot, Israel, has published numerous studies on how the brain works in bats. In his presentation to the Federation of European Neuroscience Societies (FENS) Forum 2024 [1] today (Friday), he described previous studies on how bats navigate, learn and remember details of the spaces they fly in, and how they interact socially [2]. In his new study, he digs deeper into how the nerve cells (neurons) in a specific region of the hippocampus, which is responsible for memory and spatial understanding, play a much more complex role. He believes that as the bat hippocampus is very similar to the human hippocampus, similar findings will be discovered in humans in the future.

 

“Our brain makes us who we are. Our behaviours, emotions, thoughts, memories, our successes and failures are all determined by our brains. It is therefore a fascinating question: how does the brain operate? How does the brain generate behaviour and cognition? To address this in a detailed manner, we must record the activity of individual neurons – the basic operating units of the brain – while humans or animals perform various behaviours and cognitive tasks. This is technically easier to do in animals than in humans, which is why recording the activity of individual neurons in behaving animals is crucial for understanding the brain,” he said.

 

He and his colleagues created a “bat cave” in their laboratory for colonies of wild Egyptian fruit bats, which are highly social mammals. Each group had between five and ten bats with roughly equal proportions of male and females. The bat cave measured 2.7 x 2.3 x 2.6 metres, and it was equipped with large and small nets for the bats to fly between. The bats knew each other, lived together in the bat cave for several months and were free to fly and interact with each other.

 

The researchers attached tiny wireless-electrophysiology systems to each bat, which recorded the electrical activity of neurons in the bats’ brains during natural behaviours, such as flight, navigation and social interactions. The bats were also tagged and bar-coded, which enabled the researchers to track the locations and identities of the bats in 3D. The researchers used video cameras to record the bats’ head directions and social interactions when they were hanging in the nets.

 

Prof. Ulanovsky said: “We discovered a whole host of very strong social signals in the hippocampus. We found that neurons in the hippocampus represented the positions and identities of multiple other bats, creating a social-spatial representation – that is, the neurons encoded who was located where. Moreover, these neurons represented highly important social factors such as the sex of the other bat, its place in the dominance hierarchy (is it a dominant or a subordinate bat?), its social affiliation (is the other bat my friend or not?), and also represented specific forms of social interaction.

 

“This study suggests that, beyond the classical roles of the hippocampus in representing memory and space, the hippocampus may have an additional role in social processing. In particular, it may link these three aspects – social, space and memory – into one unified representation of social-spatial memories.

 

“Brain research typically focuses on the behaviours of individual animals and humans, and when social behaviours are studied, they are usually investigated in pairs of animals that are socially interacting. But many of our social behaviours inherently involve multiple individuals: think of your class, your family dinner, the last party you went to, or the latest ball game that you watched. These are all group social behaviours. Nevertheless, to date there have been very few studies of neuronal activity in the brains of animals that are socially interacting in a group. In particular, there have been very few such studies of this in the hippocampus.”

 

He believes it is important to study the brain in animals that are behaving naturally and in social groups, and not just during the controlled behaviours that are normally used in brain research, as the results can be different.

 

“I plan to continue studying the brain during evermore naturalistic behaviours, both social behaviours and navigation behaviours. The bat hippocampus and its connections are extremely similar to the human hippocampus in terms of their structure. Therefore, I expect that similar findings will be discovered in humans in the future,” he concluded.

 

Professor Richard Roche, Deputy Head of the Department of Psychology at Maynooth University, Maynooth, County Kildare, Ireland, is chair of the FENS communication committee and was not involved in the research. He said: “If we can understand the mechanisms that contribute to who we are, where we are, our characters, our motivations, our emotions, how we think and so much else, then we can begin to discover what is different when we have conditions such as depression, anxiety, autism or other conditions related to how our brains behave. This fascinating work by Professor Ulanovsky uncovers how individual neurons in the hippocampus are encoding important information about the environment that these bats are living in and about other bats in their social groups. This gives us indicators of what to look for and where to look when we investigate this in humans.”

 

(ends)

How nerve cells in bat brains respond to their environment and social interactions with other bats

Wild Egyptian fruit bat in flight

CREDIT

Weizmann Institute of Science, Rehovot, Israel

How nerve cells in bat brains [VIDEO] | EurekAlert! Science News Releases

How nerve cells in bat brains [VIDEO] | EurekAlert! Science News Releases

Professor Nachum Ulanovsky, Head of the Center for Learning, Memory and Cognition at the Weizmann Institute of Science, Rehovot, Israel

CREDIT

Weizmann Institute of Science, Rehovot, Israel

Notes to editors
 

[1] “Hippocampal coding beyond the representation of self-location”, by Professor Nachum Ulanovsky, Session S34: The dynamism of the hippocampal neural code, 09.47-10.05, Friday 28 June, Hall B: https://fens2024.abstractserver.com/program/#/details/presentations/263

[2] “Social place-cells in the bat hippocampus”, Omer et al., Science 359, 218–224 (2018).
“Multiscale representation of very large environments in the hippocampus of flying bats”, Eliav et al., Science 372, 933 (2021).

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METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Hippocampal coding beyond the representation of self-location

ARTICLE PUBLICATION DATE

28-Jun-2024

 

Adults conceived by donors left behind by fertility industry

KING'S COLLEGE LONDON

Children conceived by using egg or sperm donors have the same well-being outcomes as non-donor conceived people.

However, they are more likely to have identity difficulties and issues with trust. Secrecy and anonymity about their genetic parentage can have a profound impact on well-being say authors. They warn that children and adults conceived using donor gametes have not been centred in the assisted reproductive industry and more information is needed about adult wellbeing.

The study is published today in the British Journal of Obstetrics and Gynaecology by researchers King’s College London. The study is the first systematic review of studies investigating the psychological experiences of donor conceived people through childhood and adulthood and is the largest body of evidence for this group.

More than 70,000 donor conceived people have been born in the UK since 1991 when records began, and a significant unknown number before this date, however little is known about their long-term psychological outcomes.

The review looked at 50 studies and 4,666 donor conceived children and adults, mostly from high-income Anglophone countries, and found most studies showed equivalent or better outcomes in donor conceived people including higher wellbeing scores, self-esteem and relationship warmth.

The findings also showed children fared better when they were told they were donor conceived early. In the UK, donor anonymity has been against the law for those conceived after 2005 but children must wait until they are 18 years old to access information.

However, there is no legal requirement for families to tell their children the truth about their genetic lineage. The proliferation of at-home commercial DNA testing can reveal family secrets and yield life-changing results. It is often adults, who were conceived before 2005 and have no legal right to information about their genetic identity, who have been left out of the research and been left behind by the fertility industry.

First author Dr Charlotte Talbot, who graduated from King’s College London and is an Academic Foundation Doctor, affiliated with the University of Birmingham, said: “This is the largest body of evidence we have for wellbeing for donor conceived children and adults but it’s a complicated picture. While most outcomes are the same or better for this group than non-donor conceived people, qualitative studies revealed common themes relating to mistrust and concerns about genetic heritage.”

Senior author Professor Susan Bewley from King’s College London said: “Donor conceived children are always planned for and wanted, as one or more of their parents would have had fertility issues. This might explain better relationships with their family and higher wellbeing. However, much of the conversation around innovation in the assisted reproductive industry concentrates on the customers and potential parents rather than the people they want to create. We need to be better about putting donor conceived offspring’s needs and priorities at the centre.”

Laura Bridgens, Founder of Donor Conceived UK (DCUK), said: “The use of a gamete donor for conception is a life-long intergenerational process with far reaching social implications. DCUK welcomes this systematic review as it highlights the necessity for further consideration for the long-term needs and outcomes of donor conceived people into adulthood. There is a duty of care by the government and the fertility industry to listen to the voices of adult donor conceived people to create a future in which charity sector intervention is not needed to repair the mistakes of the past.”

The paper, Comparing the psychological outcomes of donor and non-donor conceived people: A systematic review, can be read in the British Journal of Obstetrics and Gynaecology.

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JOURNAL

British Journal of Obstetrics and Gynaecology

 

US states shape foreign policy amid national China unease, research shows

Peer-Reviewed Publication

UNIVERSITY OF NOTRE DAME

 

IMAGE: 

KYLE JAROS, ASSOCIATE PROFESSOR OF GLOBAL AFFAIRS AT THE UNIVERSITY OF NOTRE DAME, FIELDS QUESTIONS FROM STATE- AND LOCAL-LEVEL OFFICIALS DURING THE U.S.-CHINA SUBNATIONAL SYMPOSIUM AT THE UNIVERSITY OF MICHIGAN’S LIEBERTHAL-ROGEL CENTER FOR CHINESE STUDIES IN APRIL 2024. JAROS SHARED HIS EXPERTISE AS PART OF HIS ROLE AS A FELLOW OF THE NATIONAL COMMITTEE ON U.S.-CHINA RELATIONS’ PUBLIC INTELLECTUALS PROGRAM.

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CREDIT: UNIVERSITY OF NOTRE DAME

State-level officials such as governors, state legislators and attorneys general are shaping U.S.-China relations as the two countries navigate a strained geopolitical relationship, according to new research by political scientist Kyle Jaros.

“The state level has independent importance in the U.S.-China relationship — it’s not just a reflection of what’s happening at the national level,” said Jaros, associate professor of global affairs in the Keough School of Global Affairs at the University of Notre Dame. “The actions taken by state and local officials — and their Chinese counterparts — not only affect their own communities, but also play a key role in shaping the overall U.S.-China relationship.”

While the U.S. Constitution clearly states that foreign policy is the responsibility of the federal government, it also leaves space for cities and states to have international relationships and even to enter into certain kinds of agreements, Jaros said.

Known as subnational diplomacy or paradiplomacy, state-level relations with China are the focus of a new study by Jaros and Sara Newland of Smith College, published in Publius: The Journal of Federalism, a publication of Oxford University Press.

Jaros and Newland, who were recently awarded a grant from the Luce Foundation to fund this work, found that states vary widely in how they engage with China and range from confrontation to cooperation or a combination of the two.

“Broadly speaking, our data analysis shows some states that are clearly pro-engagement,” said Jaros, who currently serves as a visiting senior fellow for U.S.-China subnational relations for the Truman Center in Washington, D.C. “They feel that it is still appropriate to have at least some forms of business cooperation with China and may pursue climate cooperation, tourism cooperation or educational partnerships.”

To assess states’ engagement with China, Jaros and Newland tracked changing patterns of state-level U.S.-China relations using an original dataset on cooperative and confrontational policies across all 50 U.S. states.

Of the 50 states, California serves as a leading example of a state that has continued to adopt policies that foster people-to-people contact with China, Jaros said. For example, Gov. Gavin Newsom made a high-profile trip to China in October 2023 to advance climate partnerships and economic changes, laying the groundwork for Chinese leader Xi Jinping’s visit to San Francisco the following month. Florida and Texas lie at the other end of the spectrum, Jaros said, adopting confrontational policies that curb contact between state institutions (such as government or universities) and China. Florida, for example, now restricts Chinese citizens’ and businesses’ abilities to purchase land or real estate in the state, and Gov. Ron DeSantis has publicly articulated his concern that the Communist party is infiltrating Florida’s institutions.

In Indiana, the picture is more complicated, according to Jaros and Newland’s in-depth case study of the state, which was included in the research.

“Until 2022, Indiana engaged fairly regularly with official Chinese counterparts, even as concerns and criticisms from some quarters increased,” Jaros said. “While some forms of low-key economic and educational cooperation are continuing today, many areas that once seemed appropriate or safe are now seen by Indiana officials as off-limits or dangerous.”

For years, Indiana has pursued state-level cooperation with China, as the state is home to several major corporations, including leading pharmaceutical and engineering companies, that see the Chinese market as crucial to their overall strategy. In addition, numerous small businesses see China as a crucial part of their supply chain, relying on it as a sizable export market.

And yet, last year, Indiana state legislators voted to divest the state’s pension fund from China, and the state has banned new sister city relationships with China. In 2021, state Attorney General Todd Rokita launched an investigation into Valparaiso University’s Confucius Institute, alleging that it functioned as a propaganda arm for the Chinese Communist Party.

Jaros has met with the State Department’s Subnational Diplomacy Unit about his work, and he and Newland are studying how the federal government can help U.S. states and cities coordinate knowledge-sharing and also how it can provide useful information to lower levels of government.

In his capacity as a Truman fellow, Jaros is also expanding the research to include city-level diplomacy. This summer, he and Newland, who is also a Truman fellow, will meet with city officials, chamber of commerce members and other local groups in Los Angeles; Hartford, Connecticut; Des Moines, Iowa; and Jacksonville, Florida.

“We will solicit views from the local level both for their own sake and also to bring some of it back to share with policymakers in Washington, to help them have a better awareness of how what they are doing affects local communities,” Jaros said.

A fellow of the National Committee on U.S.-China Relations’ Public Intellectuals Program, Jaros regularly briefs state and local officials on the U.S.-China relationship. In April, he delivered a presentation at the committee’s subnational symposium, held in coordination with the University of Michigan.

Jaros said the next stage of the research includes examining the consequences of what is happening at the state level, including its policy implications.

“We see policy impacts at several different levels: city, state and federal,” he said. “This work has implications for how cities and states think about what kinds of interactions with China are appropriate right now and what kinds of caution are needed.”

Contact: Tracy DeStazio, associate director of media relations, 574-631-9958 or tdestazi@nd.edu

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JOURNAL

Publius The Journal of Federalism

DOI

10.1093/publius/pjae014 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Paradiplomacy in Hard Times: Cooperation and Confrontation in Subnational U.S.–China Relations

 

Junior rank, male sex, younger age strongly linked to ‘harmful gambling’ among UK military

Nearly 1 in 4 say gambling has affected their personal/professional lives over past year. Better, earlier, and targeted support needed, urge researchers

Peer-Reviewed Publication

BMJ GROUP

Several indicative factors, including junior rank, male sex, and younger age, are strongly linked to ‘harmful gambling’ among serving UK military personnel, finds an analysis of survey responses, published online in the journal BMJ Military Health.

Harmful gambling refers to the toll taken on finances, health, personal relationships, and  work: nearly 1 in 4 respondents reported one or other of these effects over the past year.

The findings prompt the researchers to call for the prioritisation of better, earlier, and targeted support to stave off the harmful consequences of gambling among the military.

A growing body of international evidence indicates that Armed Forces personnel may be at greater risk of experiencing harm from gambling than the general population, point out the researchers.

Gambling is usually classified as either strategic, which involves prior knowledge or skill to influence or predict outcomes—sports betting and card games, such as poker—for example, or non-strategic, which relies on luck—fruit/slot machines and casino games like roulette. 

Strategic gamblers may be more at risk of gambling harms than their non-strategic peers, explain the researchers.

To find out if there are certain characteristic factors that might help to identify a soldier at risk of gambling harms, the researchers surveyed active Armed Forces personnel from all branches and services, excluding the Royal Fleet Auxiliary (a uniformed civilian branch of the Royal Navy) in the Spring of 2023.

After excluding those who didn’t complete the survey, the final analysis is based on the responses of 608 active service military personnel.

The information sought included branch of service; full-time regular or a part-time reservist status; year of enlistment; current rank; and deployment in the past 3 years, including where, and for how long. 

Validated measures were used to assess depression, anxiety, PTSD, alcohol consumption, and suicidal thoughts over the past year. Respondents were then asked to describe their gambling activities, if any, and the consequences.

Harmful gambling risk (low to problem) was measured using a validated scale widely used around the globe for military personnel (PGSI), while the Combined Gambling Harms (CGH) measure was used to evaluate the type  and number of harms.

The average age of the respondents was 39, and most were male (85.5%), and of White British (87%) ethnicity. Most had been educated to A-level or above (80%); 30% had a postgraduate qualification. Most were in a relationship (84%) and slightly over half lived with dependent children (54%).

Current mental health issues weren’t common: depression (54; 9%), anxiety (61;10%), or PTSD (28; 4.5%). Suicidal thoughts or attempts in the past year were reported by 105 (just over 17%). 

Nearly half the respondents were classed as heavy drinkers who exceeded recommended units at any one time daily, weekly, or monthly (279; 46%). 

In all, nearly 3 out of 4 (72%; 438) said they had gambled over the past year, and 272 (45%) reported doing so within the past week. Some 74 (12%) said they had never gambled.  

The most popular activities were the National Lottery (349; 57.5%), service-related lotteries (314; 52%), and online sports betting (218; 36%). Most gamblers preferred non-strategic (302; 69%) over strategic gambling (55;13%). The rest (81;18.5%) expressed no preference.

The PGSI score indicated that 64 (12%) were at low risk of harmful gambling, 22 (just over 3.5%) were at moderate risk, and 37 (6%) were at risk of problem gambling. 

In all, nearly 1 in 4 (23%; 123) respondents who had gambled over the past year had experienced a gambling harm, with the average number of harms totalling 2. 

Over a third 36% (44) of them had experienced at least one financial harm; over a quarter said that the quality of their relationships had been affected (32; 26%), and 1 in 5 (25) said that gambling had had a detrimental impact on their ability to work. 

Certain demographic factors were predictive of harmful gambling. These included male sex (tripling in risk), age 20–29 (more than double the risk), and living alone in service accommodation (69% heightened risk). 

Significant military risk factors included junior non-commissioned officer/other rank (more than 4 times the risk), military service lasting fewer than 10 years (more than twice the risk), and deployment twice or more in the past 3 years (86% heightened risk). 

Mental health issues predictive of harmful gambling included likely depression and/or anxiety (more than 3 times the risk), risky drinking (69% heightened risk), loneliness and suicidal thoughts/attempts over the past year (twice the risk).

Strategic gamblers were 5 times as likely to be at risk of gambling harm as non-strategic gamblers.

This is an observational study, and as such, no definitive conclusions can be drawn about cause and effect. And the researchers acknowledge various limitations to their findings, including that the respondents were older than the average age (31) of Armed Forces personnel.

But they nevertheless conclude: “These findings highlight the importance of screening for gambling engagement, gambling type, mental health and alcohol use in both currently serving personnel and new recruits to the [Armed Forces].”

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JOURNAL

BMJ Military Health

DOI

10.1136/military-2024-002726 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Demographic characteristics, gambling engagement, mental health, and associations with harmful gambling risk among UK Armed Forces serving personnel

ARTICLE PUBLICATION DATE

27-Jun-2024

COI STATEMENT

SD and JL are shareholders in Soteria Global Services, a risk management business for high-performance environments.

 

New mathematical model sheds light on the absence of breastfeeding in male mammals

Being nursed by a single parent could be an evolutionary strategy to curb the spread of harmful microbes in mammals, according to a novel theory developed by mathematicians.

Peer-Reviewed Publication

UNIVERSITY OF YORK

Being nursed by a single parent could be an evolutionary strategy to curb the spread of harmful microbes in mammals, according to a novel theory developed by mathematicians.

The rainforests of Malaysia are home to the only known case of a wild male mammal that produces milk. The Dayak fruit bat is a vanishingly rare case of male milk production, despite the fact that the potential for breastfeeding remains in place in most male mammals. 

In the 1970s, evolutionary theorists posited that the near absence of lactation in males, even though offspring could benefit from the extra nutrition provided, could be attributed to the uncertainty of paternity: As male mammals can’t be sure they are the biological father, this reduces their evolutionary drive to invest heavily in offspring care, including breastfeeding.

Now, mathematicians from the University of York have suggested a complementary perspective. Their hypothesis, published in Nature Communications, suggests that the reason male mammals don’t breastfeed might be driven by the rich community of microbes that lives in breast milk and which plays an important part in establishing the gut microbiome of the infant. 

The theory demonstrates how the transmission of the milk microbiome from both parents would allow harmful microbes to spread through mammalian populations. Maternal-only lactation stops this as restricting transmission of the milk microbiome to females in effect acts as a sieve, retaining just the microbes with beneficial effects.

One of the authors of the study, Dr George Constable from the Department of Mathematics at the University of York, said: “We became fascinated with this topic when we read about Azara's owl monkeys. They turn previous assumptions about why males don’t breastfeed upside down because they are the most devoted dads in the primate world: They do 80–90% of childcare and only hand their babies back to their female partners for nursing. 

“When both parents are involved in feeding, the chance of a microbe being passed along and getting an initial foothold in a population is essentially doubled. So our theory suggests selection against the transmission of harmful microbes through mammary milk could be an additional selection pressure against male lactation.”

First author of the study, Dr Brennen Fagan working at the Leverhulme Centre for Anthropocene Biodiversity and the Mathematics Department at the University of York, added: “Breast milk is a living substance and it plays a key role in establishing the gut microbiome of mammals, which is a complex ecosystem of bacteria, viruses and fungi, along with their genetic material. This ecosystem plays a crucial role in health including by helping to protect animals against disease, helping to digest food and in many other ways we are only just discovering. 

“While microbes are not inherently harmful or beneficial; it’s their presence and abundance that dictate the overall health of this internal community. A “wrong actor” at the early point of an animal’s life could change the microbiome at a pivotal moment.”

The mathematical model highlights the advantage of getting fed by just one parent, but the researchers say it makes evolutionary sense for this to be the mother because there has already been an inevitable transmission of microbes during birth and perhaps also in the womb.

Dr Constable added: “This theory fits with a pattern of strategies mammals have adopted in an evolutionary bid to limit the spread of potentially harmful elements. Notably, in humans mitochondrial DNA is exclusively passed down from the mother. This mechanism serves as a natural filter, maintaining genetic integrity by suppressing the proliferation of detrimental mutations. Additionally, the prevalence of monogamous relationships among certain species has been suggested as an adaptive response aimed at minimising the transmission of sexually transmitted infections (STIs).”

The researchers caution that their hypothesis is not intended as the basis for any judgements about the different ways of feeding human infants.

Dr Fagan added: “Our model is very much focused on the long-term evolution of the animal kingdom. The model does not tell us about individual families making individual choices on how to safely feed their children, especially not for humans in the modern world. 

“Our hypothesis fills a gap in evolutionary theory and is concerned with selection pressures on mammals at population level and over very long periods of time spanning multiple generations.”

Maternal transmission as a microbial symbiont sieve, and the absence of lactation in male mammals is published in Nature Communications.

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JOURNAL

Nature Communications

DOI

10.1038/s41467-024-49559-5 

ARTICLE TITLE

Maternal transmission as a microbial symbiont sieve, and the absence of lactation in male mammals

ARTICLE PUBLICATION DATE

27-Jun-2024

SOCCER

Only 4% of teen football academy prospects make top tier

UNIVERSITY OF ESSEX

Just four per cent of talented teen academy prospects make it to the top tier of professional football, a new study has shown.

A sample of nearly 200 players, aged between 13-18, also revealed only six per cent of the budding ballers even go on to play in lower leagues.

The University of Essex researchers discovered the players who succeeded excelled in self-confidence, ball reception skills, dribbling and coaches’ subjective technical assessments.

The study – published in the International Journal of Sports Science & Coaching - looked at players within the academy system in the 2009-2011 cohort and then traced their progress 10 years after their final academy test.

Dr Jason Moran, from the School of Sport, Rehabilitation, and Exercise Sciences, looked at elite Spanish academies for two LaLiga teams in Madrid, over the course of 10 years.

It is one of the most watched club competitions in the world - featuring the like of FC Barcelona, Real Madrid, and Villareal - and reaches 2.8billion people globally.

It is hoped the research will shine a light on the implications and economics of the academies amid the high-profile closure and re-opening of English Premier League side Brentford FC.

Dr Moran said: “This leaves us at a crossroads in terms of the role of the modern football academy.

“As many as 95% of teenage players aren’t ‘making it’ to pro football, yet they are continuing through these academies incurring the stresses and strains that go with intensive professional training, before they are eventually deselected.

“The question must therefore be asked if academies are providing appropriate developmental experiences for the large proportion of players who are deselected from their systems?

“This relates to anything from physical literacy, to educational initiatives to prepare for life post-football.”

It also emerged none of the players who ran out professional sides were born in the last quarter of the year and 44% of all the academy players were born in January, February, or March.

Meaning coaches may have a bias against smaller less-developed athletes who are technically sound.

Of the 12 players who became professionals, seven reached Spain's highest professional league at some point in the decade.

Five also played for teams in Spain's second highest professional league and four played abroad.

Previous studies on Premier League academies have shown just one per cent of under-nine players make it to the top tier.

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JOURNAL

International Journal of Sports Science & Coaching

DOI

10.1177/17479541241254767 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

The identification and development of young talent in Spanish soccer academies: A 10-year multi-study follow-up