Tag: cognitive ability

Categories : NeurologyTags :

New Insights into Sleep Uncover Mechanism for Enhancing Cognitive Function

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While it’s well known that sleep enhances cognitive performance, the underlying neural mechanisms, particularly those related to nonrapid eye movement (NREM) sleep, remain largely unexplored. A new study by a team of researchers coordinated by Rice University’s Valentin Dragoi, has nonetheless uncovered a key mechanism by which sleep enhances neuronal and behavioural performance, potentially changing our fundamental understanding of how sleep boosts brainpower.

The research, published in Science, reveals how NREM sleep – such as in a nap – fosters brain synchronisation and enhances information encoding, shedding new light on this sleep stage. The researchers replicated these effects through invasive stimulation, suggesting promising possibilities for future neuromodulation therapies in humans. The implications of this discovery potentially pave the way for innovative treatments for sleep disorders and even methods to enhance cognitive and behavioural performance.

The investigation involved an examination of the neural activity in multiple brain areas in macaques while the animals performed a visual discrimination task before and after a 30-minute period of NREM sleep. Using multielectrode arrays, the researchers recorded the activity of thousands of neurons across three brain areas: the primary and midlevel visual cortices and the dorsolateral prefrontal cortex, which are associated with visual processing and executive functions. To confirm that the macaques were in NREM sleep, researchers used polysomnography to monitor their brain and muscle activity alongside video analysis to ensure their eyes were closed and their bodies relaxed.

The findings demonstrated that sleep improved the animals’ performance in the visual task with enhanced accuracy in distinguishing rotated images. Meanwhile, the macaques that experienced quiet wakefulness without falling asleep did not show the same performance boost.

“During sleep, we observed an increase in low-frequency delta wave activity and synchronised firing among neurons across different cortical regions,” said first author Dr Natasha Kharas. “After sleep, however, neuronal activity became more desynchronised compared to before sleep, allowing neurons to fire more independently. This shift led to improved accuracy in information processing and performance in the visual tasks.”

The researchers also simulated the neural effects of sleep through low-frequency electrical stimulation of the visual cortex. They applied a 4-Hz stimulation to mimic the delta frequency observed during NREM sleep while the animals were awake. This artificial stimulation reproduced the desynchronization effect seen after sleep and similarly enhanced the animals’ task performance, suggesting that specific patterns of electrical stimulation could potentially be used to emulate the cognitive benefits of sleep.

“This finding is significant because it suggests that some of the restorative and performance-enhancing effects of sleep might be achieved without the need for actual sleep,” said Dragoi, study co-author, professor of electrical and computer engineering at Rice and professor of neuroscience at Weill Cornell. “The ability to reproduce sleeplike neural desynchronisation in an awake state opens new possibilities for enhancing cognitive and perceptual performance in situations where sleep is not feasible – such as for individuals with sleep disorders or in extenuating circumstances such as space exploration.”

The researchers further investigated their findings by building a large neural network model. They found that during sleep, both excitatory and inhibitory connections in the brain become weaker, but they do so asymmetrically, making inhibitory connections weaker than excitatory connections, which causes an increase in excitation.

“We have uncovered a surprising solution that the brain employs after sleep whereby neural populations participating in the task reduce their level of synchrony after sleep despite receiving synchronizing inputs during sleep itself,” Dragoi said.

The idea that NREM sleep effectively “boosts” the brain in this way, and that this resetting can be mimicked artificially, offers potential for developing therapeutic brain stimulation techniques to improve cognitive function and memory.

“Our study not only deepens our mechanistic understanding of sleep’s role in cognitive function but also breaks new ground by showing that specific patterns of brain stimulation could substitute for some benefits of sleep, pointing toward a future where we might boost brain function independently of sleep itself,” Dragoi said.

Source: Rice University

Categories : Obstetrics & GynaecologyTags :

Short-term Menopausal Hormone Therapy has no Long-term Cognitive Impact

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Women in early postmenopause taking short-term MHT had no cognitive effects a decade later

Short-term menopausal hormone therapy (MHT) did not have long-term cognitive effects when given to women in early postmenopause, according to a study published November 21st in the open-access journal PLOS Medicine by Carey Gleason from the University of Wisconsin-Madison, USA, and colleagues.

While MHT can offer relief from the challenging symptoms of menopause, many women and doctors are hesitant to start MHT due to safety concerns. Previous research has linked one form of hormone therapy to mild cognitive impairment and dementia in women older than 65 years of age, prompting research on the importance of age and timing of therapy on cognitive impairment. Other studies have suggested that transdermal oestrogen may have long-term cognitive benefits.

In the Kronos Early Estrogen Prevention Study (KEEPS), women in early postmenopause with good cardiovascular health were randomised to receive one of two types of MHT (oral or transdermal oestrogen) or placebo. At the end of four years, no cognitive benefit or harm was seen in those who received MHT compared to the placebo group. However, long-term cognitive effects of MHT are still understudied.

In this new follow-up study – the KEEPS Continuation Study – researchers revisited participants nearly ten years later to repeat a series of cognitive tests. Among 275 women, although MTH failed to protect against cognitive decline, short-term MHT also had no long-term negative cognitive impact.

These findings may offer reassurance to women considering MHT while adding to the growing body of research supporting the importance of timing for MHT. More research is needed to investigate whether these results are generalisable to women with higher cardiovascular risk.

The authors add, “For women in menopause and the health care providers caring for them, getting direct, clear and evidence-based information about menopausal hormone therapy is challenging. And they need data to guide their decisions.”

Provided by PLOS

Categories : Exercise NeurologyTags :

Workouts – or Disturbed Sleep – Impact Brain Activity Weeks Later

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In a rare, longitudinal study, researchers from Aalto University and the University of Oulu tracked one person’s brain and behavioural activity for five months using brain scans and data from wearable devices and smartphones. The results appear in PLOS Biology.

“We wanted to go beyond isolated events,” says research leader (and study participant) Ana Triana. “Our behaviour and mental states are constantly shaped by our environment and experiences. Yet, we know little about the response of brain functional connectivity to environmental, physiological, and behavioural changes on different timescales, from days to months.”

The study found that the brain does not respond to daily life in immediate, isolated bursts. Instead, brain activity evolves in response to sleep patterns, physical activity, mood, and respiration rate over many days. This suggests that even a workout or a restless night from last week could still affect the brain – and therefore attention, cognition and memory – well into next week.

The research also revealed a strong link between heart rate variability – a measure of the heart’s adaptability – and brain connectivity, particularly during rest. This suggests that impacts on the body’s relaxation response, like stress management techniques, could shape brain wiring even when not actively concentrating on a task. Physical activity was also found to positively influence the way brain regions interact, potentially impacting memory and cognitive flexibility. Even subtle shifts in mood and heart rate left lasting imprints for up to 15 days.

Study goes beyond a snapshot

The research is unusual in that few brain studies involve detailed monitoring over days and weeks. “The use of wearable technology was crucial,” says Triana. “Brain scans are useful tools, but a snapshot of someone lying still for half an hour can only show so much. Our brains do not work in isolation.”

Triana was herself the subject of the research, monitored as she went about her daily life. Her unique role as both lead author and study participant added complexity, but also brought firsthand insights into how best to maintain research integrity over several months of personalised data collection.  Data from the devices and twice-weekly brain scans were complemented by qualitative data from mood surveys. 

The researchers identified two distinct response patterns: a short-term wave lasting under seven days and a long-term wave up to 15 days. The former reflects rapid adaptations, like how focus is impacted by poor sleep, but it recovers quickly. The long wave suggests more gradual, lasting effects, particularly in areas tied to attention and memory. 

Single-subject studies offer opportunities for improving mental health care 

The researchers hope their innovative approach will inspire future studies that combine brain data with everyday life to help personalise mental health treatment. 

“We must bring data from daily life into the lab to see the full picture of how our habits shape the brain, but surveys can be tiring and inaccurate,” says study co-author, neuroscientist and physician Dr Nick Hayward. “Combining concurrent physiology with repeated brain scans in one person is crucial. Our approach gives context to neuroscience and delivers very fine detail to our understanding of the brain.”

The study is also a proof-of-concept for patient research. Tracking brain changes in real time could help detect neurological disorders early, especially mental health conditions where subtle signs might be missed.

“Linking brain activity with physiological and environmental data could revolutionise personalised healthcare, opening doors for earlier interventions and better outcomes,” says Triana.

Source: Aalto University

Categories : GenderTags :

Women’s Mental Agility is Better During Their Periods

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New research involving female football players has shown that they react more quickly and accurately during their periods, despite them feeling that they perform worse. The study, published in Neuropsychologia, is the first to assess sport-related cognition during the menstrual cycle and is part of a larger research project supported by the FIFA Research Scholarship.

The findings, from University College London, act as a proof-of-principle that specific types of cognition fluctuate throughout the menstrual cycle, which could have implications for injury and other aspects of women’s health.

Previous sports medicine research has shown that women seem to be at greater risk of sport-related injury during the luteal phase, which is the time between ovulation and menstruation. This is possibly related to the significant hormonal changes that occur throughout the menstrual cycle. But precisely how these changes are linked to an increased likelihood of injury are unknown at present.

In this study, researchers at UCL and ISEH collected reaction time and error data from 241 participants who completed a battery of cognitive tests 14 days apart. Participants also completed a mood scale and a symptom questionnaire twice. Period-tracking apps were used to estimate which phase of their cycle the participants were in when they took the tests.

The tests were designed to mimic mental processes that are typical in team sports. In one test, participants were shown smiling or winking faces and asked to press the space bar only when they saw a smiley face, to test inhibition, attention, reaction time and accuracy. In another, they were asked to identify mirror images in a 3D rotation task, which assesses spatial cognition. A task that asked them to click when two moving balls collide on screen measured spatial timing.

Though participants reported feeling worse during menstruation and perceived that this negatively impacted their performance, their reaction times were faster and they made fewer errors. For example, their timing was on average 10 milliseconds (12%) more accurate in the moving balls task, and they pressed the space bar at the wrong time 25% less in the inhibition task.

Participants’ reaction times were slower during the luteal phase, which begins after ovulation and lasts between 12–14 days up to the beginning of menstruation. They were on average 10–20 milliseconds slower compared to being in any other phase, but their error rate was unchanged.

Dr Flaminia Ronca, first author of the study from UCL Division of Surgery and Interventional Science and ISEH, said: “Research suggests that female athletes are more likely to sustain certain types of sports injuries during the luteal phase and the assumption has been that this is due to biomechanical changes as a result of hormonal variation. But I wasn’t convinced that physical changes alone could explain this association.

“Given that progesterone has an inhibitory effect on the cerebral cortex and oestrogen stimulates it, making us react slower or faster, we wondered if injuries could be a result of a change in athletes’ timing of movements throughout the cycle.

“What is surprising is that the participant’s performance was better when they were on their period, which challenges what women, and perhaps society more generally, assume about their abilities at this particular time of the month.

“I hope that this will provide the basis for positive conversations between coaches and athletes about perceptions and performance: how we feel doesn’t always reflect how we perform.”

To put the findings in context, the authors say the fluctuation in timing could be the difference between an injury or not. Previous research has shown that a variation of just 10 milliseconds can mean the difference between a concussion and a lesser injury, for example. In the colliding balls task, participants’ timing was on average 12 milliseconds slower during the luteal phase compared to every other phase, a difference of 16%.

Dr Megan Lowery, an author of the study from UCL Surgery & Interventional Science and ISEH, said: “There’s lots of anecdotal evidence from women that they might feel clumsy just before ovulation, for example, which is supported by our findings here. My hope is that if women understand how their brains and bodies change during the month, it will help them to adapt.

“Though there’s a lot more research needed in this area, these findings are an important first step towards understanding how women’s cognition affects their athletic performance at different points during their cycle, which will hopefully facilitate positive conversations between coaches and athletes around performance and wellbeing.”

Professor Paul Burgess, senior author of the study from UCL’s Institute of Cognitive Neuroscience, said: “This study emerged from listening carefully to female soccer players and their coaches. We created bespoke cognitive tests to try to mimic the demands made upon the brain at the points in the game where they were telling us that injuries and problems of timing occur at certain times of the menstrual cycle.

“As suggested by what the soccer players had told us, the data suggested that women who menstruate – whether they are athletes or not – do tend to vary in their performance at certain stages of the cycle. As a neuroscientist, I am amazed that we don’t already know more about this, and hope that our study will help motivate increasing interest in this vital aspect of sports medicine.”

Source: University College London

Categories : Diet and Nutrition NeurologyTags :

Study Reveals ‘Profound’ Link between Dietary Choices and Brain Health

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New research published in Nature has shown that a healthy, balanced diet was linked to superior brain health, cognitive function and mental wellbeing. The study, involving researchers at the University of Warwick, sheds light on how food preferences influence more than just physical health, and also significantly impact brain health.

With the help of machine learning, the researchers analysed a large sample of 181 990 participants from the UK Biobank, comparing their dietary choices against a range of physical evaluations, including cognitive function, blood metabolic biomarkers, brain imaging, and genetics.

The food preferences of each participant were collected via an online questionnaire, which the team categorised into 10 groups (eg, alcohol, fruits and meats).

A balanced diet was associated with better mental health, superior cognitive functions and even higher amounts of grey matter in the brain – linked to intelligence – compared with those with a less varied diet.

The study also highlighted the need for gradual dietary modifications, particularly for individuals accustomed to highly palatable but nutritionally deficient foods. By slowly reducing sugar and fat intake over time, individuals may find themselves naturally gravitating towards healthier food choices.

Genetic factors may also contribute to the association between diet and brain health, the scientists believe, showing how a combination of genetic predispositions and lifestyle choices shape wellbeing.

Lead Author Professor Jianfeng Feng, University of Warwick, emphasised the importance of establishing healthy food preferences early in life. He said: “Developing a healthy balanced diet from an early age is crucial for healthy growth. To foster the development of a healthy balanced diet, both families and schools should offer a diverse range of nutritious meals and cultivate an environment that supports their physical and mental health.”

Source: University of Warwick

Categories : Metabolic Disorders NeurologyTags :

Liraglutide Boosts Associative Learning in People with Obesity

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Obesity leads to altered energy metabolism and reduced insulin sensitivity of cells. The so-called “anti-obesity drugs” such as liraglutide are increasingly used to treat obesity and have caused tremendous interest, especially in the USA. Researchers in Germany have now shown in people with obesity that reduced insulin sensitivity affects learning of sensory associations. The results, published in Nature Metabolism, showed that a single dose of liraglutide was able to normalise these changes and restore the underlying brain circuit function.

The brain must be able to form associations in order to control behaviour. This involves, for example, associating a neutral external stimulus with a consequence following the stimulus. In this way, the brain learns what the implication of handling of the first stimulus are. Associative learning is the basis for forming neural connections and gives stimuli their motivational force. It is essentially controlled by a brain region called the dopaminergic midbrain. This region has many receptors for the body’s signalling molecules, such as insulin, and can thus adapt behaviour to the body’s physiological needs.

But what happens when the body’s insulin sensitivity is reduced due to obesity? Does this change brain activity, ability to learn associations and thus behaviour? Researchers at the Max Planck Institute for Metabolism Research have now measured how well the learning of associations works in participants with normal body weight (high insulin sensitivity, 30 volunteers) and in participants with obesity (reduced insulin sensitivity, 24 volunteers), and if this learning process is influenced by the anti-obesity drug liraglutide.

Low insulin sensitivity reduces the brain’s ability to associate sensory stimuli.

In the evening, they injected the participants with either the drug liraglutide or a placebo in the evening. Liraglutide is a so-called GLP-1 agonist, which activates the GLP-1 receptor in the body, stimulating insulin production and producing a feeling of satiety. It is often used to treat obesity and type 2 diabetes and is given once a day. The next morning, the subjects were given a learning task that allowed the researchers to measure how well associative learning works. They found that the ability to associate sensory stimuli was less pronounced in participants with obesity than in those of normal weight, and that brain activity was reduced in the areas encoding this learning behaviour.

After just one dose of liraglutide, participants with obesity no longer showed these impairments, and no difference in brain activity was seen between participants with normal weight and obesity. In other words, the drug returned the brain activity to the state of normal-weight subjects.

“These findings are of fundamental importance. We show here that basic behaviours such as associative learning depend not only on external environmental conditions but also on the body’s metabolic state. So, whether someone has overweight or not also determines how the brain learns to associate sensory signals and what motivation is generated. The normalisation we achieved with the drug in subjects with obesity, therefore, fits with studies showing that these drugs restore a normal feeling of satiety, causing people to eat less and therefore lose weight,” says study leader Marc Tittgemeyer from the Max Planck Institute for Metabolism Research.

“While it is encouraging that available drugs have a positive effect on brain activity in obesity, it is alarming that changes in brain performance occur even in young people with obesity without other medical conditions. Obesity prevention should play a much greater role in our healthcare system in the future. Lifelong medication is the less preferred option in comparison primary prevention of obesity and associated complications,” says Ruth Hanßen, first author of the study and a physician at the University Hospital of Cologne.

Source: Max Planck Institute for Biology of Ageing

Categories : Obstetrics & Gynaecology PaediatricsTags :

Elective Induced Labour Associated with Lower Grades at Age 12

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According to a new study published in Acta Obstetricia et Gynecologica Scandinavica, in women with uncomplicated pregnancies, elective induction of labour at any point between 37 and 41 weeks was consistently associated with those children having lower scholasti performance at age 12.

Investigators analysed data for 266 684 children born between 37 and 42 weeks from uncomplicated pregnancies in white women in the Netherlands. Scholastic performance scores at age 12 years were lower in those from pregnancies with induced labour at 37–41 weeks compared with those with uninduced labour. At 42 weeks, there was no significant difference in scholastic performance between these groups.

The proportion of children who reached higher secondary school level was significantly lower after induction of labour at each gestational week from 38–41 weeks. For example, at 38 weeks, rates were 48% versus 54% in induced versus uninduced. (In the Dutch education system, when children reach the end of primary school, around 12 years of age, they are divided over four different levels of secondary education according to their intellectual ability. All children in the last year of regular primary education take a test to guide the choice of level of secondary education.)

“Of course, if there is an indication to induce delivery before 41 weeks, there is little doubt we should do this. But if the reason is purely elective, it is reasonable to be cautious of these subtle adverse effects,” said Wessel Ganzevoort, MD, PhD, senior investigator and maternal foetal medicine specialist at Amsterdam UMC.

Source: Wiley

Categories : Neurology PaediatricsTags :

Greater Cognitive Skills in Children who Play More Video Games

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Analysing magnetic resonance imaging (MRI) brain scans of nearly 2000 children, researchers found children who played video games for three or more hours a day did better in cognitive skills tests involving impulse control and working memory compared to children who had never played video games. Published in JAMA Network Open, this study analysed data from the ongoing Adolescent Brain Cognitive Development (ABCD) Study, which is supported by the and other entities of the National Institutes of Health.

“This study adds to our growing understanding of the associations between playing video games and brain development,” said National Institute on Drug Abuse (NIDA) Director Nora Volkow, MD. “Numerous studies have linked video gaming to behaviour and mental health problems. This study suggests that there may also be cognitive benefits associated with this popular pastime, which are worthy of further investigation.”

Although a number of studies have investigated the relationship between video gaming and cognitive behaviour, the neurobiological mechanisms underlying the associations are not well understood. Only a handful of neuroimaging studies have addressed this topic, and the sample sizes for those studies have been small, with fewer than 80 participants.

To address this research gap, scientists at the University of Vermont, Burlington, analysed data obtained when children entered the ABCD Study at ages 9 and 10 years old. The research team examined survey, cognitive, and brain imaging data from nearly 2000 participants from within the bigger study cohort, comparing those who reported playing no video games at all and those who reported playing video games for three hours per day or more. This threshold was selected as it exceeds the American Academy of Paediatrics screen time guidelines, which recommend limiting videogames to one to two hours per day for older children. Researchers assessed their performance in two tasks that reflected the children’s ability to control impulsive behaviour and to memorise information, as well as brain activity while performing the tasks.

The researchers found that the children who reported playing video games for three or more hours per day were faster and more accurate on both cognitive tasks than those who never played. They also observed that the differences in cognitive function observed between the two groups was accompanied by differences in brain activity. Functional MRI brain scans found that children who played video games for three or more hours per day showed higher brain activity in regions of the brain associated with attention and memory than in never-gamers. At the same time, those children who played at least three hours of videogames per day showed more brain activity in frontal brain regions that are associated with more cognitively demanding tasks and less brain activity in brain regions related to vision.  

The researchers think these patterns may stem from practicing tasks related to impulse control and memory while playing videogames, which can be cognitively demanding, and that these changes may lead to improved performance on related tasks. Furthermore, the comparatively low activity in visual areas among children who reported playing video games may reflect that this area of the brain may become more efficient at visual processing as a result of repeated practice through video games.

While prior studies have reported associations between video gaming and increases in depression, violence, and aggressive behaviour, this study did not find that to be the case. The three hours or more group tended to report higher mental health and behavioural issues compared to the non-gaming children, but was not statistically significant. The researchers note that this will be an important measure to continue to track and understand as the children mature.

Further, the researchers stress that this cross-sectional study does not allow for cause-and-effect analyses, and that it could be that children who are good at these types of cognitive tasks may choose to play video games. The authors also emphasise that their findings do not mean that children should spend unlimited time on their computers, mobile phones, or TVs, and that the outcomes likely depend largely on the specific activities children engage in. For instance, they hypothesise that the specific genre of video games, such as action-adventure, puzzle solving, sports, or shooting games, may have different effects for neurocognitive development, and this level of specificity on the type of video game played was not assessed by the study.

“While we cannot say whether playing video games regularly caused superior neurocognitive performance, it is an encouraging finding, and one that we must continue to investigate in these children as they transition into adolescence and young adulthood,” said Bader Chaarani, PhD, assistant professor of psychiatry at the University of Vermont and the lead author on the study. “Many parents today are concerned about the effects of video games on their children’s health and development, and as these games continue to proliferate among young people, it is crucial that we better understand both the positive and negative impact that such games may have.”

Through the ABCD Study, researchers will be able to track these children into young adulthood, looking for gaming-related changes in cognitive skills, brain activity, behaviour, and mental health.

Source: National Institutes of Health

Categories : Gender NeurologyTags :

Do Women Have the Edge in Remembering Words?

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Women are popularly believed at being better at finding and remembering words than men, but are the popular science textbooks which proclaim this actually correct? If so, this has relevance for tests such as measures of dementia. Researchers investigated this supposed difference, publishing their findings in Perspectives on Psychological Science.

Marco Hirnstein, professor at The University of Bergen, Norway, is unequivocal about the results. “Women are better. The female advantage is consistent across time and life span, but it is also relatively small.”

Prof Hirnstein is interested in how biological, psychological, and social factors contribute to sex/gender differences in cognitive abilities and what the underlying brain mechanisms are.

“So far, the focus has mostly been on abilities, in which men excel. However, in recent years the focus has shifted more towards women,” said Prof Hirnstein.

Textbooks and popular science books take it for granted that women are better at finding words. For example, when naming words that begin with the letter “F,” or words that belong to a certain category like animals or fruits. It has also been considered “fact” that women are better at remembering words.

Yet, the actual findings are much more inconsistent than textbooks imply: Some studies find a female advantage, some find a male advantage, some do not find any advantage.

“Most intellectual skills show no or negligible differences in average performance between men and women. However, women excel in some tasks, while men excel in others on average.”

Prof Hirnstein and his colleagues point out how their findings can be useful in diagnosis and in healthcare. The results help to clarify whether the female advantage is real but also have relevance for for interpreting the results of diagnostic assessments.

For example, to diagnose dementia, knowing that women are generally better in those tasks is critical to not under-diagnose women, due to their better average, baseline performance and not over-diagnose men. Currently, many but not all assessments take sex/gender into account.

The researchers conducted a meta-analysis of the available literatures, encompassing more than 500 measures from more than 350,000 participants. The researchers found that women are indeed better. The advantage is small but consistent across the last 50 years and across an individual’s lifespan.

Moreover, they found that the female advantage depends on the sex/gender of the leading scientist: Female scientists report a larger female advantage, male scientists report a smaller female advantage.

Source: University of Bergen