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(https://www.psypost.org/brain-connections-to-the-amygdala-predict-withdrawn-and-depressive-behaviors-in-children/) Brain connections to the amygdala predict withdrawn and depressive behaviors in children
Oct 17th 2024, 10:00

A new study published in (https://www.sciencedirect.com/science/article/pii/S0925492724001008) Psychiatry Research: Neuroimaging sheds light on the brain connections linked to withdrawn and depressive behaviors in children. By analyzing brain scans of over 6,000 children, researchers found that connections between the left amygdala, a part of the brain that processes emotions, and other brain regions were associated with these internalizing behaviors.
Childhood is a critical time for understanding the early markers of mental health issues. Many psychological problems, such as anxiety and depression, often begin in childhood or adolescence and can persist into adulthood if not identified and treated early. Internalizing behaviors, like withdrawal and depression, are forms of distress that manifest inwardly, making them more challenging to detect than outwardly directed behaviors such as aggression. These behaviors can also indicate a higher risk of developing mental health disorders later in life.
Previous research has suggested that the amygdala, a brain region known for its role in processing emotions, plays a role in anxiety and depression. However, many prior studies had small sample sizes, limiting the reliability of the findings. The new study, using data from the large-scale Adolescent Brain Cognitive Development (ABCD) study, aimed to clarify the connections between the amygdala and other brain regions in a large, diverse population of children, providing more generalizable results.
“I have always been interested in identifying ways to improve the diagnosis and treatment of mental illnesses. My interest in internalizing behavior stems from my behaviors—I always say ‘research is me-search,'” said study author Elina Thomas, an assistant professor of neuroscience at Earlham College.
The researchers used data from the ABCD study, which tracks the development of thousands of children across the United States. For their study, they analyzed brain scans and behavioral reports from 6,371 children aged 9 to 10 years old. The brain scans used a technique called resting-state functional magnetic resonance imaging (fMRI), which measures brain activity by detecting changes in blood flow. The researchers focused specifically on the connections between the left and right amygdala and other brain regions, examining how these connections might be linked to different internalizing behaviors.
Parents provided information on their child’s behaviors using a standardized questionnaire, the Child Behavior Checklist (CBCL), which measures internalizing behaviors like depression, anxiety, and withdrawal. The researchers also gathered additional data on factors that might influence these behaviors, including whether the children had experienced traumatic events, their genetic predisposition to depression, and demographic information such as age, sex, and parental education.
The researchers did not find significant associations between overall internalizing behavior (a broader category that includes anxiety, depression, and somatic complaints) and amygdala connectivity. This suggests that specific components of internalizing behavior may have distinct brain correlates, rather than all internalizing behaviors being linked to the same brain networks.
“I was surprised that we did not see associations between amygdala connectivity and internalizing symptoms overall, as this has been shown many times in the literature,” Thomas told PsyPost. “I suspect this is due to the small sample sizes typically used to examine these associations.”
When examining specific components of internalizing behavior, the researchers observed that stronger connections between the left amygdala and regions involved in attention and social behaviors—such as the dorsal attention network and the frontoparietal network—were linked to higher levels of social anxiety, social impairment, and social problems. These networks are responsible for maintaining attention and helping the brain process sensory information from the world, making them important for how individuals interact with others.
Interestingly, stronger connections between the left amygdala and the dorsal attention network were associated with more severe social anxiety, while connections with the frontoparietal network were linked to greater social impairment. On the other hand, a connection between the amygdala and an auditory processing area was related to fewer social problems. These findings suggest that the way the amygdala communicates with different parts of the brain may influence how children experience and navigate social situations, particularly when they are feeling anxious or withdrawn.
“Mental illness is not binary,” Thomas explained. “That is to say, typically, an individual does not fit entirely into the box of one mental illness. Symptoms exist on a spectrum and should be measured accordingly. One way to do this is by looking at different subcomponents that make up a typical behavior. Our study shows that the subcomponents associated with internalizing behavior are more closely linked to the brain than the overall construct, suggesting future studies should look at these different components separately.”
While this study provides valuable insights into the brain networks associated with internalizing behaviors in children, it also has some limitations. First, the study only looked at a single snapshot in time, meaning that it cannot show how these brain connections and behaviors change as children grow older. The authors suggest that future research should explore how these brain networks develop over time, especially as many mental health issues become more pronounced in adolescence. A longitudinal approach could help determine whether these brain connections are stable markers of mental health risk or if they change as children mature.
Additionally, while the study found significant associations between certain amygdala connections and social behaviors, the effect sizes were relatively small. This is not uncommon in large studies, as small effects can still be meaningful when studying complex behaviors like depression and anxiety. Nonetheless, it suggests that these brain connections are likely only part of the puzzle when it comes to understanding internalizing behaviors in children.
“Our sample was made up of children with low levels of internalizing behavior because it was a healthy sample; we might have seen different associations in a sample with higher internalizing behaviors, or diagnosed anxiety or depression,” Thomas said.
“My lab is currently examining environmental factors that might impact amygdala connectivity, particularly perceived discrimination. We have already found a significant connection between perceived discrimination and internalizing behavior, suggesting one may lead to the other.”
The study, “(https://doi.org/10.1016/j.pscychresns.2024.111877) Amygdala connectivity is associated with withdrawn/depressed behavior in a large sample of children from the Adolescent Brain Cognitive Development (ABCD) Study,” was authored by Elina Thomas, Anthony Juliano, Max Owens, Renata B. Cupertino, Scott Mackey, Robert Hermosillo, Oscar Miranda-Dominguez, Greg Conan, Moosa Ahmed, Damien A. Fair, Alice M. Graham, Nicholas J. Goode, Uapingena P. Kandjoze, Alexi Potter, Hugh Garavan, and Matthew D. Albaugh.

(https://www.psypost.org/asian-workers-hit-hard-by-job-losses-wage-cuts-as-anti-asian-sentiment-rose-under-trump-new-study-shows/) Asian workers hit hard by job losses, wage cuts as anti-Asian sentiment rose under Trump, new study shows
Oct 17th 2024, 09:00

A study published in (https://www.nature.com/articles/s41562-024-01904-w) Nature Human Behaviour provides evidence that anti-Asian sentiment during the COVID-19 pandemic, fueled in part by political rhetoric from Donald Trump and conservative media outlets, had serious economic consequences for Asian workers in the United States. The research found that Asian individuals in jobs requiring face-to-face interaction were more likely to experience unemployment and significant wage cuts compared to other racial groups. These labor market disparities are linked to the rise in unfavorable public opinion toward Asian people, especially among Trump voters and Fox News viewers.
Anti-Asian sentiment surged following the outbreak of the COVID-19 pandemic, largely fueled by political rhetoric and media portrayal. As the virus spread, public figures, including then-President Donald Trump, began referring to it as the “Chinese virus” and “kung flu,” which many perceived as inflammatory and racist. This language, echoed by some media outlets, contributed to widespread xenophobia and a sharp rise in hate incidents against people of Asian descent in the United States.
According to reports, one in five Asian Americans experienced hate incidents in 2020 and 2021, while anti-Asian hate crimes in large U.S. cities spiked by over 180% during the early months of 2021. This rhetoric not only led to social hostility but also raised concerns about its economic impact, particularly regarding potential discrimination in the labor market.
The researchers were motivated to explore whether this surge in anti-Asian sentiment had measurable economic consequences for Asian workers in the U.S. labor market. They aimed to investigate whether negative public opinion toward Asian people, exacerbated by political rhetoric like Trump’s, resulted in higher rates of unemployment and reduced earnings for Asian workers.
To investigate this question, the researchers used several data sources, including labor market data from the U.S. Current Population Survey (CPS), public opinion data from the Nationscape survey, and 2016 U.S. presidential election data. The CPS provided monthly employment and earnings information from a large, nationally representative sample of U.S. workers. The researchers analyzed this data from January 2019 to May 2021, allowing them to compare employment outcomes before and after the onset of the pandemic.
They focused on workers between the ages of 18 and 70 and categorized them by race and ethnicity, with an emphasis on Asian, Black, Hispanic, and white (non-Hispanic) workers. In addition to standard employment measures, they also created a metric to capture the degree to which different occupations required face-to-face interaction, based on telework data collected during the pandemic.
Public opinion data from the Nationscape survey allowed the researchers to track shifts in attitudes toward Asian people before and after the pandemic. Survey respondents were asked to rate how favorable their impressions were of different racial and ethnic groups, including Asian people. The researchers also analyzed this data to determine whether changes in attitudes were more pronounced among those who had voted for Donald Trump in the 2016 presidential election or were regular viewers of Fox News, as both groups were more likely to be exposed to anti-Asian rhetoric during the pandemic.
The study’s findings revealed a stark difference in labor market outcomes for Asian workers compared to other racial groups during the pandemic. Asian workers, particularly those in jobs that required face-to-face interaction, were more likely to experience unemployment. For instance, the study found that Asian workers in such jobs were about 7% more likely to lose their jobs than their white counterparts. Interestingly, this increased risk of unemployment did not apply equally to Black or Hispanic workers, who did not see similar outcomes in face-to-face roles.
In addition to higher unemployment rates, the study also found that Asian workers who remained employed in face-to-face jobs saw significant reductions in their earnings during the pandemic. On average, these workers earned $76 less per week than white workers in similar roles, a substantial financial loss. This earnings penalty was far greater than the gap typically seen between workers with and without college degrees, indicating that Asian workers faced unique challenges in the labor market during the pandemic.
The researchers concluded that these negative labor market outcomes were likely tied to the rise in anti-Asian sentiment. Public opinion data showed a marked increase in unfavorable views toward Asian individuals during the early months of the pandemic, particularly among Trump voters and Fox News viewers. This change in sentiment appeared to correspond with the timing of labor market disruptions, suggesting that racial bias played a role in the employment and earnings losses faced by Asian workers.
While the study provides important insights into the relationship between public opinion and labor market outcomes, it does have some limitations. The researchers note that they were unable to establish direct causal links between changes in public opinion and the specific employment and earnings outcomes of individual workers. Although they provide strong evidence that anti-Asian sentiment played a significant role, other factors, such as differing responses to the pandemic by industry or region, could also have contributed to the labor market outcomes observed in the data.
Despite these limitations, the study highlights the potentially harmful economic consequences of xenophobic rhetoric and negative shifts in public opinion toward underrepresented racial and ethnic groups. The findings raise concerns about the broader implications of divisive political rhetoric and media messaging for racial minorities, particularly in times of crisis. The researchers suggest that future work could further investigate the specific mechanisms through which public opinion affects labor market outcomes, as well as explore whether other underrepresented groups might be similarly vulnerable to economic harms during periods of rising social tensions.
The study, “(https://doi.org/10.1038/s41562-024-01904-w) Public opinion, racial bias and labour market outcomes in the USA,” was authored by Kaveh Majlesi, Silvia Prina, and Paul Sullivan.

(https://www.psypost.org/taking-medicinal-cannabis-oil-for-insomnia-does-not-impair-cognition-on-the-following-day/) Taking medicinal cannabis oil for insomnia does not impair cognition on the following day
Oct 17th 2024, 08:00

A recent placebo-controlled study investigated the potential effects of medicinal cannabis oil taken for insomnia on cognitive and psychomotor abilities the following day. The study found no significant differences in 27 out of 28 tests of cognitive function, psychomotor skills, and simulated driving performance. The research was published in (https://doi.org/10.1007/s00213-024-06595-9) Psychopharmacology.
Cannabis is a plant that contains cannabinoids, the most well-known of which are tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is the primary psychoactive component responsible for the “high” associated with recreational cannabis use, while CBD is non-psychoactive and often utilized for its potential therapeutic effects. Beyond recreational use, cannabinoids have been studied for their medicinal properties, with cannabis products showing promise in treating conditions such as chronic pain, anxiety, epilepsy, and inflammation.
Medicinal cannabis oil, derived from the cannabis plant, can contain either CBD alone or a combination of CBD and THC. This combination is often used to treat various health conditions, including insomnia. The use of medicinal cannabis oil is regulated in many countries, with its legal status varying by region.
Study author Anastasia Suraev and her colleagues aimed to investigate whether medicinal cannabis oil taken before sleep to treat insomnia results in cognitive impairment the following day. Their study examined the effects of a single dose of medicinal cannabis oil on next-day cognitive function in adults with insomnia disorder.
The study analyzed data from a larger experiment that assessed the effects of THC and CBD on sleep in individuals with insomnia. The participants included 20 adults with insomnia disorder, 16 of whom were female, with an average age of 46 years. Notably, 75% of participants were either cannabis-naïve or had used cannabis fewer than 10 times in their lives. None had consumed cannabis or cannabis-derived products in the three months leading up to the study.
Each participant took part in two 24-hour overnight assessment visits in the lab. On one night, they were given 2 mL of medicinal cannabis oil containing 10 mg THC and 200 mg CBD. On the other night, they received a placebo—2 mL of oil that looked identical but contained no cannabinoids. Both the participants and the researchers administering the treatment were blinded to which oil was given on which night. The order in which participants received the cannabis oil or placebo was randomly assigned, ensuring a balanced crossover design.
On the morning following each night of treatment, about 9-11 hours after taking the cannabis oil, participants completed a battery of 28 cognitive tasks, designed to assess various cognitive functions such as attention, memory, and executive functioning. In addition, they participated in a simulated driving assessment—a 30-minute driving scenario that has been validated in previous research to detect the acute effects of THC on driving ability.
The results showed no significant differences in performance on cognitive or psychomotor tests between the days participants received the medicinal cannabis oil and the placebo. The only exception was a slight decrease in accuracy on a test of executive functioning following cannabis oil administration, but this difference was small and not considered clinically meaningful. Similarly, there were no significant differences in simulated driving performance between the two conditions.
“The results of this study indicate that a single oral dose of 10 mg THC (in combination with 200 mg CBD) does not notably impair ‘next day’ cognitive function or driving performance relative to placebo in adults with insomnia disorder who infrequently use cannabis,” the  study authors concluded.
This study contributes to the growing body of research on the medicinal use of cannabis oil, particularly in the context of insomnia. However, it is important to note that these findings pertain specifically to the effects of the particular cannabis product used in the study. Other cannabis products with different THC and CBD concentrations or ratios might produce different results, especially at higher doses or with repeated use.
The paper, “(https://doi.org/10.1007/s00213-024-06595-9) Evaluating possible ‘next day’ impairment in insomnia patients administered an oral medicinal cannabis product by night: a pilot randomized controlled trial,” was authored by Anastasia Suraev, Danielle McCartney, Nathaniel S. Marshall, Christopher Irwin, Ryan Vandrey, Ronald R. Grunstein, Angela L. D’Rozario, Christopher Gordon, Delwyn Bartlett, Camilla M. Hoyos, and Iain S. McGregor.

(https://www.psypost.org/people-with-dark-personalities-often-end-up-with-partners-who-share-their-traits/) People with dark personalities often end up with partners who share their traits
Oct 17th 2024, 07:00

A new study published in (https://www.sciencedirect.com/science/article/pii/S0191886924002149) Personality and Individual Differences highlights that romantic partners often exhibit similar levels of Machiavellianism, narcissism, and psychopathy—collectively known as the “dark triad” of personality traits. Researchers found evidence that these similarities are present early in relationships, suggesting that people may actively seek partners with similar dark traits, rather than becoming more alike over time.
The study was motivated by a desire to better understand assortative mating, a concept that describes the tendency for people to form romantic relationships with partners who are similar to them in important traits. While previous research has extensively documented assortative mating for demographic factors like age, education, and shared interests, less attention has been given to assortative mating for personality traits that are socially undesirable, particularly the “dark triad” traits.
The (https://www.psypost.org/exclusive/social/dark-triad-personality/) dark triad refers to three specific personality characteristics: Machiavellianism, narcissism, and psychopathy. Each of these traits is considered socially aversive and can have a significant impact on how people behave in relationships.
Machiavellianism is characterized by manipulativeness, strategic behavior, and a cynical view of the world. Individuals high in Machiavellianism tend to prioritize personal gain, often at the expense of others. They may engage in deceptive behavior, use others to achieve their goals, and show little regard for ethical or moral considerations.
Narcissism, in this context, refers to subclinical narcissism, which includes traits such as grandiosity, entitlement, and a strong need for admiration. People high in narcissism often see themselves as superior to others and expect special treatment. While they can be charming and self-confident, they may also lack empathy and be preoccupied with their own success and image.
Psychopathy, also in its subclinical form, is associated with impulsivity, a lack of empathy, and a disregard for social norms. Individuals with high levels of psychopathy may engage in reckless or antisocial behavior, have difficulty forming deep emotional connections, and be more prone to thrill-seeking or harmful actions without considering the consequences for others.
These dark traits are often seen as problematic in interpersonal relationships. People with high levels of these traits may struggle with long-term commitment, empathy, and cooperation, which are generally important for successful romantic relationships. They also tend (https://www.psypost.org/people-with-dark-triad-traits-are-more-likely-to-use-influence-techniques-in-romantic-relationships/) to be manipulative and are more likely (https://www.psypost.org/dark-personality-traits-are-linked-to-gaslighting-in-relationships-study-finds/) to engage in gaslighting. However, the researchers in this study wanted to explore whether individuals with these traits tend to seek out partners who share similar tendencies.
To investigate this, the researchers conducted three separate studies. The first study, based in the UK, involved 104 heterosexual couples who had been together for varying lengths of time, from one month to nearly 60 years. Participants completed the Short Dark Triad questionnaire. Additionally, the couples reported various demographic details, such as their ages, relationship length, and educational backgrounds. The second study, conducted in Fiji, included 99 heterosexual couples and used a similar procedure, though with some additional measures related to dark personality traits. Finally, the third part of the research was a meta-analysis of previous studies examining partner similarity for dark triad traits across different cultures and populations.
The results of the UK and Fijian studies revealed that romantic partners exhibited moderate similarities for Machiavellianism, narcissism, and psychopathy. This partner resemblance was stronger than would be expected by chance, suggesting that people with higher levels of dark triad traits are not randomly pairing up with just anyone—they are likely choosing partners who share these tendencies. The researchers also compared couples to randomly paired individuals and found that real couples were significantly more alike in their dark triad traits than these artificial pairings.
One key insight from the study was that this partner similarity seems to be explained by initial and active assortment, rather than convergence or social homogamy. Initial assortment means that people enter into relationships with partners who are already similar to them, while active assortment implies that individuals may be consciously seeking out partners with similar characteristics.
In contrast, convergence would suggest that partners become more alike over time through shared experiences, and social homogamy would indicate that people select partners from the same social or cultural groups, leading to similarities based on shared environments. However, the data did not support these latter explanations, as couples’ dark triad traits were not more similar the longer they had been together, nor did factors like age, education, or religious beliefs correlate with the similarity of their dark triad traits.
The meta-analysis in the third part of the study further confirmed that assortative mating for dark triad traits is a robust phenomenon. Across multiple studies and different cultures, the researchers found consistent evidence of positive assortment for these traits. Interestingly, Machiavellianism showed the strongest assortative effects, potentially because this trait is closely tied to individual values and ethical beliefs, making it a particularly salient factor in partner selection.
The results are in line (https://www.psypost.org/people-with-dark-personalities-feel-more-satisfied-in-romantic-relationships-with-partners-who-also-exhibit-similar-dark-traits/) with a previous study, which found that individuals with dark triad traits tend to be more satisfied in their romantic relationships when their partner possesses similar traits. The research, which involved 205 couples, found that similarities in these traits, particularly in psychopathy and narcissism, were linked to higher relationship satisfaction.
While the new findings shed important light on how dark triad traits influence partner choice, the study also has limitations. First, it relied on self-reported data, which could be subject to biases, particularly since people with high levels of these traits might be less honest or self-aware. Additionally, the study was cross-sectional, meaning that it could not definitively rule out the possibility of convergence over longer time periods, or the potential for couples with greater differences in dark triad traits to break up earlier in their relationships.
Future research could address these limitations by using longitudinal designs to track changes in partner similarity over time and by including more diverse samples in terms of education, socioeconomic status, and culture. It would also be beneficial to examine how these dark triad traits interact with other aspects of personality and relationship dynamics, such as conflict resolution or satisfaction, to better understand their broader impact on relationships.
The study, “(https://doi.org/10.1016/j.paid.2024.112754) Assortative mating and the dark triad: Evidence from the UK, Fiji, and meta-analytic review,” was authored by Gareth Richards, Hannah Proctor, Eva Lee, Ofa Swann, Emily Jackson, John Galvin, Robin I.M. Dunbar, Simon Baron-Cohen, and Shanhong Luo.

(https://www.psypost.org/scientists-discover-unique-neuron-density-patterns-in-children-with-autism/) Scientists discover unique neuron density patterns in children with autism
Oct 17th 2024, 06:00

Published in (https://onlinelibrary.wiley.com/doi/full/10.1002/aur.3239) Autism Research, a recent study has uncovered how brain structure differs in children with autism compared to typically developing children. The study found lower total neurite density—an indicator of neuron structure and connectivity—in the right cerebellar cortex of children with autism. Additional changes in how neurons spread in different directions were observed across various brain regions, suggesting that structural differences in the brain could be key to understanding autism.
Autism is a complex neurodevelopmental condition characterized by difficulties with social communication, repetitive behaviors, and restricted interests. While previous research has shown that children with autism often have differences in brain size and structure, the exact nature of these differences is not fully understood.
Past studies have identified increased brain volume in young children with autism, but this enlargement tends to normalize by age four. These early changes in brain structure could play a crucial role in the development of autism-related symptoms, but understanding the specific cellular and structural changes has been challenging due to the heterogeneity of autism and the limitations of available imaging techniques.
The goal of this study was to gain a better understanding of the brain’s cytoarchitecture, or cellular structure, in children with autism. The researchers aimed to explore how neuron density and connectivity differ in children with autism compared to typically developing children and those with other psychiatric conditions, like anxiety or attention disorders.
“Our lab here at the Del Monte Institute for Neuroscience in Rochester is concentrated on shedding light on the neuropathological processes that give rise to intellectual and developmental disabilities,” said John Foxe, the senior author of the study, director of the (https://www.urmc.rochester.edu/del-monte-neuroscience.aspx) Del Monte Institute for Neuroscience, and Kilian J. and Caroline F. Schmitt Chair in Neuroscience at the University of Rochester.
“We’ve had a long-standing goal of uncovering the neural differences that underpin autism. Effective therapeutic approaches are fundamentally dependent on knowing what the issue is in the first place. Simply stated, it is very difficult to fix something if you don’t know how it is broken in the first place.
“The other important aspect of our work is that we are trying to discover neuromarkers that can provide better sensitivity and objectivity in clinical trials. Many, if not most, clinical trials in neurodevelopmental disorders have failed because the measures we have to assess success are so crude (e.g. observational symptom scales). Using objective neuroimaging measures has the promise to give us much greater sensitivity to detect real neural changes.”
For their study, the researchers used data from the Adolescent Brain and Cognitive Development (ABCD) study. This large sample size is one of the study’s strengths, allowing for a more robust analysis than many previous investigations with smaller participant pools.
“A key aspect of this study is that the data come from the ABCD study, which is a national effort to map brain development across childhood and adolescence in a very large cohort of youngsters. We at Rochester, and 20 other sites nationally, have been following over 11,000 children since they were 9 years of age. The size of this study is unprecedented, and could not be achieved without the concerted effort of the National Institutes of Health. By measuring so many children, the sensitivity of this study is massively better than anything we’ve been able to do previously.”
The researchers analyzed brain imaging data from 95 children with autism and 7,339 children without the condition. The key imaging technique used in the study was diffusion-weighted imaging, which measures how water molecules move within the brain. This method provides insights into neuron structure by capturing details about neurite density—the extensions of neurons that connect different brain regions. The team specifically measured two types of diffusion: isotropic diffusion, which represents neuron cell bodies, and directional diffusion, reflecting the neurite branches like axons and dendrites.
“We’ve spent many years describing the larger characteristics of brain regions, such as thickness, volume, and curvature,” said Zachary Christensen, MD/PhD candidate at the University of Rochester School of Medicine and Dentistry, and first author of the paper. “However, newer techniques in the field of neuroimaging for characterizing cells using MRI, unveil new levels of complexity throughout development.”
Through these imaging techniques, the researchers could evaluate neurite density in 87 different brain regions. They compared these measures across three groups: children with autism, typically developing children, and children with other psychiatric diagnoses. In addition, they analyzed behavioral data, including reports from parents on their children’s social and emotional functioning, to explore any links between brain structure and behavior.
The findings revealed significant differences in neurite density in several key brain regions. The most notable was a decrease in total neurite density in the right cerebellar cortex of children with autism. This region, located in the back of the brain, is involved in motor control and higher cognitive functions, such as social behavior. Lower neurite density in this area could be related to some of the motor and social challenges experienced by individuals with autism.
Beyond the cerebellum, the researchers found changes in both isotropic and directional diffusion in various parts of the brain. For example, children with autism had lower isotropic diffusion in posterior regions like the parietal and occipital lobes, indicating fewer neuron cell bodies in these areas. At the same time, they had increased directional diffusion in frontal and temporal lobes, suggesting more extensive neuron branching and connectivity in those regions. These patterns highlight how different parts of the brain are affected differently in autism.
“I think that the extent of the brain regions that were implicated was a bit of a surprise in retrospect,” Foxe told PsyPost. “We thought that the brain regions that would be implicated would be much more localized.”
To ensure that these findings were specific to autism and not other psychiatric conditions, the team compared the results from the autism group to those of children with anxiety, depression, and other disorders. They found that the differences in neurite density, particularly in the cerebellum, were unique to children with autism, reinforcing the link between these structural changes and the condition.
Lastly, the study explored how these brain structure differences related to behavior. The researchers found a connection between decreased neurite density in the right cerebellar cortex and somatization, a condition where individuals experience physical symptoms without an apparent medical cause. Children with autism and lower cerebellar neurite density were more likely to report somatic symptoms, providing an interesting clue about how brain structure could influence physical experiences in autism.
“People with a diagnosis of autism often have other things they have to deal with, such as anxiety, depression, and ADHD. But these findings mean we now have a new set of measurements that have shown unique promise in characterizing individuals with autism,” Christensen said. “If characterizing unique deviations in neuron structure in those with autism can be done reliably and with relative ease, that opens a lot of opportunities to characterize how autism develops, and these measures may be used to identify individuals with autism that could benefit from more specific therapeutic interventions.”
According to Foxe, the research highlights “that modern neuroimaging techniques are getting ever more sensitive and that these techniques hold out promise for better understanding of neurodevelopmental disorders.”
While this study provides valuable new insights, it also has some limitations. First, the autism diagnoses in this study were based on parental reports, which may not be as reliable as clinical evaluations.
“We are very confident in our determinations but these diagnoses should be confirmed using gold-standard assessments in future work,” Foxe said.
Additionally, the study focused on a narrow age range (9-12 years), meaning that it provides a snapshot of brain development during middle childhood. The findings may not capture changes that occur earlier or later in development, and future studies will be needed to track how these brain differences evolve over time.
“The ABCD study is designed to follow these children for a decade and hopefully beyond,” Foxe said. “Our study took advantage of the first two sets of neuroimaging data, so it is just covering the ages from about 9-12. It will be fascinating to follow up the study with later neuroimaging scans to see how the brain develops in these individuals, if the differences even out or persist.”
“It doesn’t get said as often as it should, but we in the research community owe so much to the families of the ABCD study who have stuck with us for nearly 8 years now,” Foxe added. “None of this is possible without them. Every year they show up for our tests and give of their time and patience with grace and good will. What we would like them to know is that they are truly changing the face of brain research and paving the way for better care for future generations.”
The study, “(https://doi.org/10.1002/aur.3239) Autism is associated with in vivo changes in gray matter neurite architecture,” was authored by Zachary P. Christensen, Edward G. Freedman, and John J. Foxe.

(https://www.psypost.org/gender-equality-paradox-in-academic-strengths-persists-across-countries-and-time/) Gender-equality paradox in academic strengths persists across countries and time
Oct 16th 2024, 16:00

A new study published in (https://doi.org/10.1177/09567976241271330) Psychological Science revealed that sex differences in intraindividual academic strengths—favoring girls in reading and boys in mathematics and science—are larger in more gender-equal and wealthier countries.
Over the past decades, gender disparities in science, technology, engineering, and mathematics (STEM) fields have persisted, even in countries with high levels of gender equality. Despite educational advancements, women are underrepresented in many STEM disciplines. Previous research has documented a “gender-equality paradox,” where sex differences in academic preferences and STEM participation are more pronounced in gender-equal countries. This paradox challenges the expectation that greater gender equality should reduce sex differences in occupational and educational choices.
Marco Balducci and colleagues set out to explore this paradox further, focusing on intraindividual academic strengths—comparative academic advantages within individuals—rather than overall achievement.
The researchers used data from five waves of the Programme for International Student Assessment (PISA), conducted between 2006 and 2018. The PISA is an international assessment that evaluates 15- and 16-year-old students’ abilities in reading, mathematics, and science. To ensure a comprehensive analysis, the researchers included data from 2.47 million adolescents across 85 countries and regions, making this one of the largest studies of its kind.
The sample was drawn using a representative, two-stage sampling method for each country, first selecting schools and then students within those schools. Participants were administered the PISA assessment, which includes items across the three core academic areas of mathematics, reading comprehension, and science literacy.
Since administering all PISA items would take over six hours, students were randomly assigned a subset of items, allowing for comprehensive assessments in each domain. The scores from these tests were then standardized within each country and PISA wave to calculate individual strengths.
Specifically, the authors computed the students’ best, second-best, and lowest academic scores, relative to their average academic performance. The differences between these scores provided an estimate of each student’s intraindividual academic strength. The researchers also incorporated country-level data on gender equality using the Global Gender Gap Index (GGGI) and measures of wealth from the PISA family wealth index, ensuring that they could explore relationships between these variables and sex differences in academic strengths.
The findings revealed stable sex differences in academic strengths across the five PISA waves, with girls consistently showing an advantage in reading, while boys demonstrated strengths in mathematics and science. These differences were observed consistently across the globe. Interestingly, while boys and girls had similar overall average scores in some contexts, their relative strengths diverged.
For example, boys were more likely to exhibit strengths in mathematics and science as their best-performing subjects relative to their overall performance, while girls showed stronger comparative performance in reading. These sex differences remained stable across the 12-year study period, indicating a persistent pattern.
Interestingly, these sex differences were more pronounced in countries with higher levels of gender equality. In nations that scored higher on the GGGI, boys exhibited even stronger strengths in science relative to girls, while girls’ advantage in reading became more pronounced. This pattern held true across all five waves of PISA, suggesting that as gender equality increased, so too did the gap in academic strengths between boys and girls.
Additionally, the researchers found that wealthier countries exhibited similar patterns, with the gender gap in reading strengths favoring girls and the gap in science strengths favoring boys widening as wealth increased.
These results support the idea that as countries become more gender-equal and economically prosperous, personal interests and intraindividual strengths play a larger role in shaping educational outcomes, further exacerbating sex differences in academic preferences.
The authors acknowledged that the correlational nature of their study limits the ability to draw causal inferences. They also noted that while the GGGI is a comprehensive measure of gender equality, it may not capture all relevant aspects of gender equality that affect educational and occupational choices.
The research, “(https://doi.org/10.1177/09567976241271330) The Gender-Equality Paradox in Intraindividual Academic Strengths: A Cross-Temporal Analysis”, was authored by Marco Balducci, Marie-Pier Larose, Gijsbert Stoet, and David C. Geary.

(https://www.psypost.org/cat-borne-parasite-toxoplasma-gondii-linked-to-increased-anxiety-risk-study-finds/) Cat-borne parasite Toxoplasma gondii linked to increased anxiety risk, study finds
Oct 16th 2024, 14:00

A recent study published in the (https://www.sciencedirect.com/science/article/abs/pii/S0165032724007614) Journal of Affective Disorders reveals a potential link between the presence of antibodies for the parasite Toxoplasma gondii and an increased risk of developing anxiety disorders. Researchers found that individuals with detectable antibodies to the parasite had a higher likelihood of being diagnosed with anxiety, while also noting a reduced risk of epilepsy among the same group. These findings suggest that latent Toxoplasma gondii infection, though typically asymptomatic, may have broader implications for mental health.
Toxoplasma gondii is a microscopic parasite that infects warm-blooded animals, including humans. It is highly prevalent worldwide, with about 30% of the global population testing positive for antibodies indicating past or current infection. Most infections remain dormant, as the body’s immune system keeps the parasite in check. However, in people with weakened immune systems, such as those with HIV/AIDS or undergoing chemotherapy, the parasite can cause severe health complications. Infection during pregnancy can also pose significant risks to the fetus.
Common sources of Toxoplasma gondii infections include consuming undercooked meat contaminated with the parasite and ingesting food or water contaminated with oocysts from cat feces. Infections can also occur through direct contact with contaminated soil or by mother-to-child transmission during pregnancy.
In healthy individuals, Toxoplasma gondii often hides in the body in a dormant state, primarily within the central nervous system. This has led scientists to investigate its potential impact on mental and neurological health, especially given the parasite’s proximity to brain tissues. Some earlier research has suggested a connection between Toxoplasma gondii and conditions like schizophrenia, epilepsy, and depression.
However, large-scale studies exploring the link between the parasite and mental disorders, such as anxiety, have been scarce. To address this gap, the present study was designed to investigate whether latent Toxoplasma gondii infection, indicated by the presence of antibodies, could be linked to an increased risk of neuropsychiatric disorders, particularly anxiety.
The research team used data from the UK Biobank, a large and ongoing study of health outcomes in over 500,000 participants in the United Kingdom. For this specific study, 8,814 participants were selected, all of whom had data on whether they were infected with Toxoplasma gondii based on the presence of antibodies targeting a specific antigen known as P22. The P22 antigen is associated with the parasite’s active, infectious stage and serves as a marker for exposure.
Participants were divided into two groups: those who tested positive for the Toxoplasma gondii P22 antibody (indicating past or present infection) and those who tested negative. The participants were followed over time to track the development of neuropsychiatric disorders, including anxiety, depression, epilepsy, and other mental and neurological conditions. The researchers also collected a range of additional information, such as age, gender, lifestyle habits, socioeconomic status, and preexisting health conditions, to control for other factors that might influence mental health outcomes.
The study employed statistical methods to analyze the relationship between Toxoplasma gondii infection and the subsequent risk of neuropsychiatric disorders. Specifically, the researchers used Cox proportional hazards models, a common tool for analyzing time-to-event data, which allowed them to estimate the increased or decreased risk of developing these disorders over the course of the study.
The most notable finding from the study was the significant association between Toxoplasma gondii infection and anxiety disorders. Participants who tested positive for the P22 antibody were 38% more likely to develop anxiety compared to those who were not infected. This association remained even after controlling for a wide range of potential confounding factors, such as age, gender, and socioeconomic status.
Interestingly, the study also found an inverse relationship between Toxoplasma gondii infection and epilepsy. Participants with the P22 antibody were less likely to develop epilepsy than those without the antibody, suggesting that the presence of the parasite might have a protective effect against this particular neurological disorder.
This finding is somewhat surprising given that earlier studies had suggested a possible link between Toxoplasma gondii and an increased risk of epilepsy. The researchers speculated that their findings might differ from previous studies due to differences in sample size, study design, or how Toxoplasma gondii infection was measured.
In terms of other neuropsychiatric disorders, the study did not find strong evidence linking Toxoplasma gondii infection to depression, Alzheimer’s disease, or other neurodegenerative conditions. This is consistent with some previous studies but contradicts others that have suggested a potential connection between the parasite and these disorders.
As with any research, there are limitations to this study. One potential limitation is that the study only included participants aged 40 to 69, so the findings might not be generalizable to younger or older populations. Additionally, while the study controlled for many potential confounders, there may still be other factors influencing the results that were not accounted for, such as genetic predisposition to anxiety or lifestyle factors not measured in the study.
Another limitation is the way Toxoplasma gondii infection was measured. The study relied on the presence of the P22 antibody as a marker of infection, which indicates exposure to the parasite but does not provide information on the severity or timing of the infection. It is also unclear whether the immune response to the parasite, as measured by antibody levels, directly affects the development of anxiety disorders or whether the association is due to some other, yet unidentified factor.
In terms of future research, the study authors suggest that more work is needed to clarify the mechanisms behind the link between Toxoplasma gondii and anxiety. Specifically, they recommend studies that investigate how the parasite affects brain function, perhaps by altering neurotransmitter levels or inducing inflammation in the brain. Understanding these mechanisms could lead to new strategies for preventing or treating anxiety in people who are infected with Toxoplasma gondii.
Additionally, the surprising finding that Toxoplasma gondii infection might reduce the risk of epilepsy warrants further investigation. Future studies with larger sample sizes and more detailed data on the timing and severity of infections could help resolve the conflicting findings on this topic.
The study, “(https://doi.org/10.1016/j.jad.2024.05.043) Population-based cohort study of Toxoplasma gondii P22 antibody positivity correlation with anxiety,” was authored by Lili Yang, Biyun Wang, Shuizhen Wu, Zihan Yang, Zixuan Xin, Shuyu Zheng, Weihao Zou, Chi Zhang, Jiating Chen, and Hongjuan Peng.

(https://www.psypost.org/left-handed-musicians-appear-to-develop-unique-brain-pathways-for-language-processing/) Left-handed musicians appear to develop unique brain pathways for language processing
Oct 16th 2024, 12:00

Researchers have uncovered a link between musical training and how the brain processes language in left-handed individuals. In a study published in the (https://www.jneurosci.org/content/44/37/e2430232024) Journal of Neuroscience, left-handed musicians were found to have a higher likelihood of atypical language lateralization, shifting language processing to the right hemisphere. The study identifies two distinct pathways to this phenomenon, suggesting that musical training impacts brain connectivity and structure related to language functions.
Language lateralization, or the tendency for language processing to be localized in one hemisphere of the brain, is typically a left-dominant process in most right-handed individuals. However, left-handed people are more likely to exhibit atypical lateralization, where language functions shift to the right hemisphere.
Despite decades of research, there is still limited understanding of how and why this happens in healthy individuals. Past studies have suggested that factors like interhemispheric brain connectivity may play a role, but there is no definitive explanation.
Musical training is known to alter brain structure and function, particularly in regions associated with auditory and motor control. Since music and language share many cognitive processes, the researchers hypothesized that musicianship might offer clues about the mechanisms behind atypical language lateralization.
“Atypical lateralization of language among left-handers has been known for more than 150 years. Despite this long history, its causes and consequences remain largely a mystery. Given our lab’s previous experience in neuroscience of music, we saw its potential connection to this topic,” said study author Esteban Villar-Rodríguez, a postdoctoral researcher at the (https://sites.google.com/view/nnfuji/home) Neuropsychology and Functional Neuroimaging research group at Jaume I University.
To explore the relationship between left-handedness, musicianship, and language lateralization, the researchers recruited 112 left-handed or mixed-handed participants, divided into two groups: 56 musicians and 56 non-musicians. To be considered a musician, participants had to have received formal musical training for at least six years.
Both groups were comparable in age and gender distribution, and none had a history of neurological or psychiatric conditions. The participants underwent several neuroimaging tests, including functional magnetic resonance imaging (fMRI) and diffusion-weighted imaging (DWI), to examine brain structure and function.
Participants performed two main tasks: a verb generation task and a word listening task. The verb generation task required them to think of verbs corresponding to presented nouns, a well-known method for assessing language production. The word listening task involved listening to words and tones while the researchers measured brain activity. This helped the team assess how the brain processed language compared to non-linguistic sounds like tones.
Using these tasks, the researchers calculated a “laterality index” for each participant, quantifying whether language processing was more left- or right-dominant. They compared these indices between musicians and non-musicians to understand how brain lateralization differs between the two groups.
The researchers also analyzed the structural connectivity of key brain areas, focusing on the arcuate fasciculus, a white matter tract that links regions involved in language, and the corpus callosum, which connects the two hemispheres of the brain.
The study revealed distinct pathways leading to atypical language lateralization in musicians and non-musicians. In both groups, atypical lateralization was characterized by increased interhemispheric connectivity, but the underlying mechanisms were different.
Among non-musicians, atypical lateralization was linked to underdevelopment in intrahemispheric connectivity, particularly in the anterior arcuate fasciculus. This region is crucial for connecting language-related areas within the same hemisphere, suggesting that in these individuals, the brain’s normal shift from interhemispheric to intrahemispheric control of language may not have fully developed.
In contrast, musicians exhibited enhanced interhemispheric connectivity through the posterior corpus callosum. This suggests that intensive musical training can lead to a different pathway for atypical lateralization, with the corpus callosum playing a key role in transferring information between the hemispheres.
The researchers also found that the more years of musical training a participant had, the more likely they were to exhibit atypical lateralization. Interestingly, musicians who specialized in a single instrument were particularly prone to this pattern.
“Sometimes, the answers to our questions are more complex than initially thought,” Villar-Rodríguez told PsyPost. “Historically, neuroscience has sought a singular explanation for the causes and consequences of atypical language lateralization. However, our findings reveal two alternative pathways—or answers—to this phenomenon, and we have the neuroplastic potential of musical training to thank for this discovery.”
Further analysis showed that individuals with atypical lateralization also demonstrated a mirrored organization of brain activity between language and tone processing. Specifically, rightward dominance in language production corresponded with increased rightward activation in the auditory cortex when listening to speech, and a leftward bias when listening to tones. This pattern was observed in both musicians and non-musicians.
However, the study focused solely on left-handers, so it is unclear whether similar mechanisms are at play in right-handers with atypical lateralization. While left-handers are more likely to exhibit this brain organization, right-handers can also show atypical lateralization.
“Our results are based on a healthy left-handed sample,” Villar-Rodríguez said. “Thus, we can’t be certain how our findings apply to the atypically lateralized right-handed population (which includes approximately 2-4% of right-handers).”
The long-term goals of this research are to gain a deeper understanding of the cognitive effects in individuals with atypical language lateralization and examine its connection to various neurological conditions. “Considering multiple possible pathways to atypical language lateralization might be useful in understanding its role in certain neurological conditions, such as epilepsy, autism, dyslexia, and schizophrenia,” Villar-Rodríguez explained.
The study, “(https://doi.org/10.1523/JNEUROSCI.2430-23.2024) Musicianship and prominence of inter-hemispheric connectivity determine two different pathways to atypical language dominance,” was authored by Esteban Villar-Rodríguez, Lidón Marin-Marin, María Baena-Pérez, Cristina Cano-Melle, Maria Antònia Parcet, and César Ávila.

Forwarded by:
Michael Reeder LCPC
Baltimore, MD

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