1. Study looks at effect of testosterone fluctuations in fathers after baby arrives

    September 19, 2017 by Ashley

    From the University of Southern California press release:

    Postpartum depression is often associated with mothers, but a new study shows that fathers face a higher risk of experiencing it themselves if their testosterone levels drop nine months after their children are born.

    The same study revealed that a father’s low testosterone may also affect his partner — but in an unexpectedly positive way. Women whose partners had lower levels of testosterone postpartum reported fewer symptoms of depression themselves nine and 15 months after birth.

    High testosterone levels had the opposite effect. Fathers whose levels spiked faced a greater risk of experiencing stress due to parenting and a greater risk of acting hostile- such as showing emotional, verbal or physical aggression — toward their partners.

    The study was published in the journal Hormones and Behavior on Sept. 1. The findings support prior studies that show men have biological responses to fatherhood, said Darby Saxbe, the study’s lead author and an assistant professor of psychology at USC Dornsife College of Letters, Arts and Sciences.

    “We often think of motherhood as biologically driven because many mothers have biological connections to their babies through breastfeeding and pregnancy.” Saxbe said. “We don’t usually think of fatherhood in the same biological terms. We are still figuring out the biology of what makes dads tick.

    “We know that fathers contribute a lot to child-rearing and that on the whole, kids do better if they are raised in households with a father present,” she added. “So, it is important to figure out how to support fathers and what factors explain why some fathers are very involved in raising their children while some are absent.”

    Saxbe worked with a team of researchers from USC, University of California at Los Angeles and Northwestern University.

    A snapshot of paternal postpartum depression

    For the study, the researchers examined data from 149 couples in the Community Child Health Research Network. The study by the National Institute for Child Health and Human Development involves sites across the country, but the data for this study came from Lake County, Illinois, north of Chicago.

    Mothers in the study were 18 to 40 years old; African-American, white or Latina; and low-income. They were recruited when they gave birth to their first, second or third child. Mothers could invite the baby’s father to participate in the study as well. Of the fathers who participated and provided testosterone data, 95 percent were living with the mothers.

    Interviewers visited couples three times in the first two years after birth: around two months after the child was born, about nine months after birth and about 15 months after birth.

    At the nine-month visit, researchers gave the fathers saliva sample kits. Dads took samples three times a day — morning, midday and evening — to monitor their testosterone levels.

    Participants responded to questions about depressive symptoms based on a widely-used measure, the Edinburgh Postnatal Depression. They also reported on their relationship satisfaction, parenting stress and whether they were experiencing any intimate partner aggression. Higher scores on those measures signaled greater depression, more stress, more dissatisfaction and greater aggression.

    Relatively few participants — fathers and mothers — were identified as clinically depressed, which is typical of a community sample that reflects the general population. Instead of using clinical diagnoses, the researchers looked at the number of depressive symptoms endorsed by each participant.

    Men’s testosterone levels were linked with both their own and their partners’ depressive symptoms — but in opposing directions for men and for women.

    For example, lower testosterone was associated with more symptoms in dads, but fewer symptoms in moms. The link between their partners’ testosterone levels and their own depression was mediated by relationship satisfaction. If they were paired with lower-testosterone partners, women reported greater satisfaction with their relationship, which in turn helped reduce their depressive symptoms.

    “It may be that the fathers with lower testosterone were spending more time caring for the baby or that they had hormone profiles that were more synced up with mothers,” she said. “For mothers, we know that social support buffers the risk of postpartum depression.”

    Fathers with higher testosterone levels reported more parenting stress, and their partners reported more relationship aggression.

    To measure parenting stress, parents were asked how strongly they related to a set of 36 items from the Parenting Stress Index-Short Form. They responded to statements such as “I feel trapped by my responsibilities as a parent” and “My child makes more demands on me than most children.” A high number of “yes” responses signaled stress.

    Relationship satisfaction questions were based on another widely-used tool, the Dyadic Adjustment Scale. Parents responded to 32 items inquiring about their relationship satisfaction, including areas of disagreement or their degree of closeness and affection. Higher scores signaled greater dissatisfaction.

    Mothers also answered questions from another scientific questionnaire, the HITS (Hurts, Insults, and Threats Scale), reporting whether they had experienced any physical hurt, insult, threats and screaming over the past year. They also were asked if their partners restricted activities such as spending money, visiting family or friends or going places that they needed to go.

    “Those are risk factors that can contribute to depression over the long term,” Saxbe said.

    Treating fathers with postpartum depression

    Although doctors may try to address postpartum depression in fathers by providing testosterone supplements, Saxbe said that the study’s findings indicate a boost could worsen the family’s stress.

    “One take-away from this study is that supplementing is not a good idea for treating fathers with postpartum depression,” she said. “Low testosterone during the postpartum period may be a normal and natural adaptation to parenthood.”

    She said studies have shown that physical fitness and adequate sleep can improve both mood and help balance hormone levels.

    In addition, both mothers and fathers should be aware of the signs of postpartum depression and be willing to seek support and care, Saxbe said. Talk therapy can help dads — or moms — gain insight into their emotions and find better strategies for managing their moods.

    “We tend to think of postpartum depression as a mom thing,” Saxbe said. “It’s not. It’s a real condition that might be linked to hormones and biology.”


  2. Oxytocin and social norms reduce xenophobia

    August 29, 2017 by Ashley

    From the Universität Bonn press release:

    How can xenophobia be reduced and altruism strengthened? Researchers at University Hospital Bonn have shown in a new study that the bonding hormone oxytocin together with social norms significantly increases the willingness to donate money to refugees in need, even in people who tend to have a skeptical attitude towards migrants. The results are published in the Proceedings of the National Academy of Sciences (PNAS).

    We tend to be more altruistic to our own family and friends than to perfect strangers. The recent migration of Middle Eastern refugees into European societies has further magnified the issue, with a large divide in society between people who do and do not support the refugees. “This is partly due to evolution: Only through solidarity and cooperation within one’s own group was it possible to raise children and survive when competing against unknown and rivaling groups for scarce resources in pre-civilized times,” explains Prof. Rene Hurlemann from the Department of Psychiatry, University of Bonn Medical Center. However, this is diametrically opposed to the parable of the Good Samaritan, which serves as an example of selfless altruism by describing a Samaritan who incurs personal costs to help a stranger in need. “From a neurobiological perspective, the basis of xenophobia and altruism is not yet precisely understood,” says Hurlemann.

    Under the psychiatrist’s supervision, a team of researchers at the University of Bonn, the Laureate Institute for Brain Research in Tulsa (USA), and the University of Lübeck conducted three experiments in which they tested a total of 183 subjects, who were all German natives. In the Laboratory for Experimental Economics (BonnEconLab) at the University of Bonn, they completed a donation task on a computer. The donation task included 50 authentic case vignettes describing the personal needs of poor people, 25 of which were portrayed as local people in need, while the other 25 people were portrayed as refugees.

    With an endowment of 50 euros, the participants could decide for each individual case whether they wanted to donate a sum between zero and one euro. The test subjects were allowed to keep any money that was not donated. “We were surprised that the participants in the first experiment donated around 20 percent more to refugees than to local people in need,” says Nina Marsh from Prof. Hurlemann’s team.

    Questionnaire on attitude towards migrants

    In another independent experiment involving over 100 participants, the subjects’ personal attitudes towards refugees were assessed in a questionnaire. Then half of the group received the bonding hormone oxytocin via a nasal spray, while the other half of the group received a placebo before they were exposed to the donation task established in the first experiment: again the participants decided how much of their 50 euros they wanted to donate to locals or refugees.

    Under the influence of oxytocin, the individuals who tended to show a positive attitude towards refugees doubled their donations to both the locals and the refugees. However, oxytocin had no effect in individuals who expressed a rather defensive attitude towards migrants: In those participants, the tendency to donate was very low to locals and refugees alike. “Oxytocin clearly increases generosity towards those in need, however, if this altruistic fundamental attitude is missing, the hormone alone cannot create it,” says Hurlemann.

    Oxytocin in combination with social norms decreases xenophobia

    How can people who tend to have a xenophobic attitude be motivated to be more altruistic? The researchers assumed that the addition of social norms could be a starting point. In a third experiment, they thus presented the participants with the average donation their peers made in the first experiment under each case vignette. Half of the participants once again received oxytocin. The result was astounding. “Now, even people with negative attitudes towards migrants donated up to 74 percent more to refugees than in the previous round,” reports Nina Marsh. Through the combined administration of oxytocin with a social norm, the donations for refugees in those skeptical towards migrants nearly reached half of the sums donated by the group, which showed a positive attitude towards refugees.

    What conclusions can be drawn from these results? It appears that pairing oxytocin with a social norm can help counter the effects of xenophobia by enhancing altruistic behavior toward refugees. “The combined enhancement of oxytocin and peer influence could diminish selfish motives,” says Hurlemann. If people whom we trust, such as supervisors, neighbors or friends, act as a role model by making public their positive attitude towards refugees, more people would probably feel motivated to help. In such a prosocial context, oxytocin could increase trust and minimize anxiety — experience shows that the oxytocin level in the blood increases during social interaction and shared activities. “Given the right circumstances, oxytocin may help promote the acceptance and integration of migrants into Western cultures,” says Hurlemann.


  3. Study looks at links between competitiveness, aggression and hormone levels

    August 28, 2017 by Ashley

    From the University of Erlangen-Nuremberg press release:

    Feelings can run high in competitive situations and lead to heated arguments and disputes. But not everyone reacts in the same way — men react differently to women and the reactions of individuals are dissimilar to those of groups of persons. This has been demonstrated scientifically by psychologists at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) who examined the correlations between competitiveness, aggression and hormones. The researchers recently published their findings in the journal PLOS ONE.

    Participants in a laboratory study were required to master competitive tasks over ten rounds. They competed against each other either as individuals or as teams, whereby one side lost the competition and the other side won. Participants were allowed to give full rein to their aggressive impulses during the competition. For this purpose, at the beginning of each round, they were asked to specify how loud an unpleasant noise would be that the opponent would be required to listen to through headphones if they lost the round. Saliva samples were collected from the participants prior to and after the competition in order to document changes to hormone levels.

    Prof. Dr. Oliver Schultheiss and Dr. Jonathan Oxford from the Chair of General Psychology II at FAU found that men tended to behave more aggressively than women, that losers were more aggressive than winners and that teams were more aggressive than individuals. Furthermore, the researchers also detected a correlation between aggression and levels of the stress hormone cortisol; the more aggressively a person behaved, the lower their cortisol level was. “Our results show that the usual suspects are the ones who become aggressive — namely participants who are male and frustrated. But our analysis also revealed that it was easier for participants who were part of a team to attack others than it was for individuals. At the same time, elevation of stress hormones when encountering a threat that cannot be mastered is in actual fact associated with less aggression,” explains Schultheiss.

    The researchers placed a particular emphasis on the female subjects. They discovered that the hormonal reaction to victory or defeat that occurred in women or female teams was significantly dependent on their personal thirst for power. Women with a particularly marked thirst for power had higher levels of the sex hormones testosterone and estradiol after a victory than after a defeat. This reaction was not recorded in women who a less pronounced power-orientated outlook. This hormonal reaction is the reason why dominant behaviour in women is intensified by a victory and subdued by a defeat.


  4. Violent sleep patterns, stress hormones change after a violent crime in the neighborhood

    August 14, 2017 by Ashley

    From the Society for Research in Child Development press release:

    Almost 1.2 million violent crimes — homicide, sexual assault, assault, and robbery — were committed in the United States in 2015, according to the U.S. Department of Justice. A new study has found that violent crime changes youth’s sleep patterns the night immediately following the crime and changes patterns of the stress hormone cortisol the following day. Both may then disrupt academic performance in students.

    The study was conducted by researchers at Northwestern University, New York University, and DePaul University. It appears in the journal Child Development.

    “Past research has found a link between violent crimes and performance on tests, but researchers haven’t been able to say why crime affects academic performance,” explains Jennifer A. Heissel, a PhD graduate in human development and sociology at Northwestern University, who led the study. “Both sleep and cortisol are connected to the ability to learn and perform academic tasks; our study identifies a pathway by which violent crime may get under the skin to affect academic performance.” The study did so by examining the causal pathways involved with sleep and the hypothalamic-pituitary-adrenal axis, which regulates the body’s response to stress.

    Researchers tracked the sleep and stress hormones of 82 youth (ages 11 to 18) in a large Midwestern city who attended public schools that were racially, ethnically, and socioeconomically diverse. The students filled out daily diaries over four days, wore activity-tracking watches that measured sleep, and had their saliva tested three times a day to check for cortisol. Researchers also collected information on all the violent crimes reported to the police in the city during the study, including which youth had a violent crime occur in his or her neighborhood.

    For each youth, researchers compared the students’ sleep on the nights following a violent crime to their sleep on nights when there were no violent crimes committed nearby. They also compared students’ stress hormones (cortisol) on days following a violent crime to their stress hormones on days when there were no violent crimes committed nearby.

    Among the findings: Youth went to sleep later on nights when a violent crime occurred near their home, often resulting in fewer total hours of sleep. In addition, the increase in youth’s cortisol levels the morning after a crime occurred nearby the day before was larger than on mornings following no crime the previous day, a pattern that previous research suggests might reflect the body’s anticipation of more stress the day following a crime. The changes in sleep and cortisol were largest when the crime committed the previous day was homicide, moderate for assault and sexual assault, and nonexistent for robbery.

    “The results of our research have several implications for policy,” suggests Emma Adam, professor of human development and social policy at Northwestern University, who also conducted the study. “They provide a link between violent crime and several mechanisms known to affect cognitive performance. They also may help explain why some low-income youth living in high-risk neighborhoods sleep less than higher-income youth. And they suggest that although programs to reduce violent crime may be the best policy solution, schools could also provide students with programs or methods to cope with their response to stressful events like nearby violent crimes.”


  5. Stress hormone linked to mood and hippocampus volume

    August 13, 2017 by Ashley

    From the Society for Neuroscience press release:

    Individual differences in the pattern of release of the hormone cortisol in response to a stressful experience reveal how stressed a person actually feels, suggests a study of healthy women published in The Journal of Neuroscience. This approach could help to better identify and treat individuals more susceptible to the negative feelings associated with the physiological stress response.

    Most stress research in humans involves inducing a short period of stress and classifying participants as either responders or non-responders based on the level of the hormone cortisol in their saliva. These studies do not typically find differences between the two groups’ subjective experience of stress.

    Roee Admon, Diego Pizzagalli and colleagues modified existing laboratory procedures to induce stress for more than one hour in 79 women and identified three different types of cortisol response. Participants that released either very high or very low amounts of cortisol over time reported feeling more stressed than those with a pattern of moderate hormonal release. The authors also found smaller volume of the hippocampus — a structure with a large number of cortisol receptors that regulates stress response — in these high and low responders compared to the moderate responders.


  6. Study examines effects of testosterone surges in competitive sports

    August 9, 2017 by Ashley

    From the Wake Forest University press release:

    As student athletes hit training fields this summer to gain the competitive edge, a new study shows how the experiences of a tiny mouse can put them on the path to winning.

    Scientists examined how surges of testosterone both before and after aggressive encounters led the male California mouse to win in future matches.

    “Every time you experience a competitive situation, hormones such as testosterone are released to help you win, and they change your brain to get ready for what comes next,” said Matthew Fuxjager, an assistant professor of biology at Wake Forest University.

    Fuxjager, lead author of the study, has conducted research for about decade about California mice and how testosterone influences their ability to win. The paper, “What can animal research tell us about the link between androgens and social competition in humans?,” appears in the June 2017 issue of Hormones and Behavior, the peer-reviewed journal of the Society for Behavioral Neuroendocrinology.

    He published his first paper on the subject, “The ‘home advantage’ is necessary for a full winner effect and changes in post-encounter testosterone,” in 2009 in the journal Hormones and Behavior.

    For the 2017 paper, Fuxjager and colleagues Brian Trainor of the University of California-Davis and Catherine Marler of the University of Wisconsin-Madison reviewed studies focused mainly on male California mice (Peromyscus californicus) to prove that such research provides an excellent window into exactly how androgenic hormones such as testosterone influence aggression and, by extension, lead to winning competitions.

    Such insights, Fuxjager said, can help athletes and coaches develop training routines that foster winning.

    Consider the boxing world, in which training often involves pitting an up-and-coming fighter against a series of lesser opponents to build up a run of wins. In California mice, researchers have found that post-win pulses of testosterone increase aggression and likelihood to win in future encounters.

    They call this phenomenon the “winner effect.”

    “There’s this idea that winning begets winning,” Fuxjager said. “Accruing these experiences can increase your chances of winning. In terms of training, you want to have a taste of victory. I’ve talked to a lot of sports trainers over the years, and they relate to what we have been seeing in California mice.”

    But just because trainers have seen that winning effect in their athletes, they didn’t know why it happens or even how to best replicate the experience. Research on California mice shows that winning changes the way the brain detects androgens such as testosterone in future encounters. Testosterone fuels competitiveness and can raise confidence.

    Researchers have focused on California mice because they are extremely territorial, strictly monogamous and co-parent with their mate, so they closely reflect aspects of human behavior. The study of the link between baseline testosterone levels and aggression has been inconsistent in humans, so the California mouse provides a good model for understanding why the body and the brain react to testosterone in certain ways.

    “Through the California mouse work, we have shown that aggression is not just about testosterone, it’s about where it acts in the body and the brain,” Fuxjager said. “Your baseline level of testosterone isn’t always going to predict how you’re going to behave — it depends on what’s going on in the brain with androgen receptors.”

    Scientists have found evidence of this across species, according to Fuxjager’s latest study:

      • -The context of a fight makes a difference in hormone release. Male cichlid fish normally experience a large hormone release after winning a fight. But there is no hormone surge when that fight is with its own reflection in a mirror. This suggests that the competitor’s evaluation of his performance affects hormone release.

    -Male California mice that win a series of three competitions in their home cage are more likely to win subsequent competitions. That’s the home field advantage sports teams talk about.

    -Chimpanzees experience anticipatory testosterone release before regular territorial patrolling, likely to prepare them for an aggressive encounter. Pre-competition rituals could provide humans with the same pre-game surge to help them perform better and win.


  7. Study links duration of estrogen exposure with increased vulnerability to depression

    August 5, 2017 by Ashley

    From the North American Menopause Society (NAMS) press release:

    It’s no secret that the risk of depression increases for women when their hormones are fluctuating. Especially vulnerable times include the menopause transition and onset of postmenopause. There’s also postpartum depression that can erupt shortly after childbirth. But why do some women feel blue while others seem to skate through these transitions? One answer is provided through study results being published online in Menopause, the journal of The North American Menopause Society (NAMS).

    The article “Lifelong estradiol exposure and risk of depressive symptoms during the transition to menopause and postmenopause” includes data from a study of more than 1,300 regularly menstruating premenopausal women aged 42 to 52 years at study entry. The primary goal of the study was to understand why some women are more vulnerable to depression, even though all women experience hormone fluctuations.

    Previous studies have suggested a role for reproductive hormones in causing an increased susceptibility to depression. This study focused largely on the effect of estradiol, the predominant estrogen present during the reproductive years. Among other things, estradiol modulates the synthesis, availability, and metabolism of serotonin, a key neurotransmitter in depression. Whereas fluctuations of estradiol during the menopause transition are universal, the duration of exposure to estradiol throughout the adult years varies widely among women.

    A key finding of this study was that longer duration of estrogen exposure from the start of menstruation until the onset of menopause was significantly associated with a reduced risk of depression during the transition to menopause and for up to 10 years postmenopause. Also noteworthy was that longer duration of birth control use was associated with a decreased risk of depression, but the number of pregnancies or incidence of breastfeeding had no association.

    “Women are more vulnerable to depressive symptoms during and after the menopause transition because of fluctuating hormone changes,” says Dr. JoAnn Pinkerton, executive director of NAMS. “This study additionally found a higher risk for depression in those with earlier menopause, fewer menstrual cycles over lifespan, or more frequent hot flashes. Women and their providers need to recognize symptoms of depression such as mood changes, loss of pleasure, changes in weight or sleep, fatigue, feeling worthless, being unable to make decisions, or feeling persistently sad and take appropriate action.”


  8. Researchers closer to cracking neural code of love

    June 12, 2017 by Ashley

    From the Emory Health Sciences press release:

    A team of neuroscientists from Emory University’s Silvio O. Conte Center for Oxytocin and Social Cognition has discovered a key connection between areas of the adult female prairie vole’s brain reward system that promotes the emergence of pair bonds. Results from this study, could help efforts to improve social abilities in human disorders with impaired social function, such as autism. In addition to the online posting, the study is expected to be in the June 8 printed edition of Nature.

    This Conte Center study is the first to find the strength of communication between parts of a corticostriatal circuit in the brain predicts how quickly each female prairie vole becomes affiliative with her partner; prairie voles are socially monogamous and form lifelong bonds with their partners. Additionally, when researchers boosted the communication by using light pulses, the females increased their affiliation toward males, thus further demonstrating the importance of this circuit’s activity to pair bonding in prairie voles.

    “Prairie voles were critical to our team’s findings because studying pair bonding in humans has been traditionally difficult,” says Dr. Elizabeth Amadei, a co-lead author on the research. “As humans, we know the feelings we get when we view images of our romantic partners, but, until now, we haven’t known how the brain’s reward system works to lead to those feelings and to the voles’ pair bonding.”

    Building upon previous work in prairie voles that demonstrated brain chemicals, such as oxytocin and dopamine, act within the medial prefrontal cortex and nucleus accumbens to establish a pair bond, the team set out to address finding the precise neural activity leading to a pair bond. The researchers used probes to listen to neural communication between these two brain regions and then analyzed activity from individual female prairie voles as they spent hours socializing with a male — a cohabitation period that normally leads to a pair bond.

    The team discovered that during pair bond formation, the prefrontal cortex, an area involved in decision-making, helps control the rhythmic oscillations of neurons within the nucleus accumbens, the central hub of the brain’s reward system. This suggests a functional connection from the cortex shapes neurons activity in the nucleus accumbens.

    The team then noticed individual voles varied in the strength of this functional connectivity. Importantly, each subject with stronger connectivity showed more rapid affiliative behavior with her partner, measured as side-by-side huddling contact. Furthermore, the pair’s first mating, a behavior that accelerates bonding in voles, strengthened this functional connection, and the amount of strengthening correlated with how quickly the animals subsequently huddled.

    According to Larry Young, PhD, co-author and director of the Conte Center, “It is remarkable there are neural signatures of a predisposition to begin huddling with the partner. Similar variation in corticostriatal communication could underlie individual differences in social competencies in psychiatric disorders in humans, and enhancing that communication could improve social function in disorders such as autism.” Young is also chief of the Division of Behavioral Neuroscience and Psychiatric Disorders at the Yerkes National Primate Research Center.

    The study results led the team to ask more questions, including whether communication between the prefrontal cortex and nucleus accumbens not only correlates with huddling but also causally facilitates it. To answer this, the researchers used optogenetics, a technique that allowed them to enhance communication between the brain areas using light, and enhanced communication between the prefrontal cortex and nucleus accumbens of female voles during a brief cohabitation without mating, which is not conducive to pair bonding. The team discovered optogenetically stimulated animals showed greater preference toward partners compared to a stranger male when given a choice the following day. “It is amazing to think we could influence social bonding by stimulating this brain circuit with a remotely controlled light implanted into the brain,” says Zack Johnson, PhD, co-lead author.

    The study results identify an important reward circuit in the brain that is activated during social interactions to facilitate bond formation in voles. “Now, we want to know if oxytocin regulates functional connectivity and how circuit activity changes the way the brain processes social information about a partner,” says senior author Robert Liu, PhD, associate professor in Emory’s Department of Biology. “Our team’s work is an example of a larger effort in neuroscience to better quantify how brain circuits function during natural social behaviors. Our goal is to promote better neural communication to boost social cognition in disorders such as autism, in which social functioning can be impaired,” Liu continues.


  9. A flip switch for binge-eating?

    June 8, 2017 by Ashley

    From the American Association for the Advancement of Science press release:

    Researchers have identified a subgroup of neurons in the mouse brain that, upon activation, immediately prompt binge-like eating. Furthermore, repeated stimulation of these neurons over time caused the mice to gain weight. The zona incerta (ZI) is a relatively understudied part of the brain.

    Intriguingly, patients receiving deep brain stimulation of the subthalamus, which includes the ZI, for the treatment of movement disorders can exhibit characteristics of binge eating. To explore this phenomenon in greater detail, Xiaobing Zhang and Anthony N. van den Pol optogenetically labelled GABA neurons in the ZIs of mice.

    They found that stimulating ZI GABA neurons with axons extending into the paraventricular thalamus (PVT) prompted immediate binge-like eating, just two to three seconds after stimulation. Within ten minutes of continuous ZI GABA stimulation, mice rapidly consumed 35% of their daily high-fat food store, meant to be eaten over a 24-hour period.

    The researchers also found that ghrelin, a hormone that signals a reduced energy state in the gut, excited ZI GABA neurons. Upon stimulating the subgroup of ZI neurons for five minutes every three hours over a period of two weeks, the mice significantly increased their food intake, and gained weight.

    Yet, once photostimulation was over, the mice showed a significantly reduced food intake compared with that of controls.

    Lastly, the authors found that stimulation of excitatory axons from the parasubthalamic nucleus to PVT or direct stimulation of glutamate neurons in the PVT reduced food intake.


  10. Too much stress for the mother affects the baby through amniotic fluid

    June 6, 2017 by Ashley

    From the University of Zürich press release:

    If the mother is stressed over a longer period of time during pregnancy, the concentration of stress hormones in amniotic fluid rises, as proven by an interdisciplinary team of researchers from the University of Zurich. Short-term stress situations, however, do not seem to have an unfavorable effect on the development of the fetus.

    The feeling of constantly being on edge, always having to take care of everything, not being able to find a balance: If an expectant mother is strongly stressed over a longer period of time, the risk of the unborn child developing a mental or physical illness later in life — such as attention deficit hyperactivity disorder (ADHD) or cardiovascular disease — increases. The precise mechanism of how stress affects the baby in the womb is not yet been completely clarified. In cooperation with the University Hospital Zurich and the Max Planck Institute Munich, researchers of the University of Zurich have discovered that physical stress to the mother can change the metabolism in the placenta and influence the growth of the unborn child.

    Stress hormone affects the growth of the fetus

    When stressed, the human body releases hormones to handle the higher stress, such as the so-called corticotropin-releasing hormone (CRH), which results in an increase in stress hormone cortisol. This mechanism also persists during pregnancy, and the placenta, which supplies the fetus with nutrients, can also emit stress hormone CRH. As a result, a small amount of this hormone enters the amniotic fluid and fetal metabolism. Animal studies have shown that this hormone can boost the development of the unborn child: Unfavorable growth conditions in the woman lead to an increased release of the hormone, thereby improving the chances of survival in case of a premature birth. Under certain circumstances, however, this increase can also have negative consequences: “An excessive acceleration of growth may occur at the expense of the proper maturation of the organs,” says Ulrike Ehlert, psychologist and program coordinator.

    Short-term stress — no effect

    How does mental stress to the mother affect the release of stress hormones in the placenta? The research team tested 34 healthy pregnant women, who took part in amniocentesis within the scope of prenatal diagnostics. Such a test constitutes a stress situation for the expectant mother as her body secretes cortisol in the short term. To determine whether the placenta also releases stress hormones, the researchers compared the cortisol level in the mother’s saliva with the CRH level in the amniotic fluid — and determined that there was no connection: “The baby obviously remains protected against negative effects in case of acute, short-term stress to the mother,” Ehlert concludes.

    Longer-term stress can be measured in amniotic fluid

    The situation of the results regarding prolonged stress is completely different, as was determined using questionnaires for diagnosing chronic social overload: “If the mother is stressed for a longer period of time, the CRH level in the amniotic fluid increases,” says Pearl La Marca-Ghaemmaghami, psychologist and program researcher. This higher concentration of stress hormone in turn accelerates the growth of the fetus. As a result, the effect of the hormone on growth is confirmed, as has been observed in animals such as tadpoles: If their pond is on the verge of drying out, CRH is released in tadpoles, thereby driving their metamorphosis. “The corticotropin-releasing hormone CRH obviously plays a complex and dynamic role in the development of the human fetus, which needs to be better understood,” La Marca-Ghaemmaghami summarizes.

    Strengthening mental resources with specialized help

    The psychologists advise pregnant women who are exposed to longer-term stress situations to “seek support from a therapist to handle the stress better.” Stress during pregnancy cannot always be avoided, however. “A secure bond between the mother and child after the birth can neutralize negative effects of stress during pregnancy,” La Marca-Ghaemmaghami says.