Posts tagged with "Eureka Alert!"

Step-parents: Not so wicked after all?

May 7, 2021

Although fairy tales featuring wicked stepmothers are an integral part of popular culture, the effects of blending children with their new stepfamilies may not be as grim as once thought, Eureka Alert reports.

In fact, new research demonstrates that stepchildren are not at a disadvantage compared to their peers from single-parent households—and actually experience better outcomes than their half-siblings.  Wicked

And that’s very good news for the more than 113 million Americans who are part of a step-relationship.

Led by East Carolina University anthropologist Ryan Schacht and researchers from the University of Utah, the study has been published in the May edition of the Philosophical Transactions of the Royal Society B.

The study challenges the “Cinderella effect” theory—which contends that conflict within stepfamilies over physical, financial, and emotional resources leads to higher mortality risks for stepchildren, and is a main factor in higher rates of abuse and neglect. The phenomenon suggests that step-parents play a major role in this abuse, hoarding resources for their biological children and leading to negative outcomes for stepchildren.

Schacht proposes that previous studies have placed blame for the negative outcomes associated with parental loss on step-parents yet have done so through an an “apples-to-oranges comparison.” Specifically, they compare of the long-term outcomes of children who have suffered trauma like parental loss versus children from stable households. When the team compared stepchild outcomes more appropriately among those children who too have experienced the economic and emotional hardships associated with parental loss, they found no difference. Specifically, the introduction of step-parenents did not increase stepchild mortality.

“The idea of a step-parent, especially the stepmother, as being an agent of evil seems to be a story as old as time,” Schacht said. “It’s easy to sell the Cinderella effect’s result because we’ve been told these stories about the problems that stepfamilies experience for hundreds of years.

“We’re not denying that some stepchildren suffer,” he said. “However, if we truly believe it is the step-parent that is the source of negative outcomes for a stepchild, then we need to compare similar environments and experiences. A child that hasn’t lost a parent through death or divorce hasn’t experienced the same trauma that a stepchild has; comparing those two experiences and blaming the step-parent for diverging outcomes isn’t a fair comparison.”

The study compared the mortality of stepchildren whose parents remarried after the death of a spouse to children whose parents did not remarry and found three key findings:

  • Parental mortality has a negative effect on children under 18 years old, especially for infants losing a mother;
  • Children whose parents remarried after the loss of a spouse did not suffer a mortality rate any greater than children whose parents did not remarry; and
  • Stepchildren received a protective effect when a half-sibling was introduced to their new family.

“The metrics of what makes a family successful—household stability, relationship stability, and economic stability—are achieved by step-parents investing in their stepchildren to make that a reality. Coming in with an antagonistic approach doesn’t make sense if step-parents want their relationship to succeed.”

The research team analyzed a data set of more than 400,000 children from Utah from 1847-1940. Schacht said the time period provided an opportunity to analyze stepchild mortality rates in families during a natural fertility period where families were larger in size and most stepfamilies were formed due to the death of a parent.

The study adds that children who have suffered parental loss have more in common with their peers from single-parent households, facing many of the same educational, economic and health care disparities.

Schacht hopes the study will shed a light on public policy funding for interventions for families that have suffered parental loss.

Research contact: @EurekaAlert

Into the light: Babies in the womb may see more than we thought

November 26, 2019

The transitions that mark the beginning and end of human life are marked by the same phenomenon: light. In fact, a new study conducted at the University of California-Berkeley has found that, eve by the second trimester—long before a baby’s eyes can see images—they can detect light.

Previously, the light-sensitive cells in the developing retina— the thin sheet of brain-like tissue at the back of the eye— were assumed to be simple” on-off switches,” presumably there to set up the 24-hour, day-night rhythms parents hope their baby will follow.

Now, with funding from the National Institutes of Health, researchers have discovered evidence that these simple cells actually talk to one another as part of an interconnected network that gives the retina more light sensitivity than once thought, and that may enhance the influence of light on behavior and brain development in unsuspected ways.

In the developing eye, perhaps 3% of ganglion cell—the cells in the retina that send messages through the optic nerve into the brain—are sensitive to light and, to date, researchers have found about six different subtypes that communicate with various places in the brain. Some talk to the suprachiasmatic nucleus to tune our internal clock to the day-night cycle. Others send signals to the area that makes our pupils constrict in bright light.

But others connect to surprising areas: the perihabenula, which regulates mood, and the amygdala, which deals with emotions.

In mice and monkeys, recent evidence suggests that these ganglion cells also talk with one another through electrical connections called gap junctions, implying much more complexity in immature rodent and primate eyes than imagined.

“Given the variety of these ganglion cells and that they project to many different parts of the brain, it makes me wonder whether they play a role in how the retina connects up to the brain,” said Marla Feller, a UC Berkeley professor of molecular and cell biology and senior author of a paper that appeared this month in the journal Current Biology. “Maybe not for visual circuits, but for non-vision behaviors. Not only the pupillary light reflex and circadian rhythms, but possibly explaining problems like light-induced migraines, or why light therapy works for depression.”

The cells, called intrinsically photosensitive retinal ganglion cells (ipRGCs), were discovered only ten years ago, surprising those such as Feller, who had been studying the developing retina for nearly 20 years. She played a major role, along with her mentor, Carla Shatz of Stanford University, in showing that spontaneous electrical activity in the eye during development— so-called retinal waves —is critical for setting up the correct brain networks to process images later on.

“We thought they (mouse pups and the human fetus) were blind at this point in development,” said Feller. “We thought that the ganglion cells were there in the developing eye, that they are connected to the brain, but that they were not really connected to much of the rest of the retina, at that point. Now, it turns out they are connected to each other, which was a surprising thing.”

UC Berkeley graduate student Franklin Caval-Holme combined two-photon calcium imaging, whole-cell electrical recording, pharmacology, and anatomical techniques to show that the six types of ipRGCs in the newborn mouse retina link up electrically, via gap junctions, to form a retinal network that the researchers found not only detects light, but responds to the intensity of the light, which can vary nearly a billionfold.

Gap junction circuits were critical for light sensitivity in some ipRGC subtypes, but not others, providing a potential avenue to determine which ipRGC subtypes provide the signal for specific non-visual behaviors that light evokes.

“Aversion to light, which pups develop very early, is intensity-dependent,” suggesting that these neural circuits could be involved in light-aversion behavior, Caval-Holme said. “We don’t know which of these ipRGC subtypes in the neonatal retina actually contributes to the behavior, so it will be very interesting to see what role all these different subtypes have.”

The researchers also found evidence that the circuit tunes itself in a way that could adapt to the intensity of light, which probably has an important role in development, Feller said.

“In the past, people demonstrated that these light-sensitive cells are important for things like the development of the blood vessels in the retina and light entrainment of circadian rhythms, but those were kind of a light on/light off response, where you need some light or no light,” she said. “This seems to argue that they are actually trying to code for many different intensities of light, encoding much more information than people had previously thought.”

Research contact: @EurekaAlert