Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

When early life stress occurs determines its impact later

25.10.2004


Two studies presented at Society for Neuroscience Meeting (NOTE: Thise release has been updated since its original post.)
Scientists at the OHSU Oregon National Primate Research Center and the University of Pittsburgh report significant stress early in life can have varying lifelong impacts depending of the timing of the stress exposure. The research also demonstrates that the impact can become even more profound when coupled with stress in adulthood. In a related but separate study, the researchers also observed the importance of timing in initiating therapies meant to counteract the impacts of early life stress. The research is being presented this week at the 2004 Society for Neuroscience meeting in San Diego.

“Past research conducted in both humans and animals has already established that significant stresses experienced early in life can cause problems in the development of social skills and behavioral problems that can last throughout childhood and into adulthood,” said Judy Cameron, Ph.D., a scientist in the divisions of Reproductive Sciences and Neuroscience at the OHSU Oregon National Primate Research Center and the University of Pittsburgh. “These problems can manifest themselves in a number of ways including increased anxiety, anti-social behavior, depression, drug and alcohol abuse and suicide. However, to this date, little information has been obtained as to whether the timing of early life stress exposure can be linked to differing outcomes. In addition, few studies have been conducted to determine the best methods for preventing or counteracting the lifelong impacts of such early life stress exposure.”


Earlier studies have revealed that the first several months of life represent a dramatic period for brain development, especially in the neocortical regions of the brain, which are important in developing social skills. The development of neurons in this region takes place at an extremely accelerated rate during the first few months of life. In addition, important changes in brain chemistry are taking place during this period. Rapid changes in brain structure and function make the person or animal more susceptible to environmental impacts at these times in development.

Both studies being presented in San Diego were conducted using non-human primates. Past research has shown that monkeys are excellent models for studying the impacts of early childhood stress. Infant monkey behavioral changes caused by stress are very similar to those witnessed in human infants. In addition, studies using monkeys allow researchers to control factors such as the timing and duration of stress exposure, something not possible in human studies. Scientists also have a greater ability to observe the test subjects. In addition, non-human primate studies allow researchers to eliminate uncontrolled environmental factors that can skew the results of human studies.

To conduct the first study, researchers tracked a total of 15 animals. To simulate significant early-life stress in humans, the infant monkeys, who were living in social groups, experienced removal of their mother at varying times in infancy. The social groups included males and females of varying ages, much like groups naturally formed in the wild. In addition, all monkeys in the study were provided with toys and formula at the time of mother removal.

The monkeys were studied in three categories. The first category of infants was separated from their mothers during the first week of life, prior to the development of social skills. The second category of infants was separated from their mothers when they were one month of age, the stage when social skills are developing. The third category of infants had their mother removed from the social group at six months. This third category was considered a control group as monkeys in the wild become more independent from their mothers at approximately six months of age.

“We then studied the development of these three categories of monkeys and noticed differences in behavior related to the timing of separation,” explained Cameron. “Monkeys separated at one week were less social when they were young, a characteristic that continues on into adulthood. The monkeys tended to exhibit a higher than normal amount of self-comforting behaviors such as thumb or toe sucking. In addition, these monkeys tended to have less social dominance in the group setting, perhaps in relation to their reduced social skills. In contrast, monkeys separated at one month displayed increased seeking of social comfort and an increase in social dominance. In adulthood, these same monkeys spent more time involved in social play when compared to animals in the other groups. They also tended to be more dominant than other monkeys.”

Researchers also tracked the responses of these three groups of animals in adulthood when they were placed with new social groups. The one-week separated animals seemed to be the most agitated by this social change. They tried many new behaviors, increased social behavior to the level of other groups of monkeys, increased in social dominance, but also threatened other monkeys more often. The one-month separated animals showed changes in eating behaviors and decreased play when placed in new social groups. In summary, the response to stress in adulthood was strongly influenced by whether and when animals had experienced stress in early life.

One important note is that earlier research suggests that stress sensitivity is heightened in individuals that undergo stresses early in life. This research shows that is not always the case and is at least partially dependent on the timing of the early-life stress. The second, separate study that was conducted by the same research team extended the understanding of early life stress impacts. The study revealed the important role that timing plays in preventing behavioral problems associated with exposure to significant stresses during early childhood.

To simulate significant early-life stress in humans, the scientists separated nine infant monkeys from their mothers during the first week of life and placed them in social groups of three to four other monkeys. The social groups consisted of males and females ranging in ages, similar to groups formed in the wild. The researchers then introduced experienced mothers, often referred to as “super moms,” when the infant monkeys were one to three months of age. These adoptive mothers were paired with the infant monkeys as a form of corrective therapy. The timing of the introduction of these “super moms” was varied because the scientists wanted to determine the optimal timing for initiation of therapies to counteract the impacts of the early-life stress.

“After being paired with the ‘super moms,’ we then observed the baby monkeys throughout their first year of life,” explained Cameron. “As a control group for comparison, we observed the behavior of monkeys that lived with their natural mothers as well as a social group for the first six months of life. At six months the control monkeys had their mothers removed from the social group. Six months is the typical age when juvenile monkeys begin to gain independence from their mothers in the wild.”

The scientists noted that the infants separated from their mothers at one week of age displayed a series of atypical behaviors. Specifically, these animals spent significantly more time alone than animals in the control group and limited their social contact. They also developed self-comforting behaviors, such as thumb or toe sucking. However, when separated monkeys were paired with an adoptive mother within the first month, all of these behaviors were rapidly reversed. For monkeys paired with adoptive mothers in the second month of life, the reversal took place, but at a slower pace. Monkeys paired in the third month of life did not exhibit a reversal of these atypical behaviors.

The researchers believe this research shows a small but distinct window of opportunity for possibly reversing or preventing poor social skill development due to early life stress exposure. “What this work appears to be telling us is that children separated from their mothers at birth should be placed in nurturing stable care situation as soon as possible to reduce the chances of developing socioemotional problems,” explained Cameron. “This differs dramatically from the real-life policies in place in most states where a child is cared for, but not paired with a permanent family – a period that can last months - until a final decision is made as to whether they can be returned to their birth family.”

“These findings underscore three core scientific principles that guide effective early childhood policy and practice,” said Jack P. Shonkoff, M.D., dean of The Heller School for Social Policy and Management at Brandeis University and chair of the National Scientific Council on the Developing Child. “Early relationships are key to healthy development. Disrupted relationships have both immediate and long-term consequences. Relationship-based interventions can get kids back on track, but the clock is always ticking and the earlier the intervention the better the outcome.”

Craig Dunhoff | EurekAlert!
Further information:
http://www.upmc.edu

More articles from Studies and Analyses:

nachricht Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland

nachricht Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>