Animal study suggests that stress may accelerate age-related changes in the brain
A new study published in the June 18 issue of The Journal of Neuroscience adds to a body of evidence suggesting stress may accelerate cognitive decline later in life. The study found that aged rats with high levels of the stress hormone corticosterone showed structural changes in the brain and short-term memory deficits.
While most people will experience some cognitive decline as they get older, the extent of these changes and how rapidly they progress varies greatly from one person to the next. Scientists are interested in understanding the factors that contribute to these differences. Research suggests that how the body responds to stress may be one of the factors influencing how the brain ages. Multiple animal studies have linked high levels of the stress hormone corticosterone (similar to the human stress hormone cortisol) with age-related structural and functional decline in the hippocampus, a region that plays a key role in long-term memory.
Jason J. Radley of the University of Iowa wanted to know whether exposure to high levels of corticosterone is associated with other changes in the brain and memory deficits. In the current study, he and others measured the amount of the stress hormone in the blood of young and old rats and examined cells in the prefrontal cortex, a region of the brain involved in short-term memory. The researchers found that older animals with high levels of the stress hormone had fewer connections between prefrontal cortex cells than the older animals with lower levels of the hormone. In contrast, prefrontal cortex cells appeared similar in younger animals regardless of stress hormone levels.
"Older animals with higher levels of stress hormones in their blood have 'older' frontal cortexes than animals with less stress hormones," explained Stanford University professor Robert Sapolsky, PhD, an expert on the damaging effects of long-term stress who was not involved with this study. "Thus, stress may act as a pacemaker of aging in this key brain region."
Older rats with higher levels of stress hormone displayed a 20 percent reduction in the density of dendritic spines (the small protrusions on neurons that come into close contact with other cells to form synapses, the connections between cells) relative to age-matched rats with less stress hormone.
The researchers also compared how the young and old rats performed on a simple working memory task, where the animals had to remember which arm of a two-arm maze contained a food reward following varying periods of delay. Older animals with higher levels of corticosterone made more errors when attempting to predict the location of the reward than age-matched animals with less of the stress hormone after a brief period of delay.
"These findings are not meant to indicate that high stress hormones are the only factor in determining the decline of mental abilities during aging," Radley cautioned. "Nonetheless, this study suggests that the effects of these stress hormones on the brain may be much more widespread than we previously thought."
This research was funded by the National Institute of Mental Health.
The Journal of Neuroscience is published by the Society for Neuroscience, an organization of nearly 40,000 basic scientists and clinicians who study the brain and nervous system. Radley can be reached at firstname.lastname@example.org. More information on aging, stress, and memory can be found on BrainFacts.org.
Emily Ortman | Eurek Alert!
High in calories and low in nutrients when adolescents share pictures of food online
07.04.2016 | University of Gothenburg
Brain connectivity reveals hidden motives
04.03.2016 | Universität Zürich
A biological and energy-efficient process, developed and patented by the University of Innsbruck, converts nitrogen compounds in wastewater treatment facilities into harmless atmospheric nitrogen gas. This innovative technology is now being refined and marketed jointly with the United States’ DC Water and Sewer Authority (DC Water). The largest DEMON®-system in a wastewater treatment plant is currently being built in Washington, DC.
The DEMON®-system was developed and patented by the University of Innsbruck 11 years ago. Today this successful technology has been implemented in about 70...
Permanent magnets are very important for technologies of the future like electromobility and renewable energy, and rare earth elements (REE) are necessary for their manufacture. The Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany, has now succeeded in identifying promising approaches and materials for new permanent magnets through use of an in-house simulation process based on high-throughput screening (HTS). The team was able to improve magnetic properties this way and at the same time replaced REE with elements that are less expensive and readily available. The results were published in the online technical journal “Scientific Reports”.
The starting point for IWM researchers Wolfgang Körner, Georg Krugel, and Christian Elsässer was a neodymium-iron-nitrogen compound based on a type of...
In the Beyond EUV project, the Fraunhofer Institutes for Laser Technology ILT in Aachen and for Applied Optics and Precision Engineering IOF in Jena are developing key technologies for the manufacture of a new generation of microchips using EUV radiation at a wavelength of 6.7 nm. The resulting structures are barely thicker than single atoms, and they make it possible to produce extremely integrated circuits for such items as wearables or mind-controlled prosthetic limbs.
In 1965 Gordon Moore formulated the law that came to be named after him, which states that the complexity of integrated circuits doubles every one to two...
Characterization of high-quality material reveals important details relevant to next generation nanoelectronic devices
Quantum mechanics is the field of physics governing the behavior of things on atomic scales, where things work very differently from our everyday world.
When current comes in discrete packages: Viennese scientists unravel the quantum properties of the carbon material graphene
In 2010 the Nobel Prize in physics was awarded for the discovery of the exceptional material graphene, which consists of a single layer of carbon atoms...
24.05.2016 | Event News
20.05.2016 | Event News
19.05.2016 | Event News
27.05.2016 | Awards Funding
27.05.2016 | Life Sciences
27.05.2016 | Life Sciences