Rest After Trauma May Help Decrease PTSD Symptoms

New research suggests a period of rest following a traumatic event can help reduce the subsequent development of involuntary “memory intrusions,” a frequent symptom of post-traumatic stress disorder. Memory intrusions can be both visual or non-visual and are often referred to as flashbacks.

The study, published in Scientific Reports, discovered memory disturbances in PTSD may be mitigated by a process that occurs in the brain that can be facilitated by rest and sleep. Specifically, investigators discovered increased consolidation — storage and contextualization of memories in the brain — helps to alleviate memory intrusions. Experts believe this finding could shed new light on treatment and prevention.

Lead author Dr. Lone Hørlyck, from the Institute of Cognitive Neuroscience at University College London, said, “Over a lifetime, many people experience traumatic events, but most people do not develop persistent trauma symptoms.

“Identifying which mechanisms might contribute to memory intrusions in PTSD is important, as these disturbances comprise an important maintaining factor in the disorder.”

For the study, researchers presented 85 participants with emotionally negative videos, followed by either a period of wakeful rest or a simple control task, where participants were required to pay attention to numbers on a screen.

The videos comprised highly emotional content, such as badly injured people or serious accidents.

Researchers found that participants who had a period of rest following the viewing of negative videos reported fewer memory intrusions related to the videos over the following week.

In contrast, there was no difference between rest and the simple control task on a follow-up memory test assessing how much participants remembered when they wanted to.

Rest and certain phases of sleep are known to increase processing in the hippocampus, a key region of the brain that helps put memory in context.

According to the investigators, the results suggest that a strengthening of this contextual memory system is beneficial in preventing memory intrusions following trauma.

Senior author Professor Neil Burgess, of the Institute of Cognitive Neuroscience, said, “The coherence of memories is often compromised when people are exposed to psychological trauma, resulting in emotional memories popping up involuntarily and out of context.

“However, the binding of an event memory with its context may be partly restored with rest, facilitating deliberate control of the memory.

“The results show that specific brain systems could be targeted to reduce development of PTSD and may explain why treatments that focus on re-exposure and integrating the trauma with other information are beneficial.”

Hørlyck added, “Our findings contribute to a better understanding of the mechanisms that are at play when some people develop memory disturbances following trauma while others do not.”

Source: University College London/EurekAlert

Mindfulness Meditation May Benefit Older Adults with Mild Cognitive Impairment

Mindfulness meditation may benefit older adults with mild cognitive impairment (MCI), according to a small pilot study published in the Journal of Alzheimer’s Disease.

There’s currently no known way to prevent older adults with MCI from developing Alzheimer’s disease, but mindfulness meditation may be a safe and feasible non-pharmacological treatment that can help.

Mindfulness means maintaining a moment-by-moment, non-judgmental awareness of thoughts, feelings, bodily sensations, and surrounding environment.

“Our study showed promising evidence that adults with MCI can learn to practice mindfulness meditation, and by doing so may boost their cognitive reserve,” said Rebecca Erwin Wells, MD, MPH, associate professor of neurology at Wake Forest School of Medicine, a practicing neurologist at Wake Forest Baptist Medical Center and associate director of clinical research for its Center for Integrative Medicine.

Cognitive reserve is a person’s capacity to maintain normal cognitive function in the presence of deteriorating brain function.

“While the concept of mindfulness meditation is simple, the practice itself requires complex cognitive processes, discipline and commitment,” Wells explained. “This study suggests that the cognitive impairment in MCI is not prohibitive of what is required to learn this new skill.”

Previous research has shown that high levels of chronic stress negatively impact the hippocampus, a part of the brain involved in memory and learning, and are associated with increased incidence of MCI and Alzheimer’s. Other studies have indicated that non-drug interventions such as aerobic exercise can have positive effects on cognition, stress levels and the brain.

To determine whether a mindfulness-based stress-reduction (MBSR) program could benefit adults with MCI, the study team recruited 14 men and women between the ages of 55 and 90 with clinically diagnosed MCI and randomized them to either an eight-week course involving mindfulness meditation and yoga or a “waiting list” control group.

The researchers previously reported that the nine participants who completed the MBSR program showed trends toward improvements on measures of cognition and well-being and indications of positive impacts on the hippocampus as well as other areas of the brain associated with cognitive decline.

The new study adds context to those findings with an analysis of the MBSR participants’ responses in interviews conducted at the end of the eight-week course.

“While the MBSR course was not developed or structured to directly address MCI, the qualitative interviews revealed new and important findings specific to MCI,” Wells said. “The participants’ comments and ratings showed that most of them were able to learn the key tenets of mindfulness, demonstrating that the memory impairment of MCI does not preclude learning such skills.”

Participants who practiced at least 20 minutes a day were most likely to have understood the underlying concepts of mindfulness, Wells noted.

“Until treatment options that can prevent the progression to Alzheimer’s are found, mindfulness meditation may help patients living with MCI,” said Well.

The limitations of the study include the small sample size and that the results may not generalize to all patients with MCI, as two-thirds of the participants in this study had a college education or more. Additional research is needed to further test the preliminary hypotheses contained in this study.

Source: Wake Forest Baptist Medical Center

Brain Stimulation Improves Memory of Older Adults

A new study finds that stimulating the brain’s memory center with electromagnetic pulses improves the memory of older adults to the level of young adults. Specifically, Northwestern medical school researchers discovered precise stimulation to the hippocampus dramatically improved the memory of older adults with age-related memory loss.

“Older people’s memory got better up to the level that we could no longer tell them apart from younger people,” said lead investigator Joel Voss, associate professor at Northwestern University Feinberg School of Medicine. “They got substantially better.”

The study used Transcranial Magnetic Stimulation (TMS) to target the hippocampus — the brain region that atrophies as people grow older, which is responsible for memory decline.

“It’s the part of the brain that links two unrelated things together into a memory, like the place you left your keys or your new neighbor’s name,” Voss said. “Older adults often complain about having trouble with this.”

Researchers explain that this type of memory worsens as we age. Nearly all people experience a decline in their memory ability as they age.

The new study of 16 people, aged 64 to 80 years old with normal age-related memory problems, shows it’s possible to alter memory ability in older adults using this type of brain stimulation, Voss said.

“There is no previous evidence that the specific memory impairments and brain dysfunction seen in older adults can be rescued using brain stimulation or any other method.”

Study finds appear in the journal Neurology.

In the study, the hippocampus — which is smaller in older adults — was identified in each individual with an fMRI. This imaging tool (functional MRI) measures how active a part of the brain is at a given time.

Researchers then located an area of the parietal lobe that communicates with the hippocampus for stimulation delivery. This spot was behind and slightly above a person’s left ear, but everyone had a slightly different spot.

It isn’t possible to directly stimulate the hippocampus with TMS, which is noninvasive, because it’s too deep in the brain for the magnetic fields to penetrate. As an alternative, Voss and colleagues identified a superficial brain region close to the surface of the skull with high connectivity to the hippocampus.

“We stimulated where brain activity is synchronized to the hippocampus, suggesting that these regions talk to each other,” said first author Aneesha Nilakantan.

At baseline, younger and older adults were given memory tasks in which they learned arbitrary relations between paired things, such as this object goes on this spot on the computer screen. Younger adults scored about 55 percent correct and older adults less than 40 percent correct.

The research team then applied high-frequency repetitive magnetic stimulation to the spot for five consecutive days for 20 minutes a day. Stimulating this area improved the function of regions important for memory that are disrupted by aging, evident by more neural activity visible on an fMRI.

Then, 24 hours after the final stimulation, the subjects were given a new memory test in which they had to learn new arbitrary relations between paired things. After the brain stimulation, older adults scored at the level of young adults on the memory tasks.

The amazing results were also validated by the use of a fake placebo stimulation condition, which did not improve memory.

Voss and colleagues will next test this approach on participants with mild cognitive impairment, the early stage of Alzheimer’s disease. They will be stimulating the brain for longer periods of time.

Voss isn’t certain how long the effects could last. He suggests the enhanced memory effects could last longer with more stimulation. For instance, when depression is treated with TMS for five weeks, those patients get an antidepressant effect that lasts for many months, he noted.

In a future study, Voss will be stimulating the brain in persons with age-related memory loss for a longer period to test this hypothesis.

Source: Northwestern University

Imbalance in Brain Wiring May Influence Development of PTSD

New research suggests an imbalance in a key neural pathway may explain how some people reactivate negative emotional memories upon exposure to trauma while others do not. Investigators believe the finding could help scientists develop new approaches to treat psychiatric disorders such as post-traumatic stress disorder (PTSD).

The topic of emotional memory has traditionally represented a dilemma for scientists because the entire emotional event may be highly memorable, but details of the event are often fuzzy. Researchers now believe this lack of detailed recollection may lead to faulty reactivation of negative memories.

For example, if someone is bitten by a dog, he or she may become anxious around dogs of all breeds and sizes. Understanding the nature of emotional memory could have implications for the treatment of PTSD and other mental disorders.

“Emotion exerts a powerful influence on how vividly we can remember experiences,” said co-senior author Michael Yassa, professor of neurobiology and behavior, University of California Irvine (UCI).

“However, studies in humans have shown that the impact of emotion on memory is not always positive. In many cases, emotional arousal can impair a person’s ability to differentiate among similar experiences.”

This neural computation is critical for episodic memory and is vulnerable in neuropsychiatric disorders, Yassa said.

According to this new study, which appears in the journal Neuro, an imbalanced communication between the brain’s emotional center, the amygdala, and its memory hub, the hippocampus, may lead to the failure to differentiate negative experiences that have overlapping features.

On the other hand, a balanced dialogue between the amygdala and the hippocampus allows one to separate overlapping emotional experiences and make distinct memories.

Further, two types of brain rhythms — a faster (8 cycles per second) alpha oscillation and a slower (4 cycles per second) theta rhythm — diametrically regulate communications between the amygdala and the hippocampus.

Overamplified alpha rhythms from the amygdala to the hippocampus lead to faulty extrapolation of memories among similar experiences while balanced theta rhythms between the two brain regions promote correct discrimination and accurate recall.

“The teamwork between the amygdala and hippocampus is like a yin and yang and may be the key to disentangle overlapping emotional experiences and to overcome overreactions in a similar situation,” said Jie Zheng, a UCI alumnus and the study’s first author.

“Our findings provide a neural mechanism underlying this phenomenon and propose a circuit-level framework for possible neuropsychiatric therapy, such as deep brain stimulation, transcranial alternating current stimulation, and transcranial magnetic stimulation,” said Dr. Jack J. Lin, co-senior author and professor of neurology, UCI School of Medicine, and professor of biomedical engineering, UCI Henry Samueli School of Engineering.

Source: University of California Irvine