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[caliban]

Understandingnormal brain aging and developing methods to maintain or improve cognition in older adults are major goals of fundamental and translational neuroscience. Here we show a core feature of cognitive decline—working-memory deficits—emerges from disconnected local and long-range circuits instantiated by theta–gamma phase–amplitude coupling in temporal cortex and theta phase synchronization across frontotemporal cortex. We developed a noninvasive stimulation procedure for modulating long-range theta interactions in adults aged 60–76 years. After 25 min of stimulation, frequency-tuned to individual brain network dynamics, we observed a preferential increase in neural synchronization patterns and the return of sender–receiver relationships of information flow within and between frontotemporal regions. The end result was rapid improvement in working-memory performance that outlasted a 50 min post-stimulation period. The results provide insight into the physiological foundations of age-related cognitive impairment and contribute to groundwork for future non-pharmacological interventions targeting aspects of cognitive decline.

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• Scientists reverse memory decline using electrical pulses (Guardian) 
• When an older person’s brain waves are in sync, memory is boosted (Science News) 

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•  Reinhard&Nguyen2019a.pdf   2.74MB   1 downloads

[Engadin]

 

From treating depression to curtailing the effects of Parkinson's disease to awakening patients in a vegetative state, stimulating the brain with electrical currents holds all kind of potential. One very promising branch of this research centers on arresting cognitive decline by boosting memory and learning, and a string of recent studies have uncovered its exciting potential in this regard. The latest, conducted by scientists at Boston University, has outlined a non-invasive technique that was able to restore working memory in 70-year-old subjects, so much so they functioned like a healthy 20-year-old.

 

A good deal of the research on brain stimulation makes use of electrodes implanted into specific parts of the organ to deliver electrical pulses with great precision. This, known as Deep Brain Stimulation, has its advantages in that it allows greater targeting of certain brain regions, but implanting electrodes into a patient's brain simply isn't practical all of the time.

 

Alternatively, the stimulation can be delivered non-invasively through electrodes placed on the scalp, which is easier to apply and study. This was the method adopted by Rob Reinhart, a neuroscientists at Boston University, in seeking to enhance the minds of older folks whose memory may be slipping.

 

More specifically, his experiments focused on working memory, the active part of our brains that kicks into gear when we remember which items to grab at the grocery store, make decisions, or find our car keys. According to Reinhart, this can start to deteriorate as early as our late 20s as different sections of the brain grow apart and become uncoordinated. When we reach 60 or 70, this disconnect can result in observable cognitive decline.

 

Now he has discovered a way to rebuild the broken pathways, and it centers on two elements of brain function. The first is "coupling," which refers to when the various rhythms bouncing around in different parts of the brain work together in just the right way, just like a well-managed orchestra. The other is "synchronization," when slower rhythms known as theta rhythms, are properly in synch. Both of these functions deteriorate as we age, and take our memory skills along with them.

 

For his study, Reinhart enlisted a healthy group of subjects in their 20s, along with a group in their 60s and 70s, and had them all perform memory tasks. This meant viewing an image, taking a pause, viewing a second image, and then determining whether the second was slightly different to the original.

 

Unsurprisingly, the younger group performed much more accurately than the older group. But then Reinhart had 25 minutes of mild stimulation applied to the older subjects' scalps, with the pulses tuned to each patient's neural circuits. Thereafter, the performance gap between the groups disappeared and lasted at least 50 minutes after the stimulation. What's more, Reinhart found that he was able to boost memory function in even the young subjects who had performed poorly in the tasks.

 

"We showed that the poor performers who were much younger, in their 20s, could also benefit from the same exact kind of stimulation," Reinhart says. "We could boost their working memory even though they weren't in their 60s or 70s."

 

From here, Reinhart hopes to continue exploring how brain stimulation can improve the brain circuitry of humans in other ways, with Alzheimer's sufferers a particular point of focus.

 

"It's opening up a whole new avenue of potential research and treatment options," he says. "And we're super excited about it."

 

The research was published in the journal Nature Neuroscience.

 

Source: Boston University

 

Source: https://newatlas.com...50-years/59210/

 

[reason]

Researchers here report on a demonstration in which they used electrostimulation to improve the working memory of old people to put it on a par with young people. It will be interesting to watch the investigation into the underlying mechanisms in the years ahead, though I expect it will be quite difficult to work backwards from such a non-invasive stimulus focused on brain waves, and into the underlying biochemistry of the brain.

Researchers have demonstrated that electrostimulation can improve the working memory of people in their 70s so that their performance on memory tasks is indistinguishable from that of 20-year-olds. The research targets working memory - the part of the mind where consciousness lives, the part that is active whenever we make decisions, reason, recall our grocery lists, and (hopefully) remember where we left our keys. Working memory starts to decline in our late 20s and early 30s, as certain areas of the brain gradually become disconnected and uncoordinated. By the time we reach our 60s and 70s, these neural circuits have deteriorated enough that many of us experience noticeable cognitive difficulties, even in the absence of dementias like Alzheimer's disease.

Researchers asked a group of people in their 20s and a group in their 60s and 70s to perform a series of memory tasks that required them to view an image, and then, after a brief pause, to identify whether a second image was slightly different from the original. At baseline, the young adults were much more accurate at this, significantly outperforming the older group. However, when the older adults received 25 minutes of mild stimulation delivered through scalp electrodes and personalized to their individual brain circuits, the difference between the two groups vanished. Even more encouraging? That memory boost lasted at least to the end of the 50-minute time window after stimulation - the point at which the experiment ended.

Coupling occurs when different types of brain rhythms coordinate with one another, and it helps us process and store working memories. Slow, low-frequency rhythms - theta rhythms - dance in the front of your brain, acting like the conductors of an orchestra. They reach back to faster, high-frequency rhythms called gamma rhythms, which are generated in the region of the brain that processes the world around us. But when the theta rhythms lose the ability to connect with those gamma rhythms to monitor them, maintain them, and instruct them, then the melodies within the brain begin to disintegrate and our memories lose their sharpness. Meanwhile, synchronization, when theta rhythms from different areas of the brain synchronize with one another, allows separate brain areas to communicate with one another. This process serves as the glue for a memory, combining individual sensory details to create one coherent recollection. As we age, our theta rhythms become less synchronized and the fabric of our memories starts to fray.

The present work suggests that by using electrical stimulation, we can reestablish these pathways that tend to go awry as we age, improving our ability to recall our experiences by restoring the flow of information within the brain. And it's not just older adults that stand to benefit from this technique: it shows promise for younger people as well. In the study, 14 of the young-adult participants performed poorly on the memory tasks despite their age - so the researchers called them back to stimulate their brains too. "We showed that the poor performers who were much younger, in their 20s, could also benefit from the same exact kind of stimulation. We could boost their working memory even though they weren't in their 60s or 70s. Coupling and synchronization exist on a continuum. On one end of the spectrum, someone with an incredible memory may be excellent at both synchronizing and coupling, whereas somebody with Alzheimer's disease would probably struggle significantly with both. Others lie between these two extremes-for instance, you might be a weak coupler but a strong synchronizer, or vice versa."

Link: https://www.bu.edu/r...working-memory/

View the full article at FightAging