A new study suggests that a short session of brain-zapping can reverse some of the effects of aging in older people. Currently this technique is not yet ready for use in a non-experimental environment and the exact duration of the benefits of this technique is not yet defined.
The authors of the study hope that their findings will pave the way for better cognition in healthy adults and in people suffering from Alzheimer's disease or other forms of dementia. " These results are important because they not only give us new insights into how the brain works in relation to age-related memory loss, but they also show us that some of the negative age-related changes are not invariable Said study leader Robert Reinhart, a neuroscientist at the University of Boston.
Reinhart and co-author of the study, PhD candidate John Nguyen, have focused their research on an aspect of cognition called " random access memory "(Random access memory). According to Reinhart, this aspect of cognition enables people to keep information active for a few seconds and facilitates all sorts of important tasks, such as performing a mental calculation, reading or having a conversation. " This research has shown that working memory is a key element of intelligence Reinhart said.
However, this working memory decreases as an adult. Although the decline is not dramatic, it is important enough to make it less effective on average for adults than for younger people. Reinhart and Nguyen wanted to understand why this was the case and whether it was possible to change it.
To complete their study, the researchers recruited 42 adults aged 20 to 29 and 42 adults aged 60 to 76: the scientists then asked the participants to complete tasks using their working memory while their activity became brain recorded by electro-encephalogram.
The task that the participants had to perform was simple and consisted of a simple game differences In which participants saw two similar images in succession on a screen and had to identify what was different about the second image they saw. That all participants were in good health, without diagnosis of dementia or other cognitive problems.
In some sessions, participants performed this task while their brains were gently stimulated via a non-invasive electrical method called Transcranial AC stimulation. Indeed, it was the use of electrodes on the scalp that sent the researchers rhythmic electrical stimulation to the prefrontal and temporal brain regions. Communication between these regions, front and side of the brain, is considered important for the working memory.
The experiment was conducted double-blind, meaning that no participant or researcher knew when participants received brain stimulation. " Apart from a slight initial tingling sensation on the scalp, the stimulation does not even feel Reinhart said. To fool the participants in fictional sessions, the researchers conducted it false stimuli 30 seconds that mimicked that feeling. The participants came several times (on different days) to perform the actual and fictional sessions, and each stimulation lasted about 25 minutes.
Before stimulation, the elderly scored significantly lower than the younger cohort. The accuracy in young adults was on average around 90%, with scores ranging from around 80% to 100%. In older adults, however, the average was closer to 80%, with scores ranging from around 70% to just over 80%.
However, brain stimulation has bridged this gap! In fact, about 12 minutes after the onset of brain stimulation, the older adult group began to get similar results to the younger adult group. Note that this improvement was continued for the duration of the experiment, more than 50 minutes after the stimulation was stopped.
At present, researchers have not yet conducted any tests to determine how long these findings can persist even after the electrical stimulation of the brain. However, findings from other brain stimulation studies suggest that effects can last for several hours.
In follow-up experiments with 49 other older and younger adults, the researchers also tested the effects of brain stimulation on younger adults who had a low score compared to the average of participants of their age. Through these experiments, the researchers also discovered that electrical stimulation could be beneficial for the brains of younger adults, who also achieved better results during stimulation.
" This study has been performed in an impressive way Said Walter Paulus and Zsolt Turi, both clinical neurophysiologists at the University Medical Center in Göttingen, Germany. The latter were not involved in the investigation. Namely, the researchers tested their own work on follow-up samples from the participants, " which reinforces confidence in these results Added turi.
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Of course, " there is still work to be done Stuffy Paul. He also added that there are currently companies selling devices whose purpose is to stimulate the brain through the skull. However, and as the study by Reinhart and Nguyen shows, brain stimulation must be personalized. " Researchers have done a good job by improving brain function Paul said. " If you deviate from the protocol, you may not get any results or you may get counterproductive results Paul added.
Now researchers will have to do more research, because this technique is promising for patients. According to Reinhart, stimulation seems to reverse the decline of brain aging for several important reasons. First, the stimulation is tightly focused on the prefrontal cortex and the temporal lobe. For young adults using their working memory, these two areas synchronize the rhythms of their activity. " More synchronization is tight (a low-frequency configuration, about 8 Hertz, seems to be the ideal point) and the memory will perform better Reinhart said.
In older adults, this timing has just disappeared, which appears to be the most important element in the working memory. This leads to the second important characteristic of brain stimulation: rhythmicity. " We synchronize those areas of the brain that are disconnected, non-correlated or less synchronized in older people Reinhart said. He also noted that younger adults who performed poorly had a relatively desynchronized brain environment.
According to Reinhart, these new discoveries are a real starting point. At present, the research team has already begun to push these studies into the field of neurological disorders.
In addition, researchers have found (but have not yet published) evidence that older people with more dementia symptoms (but not complete dementia) have poorer brain synchronization in regions with working memory. and long-term memory. It could mean that " resynchronization technique can potentially be a non-invasive treatment for Alzheimer's disease and other forms of dementia Reinhart says.
The researchers discovered that they could stimulate the brain with rhythms that disynchronized certain parts of the brain. Now they will have to do more research: " It predicts well for the next clinical stages because we know that there are brain disorders that are characterized by hypoconnectivity (low connectivity), such as autism, schizophrenia and Alzheimer's, but there are so many disorders that are characterized by too much connectivity in the brain, such as epilepsy or Parkinson's disease Reinhart says.
" [Nous avons ici] the start of a tool that can both synchronize your brain and make it more connected, or desynchronize and make it less connected The researcher added.
A case to follow closely.