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Summary: A new study reveals how the brain responds to mental exhaustion, identifying two key regions: the right insula and the dorsolateral prefrontal cortex, which become more active as cognitive fatigue develops. Using a functional magnetic resonance, the researchers observed how the volunteers responded to the demanding memory tasks and how their willingness to continue changed depending on internal fatigue and external rewards.
The more the mentally drained participants felt, the more activity these brain regions showed, however, the highest financial incentives still pushed them to move on. These ideas could help guide treatments for fatigue related conditions such as depression and PTSD offering a measurable biological vision of mental effort.
Key facts:
Identified fatigue circuits: the right insula and the dorsolateral prefrontal cortex show greater activity during cognitive fatigue. VERSUS Effect incentives: higher monetary rewards by increasing the will of participants to exercise a mental effort, even when they fatigue.
Source: Johns Hopkins Medicine
In experiments with healthy volunteers who undergo functional magnetic resonance images, scientists have found greater activity in two areas of the brain who work together to react, and possibly regulate the brain when “you will” feel “tired and renounce or continue to exercise the mental effort.
Experiments, designed to help detect several aspects of cerebral fatigue, can provide a way for doctors to evaluate and treat people who experience overwhelming mental exhaustion, including those with depression and post -traumatic stress disorder (PTSP), scientists say.
A report on the NIH -funded study was published online on June 11 at the Journal of Neuroscience, which details the results on 18 female healthy adult volunteers and 10 men who were given tasks to exercise their memory.
“Our laboratory focuses on how (our minds) generate value for the effort,” says Vikram Chib, Ph.D., associate professor of biomedical engineering at the Johns Hopkins University Faculty of Medicine and research scientist at the Kennedy Krieger Institute.
“We understand less about the biology of cognitive tasks, including memory and retirement, than about physical tasks, although both imply a lot of effort.” Anecdotally, says Chib, scientists know that cognitive tasks are exhausting, and relatively less about why and how it develops and plays such fatigue in the brain.
The 28 participants of the study, who had ages between 21 and 29, were paid $ 50 to participate in the study, and told them that they could receive additional payments based on their performance and options. All participants received a magnetic baseline resonance of baseline before the experiments began.
The tests of his working memory, which took place while subjected to subsequent magnetic resonance scans of their brains, included looking at a series of letters, in sequence, on a screen and remembering the position of certain letters. The further back, a letter was in the series of letters, the more difficult to remember its position, increasing spent cognitive effort.
Participants received comments on their performance after each test and opportunities to receive increasing payments ($ 1– $ 8) with more difficult recovery exercises. The participants were also asked before and after each test to self -study their level of cognitive fatigue.
In general, the test results found greater activity and connectivity in two areas of the brain when participants reported cognitive fatigue: the right insula, a deep area in the brain that has been associated with feelings of fatigue and the dorsal lateral prefrontal cortex, areas on both sides of the brain that control work memory.
For each participant, the activity in both brain locations during cognitive fatigue increased by more than double the level of reference measurements taken before starting the tests.
“Our study was designed to induce cognitive fatigue and see how people’s choices to exercise effort change when they feel fatigue, as well as to identify locations in the brain where these decisions are made,” says Chib.
In particular, the members of Chib and their research team Grace Steward and Vivian Looi discovered that financial incentives must be high so that participants exercise greater cognitive effort, which suggests that external incentives promote such effort.
“That result was not quite surprising, since our previous work found the same need for incentives to stimulate physical effort,” says Chib.
“The two areas of the brain can be working together to decide to avoid a more cognitive effort unless more incentives are offered. However, there may be a discrepancy between perceptions in cognitive fatigue and what the human brain is really capable of doing,” says Chib.
Fatigue is related to many neurological conditions, including PTSD and depression, says Chib.
“Now that we have probably identified some of the neuronal circuits for cognitive effort in healthy people, we must see how fatigue in people’s brains is manifested with these conditions,” he adds.
Chib says that it may be possible to use medications or cognitive behavioral therapy to combat cognitive fatigue, and the current study that uses functional magnetic decision and resonance tasks could be a framework to objectively classify cognitive fatigue.
Functional magnetic resonance uses blood flow to measure broad areas of activity in the brain; However, it does not directly measure the activation of neurons, or the most subtle nuances in brain activity.
“This study was carried out in a magnetic resonance scanner and with very specific cognitive tasks. It will be important to see how these results are generalized to other cognitive efforts and real world tasks,” says Chib.
Financing: National Health Institutes provided funds for research (R01HD097619, R01MH119086).
On this neuroscience research news
Author: Vanessa Wasta
Source: Johns Hopkins University
Contact: Vanessa Wasta – Johns Hopkins University
Image: The image is accredited to Neuroscience News
Original research: closed access.
“The neurobiology of cognitive fatigue and its influence on the choice based on the effort” of Vikram Chib et al. Neuroscience Magazine
Abstract
The neurobiology of cognitive fatigue and its influence on the choice based on the effort
The feelings of cognitive fatigue arise through repeated mental effort and are ubiquitous in our daily lives.
However, there is a limited understanding of the neurobiological mechanisms underlying the influence of cognitive fatigue in the decisions to exert.
We used functional magnetic resonance images, while participants (18 women, 10 men) decided to exercise an effort to reward, before and after episodes of fatigue cognitive effort.
We discovered that when the participants fatigue cognitively, they were more likely to choose to give up higher levels of reward for more effort.
We describe a mechanism by which the signals related to cognitive effort in the dorsolateral prefrontal cortex influence the calculations of the value of the effort, ordered by the insula, thus influencing that the decisions of an individual exert while they are fatigued.
Our results suggest that cognitive fatigue plays a fundamental role in decisions to exercise effort and provides a mechanistic link through which information about the cognitive state shapes the choice based on effort.
