Mental Fatigue Triggers Compensatory Brain Mechanisms

 

With your brain fog post stroke  your competent? doctor has had over a decade to create a protocol to prevent brain fog! Didn't do that did s/he? So, you don't have a functioning stroke doctor, do you?

brain fog (15 posts to November 2011)

mental fatigue (5 posts to December 2012)

Mental Fatigue Triggers Compensatory Brain Mechanisms

Summary: A recent study shows that prolonged mental exertion weakens connectivity between the brain’s frontal and parietal lobes, impacting cognitive efficiency. However, the brain has built-in compensatory mechanisms that adjust neural connections to preserve function under fatigue.

Researchers observed this in participants completing memory tasks of varying difficulty; while fatigue slowed performance on simple tasks, complex tasks triggered compensatory adjustments. Findings suggest that these mechanisms allow the brain to optimize resources based on task complexity.

Understanding how these processes work can have implications for enhancing productivity and mental resilience in high-demand scenarios. This research highlights the brain’s adaptability in managing limited cognitive resources under strain.

Key Facts

• Mental fatigue reduces functional connectivity between the brain’s frontal and parietal lobes.
• Compensatory mechanisms in the brain help maintain task performance under fatigue.
• Simple tasks slow under fatigue, but complex tasks can trigger compensatory adjustments.

Source: Scientific Project Lomonosov

Scientists from Immanuel Kant Baltic Federal University found out that prolonged mental load led to decrease of functional connectivity between frontal and parietal lobes of brain, that is followed by decrease of efficiency of information processing.

However, there are compensatory mechanisms that enable brain to maintain working capacity thanks to changes of configuration of frontoparietal net.

Results of the research are published in magazine IEEE Transactions on Cognitive and Developmental Systems.

According to results, level of fatigue of all participants after fulfilling tasks became significantly higher, however number of mistakes didn’t increase. Credit: Neuroscience News

Continuous work with great deal of information, for example, databases, documents and reports, demands high concentration. Active brain activity can lead to overwork and fatigue, that causes decrease of working capacity of brain.

However, researches show that in our nervous system exist so-called compensatory mechanisms – means to cope with fatigue.

At the same time, it is not completely clear how exactly a compensatory mechanism starts and works, and also how it influences different brain functions, in particular – memory.

Scientists from Immanuel Kant Baltic Federal University (Kaliningrad) made research how brain activity and perception of information change during continuous performing of cognitive tasks.

14 people from 18 to 22 took part in the experiment in which they during 70 minutes passed Sternberg test – a set of tasks for estimation of working memory. In frames of the test trial subjects had to memorize a set of 2-7 letters during 1,5-2,5 seconds.

Then a certain letter was demonstrated to the participants and they had to answer if the original set contained it. For this purpose, researchers divided all tasks into two blocks – “simple” that required memorization of sequence of 2-3 letters, and “complex” – of 6-7 letters.

In the course of research authors used functional near-infrared spectrography (fNIRS) for registration of hemodynamic activity of brain and method of eye movement recordings (eye-tracking) for analysis of visual perception. Scientists also offered participants to pass several tests on the level of fatigue in the form of questionnaires before and after the experiment.

According to results, level of fatigue of all participants after fulfilling tasks became significantly higher, however number of mistakes didn’t increase.

By this fatigue led to increase of time of fulfilment of tasks of low complexity, whereas length of fulfilling tasks of high complexity remained unchangeable during all course of experiment.

It tells about the fact that in the second case the intenseness reached such grade by which in brain started compensatory mechanisms of struggling with fatigue.

Observations of how activity of different areas of brain changed, showed that in the course of fulfilment of tasks and increasing of fatigue test people experienced weakening of functional connections between frontal and parietal lobes of brain cortex.

The importance of these connections for fulfilment of cognitive tasks is confirmed also by the fact that participants who coped with task from “complex” category better showed higher connectivity between frontal and parietal lobes.

Probably, the maintenance of these cooperations is a part of compensatory mechanism, that enables to struggle with fatigue.

 “Because of limited resources brain has to optimize its work in order to cope with tasks efficiently, in spite of fatigue.  Complex tasks require a greater control of attention and mobilization of additional resources for solving them.

“Simple tasks, on the contrary, can be successfully fulfilled with minimal efforts, thus enabling brain to save resources. That is why, for example, when a tired driver arrives to a multiple crossing, he mobilizes his internal resources and successfully maneuvers.

“However, in condition of more simple driving situation he makes a mistake because of fatigue, that leads to an accident, for example, incidentally drives to an opposite line or a roadside”, – tells Artem Badarin, candidate of Physical and Mathematical Sciences, senior research associate Center for Neurotechnology and Machine Learning, Immanuel Kant Baltic Federal University, Kaliningrad.

About this mental fatigue and neuroscience research news

Author: Yana Khlyustova
Source: Scientific Project Lomonosov
Contact:Yana Khlyustova – Scientific Project Lomonosov
Image: The image is credited to Neuroscience News

Original Research: Open access.
“Brain compensatory mechanisms during the prolonged cognitive task: fNIRS and Eye-Tracking study” by Artem Badarin et al. IEEE Transactions on Cognitive and Developmental Systems

Brain Endurance Training Combats Age-Related Decline in Focus

 With your brain fog post stroke will your competent? doctor get this written up in a protocol and delivered to all stroke patients? NO? So, you don't have a functioning stroke doctor, do you?

Brain Endurance Training Combats Age-Related Decline in Focus

Summary: Brain endurance training (BET), a combined cognitive and exercise approach, has been shown to significantly improve cognitive and physical performance in older adults. In a study with sedentary women aged 65-78, BET participants showed greater improvements in attention and executive function, along with increased physical endurance.

This method, originally developed for athletes, could play a role in reducing age-related cognitive decline and physical challenges such as balance issues. The BET group saw higher gains in both mental and physical tests than exercise-only participants. Researchers hope these findings will inspire more older adults to incorporate BET into their routines. Further studies are planned to validate the results on a larger, more diverse sample.

Key Facts:

• BET improved cognitive performance by 7.8% vs. 4.5% in the exercise-only group.
• BET participants showed a 29.9% physical performance increase compared to 22.4%.
• BET helps counteract mental fatigue, benefiting both brain and body performance.

Source: University of Birmingham

Brain endurance training (BET), a combined cognitive and exercise training method developed for athletes, boosts cognitive and physical abilities in older adults. 

According to a new study by researchers at the Universities of Birmingham, UK, and Extremadura, Spain, brain endurance training (BET) can improve attention and executive function (cognition), as well as physical endurance and resistance exercise performance.

BET is a combined exercise and cognitive training method that was originally developed to increase endurance among elite athletes. 

This could have significant implications for improving healthspan in this population, including reducing the risk of falls and accidents. Credit: Neuroscience News

The research has implications for healthy aging. Previous studies have shown that mental fatigue can impair both cognitive and physical performance, including poorer balance control, leading to increased risk of falls and accidents.

This study, published in Psychology of Sport and Exercise, is the first to examine the benefits of BET for both cognitive and physical performance in older adults. 

Corresponding author Professor Chris Ring said: “We have shown that BET could be an effective intervention to improve cognitive and physical performance in older adults, even when fatigued. This could have significant implications for improving healthspan in this population, including reducing the risk of falls and accidents.” 

In the experiment, 24 healthy sedentary women aged between 65-78 were allocated to one of three training groups: brain endurance training (BET), exercise training, and no training (control group). The first two groups each completed three 45-minute exercise sessions per week over a period of eight weeks.

Each session included 20 minutes of resistance training and 25 minutes of endurance training. While the exercise sessions were the same for each of these groups, the BET group also completed a 20-minute cognitive task prior to exercising. 

All three groups completed a series of cognitive (reaction time and colour-matching tests) and physical tests (walk, chair-stand and arm-curl tests) to assess performance at the start and end of the study. articipants in the BET group outperformed the exercise-only group in the cognitive tasks, with a 7.8% increase in cognitive performance after exercise, compared to a 4.5% increase in the exercise-only group.

In terms of physical performance, the BET group achieved a 29.9% improvement, compared to 22.4% for the exercise-only group. 

“BET is an effective countermeasure against mental fatigue and its detrimental effects on performance in older adults,” added Professor Ring.

“While we still need to extend our research to include larger sample sizes including both men and women, these promising initial findings show we should do more to encourage older people to engage in BET to improve brain and body activities.”  

About this brain training and aging research news

Author: Beck Lockwood
Source: University of Birmingham
Contact: Beck Lockwood – University of Birmingham
Image: The image is credited to Neuroscience News

Original Research: Open access.
“Brain endurance training improves sedentary older adults’ cognitive and physical performance when fresh and fatigued” by Chris Ring et al. Psychology of Sport and Exercise

Mentally exhausted? Study blames buildup of key chemical in brain

 WHOM  in stroke will look at this and question what research is needed to see if this is causing mental exhaustion post stroke? It will never occur, there is NO stroke leadership and NO stroke strategy. All you stroke survivors can just pound sand.

But since  glutamate poisoning is already suggested as one of the 5 causes of the neuronal cascade of death in the first days. just maybe this is a following result.  And I'm obviously stroke-addled to even think that I might know more that all these Ph.D. researchers.

Mentally exhausted? Study blames buildup of key chemical in brain

Toxicity of excess glutamate may contribute to cognitive fatigue, but some experts are skeptical

• 11 Aug 2022
• 12:40 PM
• ByEmily Underwood

SolisImages/iStock

You know the feeling. You’ve been cramming for a test or presentation all day, when suddenly you can’t remember simple things, like what you ate for breakfast, or where exactly Belize is. Now, a study hints at why we get so unraveled after hours of hard mental labor: a toxic buildup of glutamate, the brain’s most abundant chemical signal.

The study isn’t the first to try to explain cognitive fatigue—and it is bound to stir up controversy, says Jonathan Cohen, a neuroscientist at Princeton University who wasn’t involved with the work. Many scientists once thought doing difficult mental tasks used up more energy than easy tasks, exhausting the brain like exercise can do to muscles. Some even suggested drinking a sugary milkshake would make you mentally sharper than an artificially sweetened one, he says. But Cohen and many others in the field are skeptical of such simplistic explanations. “It's all been debunked,” he says.

In the new study, researchers looked at whether levels of glutamate are related to behavior that so often manifests when we’re mentally exhausted. Seeking easy, immediate gratification, for example, or acting impulsively. Glutamate typically excites neurons, playing key roles in learning and memory, but too much of it can wreak havoc on brain function, causing problems ranging from cell death to seizures.

The scientists used a noninvasive technique called magnetic resonance spectroscopy, which can detect glutamate through a combination of radio waves and powerful magnets. They chose to focus on a brain region called the lateral prefrontal cortex, which helps us stay focused and make plans. When a person becomes mentally exhausted, this region becomes less active.

The researchers divided 39 paid study participants into two groups, assigning one to a series of difficult cognitive tasks that were designed to induce mental exhaustion. In one, participants had to decide whether letters and numbers flashing on a computer screen in quick succession were green or red, uppercase or lowercase, and other variations. In another, volunteers had to remember whether a number matched one they’d seen three characters earlier. The experiment lasted for about 6 hours, with two 10-minute breaks and a simple lunch of a sandwich and piece of fruit. In the second group, people did much easier versions of the same tasks.

As the day dragged on, the researchers repeatedly measured cognitive fatigue by asking participants to make choices that required self-control—deciding to forgo cash that was immediately available so they could earn a larger amount later, for example. The group that had been assigned to more difficult tasks made about 10% more impulsive choices than the group with easier tasks, the researchers observed. At the same time, their glutamate levels rose by about 8% in the lateral prefrontal cortex—a pattern that did not show up in the other group, the scientists report today in Current Biology.

Advertisement

“We’re still far from the point where we can say that working hard mentally causes a toxic buildup of glutamate in the brain,” says the study’s first author, Antonius Weihler, a computational psychiatrist at the GHU Paris Psychiatry and Neurosciences. But if it does, it underscores the well-known restorative powers of sleep, which “cleanses” the brain by flushing out metabolic waste. It might be possible to use glutamate levels in the prefrontal cortex to detect severe fatigue and monitor recovery from conditions such as depression or cancer, the team suggests.

Abnormal glutamate signaling occurs in many brain disorders. There are already drugs that target the neuronal receptors for glutamate, including esketamine, a form of the anesthetic ketamine which is used to treat depression, and memantine, which is used to treat the symptoms of Alzheimer’s disease. Researchers are also exploring glutamate-based therapies for a number of other disorders, such as schizophrenia and epilepsy.

One important limitation of the study is that the scanners used aren’t powerful enough to distinguish between glutamate and another closely related molecule, glutamine, notes Alexander Lin, a clinical spectroscopist at Brigham and Women’s Hospital. But the findings “provide the basis for examining how glutamate could potentially be modulated by medications or devices such as neurostimulation,” he says.

Sebastian Musslick, a neuroscientist at Brown University, doubts metabolic waste will turn out to be a key contributor to cognitive fatigue. He suspects instead that the uptick in glutamate as the brain tires serves a purpose. The organs in our bodies are in constant communication with our brains, letting us know when we need to eat, sleep, drink water, and go to the bathroom. Maybe the prefrontal cortex’s glutamate is sending a similar status update to the brain’s internal monitoring system, Musslick suggests.

For Cohen, the most compelling reason to be skeptical of the idea that waste products play an important role in cognitive fatigue is that it can’t explain the human ability to often push through cognitive fatigue, or effortlessly perform demanding computational tasks such as face recognition that require megawatts of energy for computers to perform. To juggle this many demanding tasks, the brain has to have a more sophisticated computational system for allocating effort than the simple buildup or depletion of metabolic byproducts, he says. “It just can’t be that easy.”

Resting State Connectivity Is Modulated by Motor Learning in Individuals After Stroke

 

I have no understanding of how this helps recovery.  In my case since most of my premotor cortex is dead there can be no transfer from prefrontal to premotor.  And since I'm not healthy it wouldn't transfer anyways. When I follow the higher cognitive load reference²⁴ I find nothing explaining that at all. I was hoping for some explanation of the mental fatigue post stroke.

Resting State Connectivity Is Modulated by Motor Learning in Individuals After Stroke

Show all authors

Sarah N. Kraeutner, PhD, Cristina Rubino, MSc, Shie Rinat, MSc, ...

First Published April 7, 2021 Research Article 

https://doi.org/10.1177/15459683211006713

Article information

Abstract

Objective

Activity patterns across brain regions that can be characterized at rest (ie, resting-state functional connectivity [rsFC]) are disrupted after stroke and linked to impairments in motor function. While changes in rsFC are associated with motor recovery, it is not clear how rsFC is modulated by skilled motor practice used to promote recovery. The current study examined how rsFC is modulated by skilled motor practice after stroke and how changes in rsFC are linked to motor learning.

Methods

Two groups of participants (individuals with stroke and age-matched controls) engaged in 4 weeks of skilled motor practice of a complex, gamified reaching task. Clinical assessments of motor function and impairment, and brain activity (via functional magnetic resonance imaging) were obtained before and after training.

Results

While no differences in rsFC were observed in the control group, increased connectivity was observed in the sensorimotor network, linked to learning in the stroke group. Relative to healthy controls, a decrease in network efficiency was observed in the stroke group following training.

Conclusions

Findings indicate that rsFC patterns related to learning observed after stroke reflect a shift toward a compensatory network configuration characterized by decreased network efficiency.

Keywords motor learning, stroke, rs-fMRI, graph theory, functional connectivity

Introduction

Damage resulting from stroke disrupts cortical networks and patterns of synchronized brain activity between disparate brain regions (termed functional connectivity).^1-3 Synchronized patterns of brain activity can be characterized across the brain at rest (ie, resting-state functional connectivity [rsFC]) and their relationships represented as coherence. These patterns characterize functional reorganization of the brain after stroke and are reliable measure that characterize neural changes across the stages of recovery.⁴ While altered rsFC is associated with motor recovery (ie, improvements in function characterized by clinical assessments),⁵ it is not clear how rsFC is modulated by skilled motor practice after stroke (ie, behavioral improvements associated with a specific motor task). Even though rsFC does not rely on task performance, there is evidence showing that active networks mapped with rsFC overlap with regions involved in task performance.^6-8 As rsFC does not rely on participant effort or compliance, it may be used to characterize neural changes that accompany motor impairment poststroke. Typically, in individuals with stroke, rsFC is disrupted in the sensorimotor network relative to healthy individuals.^9,10 Increases in rsFC in both the sensorimotor network and between regions implicated in cognitive processes (ie, working memory) have been observed as motor recovery is achieved.^9,11,12 For instance, poorly recovered individuals showed decreased connectivity within the sensorimotor network, while no differences in connectivity were observed between individuals who were well-recovered and healthy controls.⁹ Yet a typical pattern of connectivity is not necessarily restored during recovery after stroke. Even in well-recovered individuals, relative to healthy controls, reduced connectivity persists between brain regions associated with cognitive processes.^9,13 To date, changes in rsFC have largely characterized functional reorganization that occurs in association with recovery from stroke.^11,12,14,15 It remains unclear whether or not skilled motor practice drives changes in rsFC patterns.

Importantly, rsFC is thought to reflect the processing of information gained during skilled motor practice associated with motor consolidation and learning.^16,17 Short-term changes in rsFC in areas previously shown to be critical to planning and executing visually guided movement^18,19 including a network of frontal, posterior parietal, and cerebellar regions are associated with learning a visuomotor task.^16,17,20,21 However, as behavioral change associated with task-specific learning plateaus, limited long-term changes in rsFC in healthy individuals are noted.²¹ While learning (and relearning) motor skills are critical to promoting functional recovery, we know little about the alterations in processes underlying motor learning after stroke. Thus, rsFC can be employed to characterize change in consolidation of motor memories and learning that result from functional reorganization after stroke.

Specifically, functional magnetic resonance imaging (fMRI) shows that healthy individuals shift brain activity from the prefrontal regions early in skilled motor practice to premotor cortical activation after learning occurs.^16,22 This shift is not observed after stroke.²³ The persistent and greater recruitment of frontal-parietal regions during motor tasks may reflect higher cognitive load during skilled motor practice after stroke.²⁴ It also may be related to an overall decrease in network efficiency after stroke,^25,26 that represents a lower overall capacity to transmit information and indicates that a compensatory network (ie, not restored to a neurotypical pattern of functioning) underlies motor processes.²³ Taken together, alterations in consolidation and learning processes may arise after stroke, reflected by decreased network efficiency and greater reliance on cognitive processes during skilled motor practice. To test this idea, we probed (long-term) changes in rsFC induced by skilled motor practice to examine how brain reorganization supports learning after stroke.

The primary aim of the current study was to examine how rsFC is modulated by skilled motor practice after stroke. Furthermore, we sought explore how changes in rsFC are linked to motor learning. To address our objectives, we employed a between-group design whereby 2 groups of participants (individuals with stroke and age-matched controls) engaged in 4 weeks of skilled motor practice of a complex, gamified reaching task, that was designed to prevent early plateaus in performance. Clinical assessments of motor function and impairment, and brain activity were obtained before and after training.

We expected that rsFC would be differentially modulated from pre- to posttraining between groups. Because past work showed that individuals with stroke rely on prefrontal regions during skilled motor practice,^23,27,28 and that greater recovery is linked to increased functional connectivity of frontal regions implicated in working memory,^9,24 we expected to observe increased connectivity within the sensorimotor network, and between the sensorimotor network and prefrontal areas. In exploring the association between changes in rsFC and motor learning, we hypothesized that (1) improvements in motor behavior associated with task-specific learning would be related to decreased connectivity between regions implicated in working memory in individuals with stroke and (2) healthy controls would show minimal connectivity changes. Finally, we predicted that changes in network efficiency induced by skilled motor practice would occur differentially after stroke relative to healthy controls. Specifically, we predicted that healthy controls would show enhanced network efficiency that would reflect their increased capacity to transmit information. In contrast, we expected that individuals with stroke would show decreases in network efficiency reflecting a shift toward a compensatory network configuration to support learning.

 

Tested: If Mental Work Genuinely Affects Physical Tiredness

This could easily explain stroke fatigue. But I bet your doctor won't change the stupid admonition to exercise more. Three years after my stroke I had a physical where my resting heart rate was 54 at the age of 53. That means my cardiovascular fitness was that of an athlete. Yet I was still completely fatigued everyday. All researchers would have had to do is talk to a few stroke survivors to learn this. It's not rocket science, it is simply cause and effect which I don't think a lot of our stroke medical professionals understand.
http://www.spring.org.uk/2015/08/tested-if-mental-work-genuinely-affects-physical-tiredness.php?omhide=true&utm_source=PsyBlog&utm_campaign=bb0d00021d-RSS_EMAIL_CAMPAIGN_MAILCHIMP&utm_medium=email&utm_term=0_10ef814328-bb0d00021d-213838825

For the research, participants repeatedly squeezed on a hand-grip while performing mental tasks designed to fatigue them.

At the same time, an area of the brain called the prefrontal cortex was monitored.

The prefrontal cortex is the part of the brain at the front above and behind the eyes.

This area is vital to our personalities, how we plan complex actions, and more.

The researchers found that the prefrontal cortex became more ‘tired’ when people were performing both mental and physical tasks.

It appears the brain devotes some of its resources to physical tasks and some to mental tasks.

The research is one of the first to show how mental and physical tasks can interact to fatigue the brain.

Dr Mehta said:

“Not a lot of people see the value in looking at both the brain and the body together.

However, no one does purely physical or mental work; they always do both.”

So, it appears the brain is like a muscle in the sense that work — whether mental or physical — weakens its strength.

The study was published in the journal Human Factors (Mehta & Parasuraman, 2015).

More at the link.

Mindfulness-based stress reduction (MBSR) improves long-term mental fatigue after stroke or traumatic brain injury.

See how long something like this takes to get into common practice, I'll bet 20 years. Mine was not too bad, physical fatigue was horrendous however.
http://www.ncbi.nlm.nih.gov/pubmed/22794665

Abstract

Objective: Patients who suffer from mental fatigue after a stroke or traumatic brain injury (TBI) have a drastically reduced capacity for work and for participating in social activities. Since no effective therapy exists, the aim was to implement a novel, non-pharmacological strategy aimed at improving the condition of these patients. Methods: This study tested a treatment with mindfulness-based stress reduction (MBSR). The results of the programme were evaluated using a self-assessment scale for mental fatigue and neuropsychological tests. Eighteen participants with stroke and 11 with TBI were included. All the subjects were well rehabilitated physically with no gross impairment to cognitive functions other than the symptom mental fatigue. Fifteen participants were randomized for inclusion in the MBSR programme for 8 weeks, while the other 14 served as controls and received no active treatment. Those who received no active treatment were offered MBSR during the next 8 weeks. Results: Statistically significant improvements were achieved in the primary end-point-the self-assessment for mental fatigue-and in the secondary end-point-neuropsychological tests; Digit Symbol-Coding and Trail Making Test. Conclusion: The results from the present study show that MBSR may be a promising non-pharmacological treatment for mental fatigue after a stroke or TBI.