The Stress Trap: Why Your Brain Stops you From Exercising

 It is a familiar feeling for anyone who enjoys staying active: when acute stress hits, the motivation to go to the gym, step on a basketball court, or engage in any physical activity takes a hit, with motivation evaporating and stress condensing, clouding one’s mind. This phenomenon often feels like a psychological failure that one attributes to a lapse of their own self-discipline and inability to coordinate the different facets of life in a succinct fashion, but as our speaker Dr. Buhr highlighted a few weeks ago, it is actually a deeply ingrained biological response. 

In his talk, Dr. Buhr explored the relationship between stress and physical inactivity. He grounded his insights in a recent study that examined the persistent effects of stress on rats. By exposing rats to tail shocks, which acted as a acute stress, and subsequently providing them access to a running wheel, the researchers modeled the choice to exercise. The results of this exercise showed that the stressed rats exhibited a prolonged, significant decrease in voluntary running. This effect was demonstrated for weeks after the shock. Dr. Buhr mentioned that early on in the experiment they realized that they had to figure out how to give the rats more discretion in exercising because if there was a slight propensity to run, the rats were essentially forced to and were capable of running; thus, they had be given an exaggerated choice between running or not, which when given, showed that the rats opted out. 

The underlying mechanisms for this behavioral paradigm are rooted in different physiological changes. In the brain, stress weakened the normal dopamine rush in the prefrontal cortex that occurs after (and because of) exercise. The prefrontal cortex is associated with maintaining effortful, motivated behavior, so a decrease in dopamine naturally leads to a decrease in motivated behavior. Simultaneously, rats also showed elevated levels of the protein HSP70 and reduced levels of the antioxidant SOD2, which is indicative of prolonged oxidative stress, a long-term cellular imbalance (between reactive oxygen species and antioxidants) that leads to continuous damage to various classes of macromolecules. HSP70 is a protein that is induced from rising levels of reactive oxygen species and helps neutralize them to help the cell. This leads to the conclusion that stress drains the brain’s motivational neurotransmitters and increases cellular fatigue in the periphery through muscles. 

This rodent model contextualizes a 2024 report in human neuroscience from Neuroscience News that details a study from University College London (UCL) titled “Exercise Boosts Motivation to Combat Depression”, which is a sort of inverse to Dr. Buhr’s investiation. The UCL researchers found that aerobic exercises repairs motivation defecitst that were linked to severe stress and depression. It was proposed tey movement systemically decreases inflammation and restores the dopamine function that stress suppresses.

When taking a look at Dr. Buhr’s work and this paper in conjunction, a profound yet slightly cruel biological paradox emerges. Acute stress is a sort of emergency brake on our physical activity; it suppresses our dopamine and drives muscular stress. In contrast, as indicated by the UCL research, exercise is also the primary tool our biological system has to clear that inflammation and reboot our dopamine system, which inclines one to see that our bodies are essentially wired to avoid the exact activity that is necessary to restore our neurochemical balance. 

Understanding this dynamic can lead to a change in how we should approach wellness and the concept of burnout. Rather than waiting for motivation to emerge after a stressful event, one should recognize that the physiological reality is that our body is temporarily unable to generate motivation, and realize that one must take a leap and force oneself to reboot the system. 

This could lead to a shift in public health campaigns so that instead of telling stressed populations to simply “find motivation”, they could explain that the initial leap of beginning exercise is a treatment for dopamine suppression, which prevents that motivation from being found. 

How Visual Perception Shapes The World

  I recently attended a research talk by Dr. Nick Baker on how the human visual systems encodes for mental imagery. He discussed the process of abstraction, which is the changing, removal, or addition of information in an external stimulus as it is encoded in the mind. His research focused on how the visual system processes curves and corners, and whether certain shapes are easier for the brain to encode than others. 

In his research, subjects completed three tasks involving dot arrangements with sharp corners, smooth curves, or random patterns. The results showed that it is easier to perceive a shape with smooth contour than sharp contour. This suggests that the basic building blocks of our mental representations of shapes aren’t restricted to straight lines, but focus on curvatures as well. Dr. Baker also found that shapes with greater variation in curvature are more difficult to encode than shapes with a slight or consistent variation of the curve. During the presentation, he displayed several dot arrangements and line drawings to show this effect in real time. Through class participation, it became clear that smoother and rounder shapes were generally favored as more comfortable to look at. It was also easier to recognize the circular shapes in dot arrays than more angular shapes like stars and rectangles.

    After hearing about this research, I became curious about how the shapes we encounter every day affect our visual systems. The article "Modern Design Geometry Causes Visual Stress and Overload” discusses how certain features of human made environments can make visual processing more difficult. Modern day environments often contain cluttered interiors, high contrast colors, and striped patterns. The article explains that through an "evolutionary mismatch”, modern day environments stress out our visual systems. Humans developed while surrounded by nature including trees, rivers and fields, all of which are smooth and flowing. In comparison, modern environments are filled with perfect lines, repeating structures and highly compact products that create an environment where the brain is working harder than it wants to encode the information, causing exhaustion in visual pathways which can lead to physical stress. 

      This connection between modern day geometry and how it is processed in our visual systems has made me think differently about how we design everyday objects and environments. Dr. Baker's research suggests that smooth contours and consistent curves are easier for our visual systems to process, while the article shows how highly geometric environments can contribute to visual stress. Together, these ideas could be applied to the world of engineering and architecture. Engineers and architects tend to focus more on strength, cost and function, but should also try to include a design that is processed by the human brain in a simpler way. By incorporating smooth curves, simpler patterns, and more natural shapes into man made environments, we can create calmer settings in society and possibly make humans' day lives less stressful. If our visual system is able to encode visual stimuli easier, our brains can focus more on executive functional and other processes, to create a higher functioning and more peaceful society. 

References: 

Baker, N., & Kellman, P. J. (2024, May 15). Shape from dots: A window into abstraction processes in visual perception. Frontiers. https://www.frontiersin.org/journals/computer-science/articles/10.3389/fcomp.2024.1367534/full 

Neuroscience News. (2026, July 9). Modern design geometry causes visual stress and brain overload. https://neurosciencenews.com/neuroarchitecture-geometry-visual-stress-31026/ 

Why Do Some People Move Less? Examining How Adverse Experiences Shape Physical Activity

 
Physical inactivity is a common concern today, as it can lead to obesity, heart disease, chronic diseases, and so on. It is one of the leading causes of mortality and is related not only to physical but also to psychological well-being. Many people do not meet the recommended amount of physical activity, including adolescents, for whom exercising is especially important, as it could promote mental health and contribute to their physical health as well. Studies have investigated the harmful effects of the lack of exercise, however, fewer studies have looked at the possible causes of physical inactivity. There is a growing amount of literature on how stress, psychological trauma, or adverse life experiences can influence physical inactivity. Studying these causes could provide a better understanding of the physiological and psychological background of physical inactivity, leading to more effective approaches to treatment and intervention for such lifestyles. 

Recently, more studies have investigated the effects of Adverse Childhood Experiences (ACEs) and their associations with physical activity. ACEs include environmental stressors such as abuse, neglect, or household challenges, which have already been associated with a higher risk of substance abuse, obesity, depression, and so on. They pose a huge risk for youth, and it is essential to understand how they affect people's lives in the future. A 2024 study has examined several ACEs and their associations with daily step counts as a measure of physical activity. They found an inverse relationship between ACEs and daily steps, meaning that those who experienced ACEs had lower levels of physical activity. Additionally, as the number of ACEs increased, people had fewer steps, suggesting that greater exposure to adversity could be associated with a more serious decrease in physical activity. However, this study only examined associations between stress and physical activity, raising additional questions about how psychological trauma or stress could have an effect on physical activity. 

To answer these questions, Buhr and colleagues (2023) examined how acute stress affects the brain chemistry of rodents and how it affects their physical activity. To create ACEs, they administered tail shocks to mice, and after 36 hours, they gave them a running wheel and measured how much they ran compared to the control mice that had not received the tail shocks. After 9 weeks, they found that mice who received the most tail shocks ran the least among all groups. This provides evidence for previous studies claiming that stress may cause physical inactivity. Moreover, after examining the mice's brains, they found that acute stress may be related to neurological changes in the dopamine system, which is involved in reward seeking and is also implicated in movement. These results provide evidence that adverse experiences may alter brain monoamine systems, such as the dopamine system, potentially contributing to deficits in physical activity. 

Overall, these studies point to the fact that it is essential to focus on the causes of physical inactivity rather than labelling people as lazy. Providing proper treatments and developing interventions could lead to helping millions of people who live an inactive life better understand some of the possible causes and start their journey toward a more active life. 

References

Al-Shoaibi, A. A., Iyra, P., Raney, J. H., Ganson, K. T., Dooley, E. E., Testa, A., ... & Nagata, J. M. (2024). Associations between adverse childhood experiences and early adolescent physical activity in the United States. Academic pediatrics, 24(4), 662-668. https://doi.org/10.1016/j.acap.2023.10.004 

Buhr, T. J., Reed, C. H., Wee, O. M., Lee, J. H., Yuan, L. L., Fleshner, M., ... & Clark, P. J. (2023). The persistence of stress-induced physical inactivity in rats: an investigation of central monoamine neurotransmitters and skeletal muscle oxidative stress. Frontiers in behavioral neuroscience, 17, 1169151. https://doi.org/10.3389/fnbeh.2023.1169151 

Feeling Fine Does Not Mean Healed: What Neuroscience Says About Hidden Brain Recovery

                Most people think of concussions as a temporary thing. You get hit, you get dazed, you get a headache. After some time you are " well " again. But what if it is okay to feel okay and your brain isn’t all the way healed?

               I learned in a neuroscience lecture this semester that there are other ways to measure brain function other than just behavior or symptoms. For example, there’s frequency-following response (FFR), which is a measure of the brain’s ability to follow sound, particularly pitch. In the brainstem, this happens and it is important for speech understanding, especially in noisy environments.

               What I learned is that even when someone feels better after a concussion, their brain may not be hearing sound quite the same. Recovery may not be as straightforward as symptom checklists suggest.

               This is tied directly into an article I saw the other day on NPR about how many athletes are coming back to sports without the proper care or time to heal. The article notes concussion protocols are often based on self-reported symptoms and short cognitive tests. If someone can say that they feel fine, they are usually permitted to resume normal activities.

               But neuroscience indicates this might not be enough.

               If brain activity is still different after the symptoms are gone, people may be going back to school, sports or work before their brain is ready. This can impact things such as attention, learning and even comprehension of conversations, particularly in busy environments. These are not always obvious problems, but they may build up.

               That also raises bigger questions about how we define recovery. According to National Public Radio (2023), many athletes are returning to play without proper recovery. Currently, recovery is mostly based on how someone feels and how they do on simple tests. But if there are deeper processes happening in the brain we might miss some of the picture.

               Other, more objective measures such as neural responses may be used to improve concussion diagnosis and management. These tools have not yet been widely used and are less accessible and hence more complicated in real-world settings.

               Overall, this topic was eye opening to me that the brain does not always heal in ways that we can see easily. No symptoms do not mean it is back to normal. As neuroscience progresses, we may have to reconfigure what “recovered” really means.

 

References

National Public Radio. (2023, October 12). More athletes are suffering concussions. Few are getting            proper care. https://www.npr.org/2023/10/12/1205290475/concussions-athletes-treatment

Brain Stimulation and Treating Mental Illness

 

When medicine speaks the body’s language

When medicine speaks the body’s language

Most of modern medicine focuses on creating synthetic drugs in a lab, from more synthetic ingredients; treating some issues while creating new ones. Scientists Wei-Ming Yu, Madelyn A. McCullen, and Vincent C.-F. Chen explored a different approach when looking at nerve injuries by using electricity itself as the course of treatment. They mainly focused on peripheral nerves because of their role as information transmitters through electrical signals between central and peripheral nervous system, functioning as the brain’s own language. 

However, this is not the first time electricity has been used a form of treatment. Historically, other forms of electrical stimulation have been used, such as electroconvulsive therapy (ECT), which alters brain activity to simulate seizures. What makes this new study special is the fact that instead of focusing on intensity and frequency, it emphasized how the pattern of electrical stimulation influences the body’s response.  

In the case of peripheral nerves being damaged, communication between the brain and the rest of the body is affected which often leads to a loss of sensation or motor function. Because these nerves are highly dependent on electrical signals, the researchers have explored electrical stimulation as a way to restore communication and promote the regeneration of these synapses. Instead of increasing the strength or frequency of signals are delivered, the scientists suggested that the structure of the signal itself is what actually mattered.  

Ultimately, this study highlighted a shift in how medicine approaches treatment and healing by using the body’s own language. Why introduce new chemicals into the human body when the body already has successful ways of healing itself, all science needs to do is enhance these systems. 

References

Yu, W.-M., McCullen, M. A., & Chen, V. C.-F. (2022). Accelerating peripheral nerve regeneration using electrical stimulation of selected power spectral densities. Neural Regeneration Research, 17(4), 781–782. https://doi.org/10.4103/1673-5374.322458

Zhang, M. W. B., & Ho, R. C. M. (2019). Electroconvulsive therapy: Current perspectives. World Journal of Psychiatry, 9(1), 1–12. https://doi.org/10.5498/wjp.v9.i1.1

Drugs Rewire the Brain

In our generation, drugs are a concerning problem, becoming more and more common among today's youth. Modern society faces a growing challenge with substance abuse disorders, including stimulant and opioid addiction. Drugs do not simply create social pressure, but rewire and change neural pathways responsible for desire, motivation, and self-control. Cocaine addiction in particular remains a serious concern as it is responsible for altering the reward system in ways that increase cravings and decrease our ability for self-control. 

Dr. Stephan Steidl and colleagues explored this in their lab, specifically looking at pathways in the laterodorsal tegmental nucleus and ventral tegmental area. They examined how repeated cocaine exposure changes communication in the reward circuitry of the brain. Through their experiments, they studied glutamate signaling in the VTA, displaying that cocaine strengthens excitatory inputs to dopamine neurons through mechanisms like LTP. They used ontogenetic techniques and found the role of LDTg glutamate cells or their VTA afferents to be essential in the development of cocaine sensitization in male mice. They discovered that the connection between the laterodorsal tegmental nucleus and the ventral tegmental area is required for the sensitization of cocaine. Sensitization occurs when repeated drug use causes the brain to react more strongly to cocaine over time, which increases behavioral responses and reinforces addiction pathways. Repeated drug use over time leads to sensitization, the brain becomes more responsive to the drug use, and results in enhanced drug-seeking behaviors and relapse.

These studies were done on male mice; another closely related study, "Cocaine self-administration disrupts mesolimbic dopamine circuit function and attenuates dopaminergic responsiveness to cocaine," looked at what happens to the brain when humans use cocaine. Researchers in the lab of Dr. Jones in the Department of Physiology and Pharmacology at the Wake Forest School of Medicine used machines like PET scans to see how cocaine affects the dopamine pathways in people who are addicted to it. They found that people with chronic cocaine use showed reduced dopamine receptor availability and abnormal reward processing in the mesolimbic system. These structural changes make natural rewards, such as relationships, achievements, and hobbies, less satisfying, while drug-related cues become more powerful triggers for cravings. Things that are normally fun, like spending time with friends or doing something you're good at, are not as enjoyable anymore.

Together, these studies shift the concern from a societal issue to a biological issue. This reinforces the behavior addicts display and how it is difficult to reverse the effects caused by cocaine and other such drugs. Such studies inform us, the public, of the biological effects of addiction and how they actively rewire it. Drugs are a measurable condition that reshape neural pathways over time, and if not taken precautions against, will ruin every generation that abuses them. 

Works Cited: 

Siciliano CA, Ferris MJ, Jones SR. Cocaine self-administration disrupts mesolimbic dopamine circuit function and attenuates dopaminergic responsiveness to cocaine. Eur J Neurosci. 2015 Aug;42(4):2091-6. doi: 10.1111/ejn.12970. Epub 2015 Jun 28. PMID: 26037018; PMCID: PMC4540675.

Steidl, S., Wang, H., & Wise, R. A. (2017). Glutamate inputs from the laterodorsal tegmental nucleus to the ventral tegmental area are essential for the induction of cocaine sensitization in male mice. Neuropsychopharmacology, 42(11), 2232–2241. https://doi.org/10.1038/npp.2017.72