Written by Sid Udata ‘26
Edited by Josephine Chen ‘24
Running from a bear, a hiker slips off a ledge and fractures their leg, but keeps running, not even perceiving the pain until they’re rescued. Students cramming for exams miss meals—they subconsciously value their grades over their hunger. Depending on who you ask, the next Organic Chemistry midterm might be less threatening than a bear, but the concept that links these situations is called selective attention. Selective attention regulates what the brain sees as pertinent information, allowing us to make quick decisions in critical moments. Norepinephrine (NE) is a neurotransmitter that is involved in selective attention, which could explain how we subconsciously direct our attention to the most pertinent information during times of stress.
NE is involved in selective attention during moments of high stress.
A team of researchers at Northwestern University tested the levels of NE, which is indirectly measured with α-amylase, in the saliva of 20 participants during an attentional task. During the task, participants were asked to move a mouse cursor to a marked location on a computer screen. Then, participants in the stress group played a zombie shooter game, designed to simulate “human violence”. After the game, their NE levels were measured again.
The researchers observed a significant reduction in attentional inhibition (a measure of attention), as well as reaction time after the stressful video game. Importantly, they found that the level NE spikes during and after acute stress. These heightened levels of NE persisted for 20 minutes after the stressful event, indicating widespread and lasting effects of stress. [1]
Chronic stress is correlated with lasting cognitive dysfunction.
Additionally, mild psychological stress can significantly alter attentional processes. A large portion of this modulation happens in the locus coeruleus, a brain structure where NE is generated. Interestingly, this brain structure is also influenced by dopamine, a chemical precursor of NE [2].
Abnormal levels of NE are also found in patients with chronic stress. This might explain why those under constant psychological strain tend to make less “thought-out” decisions due to dysfunction of executive control.
NE, stress, and memory.
Interestingly, research has shown that increasing NE levels actually improves prefrontal cortex (PFC) function, including measures of attention. Hence, the improved performance on cognitive tasks when administered α2-NE agonists is actually due to a decrease in NE activity. These disparate results suggest that the relationship between stress and attention is complex and multifaceted.
The Northwestern University paper suggests that stress may have a differential effect on various subtypes of attentional processes, mediated by different neural networks. While mild stress can reduce selective attentional inhibition, previous work has demonstrated that similar stressors enhance memory function. Since additional environmental cues can be encoded during the salient event, reducing an organism's attentional inhibition during stress may actually have beneficial effects on memory processing [1].
Conclusion
Stress has a significant impact on attention and cognition. Further investigation of the complex interplay between neurotransmitters, anatomical localization, and cognitive processes is key to understanding the relationship between stress and attention.
References
[1] Skosnik PD, Chatterton RT, Swisher T, Park S. Modulation of attentional inhibition by norepinephrine and cortisol after psychological stress. International Journal of Psychophysiology [Internet]. 2000 Apr 3 [cited 2023 Mar 9];36(1):59–68. Doi: https://doi.org/10.1016/S0167-8760(99)00100-2
[2] Liu Q, Liu Y, Leng X, Han J, Xia F, Chen H. Impact of Chronic Stress on Attention Control: Evidence from Behavioral and Event-Related Potential Analyses. Neurosci Bull [Internet]. 2020 Sep 15 [cited 2023 Mar 9];36(11):1395–410. Doi: https://doi.org/10.1007/s12264-020-00549-9
[Image] Roberts E. How We Use Selective Attention to Filter Information and Focus [Internet] [cited 2023 Mar 9] Available from: https://www.verywellmind.com/what-is-selective-attention-2795022
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