Summary: Researchers found that breathing affects pupil size. The pupil is the lowest during inhalation and the largest during exhalation. This newly identified mechanism is independent of external stimuli and can affect vision by alternating details reinforcement and object detection.
An experiment with over 200 participants confirmed effects across a variety of conditions, including different respiratory rates, lighting, and visual tasks.
This study suggests that the brainstem may be able to control this process, as function remains intact in individuals without olfactory bulbs. Because pupil size affects visual clarity, this finding may help explain how breathing affects attention and perception.
Important facts:
Pupil Respiratory Link: The pupil size is the smallest during inhalation and the largest during exhalation. Vision Optimization: Breathing allows you to switch vision naturally between detailed focus and object detection. Clinical potential: Findings may inform new diagnostic tools for neurological disorders.
Source: Karolinska Institute
Researchers at Karolinska Institet in Sweden have discovered the fundamental mechanisms that affect student size: our breathing.
This study, published in the Journal of Physiology, shows that the pupil is the smallest during inhalation and the largest during exhalation.
Like the opening in a camera, the pupil controls the amount of light that reaches the eye. So it is fundamental to our vision and how we perceive our surroundings.
Three mechanisms that allow students to change sizes have been known for over a century. Cognitive factors such as the amount of light, focal length, and emotional and mental effort.
Now the scientists have discovered the fourth: breathing. The pupil is the lowest during inhalation and the largest during exhalation.
“This mechanism is unique in that it is cyclical, always present and does not require external stimuli,” explains Artin Arshamian, associate professor at the Department of Clinical Neuroscience at the Karolinska Institute, who led the study. .
“Since breathing affects brain activity and cognitive function, discoveries may contribute to a better understanding of how our vision and attention are regulated.”
The researchers conducted five experiments with over 200 participants to examine how breathing affects student size under different conditions.
The results show whether participants breathe quickly or slowly through the nose or mouth when lighting conditions or fixed distances are performing rest or visual tasks, if lighting conditions or fixed distances change. Despite this, the effect was shown to last.
The difference in pupil size between inhalation and exhalation was so great that it theoretically affected vision.
This study showed that this function was intact in people born without the olfactory bulb, a brain structure activated by nasal breathing. This suggests that mechanisms are controlled by the brainstem, the basic, evolutionarily conserved part of the brain.
Researchers are currently investigating whether changes in pupil size during breathing also affect vision. Previous research shows that fewer students will make the details easier, but it helps more students find objects that are difficult to see.
“Our results optimize our vision to distinguish small details when we detect faint objects within all breathing cycles, while exhale as we breathe in. It suggests switching.” The first author of the study.
Researchers say there may also be clinical applications.
“One potential use is a new way to diagnose or treat neurological conditions such as Parkinson’s disease, where pupil function is an early sign of the disease,” says Artin Arshamian. Masu. “This is something we want to explore in the future.”
Funding: This study was funded by the Swedish Research Council and the European Research Council (ERC). No conflicts of interest have been reported.
About this visual neuroscience research news
Author: Press Office
Source: Karolinska Institute
Contact: Press Office – Karolinska Institute
Image: Image credited to Neuroscience News
Original research: Open access.
“Pupil respiratory phase response: pupil size is minimal during inhalation and maximum during exhalation,” Artin Arshamian et al. Journal of Physiology
Abstract
Pupil respiratory phase response: The pupil size is the minimum during inhalation and the maximum during exhalation
There is some evidence to suggest that breathing shapes brain activity, synchronizes the effects of sensory and exploratory movements, which also affects pupil size. However, evidence of a connection between breathing and pupil size remains rare and conclusive, hampered by small sample sizes and limited controls.
Understanding the relationship with breathing is essential as a reflection of the importance of pupil size in visual perception and brain state.
Five experiments using pre-registered protocols were systematically investigated how respiratory phases affect student size under different conditions.
Experiment 1 (n = 50) examined nasal and oral respiration in a stationary state under dim lighting with nearby fixed points, and replicated these results under the same conditions in Experiment 2 (n = 53). did.
Experiment 3 (n = 112) extended this to an active visual task, and Experiment 4 (n = 57) extended this to control breathing at a different pace under ambient lighting with distant fixation .
Finally, in Experiment 5 (n = 34), individuals with isolated congenital analism (born without an olfactory bulb) were used as lesional models during visual audits to provide a link between the respiratory and the underlying link. We evaluated whether it depends on olfactory bulb-driven vibrations. .
Over all conditions – Free and controlled breathing. Various tasks, lighting, fixed distances. Additionally, with or without olfactory bulbs, we have consistently found that the pupil size during inhalation was minimal and the largest during exhalation.
This effect refers to the fourth known mechanism that affects pupil size, the pupil respiratory phase response, which is closer to fixed and psychosensory responses.
