How Breathing Patterns Affect Memory and Fear
By: Sai Srihaas Potu
Breathing is a well-described, vital, and surprisingly complex behavior, with behavioral and physiological outputs that are easy to directly measure. The science of breathing stands on quite ancient foundations. Centuries of wisdom instructs us to pay closer attention to our breathing, the most basic of things we do each day. And yet, maybe because breathing is so basic, it’s also easy to ignore. While the admonition to control breathing in order to calm the brain has been around for ages, only recently has science started uncovering how it works. In recent years, Northwestern Medicine scientists have been able to discover the true effect that certain breathing patterns can have on our memory and the formation of fear.
A part of the brain called the hippocampus is closely connected with the amygdala. The hippocampus and prefrontal cortex help the brain interpret a perceived threat. They are involved in a higher-level processing of context, which helps a person know whether a perceived threat is real. The amygdala is involved in the processing of memory, decision-making, and emotional responses. In this study, researchers have figured how certain breathing rhythms can affect the performance of certain parts of the brain.
Scientists have discovered for the first time that a certain rhythm of breathing creates electrical activity in the human brain that enhances emotional judgments and memory recall. These effects on behavior depend critically on whether you inhale or exhale and whether you breathe through the nose or mouth.
In the study, individuals were able to identify a fearful face more quickly if they encountered the face when breathing in compared to breathing out. Individuals also were more likely to remember an object if they encountered it on the inhaled breath than the exhaled one. The effect disappeared if breathing was through the mouth.
Northwestern scientists first discovered these differences in brain activity while studying seven patients with epilepsy who were scheduled for brain surgery. A week before surgery, a surgeon implanted electrodes into the patients’ brains to identify the origin of their seizures. This allowed scientists to acquire electro-physiological data directly from their brains. The recorded electrical signals showed brain activity fluctuated with breathing. The activity occurs in brain areas where emotions, memory, and smells are processed. This discovery led scientists to ask whether cognitive functions typically associated with these brain areas, in particular fear processing and memory, could also be affected by breathing.
The amygdala is strongly linked to emotional processing, in particular fear-related emotions. So scientists asked about 60 subjects to make rapid decisions on emotional expressions in the lab environment while recording their breathing. Presented with pictures of faces showing expressions of either fear or surprise, the subjects had to indicate, as quickly as they could, which emotion each face was expressing.
When faces were encountered during inhalation, subjects recognized them as fearful more quickly than when faces were encountered during exhalation. This was not true for faces expressing surprise. These effects diminished when subjects performed the same task while breathing through their mouths. Thus the effect was specific to fearful stimuli during nasal breathing only.
In an experiment aimed at assessing memory function, the same subjects were shown pictures of objects on a computer screen and told to remember them. Later, they were asked to recall those objects. Researchers found that recall was better if the images were encountered during inhalation.
The researchers were able to conclude that when a person is in a panic state their breathing rhythm becomes faster. Thus they will spend more time inhaling than when in a calm state. As a result, their body’s innate response to fear with faster breathing can have a positive impact on brain function which can result in faster response times to dangerous stimuli in the environment.
Another study has found out that controlled breathing triggers a parasympathetic response and may also improve immune system resiliency. The study also found that these breathing techniques can lead to improvements in energy metabolism and more efficient insulin secretion, which results in better blood sugar management. If accurate, the results support the conclusion that controlled breathing isn't only a counterbalance to stress, but also valuable for improving overall health.
Research in this area of medicine is very important as certain breathing techniques have the potential to provide significant health benefits. Scientists are still conducting more research on this topic to properly understand the breathing mechanisms that enhance or inhibit the function of certain areas of the brain. In some cases, certain breathing patterns might be linked to different diseases. Analyzing controlled breathing allows scientists to tap into something deeper that has never been properly researched or understood before. This will allow significant advances in a wide array of medical fields ranging from sleep medicine to cognitive psychology.
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2. Jose L Herrero, Simon Khuvis, Erin Yeagle, Moran Cerf, Ashesh D Mehta. Breathing above the Brain Stem: Volitional Control and Attentional Modulation in Humans. Journal of Neurophysiology. 2018.
3. Kevin Yackle, Lindsay A. Schwarz, Kaiwen Kam, Jordan M. Sorokin, John R. Huguenard. Breathing control center neurons that promote arousal in mice. Science. 2017.