Be Not Afraid, Just Breath

How rhythmic breathing influences neural activity that enhances memory recall and emotional judgement

When we breath we inhale oxygen (O2) and exhale carbon dioxide (CO2). If we stopped we would quickly lose consciousness and eventually die. Now, new research is showing how our breathing affects specific brain functions related to memory and behavior.

Researchers at the Feinberg School of Medicine at Northwestern University have shown for the first time that rhythmic breathing enhances electrical activity in the brain and that this is associated with emotional judgments and memory recall. The effect depends on whether you are inhaling or exhaling and whether or not you breath through your nose or mouth.

In the experiment, subjects were able to more quickly identify a fearful face when breathing in compared to when they were breathing out. They were also more likely to recall an object encountered while inhaling as compared to exhaling. These effects only occurred when the subject was breathing through their nose. When subjects were breathing through their mouth this correlation disappeared.

“One of the major findings in this study is that there is a dramatic difference in brain activity in the amygdala and hippocampus during inhalation compared with exhalation,” said lead author Christina Zelano. “When you breathe in, we discovered, you are stimulating neurons in the olfactory cortex, amygdala and hippocampus, all across the limbic system.”

Differences in brain activity associated with breathing patterns were first noticed by scientists at Northwestern who had been studying the brain activity of seven patients with epilepsy, prior to their scheduled brain surgery. Prior to having surgery, electrodes were implanted into the patients brains in order to identify the specific region of the brain causing the seizures. This allowed scientists to gather data about the electrophysiological activity directly from the patient's brain. Upon close examination, the recorded data showed brain activity that fluctuated with the patients breathing. These changes were occurring in areas of the brain responsible for processing emotions, memories, and smells.

This discovery lead the scientists to question whether behaviors associated with these regions were also being affected by breathing. In particular they wondered whether fear processing and memory recall could be affected.

Fear

The amygdalae are two strings of almond-shaped grouping of neuronal nuclei located deep within the temporal lobes of the brains of complex vertebrates, including humans. Research has shown that the amygdala is responsible for the processing of memory, decision-making, and emotional response, particularly fear-related emotions.

In order to determine if breathing patterns affected fear-based decision making, scientists showed 60 healthy subjects pictures of faces and asked them to quickly evaluate their emotional expression as depicting either fear or surprise. What they found was amazing! When subjects were shown faces depicting fear while inhaling through their nose, they were much quicker to identify them than when shown the same faces while exhaling through their nose. This was not true for faces expressing surprise. These effects disappeared when the subject was breathing through their mouth. This suggests that stimulating our olfactory center primes the brain to recognize fearful expressions and that breathing quickly through the nose may confer an advantage when faced with a dangerous situation.

Memory

In a related experiment assessing the impact of breathing patterns on memory function, subjects were shown pictures of objects on a screen and asked to remember them. Later when asked to recall those objects, researchers found that subjects who were exposed to objects during inhalation were better able to recall them later.

The research suggests that being mindful of our breathing could improve memory and emotional response. Breathing through our nose, as practiced during yoga, also has a benefit over breathing through our mouth. It also illustrates the importance of breathing when confronted with a dangerous situation. Another potent insight from this research is that breathing helps synchronized brain oscillations across the entire limbic network.

Source: Marla Paul — Northwestern University
Original Research: Abstract for “Nasal Respiration Entrains Human Limbic Oscillations and Modulates Cognitive Function” by Christina Zelano, Heidi Jiang, Guangyu Zhou, Nikita Arora, Stephan Schuele, Joshua Rosenow and Jay A. Gottfried in Journal of Neuroscience. Published online December 7 2016 doi:10.1523/JNEUROSCI.2586–16.2016