amygdala

How Slow Deep Breathing Results in Positive Emotions and More Creativity

Key Points

  • Dominance of the calming parasympathetic nervous system is associated with positive emotions and can be evoked through slow breathing.

  • Slow breathing leads to “hyperpolarization,” which literally makes neurons less excitable.

  • Slow breathing reduces activity in the amygdala, which increases relaxation and boosts creativity.

The Breathing Diabetic Summary

You probably know by now that emotional states are linked to breathing.  When you’re stressed, you breathe faster.  When you’re calm, you breathe slower.  Intuitively, it makes sense.  But how exactly does it occur?  That’s what this current paper explores.  It’s a fascinating look at how cardiorespiratory coherence can potentially influence emotions.  Of course, what matters most is simply that it works.  But here, we learn how it might be working…and it’s pretty amazing.

 

Feedforward or Feedback?

The fundamental hypothesis is that cardiorespiratory coherence (which I’m going to refer to as slow breathing for simplicity, although that’s not 100% correct) can regulate the autonomic nervous system and brainstem.  This, in turn, modulates the emotional regions of the brain.

This is a unique hypothesis because we typically think of emotions through a “feedforward” lens.  An emotion arises in the brain and “feeds” its signal to the rest of the body.  But here, they’re saying feedbacks from slow breathing, namely the ones on the nervous system and brain, can elicit positive emotions.

That is, you might be able to breathe yourself into happiness.

 

How Emotional States Correspond to Autonomic Function

 The most important indicator that this is possible is the link between positive emotional states and higher levels of cardiorespiratory coherence.  Of course, correlation doesn’t mean causation.  Still, the general conclusion from most studies is that positive emotions are associated with parasympathetic (calming) dominance, and negative moods are associated with sympathetic (fight or flight) dominance.

 This supports their hypothesis.  If we simply induce relaxation and parasympathetic dominance through slow breathing, maybe positive emotions will follow.

 

Hyperpolarization might Explain the Calming Effects of Slow Breathing and Meditation

 One fascinating way they propose this feedback might occur is through neuronal “hyperpolarization.”   Hyperpolarization seems to be a fancy way of saying that the neurons are harder to “excite.”  Meaning it actually takes a lot more energy to fire the neurons that make you stressed or anxious.  This helps explain why we feel relaxed after we meditate or breathe slowly.  These practices actually change our cells, making it harder to feel stressed…pretty crazy.

As an aside, I know I feel most joyful and optimistic after my morning breathing practice.  It feels like magic, but I guess it’s just hyperpolarization at its finest : )

 

Inhibition of the Amygdala from Slow Breathing

And here is a critical implication of hyperpolarization: inhibition of the amygdala. 

When we meditate or practice slow breathing (~4-6 breaths/minute), the neuronal hyperpolarization reduces activity in our amygdala.  This turns down negative thinking and turns up creativity.

As Steven Kotler tells us in The Art of Impossible, ““Unfortunately, to keep us safe, the amygdala is strongly biased toward negative information. …This crushes optimism and squelches creativity. When tuned toward the negative, we miss the novel.

Perhaps this is why, after interviewing the most creative people on the planet, Tim Ferriss discovered that “More than 80% of the interviewees have some form of daily mindfulness or meditation practice.

These practices naturally lead to cardiorespiratory coherence, quieting the pessimistic amygdala, allowing us to see the novelty all around us.

A Summary of How Slow Breathing Modifies Emotions 

Let’s wrap it all together to see how slow breathing can improve our emotional state. 

Positive emotional states are associated with high levels of cardiorespiratory coherence.  These states induce hyperpolarization, which inhibits the excitability of neurons.  This then modifies regions of the brainstem and inhibits the action of the amygdala and other limbic areas.  However, the opposite might also be true: simply breathing slowly will inhibit amygdala activity, allowing us to experience positive emotions, less stress, and more creativity.

Abstract

The brain is considered to be the primary generator and regulator of emotions; however, afferent signals originating throughout the body are detected by the autonomic nervous system (ANS) and brainstem, and, in turn, can modulate emotional processes. During stress and negative emotional states, levels of cardiorespiratory coherence (CRC) decrease, and a shift occurs toward sympathetic dominance. In contrast, CRC levels increase during more positive emotional states, and a shift occurs toward parasympathetic dominance. The dynamic changes in CRC that accompany different emotions can provide insights into how the activity of the limbic system and afferent feedback manifest as emotions. The authors propose that the brainstem and CRC are involved in important feedback mechanisms that modulate emotions and higher cortical areas. That mechanism may be one of many mechanisms that underlie the physiological and neurological changes that are experienced during pranayama and meditation and may support the use of those techniques to treat various mood disorders and reduce stress.

 

 

Journal Reference:

Jerath R, Crawford MW. How Does the Body Affect the Mind? Role of Cardiorespiratory Coherence in the Spectrum of Emotions. Adv Mind Body Med. 2015 Fall;29(4):4-16. PMID: 26535473.

 

Nasal breathing synchronizes brain wave activity and improves cognitive function

Zelano_et_al-2016_WTG.JPG

Key Points

  • Nasal breathing synchronizes brain wave oscillations in the piriform cortex, amygdala, and hippocampus

  • Nasal breathing improves cognitive function when compared to mouth breathing

  • Breathing affects emotional and mental state, shifting the paradigm for why we breathe

The Breathing Diabetic Summary

It is established that emotions and mental state affect breathing.  When you’re anxious, you breathe faster and shallower.  When you’re relaxed, you breathe quiet and light.  Intuitively, I think we all know that the opposite is true too: Your breathing can affect your emotions and mental state.  However, the brain mechanisms behind this shift have remained elusive.

This study sheds light on the issue.  Intracranial EEG (iEEG) was used to assess how breathing impacts electrical oscillations in different regions of the brain.  Then, emotional recognition and memory tests were used to see how breathing impacts cognitive function.

The results showed that oscillations in the piriform cortex are directly related to nasal breathing. The piriform cortex is associated with the nose through smell, so it makes sense that nasal breathing would cause oscillations in this region (although the participants were breathing odorless air).

Interestingly, two other regions of the brain also showed these oscillations: the amygdala and hippocampus.  When breathing was switched to the mouth, however, this brainwave activity became disorganized.  Thus, nasal breathing is critical to synchronizing electrical brainwave oscillations.

If nasal breathing affects these regions of the brain, it follows that it would potentially impact cognition.  And that’s exactly what they found.

They showed participants faces expressing either fear or surprise and had them quickly decide which one it was.  When breathing through the nose, the response times were faster than when breathing through the mouth.  Additionally, the participants identified fearful faces faster during inhalation than exhalation.  This effect wasn’t present when mouth breathing. 

Next, they had the participants perform a memory task involving picture recognition.  They found that their memory retrieval was more accurate during nasal inhalation, which was not observed for mouth breathing.  However, there was not a statistically significant difference in the overall accuracy between nose and mouth breathing.

Taken together, the iEEG measurements and cognitive tasks suggest that nasal breathing promotes coherent brainwave oscillations in the piriform cortex, amygdala, and hippocampus.  This coherence leads to improved cognitive function, especially during nasal inhalation.

We also found that the route of breathing was critical to these effects, such that cognitive performance significantly declined during oral breathing.

We’ve already established that breathing can no longer be thought of as a 2-gas system.  Now, we might have to extend beyond gases altogether.  Breathing acts to synchronize brain activity and enhance cognitive function…but only when performed through the nose.

I think that bears repeating.  Nasal breathing synchronizes brainwave activity and enhances cognitive function.  Pretty remarkable.

Abstract

The need to breathe links the mammalian olfactory system inextricably to the respiratory rhythms that draw air through the nose. In rodents and other small animals, slow oscillations of local field potential activity are driven at the rate of breathing (∼2-12 Hz) in olfactory bulb and cortex, and faster oscillatory bursts are coupled to specific phases of the respiratory cycle. These dynamic rhythms are thought to regulate cortical excitability and coordinate network interactions, helping to shape olfactory coding, memory, and behavior. However, while respiratory oscillations are a ubiquitous hallmark of olfactory system function in animals, direct evidence for such patterns is lacking in humans. In this study, we acquired intracranial EEG data from rare patients (Ps) with medically refractory epilepsy, enabling us to test the hypothesis that cortical oscillatory activity would be entrained to the human respiratory cycle, albeit at the much slower rhythm of ∼0.16-0.33 Hz. Our results reveal that natural breathing synchronizes electrical activity in human piriform (olfactory) cortex, as well as in limbic-related brain areas, including amygdala and hippocampus. Notably, oscillatory power peaked during inspiration and dissipated when breathing was diverted from nose to mouth. Parallel behavioral experiments showed that breathing phase enhances fear discrimination and memory retrieval. Our findings provide a unique framework for understanding the pivotal role of nasal breathing in coordinating neuronal oscillations to support stimulus processing and behavior.

 SIGNIFICANCE STATEMENT:

Animal studies have long shown that olfactory oscillatory activity emerges in line with the natural rhythm of breathing, even in the absence of an odor stimulus. Whether the breathing cycle induces cortical oscillations in the human brain is poorly understood. In this study, we collected intracranial EEG data from rare patients with medically intractable epilepsy, and found evidence for respiratory entrainment of local field potential activity in human piriform cortex, amygdala, and hippocampus. These effects diminished when breathing was diverted to the mouth, highlighting the importance of nasal airflow for generating respiratory oscillations. Finally, behavioral data in healthy subjects suggest that breathing phase systematically influences cognitive tasks related to amygdala and hippocampal functions.

Journal Reference:

Zelano C, Jiang H, Zhou G, Arora N, Schuele S, Rosenow J, Gottfried JA.  Nasal Respiration Entrains Human Limbic Oscillations and Modulates Cognitive Function.  J Neurosci. 2016;36(49):12448-12467.