Breathing is the Master Clock of the Sleeping Brain

Neuroscientists have discovered that breathing will coordinate neuronal activity in the brain while it is at rest or sleep.

The brain does not switch off when we are at sleep. Instead, it is saving important memories that happened during the day. For this to occur the regions of the brain syhchronize to coordinate transmission of data between them. But it is still not understood how these mechanisms work. The thought has been that the brain has correlated activity patterns in it. However, the team has shown that breathing will act as a pacemaker that enables these brain regions to synchronize between them.

The most essential and persistent body rhythm is breathing. It exerts a powerful physiological effect on the autonomous nervous system. It also modulates a broad area of cognitive functions which include attention, perception, and thought formation. But the components of its impact on the brain and these functions are mostly unknown.

The team performed in vivo electrophysiological recordings on a large scale in mice including thousands of neuron activity across the limbic system. The results were that respiration coordinates and entrains neuronal activity in all the brain regions investigated. These included the hippocampus, visual cortex, medial prefrontal, thalamus, nucleus accumbens and the amygdala. It did this by regulating the excitability of circuits in an olfaction independent way. They were able to prove the existence of a novel non-olfactory, intracerebral mechanism that accounted for the entrainment of distributed circuits by breathing. They deemed this as “respiratory corollary discharge”.

The findings identify the existence of a link between limbic and respiratory circuits that was currently unknown. This is a deviation from the traditional idea that breathing is modulated by brain activity through the nose-olfactory route.

Coordination of sleep related activity is mediated by this mechanism in brain regions which are important for memory consolidation. It also provides the means for the co-modulation of the cortico-hippocampul circuits synchronous dynamics. These results show a significant step forward to providing the foundation for new theories that will incorporate respiratory rhythm as a fundamental mechanism underlying the communication of distributed systems during consolidation of memory.

To view the original scientific study click below:
Breathing coordinates cortico-hippocampal dynamics in mice during offline states