A new study conducted by neuroscientists at the University of Regensburg has revealed that specific neurons in the brain can directly detect heartbeat-induced rhythmic movements of blood vessels, allowing them to feel the pulse within the brain. This discovery sheds light on the phenomenon of interoception, which involves the sensing of internal body signals to inform the brain about the state of the body.
The researchers stumbled upon these peculiar findings while studying activity in the olfactory bulb, the part of the brain responsible for processing smell. They noticed unusual oscillatory electrical signals even though no external signals were being introduced. Further investigation suggested that these signals had both non-biological and biological origins, leading to a deeper exploration of the phenomenon.
It was eventually discovered that the brain tissue was responding directly to the rhythm of a peristaltic pump that was used to supply blood to the tissue. The pressure pulses created by the pump aligned with the normal range of heartbeat-induced blood pressure variations within the brain. The researchers identified the origin of these oscillations as the mitral cells, the primary neurons in the olfactory bulb.
The next question was whether these neurons could also detect the blood pressure pulse associated with the heartbeat. Dr. Luna Jammal, a senior researcher on the team, found that the pump-induced pressure pulsations were translated into electrical activity in the mitral cells through specialized sensors called fast mechanosensitive ion channels. These sensors trigger the release of a current in the cell whenever there is a change in pressure around it. In experiments using a tarantula toxin that blocks these sensors, the oscillations ceased.
These sensors have only recently been discovered, with researchers awarded the Nobel Prize in 2021 for their identification. Additionally, Dr. Sebastian Bitzenhofer and Prof. Ileana Hanganu-Opatz at the University of Hamburg demonstrated that this sensing mechanism occurs in real animals, not just in isolated brain tissue.
The study unveiled that these heartbeat sensors are distributed throughout the brain, indicating that the pulse can be directly sensed in various regions. The researchers are still unsure of the exact purpose of this ability. However, one hypothesis suggests that the way the heart beats could influence thoughts and emotions. With the sensors located in close proximity to the brain, the effects of the heartbeat on cognition and emotions could be nearly instantaneous.
This groundbreaking study opens up new avenues of research into the intricate connection between the cardiovascular system and brain function. Further investigation into the interoceptive processes and their impact on cognition and emotions could have significant implications for understanding human physiology and potentially developing new therapies for various neurological disorders.
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1. Source: Coherent Market Insights, Public sources, Desk research
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