vagus nerve innervation

Vagus nerve and it's many connections to our organs highlighs the importance it has on the functioning and well-being of our system.
We have always expressed love and emotion from the heart and intuition from the gut; hence, the expressions heartfelt and gut feeling. Research suggests that they may have scientific explanations.

It seems both heart and gut have minds of their own. Besides communicating with the brain, they might also be helping it develop, reducing depression and increasing the level of the individual's well-being.

The gut mind

On an average, the brain has 100 billion neurons; it is the seat of all our thinking. The gut or the digestive system has close to 500 million nerve cells and 100 million neurons and is almost the size of a cat's brain. Not only does the gut 'talk' with the brain by releasing chemicals which are transported to the brain but also by sending electrical signals via the vagus nerve, one of the longest nerves in the body whose purpose is to relay the information of internal organs to the brain. It starts from the head and ends near the anus.

Most gut neurons are used in the daily grind of digestion. The gut system is an extremely complex chemical processing machine, which breaks down food, absorbs nutrients and moves waste down via muscular contraction towards the anus for expulsion. Thus the autonomous nervous system of gut allows it to work independently of the brain.

Recent research reveals that there is tremendous amount of information flow from the gut to the brain via the vagus nerve and this flow is mostly one-sided.

Body balance

The reverse interaction - from the brain to the gut - is when we get hunger pangs and the brain tells the body to get food or when something goes wrong in the gut, like pain or diarrhea, necessitating medicines for its cure. Scientific evidence also suggests that a big part of our emotions are probably influenced by chemicals and nerves in the gut. For example, 95 per cent of the body's serotonin is found in the gut.

Serotonin is an important neurotransmitter that contributes feelings of wellbeing. The ancients seem to have known something about the gut-brain connection. The colon cleansing process of ayurveda like enema or 'gut wrenching' exercises of nauli in Hatha Yoga help in cleaning the gut and increasing the feeling of wellness. In mayur asana, the body is balanced on the navel. The pressure stimulates the vagus nerve; helping improve the brain-gut connection.

There are also many instances of people experiencing extrasensory perception (ESP) after colon cleansing has taken place. One reason could be that a clean gut frees its neurons to help the brain increase its processing power. The extra neural power may help the brain process more information and help it experience samadhi or sanyam. Though gut neurons are used mostly for gut activity, they also interact with the brain via the vagus nerve.

In Patanjali Yoga, the gut is the centre of the body-universe. It says that by sanyam on the nabhi a yogi gains knowledge of body constituents.

The heart is one of the most important organs of the human body. It has nearly two billion muscle cells and 40,000 neurons. Heart neurons are very few in number compared to those in the brain, 100 billion or gut, 0.1 billion. Nevertheless, these neurons transmit the heart's signals and its condition to the brain.

The heart-mind interaction takes place both by electrical signals via the vagus and the spinal cord nerves and through chemicals. The heart is also an endocrine gland.

Recent studies have shown that the heart sends signals to the brain that are not only understood by it, but also obeyed. Scientists have discovered neural pathways and mechanisms whereby inputs from the heart to the brain inhibit or facilitate the brain's electrical activity - just as the gut is capable of doing. Thus both gut and heart-mind help in the thought process.

Besides electrical signalling, the heart also releases peptides, which help in blood pressure modulation and improving the functioning of kidneys. The peptides also stimulate the pituitary gland thereby helping it to release hormones like oxytocin commonly referred to as the 'love' hormone. Oxytocin also helps increase the wellbeing of a person. This could be the basis for saying that happy feelings emanate from the heart.

The point of interest is the rhythm patterns of the heart which result when two billion muscle cells are triggered by AV and SA nodes, which are like electrical switches. These nodes send electrical signals to the heart muscles for contraction and so are an important organ of the heart. When they do not function properly, electrical signals to muscles go haywire and the heart starts to flutter. A pacemaker attached to these nodes streamlines signals and can restore proper functions to the heart.

The speed of heartbeats or its contraction changes depending upon our emotions. For example, when we are aroused either by passion or anger, the heart speeds up and in quiet times or in meditation, it slows down. This electrical input to the AV and SA nodes from the brain comes via the vagus nerve and is reflected in the ECG patterns of the heart.

Pranayama helps

Pranayama or breathing exercises can stimulate the vagus nerve and this could have a beneficial effect on the heart and gut. Similarly the chanting of mantras or deep throat singing as practised by Buddhist lamas also stimulates the vagus nerve. It has been shown that this stimulation helps in reducing blood pressure and improves the rhythm patterns of the heart. The neural information from both these activities facilitates the cortical function and the effect is heightened mental clarity, improved decision making and increased creativity.

Similarly, the stimulation of the vagus improves the cleaning process of the colon. For example, the ancient Indian custom of applying pressure on the cheeks with fists while sitting on the toilet seat helps in bowel movement. Pressure on the cheeks stimulates the vagus nerve since its branches pass through the face. Scientists have also discovered that the heart is involved in the processing and decoding of 'intuitive information'. Tests on subjects showed that the heart appeared to receive intuitive information before the brain. This could be the basis for - 'Follow your heart; you will never go wrong'.

The ancients were aware of the heart interaction. Patanjali Yoga says that by sanyam on the heart, a yogi acquires the complete knowledge of his mind.

To produce deep thought which helps in improving the wellbeing of a person, the gut and heart brains must work together with the main brain. When all work harmoniously, it creates a healthy body and a powerful mind.