It has often been observed that fasting brings on a tranquil, contemplative state of mind. Prophets famously entered the desert to fast for days. In modern times, fasting is known to bring on a ketogenic energy cycle, and many people attest to the power of fasting to alter their mind state.
A recent study caught my eye that provides an intriguing connection. The title is Phase-locking of resting-state brain networks with the gastric basal electrical rhythm.
The enteric nervous system is a separate nervous system in the lining of the gut. It originates from parasympathetic and sympathetic neurons that colonize it from the neural crest during embryogenesis. The neurons there oscillate at a rhythm of 0.05 Hz, a lower frequency than any rhythm found regularly in the brain. The brain and the enteric nervous system communicate bidirectionally through the vagus nerve. Interestingly, the right and left vague nerve are not symmetric, and stimulating one side or the other has different effects.
It has recently been discovered that there is a gastric network in the brain itself that responds to the enteric nervous system. The study above identified three functional networks that are phase-locked to the gut rhythm:
In the network marked DMN_b, the area of highest activation appears to map to the following Neuromythograph areas:
- 7m (OBJECTIVE POV) (specifically a subarea 7md (ACTOR)
- 7PM (Herodotus, the Greek epic historian)
- PCV (Left: OTHER-PERSPECTIVE / Right: MIND’S EYE AUTOBIO RECALL)
7m is a large precuneus area that has an epithet OBJECTIVE POV. It seems to be related to third-party and the mythical ‘objective’ point of view.
7PM is engaged when recording and recounting historical experience. Herodotus of ancient Greece was considered the first historian.
PCV, as best I can tell, corresponds to a certain imaginary visual perspective. On the left it is responsible for imagining a scene from another perspective. Thus the epithet OTHER-PERSPECTIVE. On the right it manages autobiographical recall of ‘the mind’s eye’.
Side note: the 1st-person/3rd-person pronoun-confusion symptom of autism relates to underactivation in this same precuneus area.
Here is the interesting part. The rhythm of the gut brain entrains the rhythms of a specific cognitive brain region–the historian, the perspective-taker, and visualization of the past and others’ perspectives. This is really interesting physical connection between fasting and the spiritual experience of fasting that awaits further scientific exploration.
