The vagus nerve is a cranial nerve, a honking big nerve that runs from your skull, down your chest and into your abdomen. The punch-in-the-gut feeling of a jolt of adrenalin/the start of an anxiety attack is carried on the vagus nerve.
The usual paradigm for emotions is they start in the brain. Most of the body’s hormones have a dual purpose as a neurotransmitter. The vagus nerve helps coordinate the physical feeling with the emotional feeling – they are one and the same. The mind-body connection.
Most of the body’s serotonin is in the gut. A squirt of serotonin doesn’t just happen in the brain, it happens in the whole body. Ditto adrenaline. The vagus nerve conducts information in both directions. I don’t think it’s entirely accurate to blame anxiety on a brain malfunction.
An interesting treatment for anxiety is “Vagus Nerve Stimulation.” In VNS, a device is implanted that applies current to the vagus nerve is to overwhelm it. It’s kind of like a TENS unit for pain. VNS is a last resort for intractible anxiety.
One implication of this is that if you can control the physical aspects of anxiety – relax your muscles, slow down your breathing & heart rate – then the emotional component will follow. Once the emotions are managed you can work out whatever brought on the anxiety.
Candace Pert, Ph.D. discovered opium (endorphin) receptors in the brain. She wrote an enlightening book Molecules Of Emotion: The Science Behind Mind-Body Medicine.
Also check out Timothy Leary. One of his more interesting ideas is that we have receptor sites for chemicals that haven’t been invented yet. Alexander Shulgin was a chemist who formulated a lot of them, but I don’t recommend you try it. 🙂