Physical Reactions

For very stressed people, tingling in hands and feet as a reaction to neurofeedback can be a result of shifting into parasympathetic mode, so the blood gets back out to the extremities. Whole body tingling might just be a person actually being in touch enough with his sensory inputs to actually be aware of himself as a sensing being. Wild guess.

Reaction vs Rebound

The rebound effect is an autonomic phenomenon.

When a person has high levels of autonomic tone–they have a tendency to be stuck in sympathetic (fight-or-flight) mode, the brain and body believe they are in an emergency situation. That often appears as high levels of fast-wave activity, often in the back of the head and/or on the right hemisphere. It is fairly common for some brains to respond to this very demanding and tiring state by learning to produce alpha (often slow alpha) as a kind of self-medication. In the alpha state, you can numb out those feelings of fear and anxiety. When someone tells your brain to stop doing that, it’s no big surprise that the brain responds by suddenly revealing the underlying emotions being covered up by the alpha.

Strictly speaking, that’s a reaction, not a rebound. Rebounds (like panic attacks, migraines, irritable bowel, etc.) are physiological responses. When the brain is convinced that the world is a dangerous place, it believes it must maintain a high level of vigilance and readiness. That sympathetic state draws energy from the parasympathetic functions of body maintenance, including sleep, digestions, circulation, blood pressure, heart-rate, breathing, etc. When a person who is highly self-stressing is suddenly led to relax–by training or a reduction in some external event one finds stressing (e.g. end of work, completing the budget, etc.) the brain shifts back to parasympathetic (rest and digest) and stops being vigilant. For a while. But in many cases, the brain will suddenly “realize” that the security guards are all taking a nap at the same time and in a panic “rebound” into sympathetic mode. Suddenly anxiety explodes or the heart begins racing or you can’t catch your breath, but there is no “reason” identifiable. That’s a sympathetic rebound (panic attack in those who experience anxiety physically).

A parasympathetic rebound happens when the effects of releasing the emergency response cause an excessive physical change. When we are in fight-or-flight, commonly blood is drawn out of the extremities of the body into its center to be ready to go to war. Hands and feet may get cold. Blood is released from the brain (no need to think, we’re just in reactive mode). When suddenly the emergency mode ends, blood can rush back to the extremities (tingling hands or feet) or to the brain. In the latter case, if the brain doesn’t have a robust system for handling all that blood, it’s like 5 o’clock traffic hitting all at once and there’s a traffic jam. The result is a sense of pressure and throbbing (the heart trying to push blood into an area that has no room for more) which we call a migraine. Or a sudden burst of activity in the digestive system out of sync with normal digestive activity (irritable bowel.)

The key to avoiding these is often to focus on training the underlying anxiety patterns while at the same time slowly working to reduce autonomic tone.