Primer
Nervous system basics in plain language
The nervous system is the body's signalling network, made of the brain and spinal cord at the centre and a web of nerves reaching everywhere else, all of it passing messages as small electrical and chemical events.
This page is a primer, not a clinical account. It exists so the rest of the site can use ordinary words and still mean something specific.
What are the main parts of the nervous system?
The central part is the brain and spinal cord. The peripheral part is every nerve that runs out from there to muscles, skin, and organs.
Within the peripheral part, one branch carries the traffic you direct, such as moving a hand. Another branch runs the things you never think about, such as heart rate and digestion.
- Central: brain and spinal cord.
- Peripheral: the nerves reaching the rest of the body.
- Autonomic: the branch that runs background functions without your involvement.
What do sympathetic and parasympathetic mean?
They are the two halves of the autonomic branch. The sympathetic side raises readiness, quickening the heart and tensing muscle. The parasympathetic side lowers it, slowing the heart and favouring digestion and rest.
Neither side is good or bad. They shift back and forth all day, and the shifting itself is normal. Popular writing often frames one as the enemy, which is not how the system behaves.
What does the brain's electrical activity have to do with any of this?
Cells in the brain communicate partly through electrical changes. When very large numbers of them shift together, the summed effect is big enough to be detected as faint voltage changes at the scalp.
That is what a surface sensor picks up. It is a distant view of a crowd rather than a look at any individual in it.
Why is scalp activity described in frequency bands?
Because the summed activity rises and falls in rhythms, and it is convenient to group those rhythms by speed. The names you see, such as alpha and beta, are simply labels for ranges.
The labels are descriptive, not explanatory. A band is not a mood, and no band means one specific mental state. Marketing that maps a band to a feeling is stretching well past what the labels carry.
Can the nervous system change?
Nervous systems adapt. Repeated experience changes how readily patterns of activity occur, which is the ordinary basis of learning any skill.
That general fact gets borrowed to imply a great deal about specific practices. Adaptation being real does not tell you that a given session does a given thing, and we do not use it that way.
What does this primer not tell you?
It does not describe any health condition, and it makes no claim about how a session affects anything in your body.
It is background reading so the vocabulary elsewhere on this site is not doing work you cannot check. That is the whole purpose.
Questions people ask about this
Please read this
Momentous Neurofeedback is a wellness practice. We use an FDA-cleared biofeedback device indicated for relaxation training and muscle reeducation.
We do not provide medical care and we do not assess or identify health conditions. We make no promise about any outcome, and nothing on this site should be read as one.
Sessions are not a substitute for care from a licensed clinician. If you have a health concern, speak with your own provider. In an emergency, call your local emergency number.
Plain words, no borrowed authority
If a page on this site uses a term you cannot check, tell us and we will fix it. Or come sit through a session and ask in person.