The brain at rest, and 5 Hz "idling" frequency

[Jeff Kos]

Hello,

I recently read that the brain's neurons never really "rest".  That is, even
when inactive, they continue to fire at a resting rate of approximately 5
Hz.

Is this true for the entire brain?  I.e., even in the deepest sleep state,
ALL of the brain's billion of neurons are slowly pulsing away en masse?

Thanks in advance...

Jeff Kos
Portland OR