Alterations in membrane potential and excitability of cat medial pontine reticular formation neurons during changes in naturally occurring sleep-wake states.

Intracellular recordings of medial pontine reticular formation (mPRF) neurons in behaving cats show the following distinctive desynchronized sleep (D) state characteristics: excitability is greater in D than in waking (W) or synchronized sleep (S) and in D there is a tonic depolarization that persists throughout the state and upon which are superimposed phasic runs of further depolarization. In contrast, the background, tonic level of membrane potential in both W and S is more negative than in D, which phasic depolarizations associated with motor activity occurring in W but not in S. These data are compatible with a generating role for mPRF neurons in D sleep phenomena.