I assume most people either experienced or have seen people with the following phenomenon: in the early phases of sleep sometimes involuntary twitches occur that usually accompany the pause of breathing (I'm aware that there's a chronic sleeping disorder called sleeping apnea but I think it's different because what I'm asking about now is acute). I wonder if the twitching is some sort of emergency signal, so that the person would wake up (to some level not necessarily full awake) and start breathing. Is there any data that these (the pause in breathing and the twitches) are connected or they are independent? Also I'm also interested why this acute pause of breathing occurs?