The twitch when you’re falling asleep or in a light sleep is called “hypnic myoclonia”. It isn’t necessarily related to snoring at all. Snoring occurs because of flaccid tissue in the soft palate, which can be caused or exacerbated by any number of things. Hypnic myoclonia specifically has to do with how the brain behaves in light, Stage 1 sleep.
The first stage of sleep and a “level” of sleep which we may return to a few times a night is called Stage 1. It’s defined as a light sleep that we can drift in and out of; the senses of vision and hearing aren’t fully disconnected from external stimuli the way they are in deeper stages of sleep, but the neuronal firing pattern resembles that of when we’re dreaming, and people woken up from this stage often remember visual images and dream fragments.
In full REM sleep (during real dreaming), there is a sort of short-circuit in the brain* which activates to keep us from getting up and acting out our dreams physically; essentially this safety switch tells the brain that it can talk to its sensory interpretation modules, but it isn’t allowed to talk to its motor control modules. (When this short-circuit doesn’t kick in properly we can get sleepwalking.
Alternatively, when we start to wake up but the circuit doesn’t disengage, we get the kind of nightmare known as “sleep paralysis”, where you are at least semi-aware of your real physical surroundings, often mixed with visual and/or auditory hallucinations which “feel” real, but you absolutely cannot move. This may be where a lot of “alien abduction” experiences come from.)
Back to hypnic myoclonia, though. In the first few minutes of Stage 1 sleep, the brain is starting to take on the aspects of synchronised neuronal firing typical of dreaming, but that protective short-circuit hasn’t kicked in yet. This sometimes results in the pattern of firing in your brain triggering a synchronous burst in the motor neurons, and you get a “startle twitch”.
That twitch is generally absolutely nothing to worry about. It’s only when you continue that kind of startle jerk after you are in full, Stage 2, 3, or 4 deep sleep that you know that something is going wrong.
Can medication affect this? Possible; any medication which affects sleep patterns has the potential to affect it, because it has the potential to affect how your brain is acting during sleep. Unless it seems to be accompanied by other sleep disturbances, though, like night terrors or sleepwalking, or the startle is leaving you with sore muscles or a bitten tongue or suchlike, or it’s simply really bothering your ability to sleep, then it probably honestly isn’t worth worrying about.
- This circuit is composed of inhibitory GABAergic neurons in the thalamus which interfere with motoneuron firing patterns, if you wanted to know that, and motoneurons are also kept hyperpolarised to keep them from firing properly. However, messages for minor twitches in the peripheral muscles can still sneak through.
maybe this will help[/quote]
awww snap. Dirtbag knows… wow. ok, well I really am releived!
I was worried it was going to like grow into epilepsy or something. Thank you for posting sir!