-
Asked by gandalfthegrey to Fiona, Joanna on 25 Jun 2010 in Categories: General.
Question: How come the brain cannot stop actions that we don't want to do? E.g. having a twitch
-
Fiona Randall answered on 25 Jun 2010:
Muscle twitchs are generally involuntary spasms so the brain can’t consciously control them. Eyes sometimes twitch when we are tired. There are also some conditions that cause people to have a twitch or even tourettes where they say things they don’t want to. This is thought to be a problem with brain function. I have talked about the causes of Tourettes in one of my old answers.
-
-
Joanna Brooks answered on 25 Jun 2010:
Hello again! A twitch is an involuntarily muscle action – a muscle contracts several times in a row in an uncontrolled way. It happens because of a sudden burst of activity in the motor neurons in the brain (cells that control movement) – the motor neuron suddenly fires an electrochemical impulse which a certain muscle in the body responds to.
A common twitch is when the eye-lid flutters for a few seconds (or even a minute) and seems to be ‘pulsing’ – people often have this when they are tired as these sudden bursts of motor neuron activity in the brain are related to emotional moments like tiredness, joy, sadness or stress.
Comments
Joanna commented on :
Actually – Fi – Tourettes is not a twitch. Tourettes syndrome is more commonly defined as a ‘tic’.
Fiona commented on :
Thanks Jo, I typed that in a rush and didn’t make it clear. Meant muscle twitches are a type of ‘tic’ that can also be seen in Tourettes (which more commonly people associate with saying something they don’t mean) and Tourettes-type muscle twitching is controlled by different nerve pathways to muscle spasms. ‘Tic’ is the scientifically correct term, but people often refer to them as nervous twitches etc. 😉
Joanna commented on :
Hey no worries 🙂 🙂