A mindtrap is constructed of crystal and wire. It is only possible to activate it in Shayol Ghul, using the blood and saliva of the channeler, due to the malleability of reality there. Using a cour'souvra, the victim's soul, or at least the essence of it, is trapped. The victim can feel it trapped in the cour'souvra and know when someone is touching it. The holder of the person's cour'souvra has complete control over that person. Should the cour'souvra be crushed, that person will become a mindless puppet, subject to the will of the holder.
Channeling in the presence of the cour'souvra in which you are trapped is very painful; the nearer, the greater the pain. It is not known if a mindtrap is a type of ter'angreal or not. Nevertheless it seems to be more aligned to the True Power than to the One Power.
It is also unknown if Moghedien's mindtrap is still functioning after the re-sealing of the Bore by Rand al'Thor. If so she will live a very peculiar life as a damane: her cour'souvra is likely to be sequestered by the sul'dam responsible for her training, and she will be obliged to explain to them its function, in case they break it without realising the consequences.