Scientists say fear and threat can block neural circuits for the control of action, leading to involuntary immobility. Understanding this brain process "can help improve the understanding" of the facts in these crimes and "the realities of the experience of the victims and their suffering" The researchers' hypothesis is that this chain of messages sent by different parts of the brain to react to danger is paralyzed in one of the links.
It is "the blocking of neural circuits that provide voluntary control over body movements"