QUOTE : Imagine having an active mind trapped inside a body that is entirely paralyzed except for the ability to move your eyes sideways and blink your eyelids. A few people are living in this nightmare, called Locked-In Syndrome. A mere millimeter makes the difference between ending up in a coma (unconscious) or in Locked-In Syndrome (conscious). Both are caused by trauma to the brain stem (located at the base of the neck and involved in regulating basic body functions). If the trauma is to the front of the brain stem, the motor pathways are destroyed but patients are alert. Since the nerves for blinking and eye movement are at the back of the brain stem, they can still move their eyes. This tragic condition has given us an intriguing clue about the connection between acetylcholine and the enjoyment introverts gain from introspection. Although it seems as if people with Locked-In Syndrome should feel claustrophobic and terrified, researchers were shocked to find they don’t. Although sad about their situation, these patients report a sense of tranquility and lack of terror about their loss of physical freedom. In these patients acetylcholine is blocked to the muscles but not to brain pathways, so their capacity to feel good about living in their internal world (the enjoyment from thinking and feeling) remains intact.