In Secrets of the Mind we gain insights through various tragedies that have affected others, thanks to the logic and insights of Professor Ramachandran regarding what he calls the most complex organized matter in the universe.
The documentary begins with "phantom limb syndrome" - pain and sensation in missing body areas. Ramachandran's reasoning, confirmed through a CAT-scan, is that the brain has a map of various body areas, and that eg. the right arm and right face areas of the brain are adjacent. Thus, missing body areas can lead to interference by those associated brain areas trying to cope with stimulus deprivation - eg. "cross-wiring."
However, we are still left with the problem of treating pain in a body-part that no longer exists. Dr. Ramachandran found that placing the remaining opposite body part (eg. hand) into a mirror-box fools the mind into receiving feedback from the missing part and no longer sending ever-increasing (and unmet) signals that cause the pain.
Visual activities take up almost half the human brain. Dr. Ramachandran is confronted with an individual who can "see" (detect) movement but not recognize what the object is. His explanation is that there are two pathways from the eye in humans: one to the visual cortex that recognizes the object, and other to the brain stem that simply senses movement. Thus, when the visual cortex link is severed, one would only be able to recognize movement of a fly, but not the fly itself - perhaps the way a lizard views the world. Similarly, he says to driving - most of the time it is done without consciousness while the conscious brain is taken up in talking of other thinking.
Dr. Ramachandran believes that there are some 30 areas in the brain concerned with seeing - separate areas for color, movement, shape, distance and depth perception, etc. Interference/damage to any one of these areas can lead to oddities - eg. an individual believing his parents are impostors when the emotional response area is cut.
Finally, viewers are told that some people with temporal seizures have intense religious or emotional experiences, possibly believing they are a prophet or even God, or sensing an intense emotional reaction to everything - even a grain of sand.