This summary is based on a video series, found on YouTube, depicting the findings of neurologist, Dr. V.S. Ramachandran. Ramachandran is noted for his use of experimental methods that rely relatively little on complex technologies such as neuroimaging. According to Ramachandran, “too much of the Victorian sense of adventure [in science] has been lost.”
In the case of Derek Steen, who is suffering from Phantom Limb Syndrome, Dr. Ramachandran evaluated the levels of feelings on both sides of the patient’s body by touching certain parts of the patient with a q-tip. When the Dr. stroked the q-tip across the left side of the patients face, the patient felt that same movement sensation on the missing right hand. Dr. Ramachandran theorizes that the left side of the body is mapped to the right side of the brain through a strip of cortex called the somatosensory cortex. When there is a missing limb, the part of the brain the corresponds to that limb no longer gets any input.
The Dr. has learned that sensory signals that, normally, only activate facial senses, are now invading the vacated territory that corresponds to the missing hand and activates the same sensations in the hand that are felt on the face. This research has shown that there has been a massive reorganization of sensory pathways in the brain, confirming neurogenesis.
Patient, Graham Young, suffers from a paradoxical condition called Blind Sight. He is totally blind, but, he is able to sense movement with both eyes in his left field of vision and not his right. Dr. Ramachandran has determined that vision is not necessarily seeing and that blind sight is our ability to detect things, but not to be aware of them. He has discovered that there are two separate vision pathways- a newer pathway that goes to the visual cortex and an older pathway that is connected to the brain stem. Each pathway observes different aspects of vision.
The visual cortex is for consciously see something and the pathway connected to the brain stem is relative to reflexive behavior. DR. Ramachandran says that the reason Graham doesn’t see anything, but can sense its presence due to damage in the visual cortex.
In a case similar to Graham Young, Peggy Palmer suffers from visual neglect caused by a stroke in the parietal lobes of the brain. Dr. Ramachandran explains that parietal lobes create a three dimensional layout of the world around us, which allows us to navigate our direction. The patient can see, but only on one side or the other, i.e. she only sees half of what is really there.
During an experiment where the patient was asked to draw a picture of a daisy from memory, she was only able to draw the right half of the daisy. Until, it was brought to her attention, she had no idea that she was only drawing half of the picture. This gives us evidence that there is not only a sensory problem, but a problem of consciousness. With 30 areas in the brain for seeing, visual input divides into two parallel streams of processing. One called the How pathway, is concerned with navigation and the other called the “What” pathway is concerned with recognition.
David Silvera has damage to the “What” pathway and has been diagnosed with Capgras Syndrome. The patient does not recognize familiar people and places. He contends that his parents are not who they say they are and does not recognize his own home. The patient sometimes refers to himself as he was not David. He does recognize his parent’s voices over the phone.
Dr. Ramachandran believes that the cause of this condition lies in the temporal lobes. The amygdala generates visual emotion and if it isn’t getting a message from the temporal lobe when you look at an object, you can’t respond to it emotionally. Therefore you deny what you are seeing. Dr. Ramachandran has determined that a person’s intellectual view of the world is closely linked to emotional reactions to the world and that Capgras Syndrome can heal itself over time. This is further evidence of neurogenesis.
John Sharon suffers from violent seizures caused by Temporal Lobe Epilepsy. These seizures have triggered religious and extreme emotional feelings of connection to the world. Patient often gets philosophical and claims he has great, unexplainable feelings for objects as small as a grain of sand after each seizure.
Dr. Ramachandran believes it is possible that the seizure activity creates wild emotions that can be interpreted as a sense of God’s presence and that it has something to do with the temporal lobe wiring which helps to deal with the world emotionally. Basically, it helps you determine how trivial something is and how important something is.
The doctor feels that parts of the temporal lobe are conducive to religious belief and that this condition opens up subjects of God and religion to be studied by scientists. He theorizes that repeated seizures are causing a strengthening of the pathways so that everything, no matter how small, has extreme significance to the patient.
Ref.: Phantoms in the Brain: Probing the Mysteries of the Human Mind, coauthor Sandra Blakeslee, 1998, ISBN 0-688-17217-2 Ref.: https://www.youtube.com/results?search_query=ramachandran+phantom+limb