Dreamer Easy

Lots of stuff about cross-wiring between adjacent bits of brain. Ramachandran touches the cheek of an amputee, who says, "Oh my God, you're touching my left thumb". The brain has a map of the body, but there are some quirks - for example, the map of the hand is right next door to the map of the face. In the absence of input, the hand part has started to make connections with its neighbour. Synaesthesia is a similar example of cross-wiring, but one that you're born with. The part of the brain that processes numbers is right next door to the part that processes colours.

Also, a very cool thing where amputees gain control over phantom hands by using the reflection of the other hand to fool the brain - "seeing" the missing hand move causes the brain to "feel" the movement, and allows the patient to relieve the sensation of a painful cramp by telling the absent hand to relax.

The most extraordinary thing, I think, is realising how dependent we are on this lump of porridge in our skulls for the simplest, most obvious, most intuitive things. Ramachandran tried a similar experiment to the amputee one, showing a patient with "hemispheric neglect" the reflection of a pen on her left in a mirror on her right.

"Of course, any normal person would turn to their left for the pen, but my patient began clawing the surface of the mirror, even reaching behind it... because left doesn't exist in her universe the only possible explanation, however improbable, is that the object is inside the mirror. Remarkably, all her abstract knowledge about the laws of optics and mirrors is distorted accomodate this strange new senory world in which the patient finds herself trapped."

The brain is capable of all sorts of rationalisations like this, denying basic facts like paralysis, blindness, not being dead, etc. Ramachandran suggests an explanation for the creepy observation that your brain starts moving your finger before you decide to move it... it's simply that, to keep everything coordinated, your brain delays your conscious knowledge of the decision. Wrap your head around that one!

(More later. I'll put the stuff about colour vision in door_of_time.)

Reading the fascinating A Brief Tour of Human Consciousness by V.S. Ramachandran, with its accounts of strange neurological conditions, and finding various SFnal connections.

( SPOILERS for Torchwood 2.4 Adam )

In Ringworld, one of Larry Niven's cowardly aliens, the Puppeteers, explains why his species have no sense of humour: "Humor is associated with an interrupted defense mechanism... no sapient being ever interrupts a defense mechanism." Until now, I had no idea what this meant, but Ramachandran argues for exactly this theory when describing a patient who responded to pain with uncontrollable laughter. It can't just be the a-ha effect, he points out, or every great scientific discovery "would be greeted with hilarity". Instead, "laughter is nature's way of signalling 'that it's a false alarm'": someone slipping on a banana peel is funny if they're not actually hurt. (This would explain my outbursts of hysterical relieved laughter during Countrycide and also the Voyager episode The Thaw). Ramachandran suggests his patient's brain also had a cut connection: "one part of the brain signals a potential danger but the very next instant another part... does not receive a confirmatory signal, thereby leading to the conclusion 'it's a false alarm'". For Puppeteers, I guess, there are no false alarms.

(Lots of stuff on synaesthesia, which I'll scribble about in door_of_time.)