WE ARE OUR BRAINS - CHAPTER 7
THE BRAIN AND CONSCIOUSNESS
If something gets int he way of the brain's information supply, it starts to make up information to fill the gaps.
The same is true for all our memories.
Patients with a left-body paralysis due to a damage of their right-hemisphere are convinced that a doctor told them not to get up or move their paralysed hand or leg.
A coma is a situation where a patient doesn't awaken and doesn't respond to external stimuli. It results from damage to the cerebral cortex, the thalamus, or connection between them, or brain stem, which activates the cerebral cortex and thalamus.
A vegetative state is when only your brain stem functions, so breathing, heart rate, temperature, sleep-wake cycles are regulated, but you merely exist, like a vegetable.
Locked-in syndrome is the reverse of a coma. The brain and spinal chord are completely separated from damage low in the brain stem. The brain is otherwise intact and the patient fully alert. They cannot move or speak, just blink and move their eyes.
Brain death is defined by irreversibly fixed pupils, absence of brain stem reflexes and the permanent absence of higher brain functions: cognition and consciousness. They are kept alive even in indefinitely on ventilators.
Anosognia is unawareness that something is wrong with you. It is connected to reduced activity in the angular gyrus, where sensory information from the body and surroundings are combined. It is increasingly damaged as Alzheimer's progresses too.
Out of body experiences and near-death experiences are caused by malfunction in the angular gyrus because of lack of oxygen there.
Your body constantly manufactures the sense that your body belongs to you, using sensory information from muscles, joints, vision, sensation, self-consciousness, it isn't a metaphysical construct.
Phantom pain may be due to the brain getting signals back that it is impossible to move the amputated limb, ultimately forcing the phantom limb into an extremely painful, cramped position.
When the corpus callousum is damaged or severed, the two hemispheres of the brain cannot communicate, so consciousness is altered. The ability to speak and read, for example, are located in different hemispheres. So if someone would read instructions, to get up and leave, they'd do so. And if asked why, they'd say they wanted hot chocolate for example because the instruction has not been consciously registered.
Lack of input causes the brain to make up information. If almost deaf, it can constantly repeat a song, if in low light, it can see objects that aren't there, if half-paralysed, convince the person that they were told not to move, if drunk it can fake memories to fill in gaps.
Blindsight is knowing where something is, without consciously seeing it. it happens when because of damage, the visual information reaches the brain via an abnormal route.