During anesthesia, gases given off cause structural changes in the brain proteins. These disrupt our consciousness
by limiting the electrical activity of the brain. These brain protein molecules are very sensitive to changes. The energy of the water pockets in molecules are reduced. This disrupts the neuronal membrane dynamics and synaptic transmission. Drugs block brain secretions. Cocaine blocks norepinepherine ( in the locus coeruleus). LSD blocks serotonin (in the raphe nucleus). Nerve gas blocks acetylcholine. When the brain is deprived of oxygen for 6 minutes, brain cells are dead forever. Encephalitis viruses are small enough get everywhere in the brain and disturb the cell's DNA and even wipe out the cortex. The brain stem is smaller than the cortex and is in a smaller space. With swelling in this area caused by stroke, tumor or concussion, cortical neurons in the brain stem die.