In those cases, the spread between the bid & ask goes to the market maker as compensation for making a market in a stock. For a liquid stock that is easy for the market maker to turn around and buy/sell to somebody else, the spread is small (narrow).
In cerebral hypoxia, sometimes only the oxygen supply is interrupted. Brain cells are extremely sensitive to a lack of oxygen. Some brain cells start dying less than 5 minutes after their oxygen supply disappears. As a result, brain hypoxia can rapidly cause severe brain damage or death.
Lyme, Babesia, Bartonella, or other infections that lived in the brain always hurt the brain: After eradication it will take an average, more or less, of 13 months or less to heal the brain and regaining lost assets. When we have an injured brain it is similar to Traumatic brain injury.