Traditional lap pools are about 10 feet wide, though widths between 8 and 10 feet are common. (In competition pools, swim lanes are 2.5 meters wide, or about 8.2 feet.) You don't want to go too narrow with a lap pool.
The number of neurons in the brain varies dramatically from species to species. One estimate (published in 1988) puts the human brain at about 100 billion (10 11) neurons and 100 trillion (10 14) synapses.
There are over 400,094,800 cells in the human brain, while the entire body has about 50 to 75 trillion cells. There are around 200,000,000 brain cells in your brain. There are upward of 100 billion nerve cells in the human brain. 200,000,000,000 brain Cells.