“The wonders of the brain require no exaggeration. Between our ears live an estimated 85 billion neurons—as many brain cells as there are stars in the Milky Way galaxy. Each of those neurons has thousands of thread-like connections, called synapses, linked to other neurons in the brain—more than a hundred trillion connections. That’s ten times more than the estimated number of galaxies in the entire universe. The brain’s complexity is unparalleled and vast.”