Scientists believe that the brain identifies relevant patterns from incoming information, stores it and uses it to make predictions, such as recognizing a familiar face if it sees only part of the image. This study describes differences between the brain networks of a mouse and a macaque brain. The study demonstrates that, for both, the the exponential distance rule (EDR) holds. The exponential decay of connection strengthens with distance in the brain. This understanding will eventually inform treatment of Alzheimer’s and schizophrenia.