Readers weigh in on deer-vehicle collisions, mouse sperm in space and more

Cover of July 3, 2021 & July 17, 2021 issue

Neuroscience mysteries

A three-dimensional look at 50,000 brain cells taken from a woman with epilepsy uncovered some pairs with an astonishingly large number of connections, Laura Sanders reported in “An intricate brain map reveals quirks” (SN: 7/3/21 & 7/17/21, p.