Nature, Published online: 15 April 2026; doi:10.1038/d41586-026-01189-1
A type of activity in the brain’s cortex, called high gamma, is widely used in studies of brain function, but its origin has long been debated. An experiment using a brain–machine interface now shows that high-gamma activity is generated mainly by synchronized neuronal inputs, rather than outputs, which has implications for the interpretation of neuroscientific studies.