Brain–machine interface reveals the origin of a widely used neural signal

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. A type of brain signal called high gamma is found to result from neuronal inputs, not outputs.