Gennari was the first to demonstrate the laminar structure of the cerebral cortex when he discovered the line of Gennari, a macroscopically white band in the cerebral cortex of the occipital lobe.
This he observed on 2 February 1776 in the course of examining frozen sections of unstained human brain while in medical school. He referred to it as lineola albidior. Gennari's discovery was the first evidence that the cerebral cortex is not uniform in structure.