THE EXISTENCE OF A LAYER-IV IN THE RAT MOTOR CORTEX

We have reconstructed the laminar pattern of rat primary motor cortex (Fr1) using a computerized analysis system based on the so-called 'opt ical dissector'. Data were visualized on a graphics terminal. In contr ast to current views, which state that there is no prominent layer IV in the motor cortex of the rat, our method of analysis revealed a genu ine layer IV consisting of densely packed small neurons.