The positronic cortex unit was an unit in Soong-type androids. This unit was the "head" of the androids. The unit was one of the main sections of the androids, along with the locomotion subsystem, the spatial orientation servo, the primary system module, and the substrate interface. In 2365, when Commander William T. Riker was reviewing the technical specifications for Lieutenant Commander Data, this unit was mentioned in the specs. (TNG: "The Measure Of A Man" )