structural:scholar_edition, information:extraction
M1 and primary motor cortex

The term "M1" and the term "primary motor cortex" are often used interchangeably. However, they come from different historical traditions and refer to different divisions of cortex. Some scientists suggested that the motor cortex could be divided into a primary motor strip that was more posterior and a lateral premotor strip that was more anterior. Early researchers who originally proposed this view included Campbell, Vogt and Vogt, Foerster, and Fulton. Others suggested that the motor cortex could not be divided in that manner. Instead, in this second view, the so-called primary motor and lateral premotor strips together composed a single cortical area termed M1. A second motor area on the medial wall of the hemisphere was termed M2 or the supplementary motor area. Proponents of this view included Penfield and Woolsey. Today the distinction between the primary motor cortex and the lateral premotor cortex is generally accepted. However, the term M1 is sometimes mistakenly used to refer to the primary motor cortex. Strictly speaking M1 refers to the single map that, according to some previous researchers, encompassed both the primary motor and the lateral premotor cortex.