Complex sentence: Interior sections of the motor area folding into the cerebral fissurecorrespond with the legs, but not all body parts are equally represented by cell density in the motor area in proportion to their size in the body.
Split into simpler sentences: Interior sections of the motor area folding into the cerebral fissure correspond with the legs. Not all body parts are equally represented by cell density in the motor area in proportion to their size in the body.