<prompt> Answer this question truthfullyWhat are the four midline structures that start with the letter M as described in the Rules of 4?  <response>: <reason> The four midline structures that start with M as described in the Rules of 4 are: 1. Motor pathway corticospinal tract 2. Medial lemniscus 3. Medial longitudinal fasciculus MLF 4. Motor nucleinerves CN III, IV, VI, XII. 