What does MC stand for?

Eating right helps keep the muscles and organs healthy and strong, and it follows that eating nutritiously also keeps the brain healthy and the memory clear.

Roger further explains the reason for his extreme emotional shutdown: Because I worked on newspapers since I was very young I could never remember anything once I had written it down; as each day you wiped your memory clear with writing as you might wipe a blackboard clear with a sponge or a wet rag; and I still had that evil habit and now it had caught up with me.

That has the same effect as re-formatting a disc on a computer which wipes the memory clear.