Barney/Doogie Howser jokes--How I met Your Mother

TV Arts

This week Barney offered a subtle Doogie Howser MD joke, "child actors
in the 1980s were much better".

I believe he occassionally made some in the past, too.  Would anyone
remember what they were?

(I always think its fun when an actor parodies a previous role).
Well, there's this:

I couldn't access that, could you explain?