relation of substantive/verb to declarative/procedural memory
While it's true that universal nouns will link mostly to other universal nouns (a tree is a plant), and universal verbs will link mostly to other universal verbs (to climb is to move), it is not necessary that they be in separate memory areas from each other; or even that they be separate from event memory (one cat did climb one tree).  The most efficient memory scheme would minimize the length of all links.  One way would be to store all new memories in a fairly linear structure, and then use an off-line process (sleep) to spread them around to minimize total link lengths {or to optimize lengths around importance of fast access}.