FIML not only accesses individual word maps but also the maps of all communicative signs.
Here is the brain model of semantic maps.
And here is the study: Natural speech reveals the semantic maps that tile human cerebral cortex.
Here is a brief article about the study: Scans Show ‘Brain Dictionary’ Groups Words By Meaning. From this article:
Gallant says the findings contradict two beliefs nonscientists commonly have about the brain. First, that only the left hemisphere handles language. Second, that the brain has localized regions that handle specific tasks.
Edit: When you frequently access your word maps with the help of your FIML partner, both of you will become much more conscious of how these maps are structured and how they function during acts of communication.
This allows partners to make conscious meta-decisions to change and improve these maps in any way they want.
The meaning held in semantic maps (or semiotic maps) is the very meaning of your life as you understand it.
Not only do your maps form the basis of your communication with others, they also form the basis of how you understand yourself. How you communicate with yourself.
Gaining access to these maps is extremely liberating because it allows a degree of control over your own mind that few of us ever experience.
When we say that FIML has no content, no required beliefs, this can be understood as meaning that FIML gives us access to our own maps and control over them.
What you do with this access is entirely up to you and your partner.