From Pluralpedia, the collaborative plurality dictionary
memoryspace (n.)
Applies toheadspaces, system functions
CoinerThe Whitespace

Memoryspace is an innerworld, layer or place in headspace that is a recreation of a memory. The memory can be of any emotion or meaning and from any time. They are often hard to access and have more difficulty communicating with the rest of the system. Memoryspaces often have alters or subsystems that split with them, however that is not always the case.