My simplified picture of what’s going on is something like this (if I’m understanding the paper correctly). Stimulus A starts out represented by the vector (1,1

My simplified picture of what’s going on is something like this (if I’m understanding the paper correctly). Stimulus A starts out represented by the vector (1,1,1,1) and B by (-1,-1,-1,-1). Those are the sensory representations. Later A is represented by (1,1,-1,-1) and B by (-1,-1,1,1). Those are the memory representations. The last two component/neurons have “switched” their selectivity and rotated the encoding. The directions (1,1,1,1) and (1,1,-1,-1) are orthogonal, so you can store sensory info (A vs B in the present) along one and memory info (A vs B in the past) aling the other.