Here’s some more of the important data that was in this paper by Syken et al:

1. Arc induction: Arc is an immediate early gene that is induced by recent neuronal activity. Arc mRNA can be detected via in situ hybridization for a variety of purposes, one of which is to view the area of visual cortex that represents one eye. In PirB KO mice, ocular dominance plasticity is increased and it was shown that the width of the Arc induction was greater in KO compared to wt.

The current model is that PirB is an MHCI receptor that acts to limit the extent of synaptic plasticity, possibly balancing the effects of molecules (e.g. in the MAPK signaling pathway) that enhance plasticity. PirB acts as an MHCI receptor in the immune system to affect integrin-dependent cytoskeletal dynamics, and if it does the same thing in the immune system, it could fit into the story.