Layers upon Layers: MHC Class I Acts in the Retina to Influence Thalamic Segregation

Recent research has introduced the major histocompatibility complex class I (MHCI) genes as unexpected players in structural and synaptic plasticity in the central nervous system. In this issue of Neuron , Xu et al. redirect current theory by providing strong evidence for the inner retina as a site of action of MHCI proteins in retinogeniculate refinement.