Immunological contributions are increasingly associated with cognitive deficiencies that can occur during aging. In Science, Baruch et al. report that older mice exhibit altered expression profiles of genes encoding interferons in the choroid plexus, which acts as an interface between blood and the central nervous system, relative to that of younger mice. Aged mice have lower expression of genes responsive to interferon-γ but higher expression of genes dependent on type I interferons. This type I interferon signature is not altered in young-old parabiont mouse couplings. Similar expression profiles of genes encoding type I interferons are seen in postmortem sections of human brains. Notably, these differences in interferon response are accompanied by changes in choroid plexus function to regulate leukocyte trafficking and influence brain plasticity, as revealed in cognitive memory tests. What underlies the higher expression of type I interferons in the choroid plexus remains to be determined.

Science (21 August 2014) 10.1126/science.1252945