Interestingly, CB1R-CB2R heteromers were also upregulated in the hippocampus of a transgenic model of Alzheimer’s disease; it has been suggested that microglia in these animals display a neuroprotective phenotype that could explain why cognitive deficits do not appear until late in the life of the transgenic Alzheimer’s disease model [58]. This evidence concerns the gene CNR1 and Cognitive impairment.