In this project we aimed to evaluate the contribution of endoplasmic reticulum stress sensor IRE1 and its downstream transcription factor XBP1s to mammalian brain aging. We compared traits associated to aging at behavioral, electrophysiological, morphological and proteomic levels. We used transgenic animals overexpressing XBP1s in brain tissue and also wild type animals injected with adeno-associated virus to overexpress XBP1s in the brain during aging.