Sleep-related disorders are another set of age-related co-morbidities; in chronic sleep restriction mouse model, up-regulation of hippocampal PIRB coincides with synaptic loss and cognitive impairments; knockdown of neuronal PIRB or blockade of downstream ROCK2 (Rho associated coiled-coil containing protein kinase 2) with fasudil alleviates synaptic dysfunction and cognitive impairments [118]. Here, ROCK2 is linked to age.