“…Cerebral blood flow (CBF) changes early in experimental models of dementia, leading to neuronal dysfunction, and loss independently of amyloid-b-dependent contributions (Iadecola, 2004;Zlokovic, 2011;Kisler et al, 2017;Sweeney et al, 2018Sweeney et al, , 2019. In healthy ageing, previous reports have linked the effects of age on baseline CBF to behavioural performance measured outside of the scanner (Bangen et al, 2014;Hays et al, 2017;Leeuwis et al, 2018). However, brain perfusion measurements are highly dependent on other physiological factors such as autoregulation modulators (Lemkuil et al, 2013), medication, time of day, levels of wakefulness (Patricia et al, 2014), physical exercise, caffeine or smoking before the scan (Domino et al, 2004;Addicott et al, 2009;Merola et al, 2017).…”