It is now well documented that ageing is associated with brain shrinkage, particularly in late adulthood [1,2]. From age 60 onwards, the average adult brain atrophies ≈ 0.5%/yr for the whole brain, ≈ 0.33%/yr for grey matter and ≈ 0.62–0.68%/yr for white matter [3–5]. This may seem small, but cumulatively adds up to substantial volume losses over decades: between the ages of 60 and 70, approximately 54 mL (5%) of total brain volume is lost, a substantial amount when coupled with cumulative atrophy across the lifespan.