IRS1 and Insulin resistance: Interestingly, the evaluation of the insulin signalling pathway performed on the same samples in a subsequent study [94] revealed that increased IRS1 inhibition (a marker of insulin resistance) and mTOR hyper-activation can be observed in both aMCI and AD post-mortem hippocampal samples, previously shown to be characterized by BVR-A impairment [117,118] (Table 2).