This is consistent with the loss of spine density and impaired synaptic plasticity and cognition concurrently with reduced BDNF levels due to insulin resistance [70], while improved insulin signaling upregulates BDNF, increases Akt phosphorylation, enhances cognition, and halts neuroinflammation and oxidative stress in Alzheimer’s disease [71,72]. This evidence concerns the gene BDNF and early-onset autosomal dominant Alzheimer disease.