Those engineered to overproduce a mutant form of the human amyloid precursor protein, for instance, have fewer than normal neurons in the hippocampus.

• 例如，被改造成会产生过量突变形式的类淀粉前驱蛋白（amyloidprecursorprotein）的小鼠，其海马神经元数目会比正常小鼠来得少。