Mice with scopolamine-induced amnesia were treated with l-theanine (20 mg/kg, orally), and their cognitive decline was reversed through several mechanisms involving increased AMP-activated protein kinase, microtubule-associated protein 1 light chain 3-II (LC3-II) and beclin-1, and reduced phosphorylated protein kinase B (p-AKT) and mammalian target of rapamycin (p-mTOR) levels. The gene discussed is MTOR; the disease is Mental deterioration.