After reviewing the studies above, we must point out that in animal experiments32–39, the subjects were given exogenous T3 or T4 within hours of the induction of brain ischemia to explore the influence of thyroid hormone variation during the acute ischemic period, but in other studies40–43 hypothyroidism/hyperthyroidism was induced weeks before the establishment of the ischemic model, which thus involved the previous cumulative effect on the nervous system of abnormal thyroid function. The gene discussed is TG; the disease is brain ischemia.