TSHR and Graves disease: Their increased stimulation by TSH receptor antibodies in Graves’ disease, leading to an excessive local production of T3 is also thought to contribute to psychiatric symptoms.19 It has been demonstrated that thyroid hormones increase Na+ current density in the hippocampal region in rat models, thus causing neuronal excitability that could explain neurologic symptoms.20 Using positron emission tomography, Schreckenberger et al21 demonstrated altered glucose metabolism in the limbic structures of the brains of patients with untreated Graves’ hyperthyroidism.