DRD2 and early-onset autosomal dominant Alzheimer disease: Thus, the pre-symptomatic dysfunction in5HT2AR−DA/D2R connectivity and D2R hyper-sensitivity inTgF344-AD rat make this Alzheimer’s disease model a choice for preclinical studies whose aimis to improve the early diagnosis of the pathology, but also to test the effectiveness ofearly therapy before the onset of irreversible disorders.