DRD2 and Alzheimer disease: ,8,47 In our study with the TgF344-AD rat, a model of transgene-inducedamyloid accumulation and endogenous Tau pathology,22 we show that functional dysfunction in DA pathways appear earlyand that 5HT2AR-mediated control of DA/D2R function is also altered.Our study, using the translational SPECT imaging approach shows that the functional 5HT/DAconnectivity is altered in rats at an age before the onset of cognitive symptoms.24