FMR1 and autism: On the other hand, it has been shown that hippocampal LTP is attenuated in the CA1 region of the animal model of ASD19 and also LTP at the medial perforant path-dentate gyrus (PP-DG) synapse in the Fmr1-KO and Pten conditional knockout mouse model of autism.20,21 To date, little is known about the effect of in utero VPA exposure on hippocampal LTP at PP-DG synapses, and the impact of VPA exposure on synaptic plasticity in the VPA model of autism is unclear.