FMR1 and autism: Although some ASD mouse models exhibit a reduced E/I ratio, such as mice with autism-associated mutations in NRXNs or SHANKs (Etherton et al., 2009; Jiang and Ehlers, 2013), an enhanced E/I ratio can also be observed in many other ASD mouse models, such as TSC1-, MDGA2-, FMRP-, or CUL3-deficient mice (Bateup et al., 2013; Zhang et al., 2014; Connor et al., 2016; Dong et al., 2020).