FMR1 and fragile X syndrome: Furthermore, previous studies have detected sensory abnormalities in the Fragile X messenger ribonucleoprotein 1 (Fmr1) knock-out (KO) mice (Wang et al., 2016; He et al., 2017) and FXS patients (Juczewski et al., 2016), who have more robust and more frequent responses and reduced habituation to sensory stimulations, including olfactory, auditory, visual, tactile, and vestibular stimuli, as measured by electrodermal responses (Miller et al., 1999; Kazdoba et al., 2014; Kozono et al., 2020).