FMR1 and fragile X syndrome: A recent two-photon calcium imaging study of somatosensory cortex in head-fixed behaving Fmr1 KO mice reported that increased avoidance to tactile stimulation, analogous to the FXS symptom known as tactile defensiveness, was associated with a reduced fraction of cells responding to the stimuli in young mice and with impaired neuronal adaptation to repetitive tactile stimulation in young and adult mice (He et al., 2017).