Dysfunctional neural dynamics associated with sensory phenotypes in Fragile X syndrome: insights from mouse models

Fragile X Syndrome (FXS), the leading known inherited cause of atypical behaviors associated with autism spectrum disorders (ASD), arises due to the reduced expression or absence of the Fragile X Messenger Ribonucleoprotein 1 (FMRP). Individuals with ASD and FXS often experience atypical sensory processing across modalities such as touch, hearing, and/or vision. The consequences of altered sensory processing can be debilitating, leading to impairments in sensory discrimination and an inability to filter out irrelevant sensory stimuli such as innocuous sounds, smells, sights, or touches. Currently, there is a significant knowledge gap in the field of FXS regarding the circuit mechanisms that drive atypical sensory processing and how these contribute to hypersensitivity and secondary effects, such as learning impairments and increased anxiety. Animal models of FXS mirror many of the sensory hypersensitivity issues observed in humans, exhibiting heightened anxiety, as well as learning and social impairments. Here, we discuss the dysfunctional neural dynamics underlying atypical sensory processing across modalities in FXS, potential therapeutic interventions targeting specific ion channels, receptors, and circuits, and propose future research directions that could pave the way for circuit-targeted therapies.