Altered maturation of the primary somatosensory cortex in a mouse model of fragile X syndrome.

Fragile X syndrome (FXS) is the most common inherited form of intellectual disability and results from the loss of the fragile X mental retardation protein (FMRP). Many fragile X-related cognitive and behavioral features emerge during childhood and are associated with abnormal synaptic and cellular organization of the cerebral cortex. Identifying the roles of FMRP in cortical development will provide a basis for understanding the pathogenesis of the syndrome.

Critical period plasticity is disrupted in the barrel cortex of FMR1 knockout mice.

Alterations in sensory processing constitute prominent symptoms of fragile X syndrome; however, little is known about how disrupted synaptic and circuit development in sensory cortex contributes to these deficits. To investigate how the loss of fragile X mental retardation protein (FMRP) impacts the development of cortical synapses, we examined excitatory thalamocortical synapses in somatosensory cortex during the perinatal critical period in Fmr1 knockout mice. FMRP ablation resulted in dysregulation of glutamatergic signaling maturation.