Fragile X syndrome is due to the functional loss of fragile X mental retardation protein in the brain. Researchers are beginning to understand how FMRP regulates signaling pathways in the brain that are essential for learning and memory in adults. In a mouse model of fragile X syndrome, researchers found FMRP plays a key role in regulating adult neurogenesis, the process by which new neurons are generated in the adult brain. Adult neurogenesis is considered important for learning and memory.