The CX3C chemokine axis consists of fractalkine (CX3CL1) and its receptor (CX3CR1); these are expressed by neurons and microglia respectively, and are known to modulate microglial activation. Neuronal Cx3cr1 may impact Alzheimer's disease-like pathology by modulating conformational state-dependent amyloid-beta-induced synaptotoxicity. Microglial cells participate in brain development and influence neuronal loss and synaptic maturation. Fractalkine is an important neuronal chemokine whose expression increases during development and that can influence microglia function via the fractalkine receptor, CX3CR1. Mice lacking Cx3cr1 show a variety of neuronal defects thought to be the result of deficient microglia function. Knockout of the microglial chemokine receptor Cx3cr1 to prevent neuron loss.