Figure 1: Synthesis and functions of cholesterol in the CNS. Cholesterol in the CNS has four major functions. 1) It is required for brain growth and myelination of axons in the developing brain and for continued axon growth and synapse remodeling in the mature brain. 2) It participates in the construction of special parts of neuron membranes called lipid rafts. 3) It serves as precursor for the synthesis of neurosteroids. 4) It is involved in synapses, having a role in the release of neurotransmitters.