The cytoplasm that surrounds the nucleus of a neuron is called the perikaryon or cell body. It is the metabolic center of the neuron and contains all of the organelles necessary for the cell's survival, including the nucleus, mitochondria, endoplasmic reticulum, and Golgi apparatus. The perikaryon also contains neurotransmitter vesicles, which store the chemical messengers that neurons use to communicate with each other.