Nerve cells and synapses. Computer artwork of a group of nerve cells in the brain or spinal cord. These interneurones each have a star-shaped body with a nucleus near their center (dark). Each cell has branching structures called axons and dendrites. The axons have a thick, segmented, insulating sheath of myelin. The axons and dendrites carry information as electrical impulses to the terminal boutons (such as at upper left) at their ends. The gap (synapse) between the bouton & another cell's dendrite is bridged by chemicals (neurotransmitters blue circles) which stimulate that cell. The interneurones form a complex interconnecting electrical circuit.