section_path: Morphology and physiology/Internal systems/Nervous
section_name: Nervous
paragraph_text: Nervous
  
  The nervous system of an insect consists of a brain and a ventral nerve cord. The head capsule is made up of six fused segments, each with either a pair of ganglia, or a cluster of nerve cells outside of the brain. The first three pairs of ganglia are fused into the brain, while the three following pairs are fused into a structure of three pairs of ganglia under the insect's esophagus, called the subesophageal ganglion. The thoracic segments have one ganglion on each side, connected into a pair per segment. This arrangement is also seen in the first eight segments of the abdomen. Many insects have fewer ganglia than this. Insects are capable of learning.