Specific connections between nerve cells.
D000663:Amphibians; D000818:Animals; D001341:Autonomic Nervous System / Q000502:physiology; D001369:Axons / Q000502:physiology; D002415:Cats; D005399:Fishes; D009046:Motor Neurons / Q000502:physiology; D009416:Nerve Regeneration; D009434:Neural Pathways; D009474:Neurons / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology; D012160:Retina / Q000502:physiology; D012165:Retinal Ganglion Cells / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology; D013477:Superior Colliculi / Q000502:physiology / Q000601:surgery; D013569:Synapses / Q000502:physiology