Chromatophore motor fields in the squid, Lolliguncula brevis.

Chromatophore motoneurones in Lolliguncula brevis are known to originate in the suboesophageal lobes of the brain and to project directly to the mantle and fin through bilateral stellate ganglia and fin nerves. The chromatophore motor fields of stellar and fin nerves were investigated by stimulation of the cut end of individual nerves in a semi-intact preparation. This elicited expansion of yellow and brown chromatophores in distinct motor fields. Brown chromatophores extended over the entire mantle, whereas yellow chromatophores were limited to the dorsal and lateral mantle areas. Combined nerve stimulation and lesions demonstrated substantial overlap between adjacent chromatophore motor fields and innervation of individual chromatophores by different stellar nerves.