Backfilling of a control pallial nerve. The control pallial nerve, backfilled with neurobiotin, is visible in red. Fibres are seen to run straight in the pallial nerve and reach the stellate ganglion. These fibres take part in forming the neuropil of the ganglion. Some of them do not form synapsis in the ganglion but directly run through the stellar nerves to innervate the chromatophores or come from the periphery to reach the CNS. Other fibres stop in the ganglion, forming synapsis with the motoneurons, which then innervate respiratory muscles. In the ganglion it is also possible to observe the presence of cells, named centripetal cells, sending their axons toward the pallial nerve.