part of start stage end stage inferior raphe nucleus zebrafish_anatomy TAO:0000366 posterior raphe nucleus ZFA:0000366 Hindbrain nucleus that provides descending innervation to the brainstem and spinal cord. Early in development the inferior raphe nucleus emits rostrally and caudally directed projections. However, in the adult, the long projections inferior raphe nucleus are restricted to posterior. raphe nucleus hindbrain nucleus unknown adult