Cytoarchitecture of Mudskipper (Boleophthalmus pectinirostris) Brain

Mudskippers are intertidal burrowing fish with unique living habits. So far, studies on the cytoarchitecture of the brain in fish with such behaviors remain limited. Therefore, documenting the neuroanatomy of this animal is of interest because of its unique characteristics. In this study, we examined the cytoarchitecture of mudskipper (Boleophthalmus pectinirostris) brain and investigated whether it has any peculiarities in its brain structures. In general, the basic composition, morphology, and organization of mudskipper brain do not vary markedly from those of other teleosts. The main differences appear in the telencephalon and diencephalon. In addition to Nissl staining, immunostainings for catecholaminergic and cholinergic systems were performed to help identify certain nuclei. The results showed that the number of subdivisions of the central division of pallium, lateral division of pallium, and medial division of pallium were different with other teleost species. In addition, some diencephalic nuclei, including the nucleus subglomerulosus, lateral thalamic nucleus, and intermediate superficial pretectal nucleus, were absent, which suggests the corresponding functions, such as visual or gustatory function, are less developed or specialized in B. pectinirostris. These results will provide a fundamental neuroanatomical basis for future studies on neuroendocrine regulation of behavior in intertidal burrowing fish.