Cytoarchitecture of the Telencephalon in the Coral Reef Multiband Butterflyfish (<b><i>Chaetodon multicinctus</i></b>: Perciformes)

Abstract

Detailed neuroanatomical studies of model species are necessary to facilitate comparative experiments which test hypotheses relevant to brain evolution and function. Butterflyfishes (Chaetodontidae) boast numerous sympatric species that differ in social behavior, aggression and feeding ecology. However, the ability to test hypotheses relevant to brain function in this family is hindered by the lack of detailed neural descriptions. The cytoarchitecture of the telencephalon in the monogamous and territorial multiband butterflyfish, Chaetodon multicinctus, was determined with Nissl-stained serial sections and an immunohistochemical analysis of arginine vasotocin (AVT), serotonin, substance P and tyrosine hydroxylase. The ventral telencephalon was similar to that of other perciform fishes studied, with one major difference. A previously undescribed postcommissural region, the cuneate nucleus, was identified and putatively assigned to the ventral telencephalon. While the function of this nucleus is unknown, preliminary studies indicate that it may be part of a behaviorally relevant subpallial neural circuit that is modulated by AVT. The dorsal telencephalon consisted of 15 subdivisions among central, medial, lateral, dorsal and posterior zones. Several regions of the dorsal telencephalon of C. multicinctus differed from many other perciform fishes examined thus far. The nucleus taenia was in a more caudal position, and the central and lateral zones were enlarged. Within the lateral zone, an unusual third, ventral subdivision and a large-celled division were present. One hypothesis is that the enlarged ventral subdivision of the lateral zone (potential hippocampus homolog) relates to an enhancement of spatial learning or olfactory memory, which are important for this coral reef fish. This study provides the neuroanatomical basis for future comparative and evolutionary studies of brain organization and neuropeptide distributions, physiological studies of neural processing and insight into the complex social behavior of butterflyfishes.

Atlas of the telencephalon based on cytoarchitecture, neurochemical markers, and gene expressions in Rhinogobius flumineus [Mizuno, 1960]

“…The Dl of percomorph teleosts shows diverse numbers of regions recognized so far on the basis of cytoarchitecture. Only two subdivisions, dorsal and ventral, have been differentiated in the false kelpfish Sebasticus marmoratus (Murakami et al, ) and medaka Oryzias latipes (Ishikawa et al, ), four regions in the sea bass Dicentrarchus labrax (Cerdá‐Reverter, Zanuy, & Muñoz‐Cueto, ) and the cichlid Astatotilapia burtoni (Burmeister et al, ), six in the multiband butterflyfish Chaetodon multicinctus (Dewan & Tricas, ), and seven in the Japanese jack mackerel Trachurus japonicus (Ou & Yamamoto, ). The Dl of R. flumineus could be subdivided into seven regions as observed with Nissl‐stained materials, which is supported by the distributions of neurochemical markers and gene‐expression patterns (Table ).…”

“…Namely, the Dl6 is intensely positive, the Dl4 and Dl7 moderately positive, and the Dl5 negative (Figure ). In the multiband butterflyfish, a percomorph teleost like R. flumineus , rich substance‐P‐ir fibers are observed in the ventral region of the Dl, which exhibits a remarkable enlargement in this species (Dewan & Tricas, ). Thus, the presence of abundant substance‐P‐ir fibers in the Dl may be a shared character in percomorphs, in contrast to the situation of the Atlantic salmon Salmo salar , where substance‐P‐ir fibers are sparse in the dorsal telencephalon (Holmqvist & Ekström, ).…”

“…Following modification of the brightness and contrast as necessary by means of Adobe Photoshop (CC 2017; Adobe Systems Incorporated, San Jose, CA), the outline of sections and nuclear boundaries were sketched using Adobe Photoshop and a graphics tablet (CTH‐690; Wacom, Kazo, Japan). The nomenclature for the brain structure of R. flumineus followed previous studies of other fishes such as Yamamoto and Ito (, ), Giassi, Harvey‐Girard, Valsamis, and Maler (), Dewan and Tricas (), and Ou and Yamamoto (). Abbreviations of neuroanatomical terms are listed in Table .…”

The Cytoarchitecture of the Telencephalon of Betta Splendens Regan 1910 (Perciformes: Anabantoidei) with a Stereological Approach to the Supracommissural and Postcommissural Nuclei

“…The nomenclature for the B. splendens telencephalic structures was based on the original work of Nieuwenhuys (), modified by Northcutt and Bradford (1980), and the reports of Cerdá‐Reverter et al (), Burmeister et al (), Baile and Patle (), Dewan and Tricas (), and Ou and Yamamoto (). Components of the preoptic area (POA) were found as an anatomical continuum to the Tel.…”

Gene expression correlates of social evolution in coral reef butterflyfishes

“…one week). Brain regions, identified using a butterflyfish brain atlas 102,103 , were manually extracted at -30˚C using a hand-held micro-punching device (50mm diameter; Stoelting, model # 57401) (Fig. 2), incubated in RNAlater® at 4˚C over night, and then stored at -20˚C for up to one week.…”