Taste(s) and olfaction(s) in fish: a review of specialized sub-systems and central integration.

Evidence from comparative morphology and electrophysiology suggests that both, olfaction and taste in fish serve different ecological roles. The lateral olfactory system (dorsolateral olfactory bulb glomeruli and lateral olfactory tract) and the external taste buds are probably specialized for food search and amino acid discrimination. The medial olfactory system (basomedial olfactory bulb glomeruli and medial olfactory tract) and the solitary chemosensory taste cells, however, may have their roles in intra- and interspecific interactions (discriminating pheromones by olfaction, bile components by both olfaction and taste). Whereas stimulation of the taste systems alone triggers reflexes, complex, conditional or conditioned behaviours are only released when the olfactory system is intact. This points at the importance of telencephalic and diencephalic integration of olfactory and taste inputs. Consequently, caution is appropriate concerning simplistic interpretations of deprivation experiments.