| Research Abstract |
For animals, like many fishes, the timing of both the sperm- and egg-release is essential for successful fertilization to occur. In the hime salmon (landlocked red salmon, Oncorhynchus nerka) this is achieved by exchanging signals specific for this purpose between the sexes.
In this study, we aimed at clarifying (1) what are the signals and their character which are exchanged between the sexes, (2) what are the sensory systems processing these signals, and (3) how the central nervous system processes these signals to elicit the spawning behavior.
The results using both the behavioral and electrophysiological methods showed that the hime salmon exchange between the sexes both the vibrational signals arising from the body vibration and visual signals to elicit the spawning behavior. The vibrational signals are processed through the lateral line system to integrate them with those from the visual signals. Furthermore, it was found that field potentials are evoked from the medial nucleus of the medulla (the first relay station of the vibrational information) which are synchronized with the vibrational stimuli.
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