Title : Frequency analysis of electroencephalogram recorded from a bottlenose dolphin (Tursiops truncatus) during transportation by truck
Abstract:
The bottlenose dolphin (Tursiops truncatus) is a marine mammal positioned at the top of the food chain and lead social lives. These brain functions are controlled by the electrical activity of neurons in the cerebral cortex, and changes in this activity can be detected by an electroencephalogram (EEG) or electrocorticogram(ECoG).
In order to obtain information regarding the correlation between an electroencephalogram (EEG) and the state of a dolphin, we developed a noninvasive recording method of EEG of a bottlenose dolphin and an extraction method of true-EEG (EEG) from recorded-EEG (R-EEG) based on a human EEG recording method, and then carried out frequency analysis during transportation by truck. The frequency detected in the EEG of dolphin during apparent awakening was divided conveniently into three bands (5-15, 15-25, and 25-40 Hz) based on spectrum profiles. Analyses of the relationship between power ratio and movement of the dolphin revealed that the power ratio of dolphin in a situation when it was being quiet was evenly distributed among the three bands. These results suggested that the EEG of a dolphin could be detected accurately by this method, and that the frequency analysis of the detected EEG seemed to provide useful information for understanding the central nerve activity of these animals.
