Three dolphins participated in these experiments. MT is required for pressure increase and actuating the nasal apparatus to produce the correct sound. Move- ment time (MT) was measured from the onset of the nasal pressure rise until the onset of the animal’s response vocalization. NT is the time required for perception of the acoustic stimulus, deciding on the appropriate response and actuating muscles required for nasal pressure rise. NT was measured from the onset of an auditory stimulus until the onset of the nasal pressure rise.
Detection of the onset of nasal pressure increase allowed for determination of neural time (NT). , 1980 Amundin and Andersen, 1983 Ridgway and Carder, 1988). A nasal cavity pressure rise is required for sound generation (Ridgway et al. The study reported here required the animal to make a decision on an appropriate response and then to generate the correct whistle or pulse burst. However, during echolocation, voluntary cortical decision processes might operate to change pulse rates to concentrate on targets of different ranges. , 1985 Ghose and Moss, 2006 Surlykke et al. There is evidence for such rapid direct connections in echolocating bats (Jen, 1982 Masters et al. On the other hand, echolocation could be a subcortical, “hard-wired” phenomenon such that rapid direct connections exist between inferior col- liculus and sound producing structures. Startle responses are not usually voluntary, and such mechanism would not likely be employed for echolocation where decisions must be made about the character of a target-fish or fowl, predator or food. , 1982) which can produce a response in as little as 8 ms. For example, the dolphin brain might have appropriated circuitry such as that exists in rats for the acoustic startle response (Davis et al. Such a rapid operation could not be controlled on a pulse-by-pulse basis by cortical decision processes or even brainstem/midbrain processes unless the dolphin brain and sound producing apparatus had some rapid and direct links. , 1974, Kadane and Penner, 1983, Penner, 1988) suggested a brainstem/midbrain operation. On the other hand, the 20 ms echolocation click delay (Morozov, 1972 Au et al. The longer whistle response period (Caldwell and Caldwell, 1968) suggested a mechanism that depended on cognitive decision processes at the level of the cerebral cortex. If dolphin B, for example, did not respond to the whistle of dolphin A within a few hundred ms then chorusing did not begin. There was a particular timing pattern to the initiation of exchanges. The animals regularly whistled in rapid, often overlapping, whistle exchanges described as chorusing. truncatus at Marine land of the Pacific near Los Angeles (Caldwell and Caldwell, 1968). Whistle exchanges were studied among a group of T. Timing of dolphin whistles has also been considered in animal-to-animal communication. Thus, bottlenose dolphins appear to be able to time echolocation clicks so that succeeding clicks are produced about 20 ms over the round-trip travel time of the click from the animal to the target (Morozov, 1972 Au et al. Each following click in the train is not produced until about 20 ms after reception of the echo from the preceding click. Echolocating animals emit trains of clicks to detect a target. Speed of information processing in the brain is probably quite important in echolocation. Learn more about our packages or contact us to discuss your training requirements. Send us your training requirements today for a short-list of options. We work with providers to cover the complete range of organisational training requirements – take a look at our training subjects page for details of the popular subjects we source for our clients. We insist that you have direct contact with the trainers prior to making a final decision so you can be sure they are the best trainer for you. We take time to understand your organisation and recommend trainers who fit your culture. We have developed a large database of providers, including freelance trainers and subject matter experts, who we will use to help fulfil your in-house training requirements. If you struggle to find an external trainer or provider you trust to deliver consistent quality training then our service will help you. It has cost benefits too – a lower cost per head and no travel expenses. In-house training is an excellent way of providing focused learning to your employees.
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