Neural Mechanism of Mammalian Vocalization

Re: comment on Dr. White et al. presentation

Nicholas White

On Tue Dec 15, S.M. Brudzynski wrote
>Dr. White,
>I ejoyed reading your and your co-authors presentation which is organizing and reviewing the subject in a very informative way. It is important to realize that, among other behavioural manifestations, rodent vocalization has also a regulatory influence on the production of calls themselves by their conspecifics. This behavioural regulatory mechanism is nicely reviewed in your presentation.
>I would like to ask you about calls with acoustic parameters of 100 ms or more and sound frequency of approx. 35 kHz, emitted by rats in the pre-ejaculatory situation. Based on your behavioural experiments, do you regard these calls as a separate category, different from 50 kHz and 22 kHz calls, or as a low end of the 50 kHz call range?

At present, I cannot make a definitive answer to your question.

Some evidence suggests that the calls are distinct.  The longer duration 35kHz calls are distinct structurally from the shorter 50 kHz calls.  There is no overlap in spectral frequency, and minimal overlap in duration.  Furthermore, the 35 kHz calls generally occur prior to ejaculation, whereas the 50 kHz calls occur ubiquitiously throughout the ejaculatory series.

On the other hand, the 50 kHz and 35 kHz calls occur together in bursts, prior to ejaculation.  In addition, playback of tape recorded calls of either frequency will increase the likelihood of lordosis in females paired with devocalized males.  The 35 kHz calls, however, are more effective.

Resolution of this question awaits further research.

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