Processing of Paired Biosonar Signals in the Cortices of Rhinolophus Rouxi and Pteronotus P. Parnellii: A Comparative Neurophysiological and Neuroanatomical Study
The old world horseshoe bat, Rhinolophus rouxi, and the new world mustached bat, Pteronotus p. parnellii, belong phylogenetically to different bat families. On the other hand they share similar types of echolocation calls, both using long constant frequency (CF) pulses terminated by a downward frequency sweep (FM). The behavioural strategies of the two species also show striking resemblences in that they both are compensating for frequency shifts introduced into the echo by the Doppler effect when flying, and they are known to hunt for prey preferably in acoustically dense and cluttered surroundings. Suga, O’Neill and coworkers have studied in detail the auditory cortex of Pteronotus and especially the processing of paired biosonar signals in this area (for review: Suga, this volume). They found at least three cortical fields in which neurons could only be stimulated if the two stimuli satisfied distinct spectral and temporal conditions (CF/CF-, FM/FM-fields and the dorsal fringe area). These specialized cortical fields lie dorsal and dorsoanterior to the tonotopically organized primary auditory cortex. Paired stimuli have not been used previously in the auditory cortex of Rhinolophus and therefore no equivalent information is available in this species.
KeywordsAuditory Cortex Stimulus Pair Cortical Surface Constant Frequency Primary Auditory Cortex
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