Are the mechanisms for stream segregation shared among anurans and other tetrapods?

Many male anurans (frogs and toads) call in large aggregations. Since the fundamental task of anuran auditory communication prob-
ably is to attract and localize potential mates, segregation of the callers is likely an important task for the auditory system. Behavioral
experiments have shown that elements of stream segregation, based on frequency separation and spatial separation, can be demonstrated
in anurans. The neural processing of these cues is interesting, because most auditory processing probably takes place in the midbrain
torus semicircularis (TS, homolog to the inferior colliculus). It has been shown that spatial release from masking is sharpened by 6 dB in
the TS, and that neurons in the TS are selective for call rates and number of call pulses. However, recently electrical stimulation of tha-
lamic structures have demonstrated possible attentional modulation of TS responses that could also function in stream segregation. The
modulation was call-specific and could also enhance binaural cues. In conclusion, many of the elements involved in auditory segregation
in other animals are also found in anurans. However, it is uncertain whether the underlying mechanisms are similar. One crucial element
in primate sound segregation—the representation of the competing streams in the neural responses—has so far not been demonstrated in
anurans, and the most robust elements of stream segregation is really based on frequency processing, a relatively simple and ubiquitous
property of most auditory systems.