Discrimination of phase spectra in complex sounds by the bullfrog (Rana catesbeiana)

Abstract

1. Male bullfrogs at two different natural calling sites were presented with playbacks of synthetic advertisement calls differing in phase spectra. Sounds were presented in a ABA design to analyze the ability of the animals to perceive changes in repeated series of stimuli. 2. The number of individual croaks in an answering call significantly increased over repeated presentations of two of the three stimulus phase types in condition A1. There were significantly fewer croaks to the third stimulus. These data suggest that two stimuli were perceived in a similar manner. 3. Latency of calling to stimuli presented in conditions A and B changed in response to shifts in phase spectrum at a low density calling site. These differences were significant when comparing latency to playbacks where shifts in the phase spectrum changed the temporal fine-structure and waveform periodicity of the stimulus. 4. The increase in number of croaks and decrease in response latency across condition A1 and the increase in latency in condition B suggest that discrimination may take the form of stimulus-specific sensitization. In this context, sensitization might reflect an increase in arousal due to repeated presentation of a salient stimulus. 4. The operation of a hypothetical 'mating call detector', based on linear summation of temporal responses from the eighth nerve, provides output similar to the behavioral results.

Spectral preferences and the role of spatial coherence in simultaneous integration in gray treefrogs (Hyla chrysoscelis).

“…For example, the magnitude of arrival time disparities described earlier translate into phase differences between the two harmonics in an ongoing pulse of between 68 o and 159 o in the 60 o and 7.5 o conditions, respectively (based on using a period of 0.91 ms for the 1.1-kHz fundamental frequency). Although some frogs may be capable of discriminating between harmonic stimuli differing in phase spectrum (e.g., Hainfeld, Boatright-Horowitz, Boatright-Horowitz, & Simmons, 1996), it is currently unknown whether such phase differences would interfere with selective phonotaxis. It would be somewhat surprising, however, if variation in the relative phases of the two harmonics experienced during phonotaxis had large influences on determining the attractiveness of a male's advertisement call.…”

Patterns of Vocal Interactions in a Bullfrog (Rana catesbeiana) Chorus: Preferential Responding to Far Neighbors

“…This is consistent with data from other studies, showing the importance of call amplitude as a cue for spacing (Rosen & Lemon 1974; Whitney & Krebs 1975; Wilczynski & Brenowitz 1988). In addition, playback experiments with chorusing male bullfrogs reveal that calling behavior is influenced by both spectral and temporal features in the advertisement call (Hainfeld et al 1996; Simmons & Bean 2000). Simmons & Bean (2000) showed that the male bullfrog's ability to perceive the changed spectral composition of a synthetic advertisement call is not significantly influenced by the call's amplitude, within a biologically realistic range of amplitudes.…”

Bats and frogs and animals in between: evidence for a common central timing mechanism to extract periodicity pitch

“…The fundamental frequency around 100 Hz is missing, but overall waveform periodicity of individual notes ranges from about 80 to 125 Hz for different individual males, and the envelopes of these notes can also contain superimposed, prominent AM around 10–20 Hz (Suggs and Simmons 2005). This waveform periodicity is important in mediating the calling behavior of male bullfrogs (Hainfeld et al 1996; Bee and Bowling 2002). …”