Figure 1. The same chirp stimulus gives rise to heterogeneous waveforms depending on time of occurrence within the beat cycle.
(A) Two weakly electric fish with their electric organ discharges (EODs) in red and blue. (B) The EOD waveforms of both fish (top red and blue traces) show alternating regions of constructive and destructive interference when the instantaneous EOD frequencies do not vary in time (middle red and blue traces). Interference between the EODs leads to a sinusoidal amplitude modulation (i.e. a beat, bottom black trace) of the summed signal (bottom brown trace). (C) Schematic showing communication between the emitter (red) and receiver (blue) fish. (D) During a communication call, the emitter fish’s EOD frequency (top red trace) transiently increased by maximum of Δf for a duration Δt (top green trace), while the receiver fish’s EOD frequency (top blue trace) remains constant. The communication call results in a phase reset of the beat (bottom black trace). (E) Ongoing unperturbed beat (top) and stimulus waveforms (bold black traces within gray bands) resulting when a chirp with the same frequency increase Δf and duration Δt occurs at different phases during the beat cycle. We note that these waveforms are very similar to those recorded from actual fish (Aumentado-Armstrong et al., 2015).
Figure 1—figure supplement 1. EOD amplitude modulations resulting from chirps display large heterogeneities.
