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. 2013 Feb 19;110(10):4063–4068. doi: 10.1073/pnas.1211533110

Fig. 1.

Fig. 1.

Behavioral setup and design of stimulus presentation. (A) Audiogram of horseshoe bats (modified from ref. 26) and its relationship with the frequency ranges covered by BFN (D). (B) Behavioral setup. A microphone was placed 15 cm in front of a stationary horseshoe bat. Acoustic stimuli were presented via two speakers (one for BFN, one for call echo), both placed 10 cm next to the bat's left ear. (C) Spectrograms of horseshoe bat echolocation calls showing the characteristic CF and FM components. A brief frequency component (FM) at the beginning (initial FM) and end (terminal FM) surround a long (>40 ms) constant frequency (CF) component, typically between 65 and 80 kHz in greater horseshoe bats. (D) Frequency ranges covered by BFN (horizontal bold lines; conditions 1–6). RF, resting frequency; RF/2, fundamental resting frequency. Condition 1: BFN extended 20 kHz above RF +500 Hz; condition 2: BFN centered on RF; condition 3: BFN extends 20 kHz below RF −500 Hz; condition 4: BFN centered 20 kHz below RF; condition 5: BFN centered on RF/2; condition 6: BFN presented between 10 and 30 kHz.