TY  - JOUR
A1  - Hechavarria, Julio C.
A1  - Macias, Silvio
A1  - Vater, Marianne
A1  - Voss, Cornelia
A1  - Mora, Emanuel C.
A1  - Kossl, Manfred
T1  - Blurry topography for precise target-distance computations in the auditory cortex of echolocating bats
JF  - Nature Communications
N2  - Echolocating bats use the time from biosonar pulse emission to the arrival of echo (defined as echo delay) to calculate the space depth of targets. In the dorsal auditory cortex of several species, neurons that encode increasing echo delays are organized rostrocaudally in a topographic arrangement defined as chronotopy. Precise chronotopy could be important for precise target-distance computations. Here we show that in the cortex of three echolocating bat species (Pteronotus quadridens, Pteronotus parnellii and Carollia perspicillata), chronotopy is not precise but blurry. In all three species, neurons throughout the chronotopic map are driven by short echo delays that indicate the presence of close targets and the robustness of map organization depends on the parameter of the receptive field used to characterize neuronal tuning. The timing of cortical responses (latency and duration) provides a binding code that could be important for assembling acoustic scenes using echo delay information from objects with different space depths.
Y1  - 2013
U6  - https://doi.org/10.1038/ncomms3587
SN  - 2041-1723
VL  - 4
IS  - 10
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Mora, Emanuel C.
A1  - Macias, S.
A1  - Vater, Marianne
A1  - Coro, Frank
A1  - Kossl, Manfred
T1  - Specializations for aerial hawking in the echolocation system of Molossus molossus (Molossidae, Chiroptera)
N2  - While searching for prey, Molossus molossus broadcasts narrow-band calls of 11.42 ms organized in pairs of pulses that alternate in frequency. The first signal of the pair is at 34.5 kHz, the second at 39.6 kHz. Pairs of calls with changing frequencies were only emitted when the interpulse intervals were below 200 ms. Maximum duty cycles during search phase are close to 20%. Frequency alternation of search calls is interpreted as a mechanism for increasing duty cycle and thus the temporal continuity of scanning, as well as increasing the detection range. A neurophysiological correlate for the processing of search calls was found in the inferior colliculus. 64% of neurons respond to frequencies in the 30- to 40-kHz range and only in this frequency range were closed tuning curves found for levels below 40 dB SPL. In addition, 15% of the neurons have double-tuned frequency-threshold curves with best thresholds at 34 and 39 kHz. Differing from observations in other bats, approach calls of M. molossus are longer and of higher frequencies than search calls. Close to the roost, the call frequency is increased to 45.049.8 kHz and, in addition, extremely broadband signals are emitted. This demonstrates high plasticity of call design
Y1  - 2004
SN  - 0340-7594
ER  -