Transformation of external-ear spectral cues into perceived delays by the big brown bat, <i>Eptesicus fuscus</i>

Simmons, James A.; Wotton, Janine M.; Ferragamo, Michael J.; Moss, Cynthia F.

doi:10.1121/1.1466869

Cited by 6 publications

(2 citation statements)

References 66 publications

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“…Phyllostomus discolor, a bat species in the same family (Phyllostomidae) as most nectar-feeding bats, shows directionspecific spectral IIDs of up to 42·dB (Firzlaff and Schuller, 2003). Behavioural experiments with an insectivorous bat confirmed ambiguities introduced by direction-specific spectral notches (Simmons et al, 2002). In order to extract objectspecific information, those spectral features that are part of the directional filtering would need to be identified and actively disregarded.…”

Section: Extraction Of Object-specific Information From Echoes By Batsmentioning

confidence: 99%

`Binaural echo disparity' as a potential indicator of object orientation and cue for object recognition in echolocating nectar-feeding bats

Holderied

Helversen

2006

Journal of Experimental Biology

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Echolocating bats emit ultrasonic calls through their mouth or their nostrils and receive echoes from objects with both their ears. Information conveyed in the echoes is the basis for their three-dimensional acoustic perception of the surroundings. The direction of an object is encoded in binaural echo differences, i.e. on the one hand in the different arrival times of its echo at the two ears, and on the other hand in spectral differences through directiondependent frequency filtering of head and pinnae. Insufficient attention has been paid, however, to the fact that three-dimensional objects produce structured spatial echo fields, and that the position of the ear in this field determines the echo it receives. We were interested to determine whether the two ears, in addition to directionspecific echo differences, receive object-specific echo disparities that might be useful for the bat. Our measurements with an artificial bat head, which consisted of two microphones and a small ultrasound loudspeaker arranged to resemble a bat's ears and mouth, revealed that echoes at the two ears differed largely depending on the shape and orientation of the echo-giving object. Binaural echo disparities of a bat-pollinated flower did indeed carry information about the orientation and, to a lesser extent, the shape of the flower. During flower approach such object-specific binaural echo disparities even exceed the binaural differences encoding direction of echo incidence, because the echo from the flower in front undergoes the same directional filtering by the two symmetrical ears. Nectar-feeding bats could use these object-specific binaural echo disparities not only to determine the object's orientation relative to the approaching bat, facilitating flight planning, but also to improve object recognition through spatial reconstruction of details of the object creating the echo. Our results suggest that the evaluation of binaural echo disparity has a greater importance for these tasks than has previously been assumed.

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Section: Extraction Of Object-specific Information From Echoes By Batsmentioning

confidence: 99%

`Binaural echo disparity' as a potential indicator of object orientation and cue for object recognition in echolocating nectar-feeding bats

Holderied

Helversen

2006

Journal of Experimental Biology

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“…where only the first spike is taken into account, and compare this to the model where all spikes are considered. Finally, as an example, we will reconstruct the full cochleagram, and inspect if notches along the frequency axis, a common acoustic feature shown to be important for echolocation (Simmons et al 2002;Mogdans and Schnitzler 1990), survive neural encoding.…”

Section: Introductionmentioning

confidence: 99%

On population encoding and decoding of auditory information for bat echolocation

Reijniers

Peremans

2010

Biol Cybern

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In this article, we study the neural encoding of acoustic information for FM-bats (such as Eptesicus fuscus) in simulation. In echolocation research, the frequency-time sound representation as expressed by the spectrogram is often considered as input. The rationale behind this is that a similar representation is present in the cochlea, i.e. the receptor potential of the inner hair cells (IHC) along the length of the cochlea, and hence similar acoustic information is relayed to the brain. In this article, we study to what extent the latter assumption is true. The receptor potential is converted into neural activity of the synapting auditory nerve cells (ANC), and information might be lost in this conversion process. Especially for FM-bats, this information transmission is not trivial: in contrast to other mammals, they detect short transient signals, and consequently neural activity can only be integrated over very limited time intervals. To quantify the amount of information transmitted we design a neural network-based algorithm to reconstruct the IHC receptor potentials from the spiking activity of the synapting auditory neurons. Both the receptor potential and the resulting neural activity are simulated using Meddis' peripheral model. Comparing the reconstruction to the IHC receptor potential, we quantify the information transmission of the bat hearing system and investigate how this depends on the intensity of the incoming signal, the distribution of auditory neurons, and previous masking stimulation (adaptation). In addition, we show how this approach allows to inspect which spectral features survive neural encoding and hence can be relevant for echolocation.

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Piezo-polymer based sonar for mobile robots

Fiorillo

Lamonaca

Pullano

2009

2009 IEEE International Workshop on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications

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Transformation of external-ear spectral cues into perceived delays by the big brown bat, Eptesicus fuscus

Cited by 6 publications

References 66 publications

`Binaural echo disparity' as a potential indicator of object orientation and cue for object recognition in echolocating nectar-feeding bats

`Binaural echo disparity' as a potential indicator of object orientation and cue for object recognition in echolocating nectar-feeding bats

On population encoding and decoding of auditory information for bat echolocation

Piezo-polymer based sonar for mobile robots

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