Neural coding of echo-envelope disparities in echolocating bats

Borina, Frank; Firzlaff, Uwe; Wiegrebe, Lutz

doi:10.1007/s00359-010-0571-z

Cited by 8 publications

(7 citation statements)

References 33 publications

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“…Width-dependent correlation changes are shown in Figure 10B. Such binaural echo-envelope features are reliably encoded in the IC of P. discolor (Borina et al, 2011).…”

Section: Discussionmentioning

confidence: 83%

The Sonar Aperture and Its Neural Representation in Bats

Heinrich

Warmbold²,

Hoffmann

et al. 2011

J. Neurosci.

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As opposed to visual imaging, biosonar imaging of spatial object properties represents a challenge for the auditory system because its sensory epithelium is not arranged along space axes. For echolocating bats, object width is encoded by the amplitude of its echo (echo intensity) but also by the naturally covarying spread of angles of incidence from which the echoes impinge on the bat's ears (sonar aperture). It is unclear whether bats use the echo intensity and/or the sonar aperture to estimate an object's width. We addressed this question in a combined psychophysical and electrophysiological approach. In three virtual-object playback experiments, bats of the species Phyllostomus discolor had to discriminate simple reflections of their own echolocation calls differing in echo intensity, sonar aperture, or both. Discrimination performance for objects with physically correct covariation of sonar aperture and echo intensity ("object width") did not differ from discrimination performances when only the sonar aperture was varied. Thus, the bats were able to detect changes in object width in the absence of intensity cues. The psychophysical results are reflected in the responses of a population of units in the auditory midbrain and cortex that responded strongest to echoes from objects with a specific sonar aperture, regardless of variations in echo intensity. Neurometric functions obtained from cortical units encoding the sonar aperture are sufficient to explain the behavioral performance of the bats. These current data show that the sonar aperture is a behaviorally relevant and reliably encoded cue for object size in bat sonar.

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“…Width-dependent correlation changes are shown in Figure 10B. Such binaural echo-envelope features are reliably encoded in the IC of P. discolor (Borina et al, 2011).…”

Section: Discussionmentioning

confidence: 83%

The Sonar Aperture and Its Neural Representation in Bats

Heinrich

Warmbold²,

Hoffmann

et al. 2011

J. Neurosci.

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“…This profile-oriented stereotaxic procedure was described in detail in Schuller et al ( 1986 ) and is recommended as standard adjustment procedure. It has been successfully used in Phyllostomus discolor in many studies involving forebrain and midbrain structures (Borina et al 2008 , 2011 ; Bartenstein et al 2014 ; Fenzl and Schuller 2002 , 2005 ; Firzlaff and Schuller 2007 ; Firzlaff et al 2006 , 2007 ; Greiter and Firzlaff 2017a , b ; Genzel et al 2015 ; Heinrich et al 2011 ; Hörpel and Firzlaff 2019 ; Hoffmann et al 2008a , b , 2010 , 2013 , 2015 , 2016 , 2019 ). These studies used a lab-internal series of Nissl stained sections that were relocatable to the present atlas series and fitted to the skull profile used here.…”

Section: Methods and Resultsmentioning

confidence: 99%

Cyto- and myeloarchitectural brain atlas of the pale spear-nosed bat (Phyllostomus discolor) in CT Aided Stereotaxic Coordinates

et al. 2020

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The pale spear-nosed bat Phyllostomus discolor, a microchiropteran bat, is well established as an animal model for research on the auditory system, echolocation and social communication of species-specific vocalizations. We have created a brain atlas of Phyllostomus discolor that provides high-quality histological material for identification of brain structures in reliable stereotaxic coordinates to strengthen neurobiological studies of this key species. The new atlas combines high-resolution images of frontal sections alternately stained for cell bodies (Nissl) and myelinated fibers (Gallyas) at 49 rostrocaudal levels, at intervals of 350 µm. To facilitate comparisons with other species, brain structures were named according to the widely accepted Paxinos nomenclature and previous neuroanatomical studies of other bat species. Outlines of auditory cortical fields, as defined in earlier studies, were mapped onto atlas sections and onto the brain surface, together with the architectonic subdivisions of the neocortex. X-ray computerized tomography (CT) of the bat’s head was used to establish the relationship between coordinates of brain structures and the skull. We used profile lines and the occipital crest as skull landmarks to line up skull and brain in standard atlas coordinates. An easily reproducible protocol allows sectioning of experimental brains in the standard frontal plane of the atlas. An electronic version of the atlas plates and supplementary material is available from 10.12751/g-node.8bbcxy

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“…Both Yamada et al [48] and Eliakim et al [49] presented robot-based models in which obstacle location is used as input to an obstacle avoidance algorithm. Both studies estimated the azimuth location of obstacles using interaural time differences, a cue that might not be available to bats to localize individual reflectors [50,51].…”

Section: Avoidance Of Non-localized Obstaclesmentioning

confidence: 99%

“…Given the small size of the bat's head and time-intensity trading occurring in the neural responses to received echoes, it has been argued that the most robust source of angular information available to bats is the interaural level difference [51]. On the other hand, when confronted with complex echo signals, bats possess neural populations that code for interaural time differences of the envelopes of these complex echoes [50]. The acoustic attention scheme proposed by Simmons et al [55] describes how time and intensity cues can be consistently combined, whereby level differences amplify, through time-intensity trading, the physically occurring time differences.…”

Section: The Delayed Linear Adaptive Law (Dlal) Strategy and Fixed Hementioning

confidence: 99%

Avoidance of non-localizable obstacles in echolocating bats: A robotic model

et al. 2019

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Most objects and vegetation making up the habitats of echolocating bats return a multitude of overlapping echoes. Recent evidence suggests that the limited temporal and spatial resolution of bio-sonar prevents bats from separately perceiving the objects giving rise to these overlapping echoes. Therefore, bats often operate under conditions where their ability to localize obstacles is severely limited. Nevertheless, bats excel at avoiding complex obstacles. In this paper, we present a robotic model of bat obstacle avoidance using interaural level differences and distance to the nearest obstacle as the minimal set of cues. In contrast to previous robotic models of bats, the current robot does not attempt to localize obstacles. We evaluate two obstacle avoidance strategies. First, the Fixed Head Strategy keeps the acoustic gaze direction aligned with the direction of flight. Second, the Delayed Linear Adaptive Law (DLAL) Strategy uses acoustic gaze scanning, as observed in hunting bats. Acoustic gaze scanning has been suggested to aid the bat in hunting for prey. Here, we evaluate its adaptive value for obstacle avoidance when obstacles can not be localized. The robot's obstacle avoidance performance is assessed in two environments mimicking (highly cluttered) experimental setups commonly used in behavioral experiments: a rectangular arena containing multiple complex cylindrical reflecting surfaces and a corridor lined with complex reflecting surfaces. The results indicate that distance to the nearest object and interaural level differences allows steering the robot clear of obstacles in environments that return non-localizable echoes. Furthermore, we found that using acoustic gaze scanning reduced performance, suggesting that gaze scanning might not be beneficial under conditions where the animal has limited access to angular information, which is in line with behavioral evidence.

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Neural coding of echo-envelope disparities in echolocating bats

Cited by 8 publications

References 33 publications

The Sonar Aperture and Its Neural Representation in Bats

The Sonar Aperture and Its Neural Representation in Bats

Cyto- and myeloarchitectural brain atlas of the pale spear-nosed bat (Phyllostomus discolor) in CT Aided Stereotaxic Coordinates

Avoidance of non-localizable obstacles in echolocating bats: A robotic model

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