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Through echolocation, a bat can perceive not only the position of an object in the dark; it can also recognize its 3D structure. A tree, however, is a very complex object; it has thousands of reflective surfaces that result in a chaotic acoustic image of the tree. Technically, the acoustic image of an object is its impulse response (IR), i.e., the sum of(More)
  • L Wiegrebe
  • 2001
Multichannel, auditory models have been repeatedly used to explain many aspects of human pitch perception. Among the most successful ones are models where pitch is estimated based on an analysis of periodicity in the simulated auditory-nerve firing. This periodicity analysis is typically implemented as a running autocorrelation, i.e., the autocorrelation is(More)
The precedence effect describes the phenomenon whereby echoes are spatially fused to the location of an initial sound by selectively suppressing the directional information of lagging sounds (echo suppression). Echo suppression is a prerequisite for faithful sound localization in natural environments but can break down depending on the behavioral context.(More)
Many blind people rely on echoes from self-produced sounds to assess their environment. It has been shown that human subjects can use echolocation for directional localization and orientation in a room, but echo-acoustic distance perception--e.g. to determine one's position in a room--has received little scientific attention, and systematic studies on the(More)
The mammalian auditory system is the temporally most precise sensory modality: To localize low-frequency sounds in space, the binaural system can resolve time differences between the ears with microsecond precision. In contrast, the binaural system appears sluggish in tracking changing interaural time differences as they arise from a low-frequency sound(More)
Using echolocation, bats can not only locate objects in space but also discriminate objects of different shape. The acoustic image of an object is its impulse response (IR). The current experiments investigate whether bats just perceive changes in echo composition or whether bats perceive the IR itself through a detailed comparison of the emitted sound with(More)
1. We have examined the temporal discharge patterns of single units from the ventral cochlear nucleus (VCN) of anaesthetized guinea-pigs in response to iterated rippled noise (IRN). The pitch range evoked by the stimuli was from 32 to 1000 Hz. 2. Single units were classified into four groups using existing classification schemes: primary-like (PL), onset(More)
Echolocating bats can identify three-dimensional objects exclusively through the analysis of acoustic echoes of their ultrasonic emissions. However, objects of the same structure can differ in size, and the auditory system must achieve a size-invariant, normalized object representation for reliable object recognition. This study describes both the(More)
The ability of blind humans to navigate complex environments through echolocation has received rapidly increasing scientific interest. However, technical limitations have precluded a formal quantification of the interplay between echolocation and self-motion. Here, we use a novel virtual echo-acoustic space technique to formally quantify the influence of(More)