Neural axis representing target range in the auditory cortex of the mustache bat.

  title={Neural axis representing target range in the auditory cortex of the mustache bat.},
  author={Nobuo Suga and William E. O'Neill},
  volume={206 4416},
In echolocating bats, the primary cue for determining distance to a target is the interval between an emitted orientation sound and its echo. Whereas frequency is represented by place in the bat cochlea, no anatomical location represents of primary range. Target range is coded by the time interval between grouped discharges of primary auditory neurons in response to both the emitted sound and its echo. In the frequency-modulated-signal processing area of the auditory cortex of the mustache bat… 

Encoding of target range and its representation in the auditory cortex of the mustached bat

  • W. O'NeillN. Suga
  • Biology
    The Journal of neuroscience : the official journal of the Society for Neuroscience
  • 1982
The auditory cortex of the mustached bat is explored using pairs of acoustic stimuli mimicking the multiharmonic biosonar signals (pulses) used by this species and their echoes to explore a new type of cortical organization which is not tonotopic but which represents an important acoustic cue related to the time course of acoustic events.

Neural processing of target distance by echolocating bats: Functional roles of the auditory midbrain

Chronotopically organized target-distance map in the auditory cortex of the short-tailed fruit bat.

Cortical chronotopic cortical organization is not only used exclusively for precise insect localization in constant frequency bats but could also be of advantage for general orientation tasks.

Short delays and low pulse amplitudes produce widespread activation in the target-distance processing area of auditory cortex of the mustached bat.

The results show that a chronotopic activation of the cortex is evident only at loud pulse amplitudes, and the fact that cortical activity is more widespread in response to combinations of short echo-delays and faint pulse Amplitudes could represent an adaptation that enhances cortical activity in the late stages of echo-level compensation.

Spatially Selective Auditory Responses in the Superior Colliculus of the Echolocating Bat

Using single-unit neurophysiological methods and free-field auditory stimulation, data is presented on biologically relevant specializations in the superior colliculus of the bat for orientation by sonar, suggesting that this class of neurons represents the location of a target in three dimensions.

Combination-sensitive neurons in the primary auditory cortex of the mustached bat

The results show that AI neurons in the mustached bat are specialized to respond to complex, behaviorally relevant stimuli during the search and approach phases of insect pursuit.

Representation of three-dimensional space in the auditory cortex of the echolocating bat P. discolor

The results demonstrate that combination sensitive neurons in the AC responded selectively to specific positions in 3-D space, and revealed a topographic distribution of best elevation of the combinationsensitive neurons along the rostro-caudal axis i.e., neurons inthe rostral part of the target distance map representing short delays prefer elevations below the horizon.

The inferior colliculus of the mustached bat has the frequency-vs-latency coordinates

The aim of the present study is to explore whether the central nucleus of the inferior colliculus has a latency axis incorporated into iso-best frequency slabs, regardless of best frequency.



Target range-sensitive neurons in the auditory cortex of the mustache bat.

Range-tuned neurons are specialized for processing echoes only during a particular period of the search, approach, or terminal phases of echolocation, and they provide support for a theory of ranging in bats that incorporates groups of neurons with a spectrum of preferred echo delays to detect target distance.

Amplitude spectrum representation in the Doppler-shifted-CF processing area of the auditory cortex of the mustache bat.

The mustache bat, Pteronotus parnellii rubiginosus, emits orientation sounds containing a long constant-frequency (CF) component that is ideal for echo detection and Doppler shift measurement. About

Aural representation in the Doppler-shifted-CF processing area of the auditory cortex of the mustache bat.

Neurons tuned to weaker echoes integrate or even multiply faint signals from both ears for effective detection of a distant small target, while neurons tuned to moderate to intense echoes are suited for processing directional information and are stimulated when a bat approaches a target at short range.

Cortical neurons sensitive to combinations of information-bearing elements of biosonar signals in the mustache bat.

The properties of neurons in the major clusters of the auditory cortex of the mustache bat indicate that processing of information carried by the frequency-modulated components of echoes is facilitated by the first harmonic of the emitted biosonar signal.

Disproportionate tonotopic representation for processing CF-FM sonar signals in the mustache bat auditory cortex.

A disproportionately large part of the auditory cortex of this bat is occupied by neurons processing the predominant components in the orientation signal and Doppler-shifted echoes, comparable to that in the somatosensory and visual systems in many mammals, but it has not previously been observed in the auditory system.

Harmonic-sensitive neurons in the auditory cortex of the mustache bat.

How meaningful components of sound are assembled by neural circuits in the central nervous system is shown and a method by which sounds with important harmonics may be detected and recognized by the brain in other species, including humans is suggested.


  • J. Simmons
  • Biology
    Annals of the New York Academy of Sciences
  • 1971
It would appear that target ranging is a critically important aspect of echolocation, and the processing of range information may characterize major components of the bat’s sonar receiver.


1. The distance at which bats (Myotis lucifugus) react to the presence of a row of small wires has been measured by a photographic determination of the distance at which the pulse repetition rate

Information content of bat sonar echoes.