Adaptations of the auditory nervous system for echolocation

  title={Adaptations of the auditory nervous system for echolocation},
  author={Alan D. Grinnell and Susumu Hagiwara},
  journal={Zeitschrift f{\"u}r vergleichende Physiologie},
Summary1.Seven species of paleotropical echolocating bats were studied in an effort to correlate differences in emitted orientation pulses with differences in neural analysis mechanisms. Major emphasis was on species of the genus Hipposideros, which emit extremely high frequencies in pulses consisting of a constant frequency for several msec followed by a fast downward sweep in frequency.2.Evoked potentials and single unit responses were recorded from the posterior colliculi and more peripheral… 

Comparative auditory neurophysiology of the inferior colliculus of two molossid bats,molossus ater andmolossus molossus

Data are compared with results from “long CF-FM-bats”, revealing striking species differences in frequency selectivity of single neurons and organization of the ascending auditory pathway, suggesting different strategies in information processing which are discussed as adaptations to the species specific orientation calls.

Responses of inferior collicular neurones to acoustic stimuli in certain FM and CF-FM paleotropical bats

Summary1.Electrophysiological properties of auditory units of six species of paleotropical echolocating bats, including two FM bats and four CF-FM bats were studied by recording the responses to tone

Studies of auditory neurophysiology in non-echolocating bats, and adaptations for echolocation in one genus, Rousettus

It is concluded that non-echolocating bats, like other small mammals, lack several of the auditory adaptations considered to be adaptations for echolocation: sharp restriction of sensitivity to the region of emitted sounds, sensitivity at extremely high frequencies, fast temporal resolution, facilitation of responsiveness to the second of a pair of sounds, and sharply directional hearing in front of the bats.

Electrophysiological properties of auditory neurons in the superior olivary complex of echolocating bats

  • P. Jen
  • Biology
    Journal of comparative physiology
  • 2004
Electrophysiological properties of the neurons in the superior olivary complex of the bat, Myotis lucifugus, are studied and evidence for the existence of binaural neurons is presented and discussed.

Response characteristics of inferior colliculus neurons of the awake CF-FM batRhinolophus ferrumequinum

Inhibition is discussed in terms of improving the neuronal signal/spontaneous noise ratio and altering responsiveness of neurons after stimulation, so that these neurons may be suited to time processing in the acoustic pathway.

Comparative auditory neurophysiology of the inferior colliculus of two molossid bats,molossus ater andmolossus molossus

Response patterns of single neurons were found to depend on the frequency-time-course of the stimulus, especially with slowly sweeping FM-signals, neuronal response activity could be greater than to any other stimulus configuration employed.

Auditory fovea and Doppler shift compensation: adaptations for flutter detection in echolocating bats using CF-FM signals

The frequency range of the foveal areas with their flutter processing neurons overlaps exactly with the frequency range where DS compensating bats most likely receive echoes from fluttering insects, indicating that auditory fovea and DSC are adaptations for the detection and evaluation of insects flying in clutter.

Rebound excitation (Off-responses) following non-neural suppression in the cochleas of echolocating bats

  • A. Grinnell
  • Biology
    Journal of comparative physiology
  • 2004
Auditory nerve evoked potential responses (N1) occur at the termination of tone pips as well as the onset in several species of bats that emit orientation sounds having a constant frequency component of several msec duration, it is concluded that the suppression is unlikely to be mediated by chemical neural inhibition.



Comparative auditory neurophysiology of neotropical bats employing different echolocation signals

  • A. Grinnell
  • Biology
    Zeitschrift für vergleichende Physiologie
  • 2004
Five species of neotropical bats, which emit echolocation pulses different than those employed by bats previously studied, were investigated in an attempt to find corresponding differences in mechanisms of neural analysis, concluding that species differences in response patterns are at least in part a result of evolutionary adaptation governed by the type of emitted orientation sounds employed.

The neurophysiology of audition in bats: intensity and frequency parameters

This is the first of a series of papers describing initial efforts to find neural correlates for these auditory abilities in two species of the family Vespertilionidae: Myotis 1.

Neural responses in the inferior colliculus of echolocating bats to artificial orientation sounds and echoes

The responses of single units and evoked potentials to a pair of artificial sounds, mimicking the orientation sound and echo, and to tape recorded actual orientation sounds were studied in terms of recovery cycle, finding the reception of echoes is probably improved by contraction of middle ear muscles resulting in attenuation of self‐stimulation by the out‐going pulse.

The neurophysiology of audition in bats: resistance to interference

  • A. Grinnell
  • Environmental Science
    The Journal of physiology
  • 1963
The preceding papers have discussed the nature ofthe auditory responses in the bats Myotis 1. lucifugus and Plecotus townsendii and the effects on these responses of stimulus frequency, intensity,

The neurophysiology of audition in bats: temporal parameters

The electrophysiological data that exist for mammals, mostly cats, suggest a recovery time very similar to that ofhuman listeners, when comparable stimulus conditions are employed, conditions analogous to those facing an echolocating bat.

The neurophysiology of audition in bats: directional localization and binaural interaction

This is the third in a series of papers on the neurophysiological correlates of echolocation in the bats Myotis 1. lucifugus and Plecotus toumsendii. Previous papers (Grinnell, 1963a, b) have

Analysis of frequency‐modulated and complex sounds by single auditory neurones of bats

  • N. Suga
  • Biology, Physics
    The Journal of physiology
  • 1968
Single unit activity in the inferior colliculus of bats was studied in relation to the analysis of frequency‐modulated (FM) and complex sounds and collicular neurones were classified into five types, depending on characteristics of responses to tonal stimuli.

Functional properties of auditory neurones in the cortex of echo‐locating bats.

  • N. Suga
  • Biology
    The Journal of physiology
  • 1965
In echo-locating bats, the auditory system from the cochlear nucleus to the inferior colliculus is enormously hypertrophied compared to most other mammals, but this is not true of either the geniculate body or the auditory cortex.


These bats seem capable of some qualitative discrimination based on the “fine structure” of echoes from small moving targets, as evidenced by the overlap in intensity both in the peak amplitudes and in each of the ten 8 kc bands from 100–20 kc.

Orientation in Neotropical Bats. I. Natalidae and Emballonuridae

The orientation pulses of Natalus (Natalidae) have been recorded for the first time. These pulses are of a frequency modulated design with an initial frequency of about 85 kc and a terminal frequency