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1.
R. Rübsamen M. Schäfer 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1990,167(6):771-784
Summary Horseshoe bats (Rhinolophus rouxi) were deafened in their 3rd–5th postnatal week. Subsequently their vocalisations were monitored to evaluate the impact of audition on the development of echolocation pulses. Hearing impairment affected the echolocation pulses as follows: the frequency of the constant frequency (CF) component was altered by between + 4 kHz and – 14 kHz, and the dominance of the second harmonic of the pulses was neutralised by a relative increase in intensity of the first and third harmonics.A second experiment focused on possible influences of acoustical self-stimulation with echolocation pulses on the establishment of auditory fovea representation in the inferior colliculus (IC). Frequency control of echolocation pulses was disrupted by larynx denervation. Thereafter, the bats produced multiharmonic echolocation signals (4–11 harmonics) varying in frequency. IC tonotopy, however, as monitored by stereotaxic electrophysiology, showed the same developmental dynamics as seen in control specimens (Fig. 10).Both experiments indicate that throughout postnatal development echolocation pulses are under auditory feedback control, whereas maturation of the auditory fovea and shifts in its frequency tuning represent an innate process. The significance of this postnatal development might be the adjustment of the vocal motor system of each bat to the frequency of its personal auditory fovea.Abbreviations
CF
constant frequency
-
CF1, CF2, CF3
harmonics of pure tone components of the echolocation pulses
-
FM
frequency modulation
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IC
inferior colliculus of the midbrain 相似文献
2.
R. Rübsamen M. Schäfer 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1990,167(6):757-769
Summary This report describes the ontogenesis of tonotopy in the inferior colliculus (IC) of the rufous horseshoe bat (Rhinolophus rouxi). Horseshoe bats are deaf at birth, but consistent tonotopy with a low-to-high frequency gradient from dorsolateral to ventromedial develops from the 2nd up to the 5th week. The representation of the auditory fovea is established in ventro-mediocaudal parts of the IC during the 3rd postnatal week (Fig. 3). Then, a narrow frequency band 5 kHz in width, comprising 16% of the bat's auditory range, captures 50–60 vol% of the IC (Fig. 3c). However, foveal tuning is 10–12 kHz (1/3 octave) lower than in adults; foveal tuning in females (65–68 kHz) is 2–3 kHz higher than in males (62–65 kHz). Thereafter, foveal tuning increases by 1–1.5 kHz per day up to the 5th postnatal week, when the adult hearing range is established (Figs. 4, 5). The increase of sensitivity and of tuning sharpness of single units also follows a low-to-high frequency gradient (Fig. 6).Throughout this development the foveal tuning matches the second harmonic of the echolocation pulses vocalised by these young bats. The results confirm the hypothesis of developmental shifts in the frequency-place code for the foveal high frequency representation in the IC.Abbreviations
BF
best frequency
-
CF
constant frequency
-
FM
frequency modulation
-
IC
inferior colliculus
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IHC
inner hair cell;
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OHC
outer hair cell
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RR
Rhinolophus rouxi 相似文献
3.
R. Rübsamen G. Neuweiler K. Sripathi 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1988,163(2):271-285
Summary The tonotopic organization of the inferior colliculus (IC) in two echolocating bats,Hipposideros speoris andMegaderma lyra, was studied by multiunit recordings.InHipposideros speoris frequencies below the range of the echolocation signals (i.e. below 120 kHz) are compressed into a dorsolateral cap about 400–600 m thick. Within this region, neuronal sheets of about 4–5 m thickness represent a 1 kHz-band.In contrast, the frequencies of the echolocation signals (120–140 kHz) are overrepresented and occupy the central and ventral parts of the IC (Fig. 3). In this region, neuronal sheets of about 80 m thickness represent a 1 kHz-band. The largest 1 kHz-slabs (400–600 m) represent frequencies of the pure tone components of the echolocation signals (130–140 kHz).The frequency of the pure tone echolocation component is specific for any given individual and always part of the overrepresented frequency range but did not necessarily coincide with the BF of the thickest isofrequency slab. Thus hipposiderid bats have an auditory fovea (Fig. 10).In the IC ofMegaderma lyra the complete range of audible frequencies, from a few kHz to 110 kHz, is represented in fairly equal proportions (Fig. 7). On the average, a neuronal sheet of 30 m thickness is dedicated to a 1 kHz-band, however, frequencies below 20 kHz, i.e. below the range of the echolocation signals, are overrepresented.Audiograms based on thresholds determined from multiunit recordings demonstrate the specific sensitivities of the two bat species. InHipposideros speoris the audiogram shows two sensitivity peaks, one in the nonecholocating frequency range (10–60 kHz) and one within the auditory fovea for echolocation (130–140 kHz).Megaderma lyra has extreme sensitivity between 15–20 kHz, with thresholds as low as –24 dB SPL, and a second sensitivity peak at 50 kHz (Fig. 8).InMegaderma lyra, as in common laboratory mammals, Q10dB-values of single units do not exceed 30, whereas inHipposideros speoris units with BFs within the auditory fovea reach Q10dB-values of up to 130.InMegaderma lyra, many single units and multiunit clusters with BFs below 30 kHz show upper thresholds of 40–50 dB SPL and respond most vigorously to sound intensities below 30 dB SPL (Fig. 9). Many of these units respond preferentially or exclusively to noise. These features are interpreted as adaptations to detection of prey-generated noises.The two different tonotopic arrangements (compare Figs. 3 and 7) in the ICs of the two species are correlated with their different foraging behaviours. It is suggested that pure tone echolocation and auditory foveae are primarily adaptations to echo clutter rejection for species foraging on the wing close to vegetation.Abbreviations
BF
Best frequency
-
CF
constant frequency
-
FM
frequency modulated
-
IC
inferior colliculus
-
HS
Hipposideros speoris 相似文献
4.
Catherine Poussin Peter Schlegel 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1984,154(2):253-261
Summary Electrophysiological recordings were made from 130 single neurons of the superior colliculus (SC) of big brown bats,Eptesicus fuscus, in order to test their general as well as directional auditory response properties. Bursts of constant frequency and frequency modulated signals were broadcasted through a condenser loudspeaker, which could be placed at any azimuth and elevation on a hemisphere in front of the bat's head. The SC units responded equally well to both types of signals. The best frequencies of SC neurons ranged from 25 up to 82 kHz, and their tuning curves appeared to be broad (compared to those of the main auditory nuclei of the same and other bats) with Q10dB values of 1.8–17.5. All units encountered revealed directional sensitivity and were classified in two groups: the majority of them had a constant best angle of response (BA) whatever the sound intensity was (unidirectional type); the others showed a shift in their BA towards the center of the stimulating hemisphere as the intensity decreased (pluridirectional type). In both response types, the BA results are corroborated by the properties of the receptive fields. The presence of an auditory space map in the horizontal plane is not obvious for the superior colliculus of this bat.Abbreviations
BA
best angle
-
BF
best frequency
-
CF
constant frequency
-
FM
frequency modulated
-
FTC
frequency threshold curve
-
IC
inferior colliculus
-
MLD
nucleus mesencephalicus dorsalis
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MT
minimum threshold
-
RF
receptive field
-
RP
reference point
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SC
superior colliculus
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SPL
sound pressure level re. 20 Pa·cm–2 相似文献
5.
Rudolf Rübsamen 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1992,170(2):129-143
Summary In the early postnatal period of many mammals and in the perihatching period of chicks the auditory ranges are restricted to the species-specific low- and mid-frequency ranges. During subsequent development, the high frequency hearing expands (depending on the species) by 1–4 octaves. Adult-like audition is established between the 4th and the 7th week. It is still discussed controversially, how the extension of the auditory ranges relates to the maturation of orderly frequency representation in the cochleae of the respective species. The present review summarizes investigations of the development of tonotopy in nuclei of the central auditory system, and discusses how the centrally acquired data might contribute to the understanding of the maturation of cochlear stimulus transduction and to the development of frequency maps.Abbreviations
ANF
auditory nerve fibers
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BF
best frequency
-
CN
cochlear nucleus
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DAB
days after birth
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DCN
dorsal cochlear nucleus
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IC
inferior colliculus
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IHC
inner hair cells
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HS
Hipposideros speoris
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LSO
lateral superior olive
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MGB
medial geniculate body (auditory thalamus)
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NL
Nucleus laminaris
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NM
Nucleus magnocellularis
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OHC
outer hair cells
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RR
Rhinolophus rouxi
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SOC
superior olivary complex
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2-DG
2-deoxyglucose 相似文献
6.
Andre N. Temchin 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1988,163(1):99-115
Summary Extracellular recording from single auditory nerve fibers in the pigeon,Columba livia, revealed some unusual discharge patterns of spontaneous and evoked activity.Time interval histograms (TIHs) of spontaneous activity showed a random interval distribution in 73% of the auditory fibers (Fig. 1a). The remaining 27% revealed periodicity in the TIHs (Fig. 1b–e), determined by the characteristic frequency (CF) of a given fiber. Normally, those fibers had a CF<2.2 kHz. In both cases spontaneous activity was irregular.The time pattern of quasiperiodic spontaneous firing in different auditory fibers is described by three main types of autocorrelation histograms (ACHs; decaying, nondecaying, and modulated), reflecting the spontaneous oscillations of the hair cell membrane potential (Fig. 1b–d).Single-tone suppression in auditory fibers with quasi-periodic spontaneous activity was found (Figs. 2, 10) and it could be observed if the eighth nerve was cut. There was no suppressive effect in fibres with random spontaneous firing.The frequency selectivity properties of auditory fibers were studied by means of an automatic method. Both simple (Fig. 4) and complex (Figs. 7, 8) response maps were found. Apart from the usual excitatory area, complex response maps were characterized by suppressive areas lying either above (Fig. 7), below (Fig. 8e), or on both sides of the CF (Fig. 8a–c). Generally, complex response maps were observed for fibers showing quasiperiodic spontaneous activity (Figs. 7, 8).Input-output functions at frequencies evoking single-tone suppression were nonmonotonic, while they were always monotonic at frequencies near the CF (Fig. 12).No difference in sharpness was observed between normal frequency threshold curves (FTCs) and exitatory areas of complex response maps (Fig. 9).On-off responses evoked by suppressive stimuli were found (Figs. 2, 3). They had a periodic pattern determined by the CF and did not depend on the stimulus frequency (Fig. 3).Low-CF fibers were observed which changed their time discharge structure to tone levels about 45 dB lower than their thresholds at the CF (Fig. 6).The observed features of the discharge patterns of the pigeon's auditory fibers reflect the distinctive nature of the fundamental mechanisms of auditory analysis in birds that are connected with electrical tuning of the hair cells and probably with the micromechanics of the bird's cochlea.Abbreviations
ACH
autocorrelation histogram
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BP
base period
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CF
characteristic frequency
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FTC
frequency threshold curve
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IHC
inner hair cell
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OHC
outer hair cell
-
PSTH
peristimulus time histogram
-
TIH
time interval histogram 相似文献
7.
U. Schmidt P. Schlegel H. Schweizer G. Neuweiler 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1991,168(1):45-51
1. | Within the tonotopic organization of the inferior colliculus two frequency ranges are well represented: a frequency range within that of the echolocation signals from 50 to 100 kHz, and a frequency band below that of the echolocation sounds, from 10 to 35 kHz. The frequency range between these two bands, from about 40 to 50 kHz is distinctly underrepresented (Fig. 3B). |
2. | Units with BFs in the lower frequency range (10–25 kHz) were most sensitive with thresholds of -5 to -11 dB SPL, and units with BFs within the frequency range of the echolocation signals had minimal thresholds around 0 dB SPL (Fig. 1). |
3. | In the medial part of the rostral inferior colliculus units were encountered which preferentially or exclusively responded to noise stimuli. — Seven neurons were found which were only excited by human breathing noises and not by pure tones, frequency modulated signals or various noise bands. These neurons were considered as a subspeciality of the larger sample of noise-sensitive neurons. — The maximal auditory sensitivity in the frequency range below that of echolocation, and the conspicuous existence of noise and breathing-noise sensitive units in the inferior colliculus are discussed in context with the foraging behavior of vampire bats. |
8.
A. Stumpner G. Atkins J. F. Stout 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1995,177(3):379-388
1. | When tested with legphone stimulation at 5 and 16 kHz, two prothoracic low-frequency neurons', ON1 and L1 of Acheta domesticus females, receive mainly excitation from one side (soma-ipsilateral in ON1, soma-contralateral in L1) and inhibition from the opposite side as is described for other cricket species (Figs. 2,3). While thresholds at 5 kHz are similar in L1 and ON1, L1 receives 16 kHz excitation with a 15- 20 dB higher threshold (lower than in other cricket species) than ON1. Stimulation of L1 with lower intensity 16 kHz sound on the side of its major input results in a clear IPSP visible in dendritic recordings (Figs. 3,4). In L1 and ON1 the intensity response at 16 kHz rises steeper than that at 5 kHz. |
2. | The most sensitive auditory low-frequency receptors recorded have similar thresholds as ON1 and L1 at 5 kHz. Responses of the most sensitive auditory high-frequency receptors recorded show an intensity dependence which is similar to that of ON1 at 16 k Hz (Fig. 1C). |
3. | Results of two-tone experiments show a tuning of inhibition in ON1 and L1 which is similar to excitatory tuning of ON1 (Fig. 4), however with about 10 to 15 dB higher thresholds. In contrast, in Gryllus bimaculatus an exact match between ON1-excitation and ON1/AN1 inhibition has been described. |
9.
Joachim Ostwald 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1984,155(6):821-834
Summary Tonotopical organization and frequency representation in the auditory cortex of Greater Horseshoe Bats was studied using multi-unit recordings.The auditory responsive cortical area can be divided into a primary and a secondary region on the basis of response characteristics forming a core/belt structure.In the primary area units with best frequencies in the range of echolocation signals are strongly overrepresented (Figs. 6–8). There are two separate large areas concerned with the processing of the two components of the echolocation signals. In one area frequencies between the individual resting frequency and about 2 kHz above are represented, which normally occur in the constant frequency (CF) part of the echoes (CF-area), in a second one best frequencies between resting frequency and about 8 kHz below are found (FM-area).In the CF-area tonotopical organization differs from the usual mammalian scheme of dorso-ventral isofrequency slabs. Here isofrequency contours are arranged in a semicircular pattern.The representation of the cochlear partition (cochleotopic organization) was calculated. In the inferior colliculus and auditory cortex there is a disproportionate representation of the basilar membrane. This finding is in contradiction to the current opinion that frequency representation in the auditory system of Horseshoe Bats is only determined by the mechanical tuning properties of the basilar membrane.Response characteristics for single units were studied using pure tone stimuli. Most units showed transient responses. In 25% of units response characteristics depended on the combination of frequency and sound pressure level used.Frequency selectivity of units with best frequencies in the range of echolocation sounds is very high. Q-10dB values of up to 400 were found in a small frequency band just above resting frequency.Abbreviations
BF
best frequency
-
CF
constant frequency
-
FM
frequency modulated
-
MT
minimal threshold 相似文献
10.
Andreas Baader 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1991,169(1):87-100
Locusts (Locusta migratoria) were stimulated with pulses of pure tones of frequencies between 5 kHz and 25 kHz. Interneurons responding to these stimuli (auditory interneurons) were recorded intracellularly and identified by dye injection. Their output functions were investigated by injection of depolarizing current during simultaneous registration of components of flight steering behavior of the animals, i.e. movements of the head and the abdomen and flight activity. Three different types of effects were found, corresponding to 3 functional classes of interneurons:
The frequency responses of the interneurons and their output effects are discussed in the context of two basically different behaviors: a positive phonotaxis, which might be used during intraspecific communication, and an avoidance steering behavior to escape hunting bats. 相似文献
(1) | Auditory interneurons in the metathoracic ganglion can activate (Fig. 1) or inhibit (Fig. 2) the flight oscillator when depolarized. |
(2) | Resting tethered locusts can perform lateral bending of the abdomen and, less prominent, head turns towards the sound source at frequencies between 5 and 15 kHz and at high intensities (70 dB and up, Fig. 3). Auditory interneurons were found which are sensitive to sound pulses with frequencies of 5 kHz to 15 kHz and some of them are directional (Fig. 4). Injection of depolarizing current into these cells causes movements of head and abdomen to the same side (Figs. 6, 7). |
(3) | A third population of metathoracic and abdominal interneurons is also excited by pure tone pulses (Figs. 9, 11, 12). Current injected into these cells, and into a descending auditory interneuron (Fig. 8) results in spike activity, driving the head and the abdomen in opposite directions. These movements are components of the characteristic steering behavior seen in the negatively phonotactic response to pulsed ultrasound of intact tethered animals, which is thought to be involved in bat avoidance (Robert 1989). |
11.
Rudolf Rübsamen 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1987,161(6):899-904
1. The development of vocalization and hearing was studied in Sri Lankan horseshoe bats (Rhinolophus rouxi) during the first postnatal month. The young bats were caught in a nursing colony of rhinolophids in which birth took place within a two week period. 2. The new-born bats emitted isolation calls through the mouth. At the beginning these calls consisted of pure tones with frequencies below 10 kHz (Fig. 1). During the first postnatal week the call frequency increased to about 15 kHz, and the fundamental was augmented by two to four harmonics. No evoked potentials to pure tone stimuli could be elicited in the inferior colliculus of this age group, i.e., auditory processing at the midbrain level was not demonstrable. 3. Evoked potentials were first recorded in the second week, broadly tuned to 15-45 kHz, with a maximum sensitivity between 15-25 kHz. In the course of the second week, however, higher frequencies up to 60 kHz became progressively incorporated into the audiogram (Fig. 3). The fundamental frequency of the multiharmonic isolation calls, emitted strictly through the mouth, increased to about 20 kHz. 4. In the bats' third postnatal week an increased hearing sensitivity (auditory filter) emerged, sharply tuned at frequencies between 57 and 60 kHz (Fig. 4e). The same individuals were also the first to emit long constant frequency echolocation calls through the nostrils (Fig. 4c). The energy of the calls was arranged in harmonic frequency bands with the second harmonic exactly tuned to the auditory filter. These young bats continued to emit isolation calls through the mouth, which were, however, not harmonically related to the echolocation calls (Fig. 4b, d). 5. During the fourth week, both the auditory filter and the matched echolocation pulses (the second harmonic) shifted towards higher frequencies (Fig. 5). During the fifth week the fundamental frequency of the calls was progressively attenuated, and both the second harmonic of the pulses and the auditory filter reached the frequency range typical for adult bats of 73-78 kHz (Fig. 6). 6. The development of audition and vocalization is discussed with regard to possible interactions of both subsystems, and their incorporation into the active orientation system of echolocation. 相似文献
12.
Manfred Kössl Marianne Vater 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1990,166(5):711-720
Summary The cochlea of the mustache bat, Pteronotus parnellii, is very sensitive and sharply tuned to the frequency range of the dominant second harmonic of the echolocation call around 61 kHz. About 900 Hz above this frequency the cochlear microphonic potential (CM) reaches its maximum amplitude and lowest threshold. At exactly the same frequency, pronounced evoked otoacoustic emissions (OAE) can be measured in the outer ear canal, indicating mechanical resonance. The CM amplitude maximum and the OAE are most severely masked by simultaneous exposure to tones within the range from about 61–62 kHz up to about 70 kHz. The data suggest that the mechanism of mechanical resonance involves cochlear loci basal to the 61 kHz position.The resonance contributes to auditory sensitivity and sharp tuning: At the frequency of the OAE, single unit responses in the cochlear nucleus have the lowest thresholds. Maximum tuning sharpness occurs at frequencies about 300 Hz below the OAE-frequency, where the threshold is about 10 dB less sensitive than at the OAE-frequency. In addition, in the frequency range around the OAE-frequency several specialized neuronal response features can be related to mechanical resonance: Long lasting excitation after the end of the stimulus, asymmetrical tuning curves with a shallow high frequency slope and phasic on-off neuronal response patterns. In particular the latter phenomenon indicates the occurrence of local mechanical cancellations in the cochlea.Abbreviations
CF
constant frequency component of echolocation calls
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CM
cochlear microphonic potential
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FM
frequency modulated component of echolocation calls
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N1
compound action potential of the auditory nerve
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OAE
octoacoustic emission
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SEOAE
synchronous evoked OAE 相似文献
13.
F. Libersat J. A. Murray R. R. Hoy 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1994,174(4):485-494
- The courtship behavior of male field crickets, Gryllus bimaculatus (De Geer) and Teleogryllus oceanicus, is a complex, multimodal behavioral act that involves acoustic signals (a courtship song; Fig. 1A,B). The dominant frequency is 4.5 kHz for T. oceanicus song (Fig. 1A) and 13.5 kHz for G. bimaculatus (Fig. IB).
- When courting males are deprived of their courtship song by wing amputation, their courtship success declines markedly but is restored when courting is accompanied by tape-recordings of their courtship songs or a synthetic courtship song with only the dominant frequency of the natural song; other naturally occurring frequency components are ineffective for restoring mating success (Figs. 4, 5).
- It has been suggested that an identified auditory interneuron, AN2, plays a critical role in courtship success. Chronic recordings of AN2 in an intact, tethered female show that AN2's response to the natural courtship song and synthesized songs at 4.5 and 13.5 kHz is similar in T. oceanicus. By contrast, in G. bimaculatus, AN2's response to the natural courtship song and synthesized song at 13.5 kHz, but not at 4.5 kHz, is similar (Figs. 2,3).
- In behavioral experiments, playback of a 30 kHz synthetic courtship song in G. bimaculatus does not restore courtship success, yet this same stimulus elicits as strong a response from AN2 as does the normal courtship song (Fig. 6). Thus, contrary to earlier work by others, we conclude AN2 is not, by itself, a critical neural link in the courtship behavior of these two species of crickets.
14.
K. -H. Esser R. Kiefer 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1996,178(6):787-796
In a two-alternative forced-choice procedure lesser spear-nosed bats, Phyllostomus discolor, had to discriminate between a pure tone stimulus and a sinusoidally frequency-modulated signal generated at the same carrier frequency as the tone. Modulation depths of the SFM stimuli were reduced until the animals' performance dropped below the 75%-correct level which was used to determine difference limens for detection of frequency modulation (FMDL). The dependence of FMDLs on modulation and carrier frequency was systematically investigated. For a carrier frequency of 18.5 kHz, average FMDLs increased from 95 Hz at a modulation frequency of 10 Hz to 820 Hz at a modulation frequency of 2000 Hz which corresponds to Weber ratios (2f/f) of 0.005 and 0.044 respectively. Further, difference limens were found to increase linearly in proportion to carrier frequency throughout a major part (9–74 kHz) of the species' hearing range. In comparison to other mammals, P. discolor has a pronounced capability for frequency discrimination which might be related to the extensive use of individually distinct frequency-modulated communication calls and audio-vocal learning.Abbreviations
FM
frequency modulation
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SFM
sinusoidal frequency modulation
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FMDL
frequency modulation difference limen
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CF
constant frequency
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DLF
difference limen for frequency
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VCO
voltage-controlled oscillator
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SPL
sound pressure level
-
WR
Weber ratio 相似文献
15.
C. H. Keller T. T. Takahashi 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1996,178(4):499-512
The natural acoustical environment contains many reflective surfaces that give rise to echoes, complicating the task of sound localization and identification. The barn owl (Tyto alba), as a nocturnal predator, relies heavily on its auditory system for tracking and capturing prey in this highly echoic environment. The external nucleus of the owl's inferior colliculus (ICx) contains a retina-like map of space composed of space-specific auditory neurons that have spatially limited receptive fields. We recorded extracellularly from individual space-specific neurons in an attempt to understand the pattern of activity across the ICx in response to a brief direct sound and a simulated echo. Space-specific neurons responded strongly to the direct sound, but their response to a simulated echo was suppressed, typically, if the echo arrived within 5 ms or less of the direct sound. Thus we expect there to be little or no representation within the ICx of echoes arriving within such short delays.Behavioral tests using the owl's natural tendency to turn their head toward a sound source suggested that owls, like their space-specific neurons, similarly localize only the first of two brief sounds. Naive, untrained owls were presented with a pair of sounds in rapid succession from two horizontally-separated speakers. With interstimulus delays of less than 10 ms, the owl consistently turned its head toward the leading speaker. Longer delays elicited head turns to either speaker with approximately equal frequency and in some cases to both speakers sequentially.Abbreviations
IC
inferior colliculus
-
ICx
external nucleus of the inferior colliculus
-
ITD
interaural time difference
-
ISI
interstimulus interval
-
LS
left speaker
-
RS
right speaker
-
CS
centering speaker
-
RF
receptive field 相似文献
16.
D. D. Yager 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1996,178(4):463-475
Unlike most praying mantises that have a single region of auditory sensitivity, species in the genus Creobroter have equally sensitive hearing at 2–4 and at 25–50 kHz and and are relatively insensitivity at 10–15 kHz — they have a W-shaped audiogram. Ultrasonic sensitivity originates from an auditory organ in the ventral midline of the metathorax that closely resembles the ear of other mantises. Ablation experiments demonstrate that low frequency sensitivity derives from a serially homologous mesothoracic auditory organ. Extracellular recordings suggest that these two ears operate largely, if not entirely, independently of one another in the thorax. The low frequency response has a longer latency, more action potentials per stimulus, and different patterns of change with increasing SPL than the high frequency response. Separate interneurons mediate responses in the two frequency ranges, but our evidence suggests that they are two serially homologous sets of cells. Neither auditory organ shows any physiological evidence of directional sensitivity. Ultrasound triggers a set of behaviors in flying hymenopodid mantises much like those in other mantises, but the behavioral significance of low frequency hearing in these animals is still unknown.Abbreviations
SPL
sound pressure level
-
dB SPL
sound pressure level re: 20 Pa
-
HF
high frequency
-
LF
low frequency 相似文献
17.
While searching for prey, Molossus molossus broadcasts narrow-band calls of 11.42 ms organized in pairs of pulses that alternate in frequency. The first signal of the pair is at 34.5 kHz, the second at 39.6 kHz. Pairs of calls with changing frequencies were only emitted when the interpulse intervals were below 200 ms. Maximum duty cycles during search phase are close to 20%. Frequency alternation of search calls is interpreted as a mechanism for increasing duty cycle and thus the temporal continuity of scanning, as well as increasing the detection range. A neurophysiological correlate for the processing of search calls was found in the inferior colliculus. 64% of neurons respond to frequencies in the 30- to 40-kHz range and only in this frequency range were closed tuning curves found for levels below 40 dB SPL. In addition, 15% of the neurons have double-tuned frequency-threshold curves with best thresholds at 34 and 39 kHz. Differing from observations in other bats, approach calls of M. molossus are longer and of higher frequencies than search calls. Close to the roost, the call frequency is increased to 45.0–49.8 kHz and, in addition, extremely broadband signals are emitted. This demonstrates high plasticity of call design.Abbreviations BF best frequency - CF constant frequency - IC inferior colliculus - Fmax maximal frequency - Fmin minimal frequency - PF peak frequency - PSTH post-stimulus time histogram - QCF quasi-constant frequency - SPL sound pressure level 相似文献
18.
Walter Metzner Walter Heiligenberg 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1991,169(2):135-150
Summary In the context of aggression and courtship, Eigenmannia repeatedly interrupts its electric organ discharges (EODs) These interruptions (Fig. 1) contain low-frequency components as well as high-frequency transients and, therefore, stimulate ampullary and tuberous electroreceptors, respectively (Figs. 2, 3). Information provided by these two classes of receptors is relayed along separate pathways, via the electrosensory lateral line lobe (ELL) of the hindbrain, to the dorsal torus semicircularis (TSd) of the midbrain. Some neurons of the torus receive inputs from both types of receptors (Figs. 14, 15), and some respond predominantly to EOD interruptions while being rather insensitive to other forms of signal modulations (Figs. 12, 13). This high selectivity appears to result from convergence and gating of inputs from individually less selective neurons.Abbreviations
CP
central posterior thalamic nucleus
-
Df
frequency difference between neighbor's EOD and fish's own
-
DPn
dorsal posterior nucleus (thalamus)
-
EOD
electric organ discharge
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ELL
electrosensory lateral line lobe
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JAR
jamming avoidance response
-
LMR
lateral mesencephalic reticular formation
-
nE
nucleus electrosensorius
-
nEb
nucleus electrosensorius, beat-related area
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nE
nucleus electrosensorius, area causing rise of EOD frequency
-
nE
nucleus electrosensorius, area causing fall of EOD frequency
-
nEar
nucleus electrosensorius-acusticolateralis area
-
NPd
nucleus praeeminentialis, pars dorsalis
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PPn
prepacemaker nucleus
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PT
pretectal nucleus
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SE
nucleus subelectrosensorius
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TeO
optic tectum
-
TSd
dorsal (electrosensory) torus semicircularis
-
TSv
ventral (mechano-sensory and auditory) torus semicircularis 相似文献
19.
M. Vater A. S. Feng M. Betz 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1985,157(5):671-686
Summary The frequency-place map of the horseshoe bat cochlea was studied with the horseradish peroxidase (HRP) technique involving focal injections into various, physiologically defined regions of cochlear nucleus (CN). The locations of labeled spiral ganglion cells and their termination sites on inner hair cells of the organ of Corti from injections into CN-regions responsive to different frequencies were analyzed in three dimensional reconstructions of the cochlea. Horseshoe bats from different geographical populations were investigated. They emit orientation calls with constant frequency (CF) components around 77 kHz (Rhinolophus rouxi from Ceylon) and 84 kHz (Rhinolophus rouxi from India) and their auditory systems are sharply tuned to the respective CF-components.The HRP-map shows that in both populations: (i) the frequency range around the CF-component of the echolocation signal is processed in the second half-turn of the cochlea, where basilar membrane (BM) is not thickened, secondary spiral lamina (LSS) is still present and innervation density is maximal; (ii) frequencies more than 5 kHz above the CF-component are processed in the first halfturn, where the thickened BM is accompanied by LSS and innervation density is low; (iii) frequencies below the spectral content of the orientation call are represented in apical turns showing no morphological specializations. The data demonstrate that the cochlea of horseshoe bats is normalized to the frequency of the individual specific CF-component of the echolocation call.The HRP-map can account for the overrepresentation of neurons sharply tuned to the CF-signal found in the central auditory system. A comparison of the HRP-map with a map derived with the swollen nuclei technique following loud sound exposure (Bruns 1976b) reveals that the latter is shifted towards cochlear base by about 4 mm. This discrepancy warrants a new interpretation of the functional role of specialized morphological structures of the cochlea within the mechanisms giving rise to the exceptionally high frequency selectivity of the auditory system.Abbreviations
AVCN
anteroventral CN
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BF
best frequency
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BM
basilar membrane
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CF
constant frequency
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CN
cochlear nucleus
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DCN
dorsal CN
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FM
frequency modulated
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HRP
horseradish peroxidase
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IHC
inner hair cell
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LSS
secondary spiral lamina
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OHC
outer hair cell
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PVCN
posteroventral CN
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RF
resting frequency
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RRc
Rhinolophus rouxi from Ceylon
-
RRi
Rhinolophus rouxi from India 相似文献
20.
Russell F. Huffman O. W. Henson Jr. 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1993,171(6):725-734
Summary Acoustic stimuli near 60 kHz elicit pronounced resonance in the cochlea of the mustached bat (Pteronotus parnellii parnellii). The cochlear resonance frequency (CRF) is near the second harmonic, constant frequency (CF2) component of the bat's biosonar signals. Within narrow bands where CF2 and third harmonic (CF3) echoes are maintained, the cochlea has sharp tuning characteristics that are conserved throughout the central auditory system. The purpose of this study was to examine the effects of temperature-related shifts in the CRF on the tuning properties of neurons in the cochlear nucleus and inferior colliculus.Eighty-two single and multi-unit recordings were characterizedin 6 awake bats with chronically implanted cochlear microphonic electrodes. As the CRF changed with body temperature, the tuning curves of neurons sharply tuned to frequencies near the CF2 and CF3 shifted with the CRF in every case, yielding a change in the unit's best frequency. The results show that cochlear tuning is labile in the mustached bat, and that this lability produces tonotopic shifts in the frequency response of central auditory neurons. Furthermore, results provide evidence of shifts in the frequency-to-place code within the sharply tuned CF2 and CF3 regions of the cochlea. In conjunction with the finding that biosonar emission frequency and the CRF shift concomitantly with temperature and flight, it is concluded that the adjustment of biosonar signals accommodates the shifts in cochlear and neural tuning that occur with active echolocation.Abbreviations BF
best frequency
- CF
characteristic frequency
- CF2, CF3
second and third harmonic, constant frequency components of the biosonar signal
- CM
cochlear microphonic
- CN
cochlear nucleus
- CRF
cochlear resonance frequency
- IC
inferior colliculus
- MT
minimum threshold
- OAE
otoacoustic emission
- Q10dB
BF (or CF) divided by the response bandwidth at 10 dB above MT 相似文献