共查询到20条相似文献,搜索用时 15 毫秒
1.
Terry T. Takahashi Clifford H. Keller 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1992,170(2):161-169
Summary In the barn owl (Tyto alba), the posterior nucleus of the ventral lateral lemniscus (VLVp) is the first site of binaural convergence in the pathway that processes interaural level difference (ILD), an important sound-localization cue. The neurons of VLVp are sensitive to ILD because of an excitatory input from the contralateral ear and an inhibitory input from the ipsilateral ear. A previously described projection from the contralateral cochlear nucleus, can account for the excitation. The present study addresses the source of the inhibitory input.We demonstrate with standard axonal transport methods that the left and right VLVps are interconnected via fibers of the commissure of Probst. We further show that the anesthetization of one VLVp renders ineffective the inhibition that is normally evoked by stimulation of the ipsilateral ear. Thus, one cochlear nucleus (driven by the ipsilateral ear) appears to provide inhibition to the ipsilateral VLVp by exciting commissurally-projecting inhibitory neurons in the contralateral VLVp.Abbreviations
ABL
average binaural level
-
CP
commissure of Probst
-
DNLL
dorsal nucleus of the lateral lemniscus
-
IC
inferior colliculus
-
ILD
interaural level difference
-
IPc
nucleus isthmi, pars parvocellularis
-
ITD
interaural time difference
-
LSO
lateral superior olive
-
MNTB
medial nucleus of the trapezoid body
-
NA
nucleus angularis
-
SL
nucleus semilunaris
-
VLVa
nucleus ventralis lemnisci lateralis, pars anterior
-
VLVp
nucleus ventralis lemnisci lateralis, pars posterior 相似文献
2.
Peter Bremen Iris Poganiatz Mark von Campenhausen Hermann Wagner 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2007,193(1):99-112
Standard electrophysiology and virtual auditory stimuli were used to investigate the influence of interaural time difference
on the azimuthal tuning of neurons in the core and the lateral shell of the central nucleus of the inferior colliculus of
the barn owl. The responses of the neurons to virtual azimuthal stimuli depended in a periodic way on azimuth. Fixation of
the interaural time difference, while leaving all other spatial cues unchanged, caused a loss of periodicity and a broadening
of azimuthal tuning. This effect was studied in more detail in neurons of the core. The azimuthal range tested and the frequency
selectivity of the neurons were additional parameters influencing the changes induced by fixating the interaural time difference.
The addition of an interaural time difference to the virtual stimuli resulted in a shift of the tuning curves that correlated
with the interaural time difference added. In this condition, tuning strength did not change. These results suggest that interaural
time difference is an important determinant of azimuthal tuning in all neurons of the core and lateral shell of the central
nucleus of the inferior colliculus, and is the only determinant in many of the neurons from the core. 相似文献
3.
Nikodemus Gessele Elisabet Garcia-Pino Damir Omerba?i? Thomas J. Park Ursula Koch 《PloS one》2016,11(1)
Naked mole-rats (Heterocephalus glaber) live in large eu-social, underground colonies in narrow burrows and are exposed to a large repertoire of communication signals but negligible binaural sound localization cues, such as interaural time and intensity differences. We therefore asked whether monaural and binaural auditory brainstem nuclei in the naked mole-rat are differentially adjusted to this acoustic environment. Using antibody stainings against excitatory and inhibitory presynaptic structures, namely the vesicular glutamate transporter VGluT1 and the glycine transporter GlyT2 we identified all major auditory brainstem nuclei except the superior paraolivary nucleus in these animals. Naked mole-rats possess a well structured medial superior olive, with a similar synaptic arrangement to interaural-time-difference encoding animals. The neighboring lateral superior olive, which analyzes interaural intensity differences, is large and elongated, whereas the medial nucleus of the trapezoid body, which provides the contralateral inhibitory input to these binaural nuclei, is reduced in size. In contrast, the cochlear nucleus, the nuclei of the lateral lemniscus and the inferior colliculus are not considerably different when compared to other rodent species. Most interestingly, binaural auditory brainstem nuclei lack the membrane-bound hyperpolarization-activated channel HCN1, a voltage-gated ion channel that greatly contributes to the fast integration times in binaural nuclei of the superior olivary complex in other species. This suggests substantially lengthened membrane time constants and thus prolonged temporal integration of inputs in binaural auditory brainstem neurons and might be linked to the severely degenerated sound localization abilities in these animals. 相似文献
4.
S. Haplea E. Covey J. H. Casseday 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1994,174(6):671-683
To determine the level at which certain response characteristics originate, we compared monaural auditory responses of neurons in ventral cochlear nucleus, nuclei of lateral lemniscus and inferior colliculus. Characteristics examined were sharpness of frequency tuning, latency variability for individual neurons and range of latencies across neurons.Exceptionally broad tuning curves were found in the nuclei of the lateral lemniscus, while exceptionally narrow tuning curves were found in the inferior colliculus. Neither specialized tuning characteristic was found in the ventral cochlear nuclei.All neurons in the columnar division of the ventral nucleus of the lateral lemniscus maintained low variability of latency over a broad range of stimulus conditions. Some neurons in the cochlear nucleus (12%) and some in the inferior colliculus (15%) had low variability in latency but only at best frequency.Range of latencies across neurons was small in the ventral cochlear nucleus (1.3–5.7 ms), intermediate in the nuclei of the lateral lemniscus (1.7–19.8 ms) and greatest in the inferior colliculus (2.9–42.0 ms).We conclude that, in the nuclei of the lateral lemniscus and in the inferior colliculus, unique tuning and timing properties are built up from ascending inputs.Abbreviations AVCN
anteroventral cochlear nucleus
- BF
best frequency
- CV
coefficient of variation
- DCN
dorsal cochlear nucleus
- FM
frequency modulation
- IC
inferior colliculus
- NLL
nuclei of lateral lemniscus
- PSTH
post stimulus time histogram
- PVCN
posteroventral cochlear nucleus
- SD
standard deviation
- SPL
sound pressure level
- VCN
ventral cochlear nuclei
- VNLLc
ventral nucleus of the lateral lemniscus, columnar division 相似文献
5.
Hermann Wagner 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1992,170(1):3-11
Summary This paper investigates the ability of neurons in the barn owl's (Tyto alba) inferior colliculus to sense brief appearances of interaural time difference (ITD), the main cue for azimuthal sound localization in this species. In the experiments, ITD-tuning was measured during presentation of a mask-probe-mask sequence. The probe consisted of a noise having a constant ITD, while the mask consisted of binaurally uncorrelated noise. Collicular neurons discriminated between the probe and masking noise by showing rapid changes from untuned to tuned and back to untuned responses.The curve describing the relation between probe duration and the degree of ITD-tuning resembled a leaky-integration process with a time constant of about 2 ms. Many neurons were ITD-tuned when probe duration was below 1 ms. These extremely short effective probe durations are interpreted as evidence for neuronal convergence within the pathway computing ITD. The minimal probe duration necessary for ITD-tuning was independent of the bandwidth of the neurons' frequency tuning and also of the best frequency of a neuron. Many narrowly tuned neurons having different best frequencies converge to form a broad-band neuron. To yield the short effective probe durations the convergence must occur in strong temporal synchronism.Abbreviations
ICc
central nucleus of the inferior colliculus;
-
ICx
external nucleus of the inferior colliculus;
-
ITD
interaural time difference
-
LP
Likelihood parameter 相似文献
6.
The subjective representation of the sounds delivered to the two ears of a human listener is closely associated with the interaural delay and correlation of these two-ear sounds. When the two-ear sounds, e.g., arbitrary noises, arrive simultaneously, the single auditory image of the binaurally identical noises becomes increasingly diffuse, and eventually separates into two auditory images as the interaural correlation decreases. When the interaural delay increases from zero to several milliseconds, the auditory image of the binaurally identical noises also changes from a single image to two distinct images. However, measuring the effect of these two factors on an identical group of participants has not been investigated. This study examined the impacts of interaural correlation and delay on detecting a binaurally uncorrelated fragment (interaural correlation = 0) embedded in the binaurally correlated noises (i.e., binaural gap or break in interaural correlation). We found that the minimum duration of the binaural gap for its detection (i.e., duration threshold) increased exponentially as the interaural delay between the binaurally identical noises increased linearly from 0 to 8 ms. When no interaural delay was introduced, the duration threshold also increased exponentially as the interaural correlation of the binaurally correlated noises decreased linearly from 1 to 0.4. A linear relationship between the effect of interaural delay and that of interaural correlation was described for listeners participating in this study: a 1 ms increase in interaural delay appeared to correspond to a 0.07 decrease in interaural correlation specific to raising the duration threshold. Our results imply that a tradeoff may exist between the impacts of interaural correlation and interaural delay on the subjective representation of sounds delivered to two human ears. 相似文献
7.
Barn owls use interaural intensity differences to localize sounds in the vertical plane. At a given elevation the magnitude of the interaural intensity difference cue varies with frequency, creating an interaural intensity difference spectrum of cues which is characteristic of that direction. To test whether space-specific cells are sensitive to spectral interaural intensity difference cues, pure-tone interaural intensity difference tuning curves were taken at multiple different frequencies for single neurons in the external nucleus of the inferior colliculus. For a given neuron, the interaural intensity differences eliciting the maximum response (the best interaural intensity differences) changed with the frequency of the stimulus by an average maximal difference of 9.4±6.2 dB. The resulting spectral patterns of these neurally preferred interaural intensity differences exhibited a high degree of similarity to the acoustic interaural intensity difference spectra characteristic of restricted regions in space. Compared to stimuli whose interaural intensity difference spectra matched the preferred spectra, stimuli with inverted spectra elicited a smaller response, showing that space-specific neurons are sensitive to the shape of the spectrum. The underlying mechanism is an inhibition for frequency-specific interaural intensity differences which differ from the preferred spectral pattern. Collectively, these data show that space-specific neurons are sensitive to spectral interaural intensity difference cues and support the idea that behaving barn owls use such cues to precisely localize sounds.Abbreviations ABI
average binaural intensity
- HRTF
head-related transfer function
- ICx
external nucleus of the inferior colliculus
- IID
interaural intensity difference
- ITD
interaural time difference
- OT
optic tectum
- RMS
root mean square
- VLVp
nucleus ventralis lemnisci laterale, pars posterior 相似文献
8.
Konishi M 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2000,86(7):884-897
Barn owls localize sound by using the interaural time difference of the horizontal plane and the interaural intensity difference for the vertical plane. The owl's auditory system possesses the two binaural cues in separate pathways in the brainstem. Owls use a process similar to cross-correlation to derive interaural time differences. Convergence of different frequency bands in the inferior colliculus solves the problems of phase-ambiguity which is inherent in cross-correlating periodic signals. The two pathways converge in the external nucleus of the inferior colliculus to give rise to neurons that are selective for combinations of the two cues. These neurons form a map of auditory space. The map projects to the optic tectum to form a bimodal map which, in turn, projects to a motor map for head turning. The visual system calibrates the auditory space map during ontogeny in which acoustic variables change. In addition to this tectal pathway, the forebrain can also control the sound-localizing behaviour. 相似文献
9.
Michael B. Calford Lisa Z. Wise John D. Pettigrew 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1985,157(2):149-160
Summary The coding of sound frequency and location in the avian auditory midbrain nucleus (nMLD) was examined in three diurnal raptors: the brown falcon (Falco berigora), the swamp harrier (Circus aeruginosus) and the brown goshawk (Accipiter fasciatus). Previously this nucleus has been studied with free field stimuli in only one other species, the barn owl (Tyto alba).We found some parallels between the organisation of nMLD in the diurnal raptors and that reported in the barn owl in that the central region of nMLD was tonotopically organised and contained cells that did not encode location, and the lateral region (nMLDl) contained cells which were sensitive to stimulus position. However, unlike the barn owl, which has units with circumscribed receptive fields, cells sensitive to stimulus location had large receptive fields which were restricted in azimuth but not in elevation (hemifield units). Such cells could not provide an acoustic space map in which both azimuthal and elevational dimensions were represented, but there was a tendency for units with contralateral borders to be found superficially, and those with ipsilateral borders to be found deep, in nMLDl. Hemifield units displayed receptive field properties consistent with the directional properties of the tympana in the presence of sound transmission through the interaural canal, if there is a central mechanism which is sensitive to interaural intensity differences.Abbreviations
nMLD
nucleus mesencephalicus lateralis pars dorsalis
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SPL
sound pressure level re 20 Pa
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nMLDl
lateral region of nMLD
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ICC
central nucleus of the inferior colliculus
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ICX
external nucleus of the inferior colliculus
-
IID
interaural intensity difference
-
EI
excitatory inhibitory 相似文献
10.
Wiktor M?ynarski 《PLoS computational biology》2015,11(5)
In mammalian auditory cortex, sound source position is represented by a population of broadly tuned neurons whose firing is modulated by sounds located at all positions surrounding the animal. Peaks of their tuning curves are concentrated at lateral position, while their slopes are steepest at the interaural midline, allowing for the maximum localization accuracy in that area. These experimental observations contradict initial assumptions that the auditory space is represented as a topographic cortical map. It has been suggested that a “panoramic” code has evolved to match specific demands of the sound localization task. This work provides evidence suggesting that properties of spatial auditory neurons identified experimentally follow from a general design principle- learning a sparse, efficient representation of natural stimuli. Natural binaural sounds were recorded and served as input to a hierarchical sparse-coding model. In the first layer, left and right ear sounds were separately encoded by a population of complex-valued basis functions which separated phase and amplitude. Both parameters are known to carry information relevant for spatial hearing. Monaural input converged in the second layer, which learned a joint representation of amplitude and interaural phase difference. Spatial selectivity of each second-layer unit was measured by exposing the model to natural sound sources recorded at different positions. Obtained tuning curves match well tuning characteristics of neurons in the mammalian auditory cortex. This study connects neuronal coding of the auditory space with natural stimulus statistics and generates new experimental predictions. Moreover, results presented here suggest that cortical regions with seemingly different functions may implement the same computational strategy-efficient coding. 相似文献
11.
B. Grothe G. Neuweiler 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2000,186(5):413-423
Traditionally, the medial superior olive, a mammalian auditory brainstem structure, is considered to encode interaural time
differences, the main cue for localizing low-frequency sounds. Detection of binaural excitatory and inhibitory inputs are
considered as an underlying mechanism. Most small mammals, however, hear high frequencies well beyond 50 kHz and have small
interaural distances. Therefore, they can not use interaural time differences for sound localization and yet possess a medial
superior olive. Physiological studies in bats revealed that medial superior olive cells show similar interaural time difference
coding as in larger mammals tuned to low-frequency hearing. Their interaural time difference sensitivity, however, is far
too coarse to serve in sound localization. Thus, interaural time difference sensitivity in medial superior olive of small
mammals is an epiphenomenon. We propose that the original function of the medial superior olive is a binaural cooperation
causing facilitation due to binaural excitation. Lagging inhibitory inputs, however, suppress reverberations and echoes from
the acoustic background. Thereby, generation of antagonistically organized temporal fields is the basic and original function
of the mammalian medial superior olive. Only later in evolution with the advent of larger mammals did interaural distances,
and hence interaural time differences, became large enough to be used as cues for sound localization of low-frequency stimuli.
Accepted: 28 February 2000 相似文献
12.
In birds and mammals, precisely timed spikes encode the timing of acoustic stimuli, and interaural acoustic disparities propagate to binaural processing centers. The Jeffress model proposes that these projections act as delay lines to innervate an array of coincidence detectors, every element of which has a different relative delay between its ipsilateral and contralateral excitatory inputs. Thus, interaural time difference (ITD) is encoded into the position of the coincidence detector whose delay lines best cancel out the acoustic ITD. Neurons of the avian nucleus laminaris and mammalian MSO phase-lock to both monaural and binaural stimuli but respond maximally when phase-locked spikes from each side arrive simultaneously, i.e. when the difference in the conduction delays compensates for the ITD. McAlpine et al. [Nat. Neurosci. 4 (2001) 396] identified an apparent difference between avian and mammalian ITD coding. In the barn owl, the maximum firing rate appears to encode ITD. This may not be the case for the guinea pig, where the steepest region of the function relating discharge rate to interaural time delay (ITD) is close to midline for all neurons, irrespective of best frequency (BF). These data suggest that low BF ITD sensitivity in the guinea pig is mediated by detection of a change in slope of the ITD function, and not by maximum rate. We review coding of low best frequency ITDs in barn owls and mammals and discuss whether there may be differences in the code used to signal ITD in mammals and birds. 相似文献
13.
Iris Poganiatz Hermann Wagner 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2001,187(3):225-233
Interaural level differences play an important role for elevational sound localization in barn owls. The changes of this cue with sound location are complex and frequency dependent. We exploited the opportunities offered by the virtual space technique to investigate the behavioral relevance of the overall interaural level difference by fixing this parameter in virtual stimuli to a constant value or introducing additional broadband level differences to normal virtual stimuli. Frequency-specific monaural cues in the stimuli were not manipulated. We observed an influence of the broadband interaural level differences on elevational, but not on azimuthal sound localization. Since results obtained with our manipulations explained only part of the variance in elevational turning angle, we conclude that frequency-specific cues are also important. The behavioral consequences of changes of the overall interaural level difference in a virtual sound depended on the combined interaural time difference contained in the stimulus, indicating an indirect influence of temporal cues on elevational sound localization as well. Thus, elevational sound localization is influenced by a combination of many spatial cues including frequency-dependent and temporal features. 相似文献
14.
《Journal of Russian & East European Psychology》2013,51(2):33-43
In spite of the large quantity of psychophysiological investigations of binaural hearing, a systematic study of its concrete mechanisms has only been begun comparatively recently (cf. review [1]). In particular, changes in neuron response under conditions of lateral differentiation brought about by varying the intensity of one of the monaural components of binaurally presented stimuli have been studied in detail only at the site of the superior olivary body (3, 4, 6) — the first section of the auditory system — where afferent fibers from the right and left cochlea converge (7, 9). Published data provide evidence that variations in the intensity of one of the monaural components of binaurally presented signals has an appreciable effect on the firing rate of single neurons of the inferior colli cuius (5, 8), which is situated directly behind the superior olivary body of the auditory system. in the present report, the types of response of neurons in the inferior colliculus to variations in the intensity of one of the monaural components of binaurally presented stimuli are systematically investigated. 相似文献
15.
A R Palmer A Rees D Caird 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》1992,336(1278):415-422
The binaural masking level difference (BMLD) is a psychophysical effect whereby signals masked by a noise at one ear become unmasked by sounds reaching the other. BMLD effects are largest at low frequencies where they depend on signal phase, suggesting that part of the physiological mechanism responsible for the BMLD resides in cells that are sensitive to interaural time disparities. We have investigated a physiological basis for unmasking in the responses of delay-sensitive cells in the central nucleus of the inferior colliculus in anaesthetized guinea pigs. The masking effects of a binaurally presented noise, as a function of the masker delay, were quantified by measuring the number of discharges synchronized to the signal, and by measuring the masked threshold. The noise level for masking was lowest at the best delay for the noise. The mean magnitude of the unmasking across our neural population was similar to the human psychophysical BMLD under the same signal and masker conditions. 相似文献
16.
Nikitin NI Varfolomeev AL Kotelenko LM 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2003,89(6):625-638
Unit responses in the primary auditory cortex of anesthetized cats to stationary and apparently moving stimuli resulted from a static and dynamically varying interaural delay (ITD) were recorded. The static stimuli consisted of binaurally presented tones and clicks. The dynamic stimuli were produced by in-phase and out-of-phase binaurally presented click trains with time-varying ITD. Sensitivity to ITDs was mostly seen in responses of the neurons with low characteristic frequency (below 2.8 kHz). All cells sampled with static stimuli responded to simulated motion. A motion effect could take the form of a difference in response magnitude depending on the direction of stimulus motion and a shift in the ITD-function opposite the direction of motion. The magnitude of motion effects was influenced by the position of motion trajectory relative to the ITD-function. The greatest motion effect was produced by motion crossing the ITD-function slopes. 相似文献
17.
Al'tman IaA Bekhterev NN Vaĭtulevich SF Nikitin NI 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2003,89(3):271-279
The work presents experimental data on certain changes in electrical responses of the auditory system's midbrain centre in a contraphasic binaural presentation of sound impulse series. Neuronal cortical activity is selective in respect to dynamic interaural changes of signals' phasic spectre which may serve as a basis for the mechanisms of localising a moving source of sound. Human auditory evoked potentials reveal a manifestation of memorizing the auditory image movement direction as shown by appearance of stimuli deviant from standard mismatch negativity. 相似文献
18.
《Electronic Notes in Theoretical Computer Science》1991,80(2):146-154
When uncorrelated random noise signals presented to the two ears suddenly become identical (coherent), a centrally located sound image is abruptly perceived and long latency scalp potentials are evoked. When the same signals are presented monaurally there is no perceived change and no potentials are evoked: hence the response must be purely a function of the binaural interaction.P70, N130 and P220 components were consistently recorded to both coherence and discoherence. N130 was usually largest at Fz and P220 at Cz. No potentials of shorter latency were identified, even after averaging 5000 or more sweeps. When the noise became coherent with an inter-aural time difference (δT) of ±0.5 msec (giving rise to an off-centre sound image), the responses were of slightly longer latency and showed no significant asymmetries between C3 and C4. In binaurally coherent noise, δT changes of ±0.5 or ±1.0 msec evoked similar responses which showed no significant asymmetries on the scalp. N130 was of longer latency when δT was changed from ±0.5 msec to zero, as compared with the converse change.In view of the similarity of all these responses it is considered unlikely that they were due to specific populations of binaurally responsive cortical neurones. The N130 and P220 components are thought to be non-specific potentials which are elicited by amy perceptible change in steady auditory stimulus conditions, due to a “mismatch” between the stimulus and the contents of a short-term auditory memory. 相似文献
19.
We propose a neural network model of the inferior colliculus (IC) for human echolocation. Neuronal mechanisms for human echolocation
were investigated by simulating the model. The model consists of the neural networks of the central nucleus (ICc) and external
nucleus (ICx) of the inferior colliculus. The neurons of the ICc receive interaural sound stimuli via multiple contralateral
delay lines and a single ipsilateral delay line. The neurons of the ICc send output signals to the neurons of the ICx in a
convergent manner. We stimulated the ICc with pairs of a direct sound (a sonar sound) and an echo sound (the reflection from
an object). Information about the distance between the model and the object is expressed by the delay time of the echo sound
with respect to the direct sound. The results presented here show that neurons of the ICc responsive to interaural onset time
differences contribute to the creation of an auditory distance map in the ICx. We trained the model with various pairs of
direct-echo sounds and modified synaptic connection strengths of the networks according to the Hebbian rule. It is shown that
self-organized long-term depression of lateral inhibitory synaptic connections plays an important role in enhancing echolocation
skills.
Received: 26 November 2000 / Accepted in revised form: 16 October 2001 相似文献
20.
Laura Hausmann Mark von Campenhausen Frank Endler Martin Singheiser Hermann Wagner 《PloS one》2009,4(11)