共查询到20条相似文献,搜索用时 31 毫秒
1.
Laura Hausmann Mark von Campenhausen Hermann Wagner 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2010,196(9):601-612
The barn owl (Tyto alba) possesses several specializations regarding auditory processing. The most conspicuous features are the directionally sensitive
facial ruff and the asymmetrically arranged ears. The frequency-specific influence of these features on sound has consequences
for sound localization that might differ between low and high frequencies. Whereas the high-frequency range (>3 kHz) is well
investigated, less is known about the characteristics of head-related transfer functions for frequencies below 3 kHz. In the
present study, we compared 1/3 octaveband-filtered transfer functions of barn owls with center frequencies ranging from 0.5
to 9 kHz. The range of interaural time differences was 600 μs at frequencies above 4 kHz, decreased to 505 μs at 3 kHz and
increased again to about 615 μs at lower frequencies. The ranges for very low (0.5–1 kHz) and high frequencies (5–9 kHz) were
not statistically different. Interaural level differences and monaural gains increased monotonically with increasing frequency.
No systematic influence of the body temperature on the measured localization cues was observed. These data have implications
for the mechanism underlying sound localization and we suggest that the barn owl’s ears work as pressure receivers both in
the high- and low-frequency ranges. 相似文献
2.
P. J. Fonseca A. V. Popov 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(4):417-427
1. Laser vibrometry and acoustic measurements were used to study the biophysics of directional hearing in males and females
of a cicada, in which most of the male tympanum is covered by thick, water filled tissue “pads”. 2. In females, the tympanal
vibrations are very dependent on the direction of sound incidence in the entire frequency range 1–20 kHz, and especially at
the main frequencies of the calling song (3–7 kHz). At frequencies up to 10 kHz, the directionality disappears if the contralateral
tympanum, metathoracic spiracle, and folded membrane are blocked with Vaseline. This suggests some pressure-difference receiver
properties in the ear. 3. In males, the tympanal vibrations depend on the direction of sound incidence only within narrow
frequency bands (around 1.8 kHz and at 6–7 kHz). At frequencies above 10–12 kHz, the directionality appears to be determined
by diffraction, and the ear seems to work as a pressure receiver. The peak in directionality at 6–7 kHz disappears when the
contralateral timbal, but not the tympanum, is covered. Covering the thin ventral abdominal wall causes the peak around 1.8 kHz
to disappear. 4. Most observed tympanal directionalities, except around 1.8 kHz in males, are well predicted from measured
transmissions of sound through the body and measured values of sound amplitude and phase at the ears at various directions
of sound incidence.
Accepted: 18 October 1996 相似文献
3.
H. Römer M. Krusch 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2000,186(2):181-191
The representation of alternative conspecific acoustic signals in the responses of a pair of local interneurons of the bushcricket
Tettigonia viridissima was studied with variation in intensity and the direction of sound signals. The results suggest that the auditory world of
the bushcricket is rather sharply divided into two azimuthal hemispheres, with signals arriving from any direction within
one hemisphere being predominantly represented in the discharge of neurons of this side of the auditory pathway. In addition,
each pathway also selects for the most intense of several alternative sounds. A low-intensity signal at 45 dB sound pressure
level is quite effective when presented alone, but completely suppressed when given simultaneously with another signal at
60 dB sound pressure level. In a series of intracellular experiments the synaptic nature of the intensity-dependent suppression
of competitive signals was investigated in a number of interneurons. The underlying synaptic mechanism is based on a membrane
hyperpolarisation with a time-constant in the order of 5–10 s. The significance of this mechanism for hearing in choruses,
and for the evolution of acoustic signals and signalling behaviour is discussed.
Accepted: 20 November 1999 相似文献
4.
Hans A. Schnyder Dieter Vanderelst Sophia Bartenstein Uwe Firzlaff Harald Luksch 《PloS one》2014,9(11)
Accurate sound source localization in three-dimensional space is essential for an animal’s orientation and survival. While the horizontal position can be determined by interaural time and intensity differences, localization in elevation was thought to require external structures that modify sound before it reaches the tympanum. Here we show that in birds even without external structures like pinnae or feather ruffs, the simple shape of their head induces sound modifications that depend on the elevation of the source. Based on a model of localization errors, we show that these cues are sufficient to locate sounds in the vertical plane. These results suggest that the head of all birds induces acoustic cues for sound localization in the vertical plane, even in the absence of external ears. 相似文献
5.
Animals such as bats and dolphins exhibit impressive echolocation abilities in terms of ranging, resolution and imaging and therefore represent a valuable learning model for the study of spatial hearing and sound source localization leading to a better understanding of the hearing mechanism and further improvement of the existing localization strategies. This study aims to examine and understand the directional characteristics of a sonar receiver modeled upon the bat auditory system via measurements of the head-related transfer function (HRTF) in the horizontal plane. Four different models of the bat head were considered here and used to evaluate acoustic spectral characteristics of the sound received by the bat's ears – a sphere model, a sphere model with a pinna attached (two pinnae of different size were used in this study) and a bat-head cast. The performed HRTF measurements of the bat-head models were further analyzed and compared to identify monaural spectral localization cues in the horizontal plane defined by the bat's head and pinna shape and size. Our study suggests that the acoustical characteristics of a bio-inspired sonar head measured and specified in advance can potentially improve the performance of a receiver. Moreover, the generated auditory models may hold clues for the design of receiver characteristics in ultrasound imaging and navigation systems. 相似文献
6.
F. Ladich H. Y. Yan 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1998,182(6):737-746
Several anabantoid species produce broad-band sounds with high-pitched dominant frequencies (0.8–2.5 kHz), which contrast
with generally low-frequency hearing abilities in (perciform) fishes. Utilizing a recently developed auditory brainstem response
recording-technique, auditory sensitivities of the gouramis Trichopsis vittata, T. pumila, Colisa lalia, Macropodus opercularis and Trichogaster trichopterus were investigated and compared with the sound characteristics of the respective species. All five species exhibited enhanced
sound-detecting abilities and perceived tone bursts up to 5 kHz, which qualifies this group as hearing specialists. All fishes
possessed a high-frequency sensitivity maximum between 800 Hz and 1500 Hz. Lowest hearing thresholds were found in T. trichopterus (76 dB re 1 μPa at 800 Hz). Dominant frequencies of sounds correspond with the best hearing bandwidth in T. vittata (1–2 kHz) and C. lalia (0.8–1 kHz). In the smallest species, T. pumila, dominant frequencies of acoustic signals (1.5–2.5 kHz) do not match lowest thresholds, which were below 1.5 kHz. However,
of all species studied, T. pumila had best hearing sensitivity at frequencies above 2 kHz. The association between high-pitched sounds and hearing may be caused
by the suprabranchial air-breathing chamber, which, lying close to the hearing and sonic organs, enhances both sound perception
and emission at its resonant frequency.
Accepted: 26 November 1997 相似文献
7.
Veronica L. Bura Antoine K. Hnain Justin N. Hick Jayne E. Yack 《Journal of Insect Behavior》2012,25(2):114-126
The tobacco hornworm (Manduca sexta) is a model organism extensively studied for many aspects of its biology, including its anti-predator strategies. We report
on a novel component of this caterpillar’s defence repertoire: sound production. Late instar caterpillars produce discrete
clicking sounds in response to disturbance. Click trains range in duration from 0.3–20.0 s (mean 3.3 ± 4.8 s) and contain
2–41 clicks (mean 7.1 ± 9.5). Sounds are broadband with a dominant frequency of 29.8 ± 4.9 kHz. We investigated the mechanism
of sound production by selectively ablating three identified sets of ridges on the mandibles, and determined that ridges on
the inner face strike the outer and incisor ridges on the opposing mandible to produce multi-component clicks. We tested the
hypothesis that clicks function in defence using simulated attacks with blunt forceps. In single attack trials 77% of larvae
produced sound and this increased to 100% in sequential attacks. Clicks preceded or accompanied regurgitation in 93% of multiple
attack trials, indicating that sound production may function in acoustic aposematism. Sound production is also accompanied
by other behaviours including directed thrashing, head curling, and biting, suggesting that sounds may also function as a
general warning of unprofitability. 相似文献
8.
Morten Buhl Jørgensen Jakob Christensen-Dalsgaard 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(5):493-502
We studied the directionality of spike rate responses of auditory nerve fibers of the grassfrog, Rana temporaria, to pure tone stimuli. All auditory fibers showed spike rate directionality. The strongest directionality was seen at low
frequencies (200 – 400 Hz), where the spike rate could change by up to nearly 200␣spikes s−1. with sound direction. At higher frequencies the directional spike rate changes were mostly below 100 spikes s−1. In equivalent dB SPL terms (calculated using the fibers' rate-intensity curves) the maximum directionalities were up to
15 dB at low frequencies and below 10 dB at higher frequencies. Two types of directional patterns were observed. At frequencies
below 500 Hz relatively strong responses were evoked by stimuli from the ipsilateral (+90o) and contralateral (−90o) directions while the weakest responses were evoked by stimuli from frontal (0o or +30o) or posterior (−135o) directions. At frequencies above 800 Hz the strongest responses were evoked by stimuli from the ipsilateral direction while
gradually weaker responses were seen as the sound direction shifted towards the contralateral side. At frequencies between
500 and 800 Hz both directional patterns were seen. The directionality was highly intensity dependent. No special adaptations
for localization of conspecific calls were found.
Accepted: 23 November 1996 相似文献
9.
A. Michelsen P. Fonseca 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2000,186(2):163-168
The spatial pattern of sound radiation of grass cicadas emitting normally patterned calling songs was measured in the acoustic
far field with an array of eight microphones at a distance of 15 cm. The array could be rotated to cover the sphere around
the cicada. The sound was analysed in one-third-octave bands with centre frequencies from 3.15 kHz to 16 kHz, the frequency
range of the calling song. The seven cicadas studied had very similar spatial radiation patterns, but somewhat different emitted
sound powers (range 190–440 nW, mean 280 nW, at 22 °C). At low frequencies, the pattern of sound radiation was close to spherical.
At higher frequencies, systematic deviations from a spherical pattern were evident. The deviations were of the order of magnitude
expected for monopolar sound sources located on sound-shielding bodies. We conclude that, although the singing cicada produces
a quite complex acoustic near field, it behaves as a monopole in the far field. These findings are compared with data from
a singing grasshopper of similar size, which in the far field behaves as a multipole.
Accepted: 20 November 1999 相似文献
10.
The modulation of brain activity as a function of auditory location was investigated using electro-encephalography in combination with standardized low-resolution brain electromagnetic tomography. Auditory stimuli were presented at various positions under anechoic conditions in free-field space, thus providing the complete set of natural spatial cues. Variation of electrical activity in cortical areas depending on sound location was analyzed by contrasts between sound locations at the time of the N1 and P2 responses of the auditory evoked potential. A clear-cut double dissociation with respect to the cortical locations and the points in time was found, indicating spatial processing (1) in the primary auditory cortex and posterodorsal auditory cortical pathway at the time of the N1, and (2) in the anteroventral pathway regions about 100 ms later at the time of the P2. Thus, it seems as if both auditory pathways are involved in spatial analysis but at different points in time. It is possible that the late processing in the anteroventral auditory network reflected the sharing of this region by analysis of object-feature information and spectral localization cues or even the integration of spatial and non-spatial sound features. 相似文献
11.
Rhinolophidae or Horseshoe bats emit long and narrowband calls. Fluttering insect prey generates echoes in which amplitude and frequency shifts are present, i.e. glints. These glints are reliable cues about the presence of prey and also encode certain properties of the prey. In this paper, we propose that these glints, i.e. the dominant glints, are also reliable signals upon which to base prey localization. In contrast to the spectral cues used by many other bats, the localization cues in Rhinolophidae are most likely provided by self-induced amplitude modulations generated by pinnae movement. Amplitude variations in the echo not introduced by the moving pinnae can be considered as noise interfering with the localization process. The amplitude of the dominant glints is very stable. Therefore, these parts of the echoes contain very little noise. However, using only the dominant glints potentially comes at a cost. Depending on the flutter rate of the insect, a limited number of dominant glints will be present in each echo giving the bat a limited number of sample points on which to base localization. We evaluate the feasibility of a strategy under which Rhinolophidae use only dominant glints. We use a computational model of the echolocation task faced by Rhinolophidae. Our model includes the spatial filtering of the echoes by the morphology of the sonar apparatus of Rhinolophus rouxii as well as the amplitude modulations introduced by pinnae movements. Using this model, we evaluate whether the dominant glints provide Rhinolophidae with enough information to perform localization. Our simulations show that Rhinolophidae can use dominant glints in the echoes as carriers for self-induced amplitude modulations serving as localization cues. In particular, it is shown that the reduction in noise achieved by using only the dominant glints outweighs the information loss that occurs by sampling the echo. 相似文献
12.
J. R. Coelho 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1998,183(6):745-751
Cicada killers (Sphecius speciosus) are large solitary wasps capable of producing a high-amplitude buzzing sound. The buzz was acoustically characterized and
its thermal and energetic effects examined. The sound was amplitude modulated, variable in frequency, had many harmonics,
and was sometimes interrupted by broad-band buzz pulses. Cicada killer body size was directly related to sound pressure level
and inversely related to frequency. Buzzing in males was 70 ± 0.8(21) dB (re 20 μPa measured 3 cm from the dorsum of the thorax)
in sound pressure amplitude, with a fundamental frequency of 209 ± 6(20) Hz, while in females buzzes were 72.6 ± 8.3(30) dB
and 152.5 ± 5.2(29) Hz. Males, the smaller of the sexes, had buzzes of significantly lower amplitude and higher frequency.
Metabolic rate was 0.293 ± 0.024(13) W g−1, or 88% of maximal, during buzzing, and was 5–100 times more costly than file-and-scraper stridulation. Thorax temperature
climbed rapidly during sound production and peaked at levels that were nearly optimal for flight. Buzzing may play a role
in both interspecific and intraspecific defensive interations.
Accepted: 16 July 1998 相似文献
13.
Phototaxis in water fleas (Daphnia magna) is differently influenced by visible and UV light 总被引:3,自引:0,他引:3
U. C. Storz R. J. Paul 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1998,183(6):709-717
The effects of vertical illumination with monochromatic lights on phototaxis of Daphnia magna in a test chamber were determined at five levels of equal quantal flux density (between 188 and 6.42 · 10−5 nEinstein). Visible adaptation light (500 nm) and subsequent spectral test light had the same quantal flux density. The animals
reacted to ultraviolet light (260–380 nm) with negative phototaxis, whereas visible light (420–600 nm) caused positive phototaxis.
Action spectra were determined, based on the evaluation of different parameters of phototactic behavior. The maximum spectral
sensitivity in the ultraviolet was found at 340 nm. The maximum spectral efficiency in the visible varied in dependence on
light intensity. Ecological consequences of the results are discussed.
Accepted: 3 August 1998 相似文献
14.
E. Golomer P. Dupui H. Monod 《European journal of applied physiology and occupational physiology》1997,76(2):140-144
We investigated the effects of maturation on the dynamic body sways of healthy girls. Prepubertal and postpubertal girls
practising professional physical activities requiring a good ability to maintain equilibrium (acrobats and dancers) were asked
to stand on a free seesaw platform and the results compared to those for untrained age-matched girls. This platform (stabilometer)
allows self-induced body sways. Stabilograms were obtained by a double integration of the angular acceleration from the recordings
of the platform sways made with an accelerometer. Fast Fourier transform processing of stabilograms allowed spectral frequency
analysis. The total spectrum energy and the energies of three frequency bands (0–0.5 Hz, 0.5–2 Hz, 2–20 Hz) were determined.
ANOVA showed that, for all groups of different equilibrium activity and independent of visual input, prepubertal girls had
higher energy values than postpubertal girls in the 0- to 0.5-Hz band whereas the opposite was true for 0.5- to 2-Hz band.
Ballet dancers were more dependent than acrobats on visual inputs for the regulation of their postural control but were less
dependent than untrained girls at both ages. Maturation seemed to shift body sways towards higher frequencies and the utilization
of the cues of postural control was different according to the type of equilibrium activity practised by the subjects.
Accepted: 7 February 1997 相似文献
15.
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
16.
Sound pressure level of tone was measured using a probe tube microphone at entrance to the dog's external meatus as a function of the azimuth of the sound source. It was demonstrated that directionality of the dog's external ear and corresponding values of interaural intensity differences (delta I) were gradually increased as the tone frequency raised from 0.5 to 40 kHz. Transfer in pinnae locations from lateral to frontal positions (one of the components of orientation reaction to an unexpected sound) resulted in some narrowing of directionality diagrams and in a displacement of their maxima towards the head midline. It was calculated that owing to this effects the extent of monotonic part of the function relating delta I and azimuth of a source were enlarged. The lateral pinnae position was suggested to be optimal for sound detection and the frontal one for localization of the moving sound source. 相似文献
17.
Light-induced fluorescence (LIF) was evaluated as a process analytical technology to monitor blend homogeneity and establish
a relationship with high-performance liquid chromatography (HPLC). Secondary aims for this study included a determination
of blend steady-state, acceptable mixing time interval, and mixing end point. Also, identification of potential “dead spots”
in the 124 L intermediate bulk container mixing tote was explored. Individual samples from 13 sample locations were collected
at 0.25, 0.5, 0.75, 1, 2, 5, 10, and 20 min and analyzed using LIF and HPLC. LIF and HPLC methods showed similar mixing profiles.
A coefficient of determination (R
2) of 0.86 (p value < 0.0001) was obtained for a second-degree polynomial bivariate fit of LIF counts by HPLC percent label claim (%LC).
A significant linear relationship was determined between LIF percent relative standard (%RSD) and HPLC %RSD (R
2 = 0.97, p < 0.0001). The LIF steady-state, acceptable mixing time interval, and mixing end point were determined to be 1–20, 2–20,
and 2 min, respectively. The steady-state, acceptable mixing time interval, and mixing end point determined by HPLC were 1–20,
5–10, and 5 min, respectively. The Tukey–Kramer honestly significant difference analysis of HPLC %LC by sample location at
5 and 10 min mixing times showed that there was a statistical difference between the HPLC %LC group means at two blender locations. 相似文献
18.
The characteristics of absolute auditory sensitivity of the bottlenose dolphin (Tursiops truncatus) in the transverse plane have been measured using short broadband stimuli simulating dolphin clicks (with energy maximum
at frequencies 8, 16, 30, 50 and 100 kHz). Experiments were performed using the method of conditioned reflexes with food reinforcement.
It is shown that, in the frequency range of 8–30 kHz, the absolute sensitivity of dolphin hearing in any ventral and lateral
directions of the transverse plane is only 2–8 dB worse than in the rostral direction. Moreover, it is 25–30 dB better than
at 50–100 kHz. At 8–30 kHz, pronounced dorsoventral asymmetry has been observed. In this frequency range, it reaches 15–18
dB whereas at 50–100 kHz this asymmetry decreases to 2–3 dB. In the dorsal direction, the auditory sensitivity is 18 dB worse
than in the rostral one at ∼8 kHz, and the difference rises smoothly to 33 dB at ∼100 kHz. At 50–100 kHz, the acoustical thresholds
in the transverse plane relative to those for the with rostral direction get worse almost uniformly in all directions by 25–33
dB. As a result, in the transverse plane the beam patterns are nearly circular, unlike those at 8–30 kHz. The results are
discussed in terms of the model of sound perception through the left and right mental foramens. The biological relevance of
such asymmetry is emphasized. 相似文献
19.
The purpose of this experiment was to explore the application of co-ordination dynamics to the analysis of discrete rather
than cyclical movements. Subjects, standing in a fixed position, were required to return table-tennis balls delivered to different
spatial locations in the direction of a fixed target. This was achieved in condition 1 by systematically scaling, from left
to right and vice versa, the `spatial location' of the ball–identified as a control parameter. In condition 2, the control
condition, the spatial location was varied randomly over the same range. The changes between regimes of the stroke co-ordination
pattern, defined at two different levels, (1) organisational – forehand or backhand drive, and (2) kinematic–the distance
of the bat at ball–bat contact relative to the leading edge of the table, were identified as collective variables, the values
of which changed spontaneously at the transition points exposed by the control parameter. The switch between regimes was shown
to be dependent upon the direction of scaling, i.e. a hysteresis effect was identified in both conditions. These findings
confirm that the conceptual and methodological frameworks of co-ordination dynamics can be applied, appropriately, to the
analysis of discrete movements. Moreover, it would seem that control parameter values (spatial location of the ball) do not
necessarily have to be scaled in a systematic way in order to produce the required effects.
Received: 22 April 1999 / Accepted in revised form: 8 May 2000 相似文献
20.
Kåre Edvardsen Ola Engelsen Magritt Brustad 《International journal of biometeorology》2009,53(5):451-459
In order to investigate the influence of solar radiation on vitamin D status and its association with different health outcomes
in population based studies, appropriate estimates of the subjects’ UV radiation exposure are needed. This unique study describes
a method that estimates the daily number of vitamin D effective hours (VD-hours) at arbitrary ground locations throughout
the period 1957–2002. The method is particularly suited for large-scale prospective epidemiological studies with questionnaire-based
information on sun exposure, and where blood measures of vitamin D status are not available. The model takes total cloud cover
fraction and total ozone column at noon as input from the ERA-40 data series (i.e. the 40 + year European Centre for Medium-Range
Weather Forecasts Re-Analysis archive). By comparing the model results against high accuracy measurements at two different
locations in Norway, we found the method for estimating the number of VD-hours to be accurate within 2.5 ± 7% or better for
moderate solar zenith angles (< 65°). For higher solar zenith angles (> 65°) the results are more variable, but the contribution
to a population’s vitamin D level from solar radiation when the sun is this low in the sky is rather small. The program code
to compute VD-hours from ERA–40 files is written in Perl (v 5.8.7) and may be obtained free of charge by contacting corresponding
author. 相似文献