摘要:

Most attempts to design artificial ears have concentrated on displaying frequency information to the skin of deaf subjects in the hope that they may recognize complex patterns of sounds and thus have some ’’auditory function’’ restored. The problem from a practical standpoint is that simultaneously occurring sounds that originate from different sources are difficult if not impossible to unscramble. In normal audition, auditory localization not only enables subjects to perceive the locus of origin of sounds with a high degree of accuracy, but also appears to be the most important determinant of selective auditory attention. The three experiments reported in this paper demonstrate first of all that tactile sound localization is possible with an accuracy that approaches normal audition, and secondly that subjects can track moving sound sources. Finally, an analog of selective auditory attention was found by using tactile localization. These experiments show the utility of incorporating a localization unit in future designs of artificial ears for the completely deaf.Subject Classification: [43]65.62, [43]65.70.

ISSN:0001-4966    

DOI:10.1121/1.380950

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Two cats were tested on their ability to perceive the missing fundamental through the use of an avoidance technique. The animals were trained to discriminate between rising and falling pitch sequences first with single and then with multiple tones. They were then tested by presenting them with tone triads known to produce the perception of the missing fundamental in humans. In these triads, the pitch of the frequencies composing the triad either remained the same or shifted in the direction opposite the shift of the missing fundamental. The results show that the animals’ response to these triads was not in conformity with that expected from the direction of change of the component frequencies, but could be accounted for if it were assumed that the cats were responding on the basis of the missing fundamental. A further test given one of the cats indicated that this phenomenon declined progressively as the center frequency was raised, until at 6 kHz it was apparently completely absent. A similar decline in the strength of the fundamental pitch occurs over the same range in humans. Thus, there is reason to believe that cats perceive the missing fundamental.Subject Classification: [43]65.75, [43]65.56, [43]65.54; [43]80.50.

ISSN:0001-4966    

DOI:10.1121/1.380951

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Two theories of temporal summation in hearing were compared. In both theories the ear performs a running average on the incoming sound in accordance with the convolution integral. In one of the theories, called the ’’rectangular’’ theory, sound is transformed by a power function and weighted by a brief rectangular function; in the other theory, called the ’’exponential’’ theory, sound is transformed so that an initial large effect decays to a steady level and it is weighted by a decaying exponential function. The rectangular theory was shown to predict that brief tone bursts and brief gaps in a tone are equally detectable if the duration of the burst and gap are equal, but the exponential theory was shown to predict that brief tone bursts are more readily detectable than brief gaps of equal duration. Experimental findings support the exponential theory: The percentage of correct responses in a two‐alternative forced‐choice task was greater for tone bursts than for tone gaps of equal duration. This result was obtained for tones and gaps from 25 to 200 msec in duration and for two different levels of a 1000‐Hz tone. In addition, the exponential theory, with a time constant of 5 sec−1for the weighting function, was compatible with the relation between the percentage of correct responses and the theoretical quantity determining detectability.Subject Classification: [43]65.68, [43]65.50, [43]65.75.

ISSN:0001-4966    

DOI:10.1121/1.380952

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Measurements of the transient response of the basilar membrane were conducted using the Mössbauer effect on 33 squirrel monkeys using an experimental preparation identical to that of Rhode (1971). The stimuli were acoustic clicks 150 μsec in duration repeated 100 000–400 000 times. The amplitude of the click was varied and the responses of the malleus and of the basilar membrane at a point in the basal turn were measured. The basilar membrane’s click response is oscillatory, with a period near that of the characteristic frequency. The first few response peaks behave almost linearly with stimulus intensity, while the later peaks exhibit a pronounced nonlinearity. This behavior is shown to be consistent with the nonlinearity reported using steady‐state measurement methods (Rhode, 1971). The transient response observed in some of the preparations was very lightly damped; however, a wide range in the damping of the responses was found in the different animals. A progressive increase in the rate of decay of the transient response with the duration of the experiment was observed. Any damage to the cochlea also resulted in increased damping. The measured cochlear delay time of 300–390 μsec agrees with that derived from phase curves of the transfer ratio measured with steady‐state methods.Subject Classification: [43]65.26, [43]65.20.

ISSN:0001-4966    

DOI:10.1121/1.380953

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

The biochemical mechanism of neomycin ototoxicity was investigatedinvivoandinvitro.Invivo, the incorporation of [32P]–orthophosphate into the phosphoinositide lipids of inner ear tissues was measured in normal and in neomycin‐treated guinea pigs. These lipids are believed to be involved in the control of membrane permeability. There was a decrease of labeling of phosphatidylinositol diphosphate in the organ of Corti and stria vascularis following three weeks of daily injections of neomycin (100 mg/kg body weight). In homogenates of organ of Corti and stria vascularis the hydrolysis of phosphatidylinositol diphosphate was blocked and the binding of radioactive calcium was inhibited in the presence of neomycin. Furtherinvitrostudies with brain subfractions demonstrated that the effect on phosphoinositide metabolism is exerted by neomycin and related antibiotics that are toxic to the cochlea and the kidney. The hypothesis is discussed that the ototoxic action of neomycin involves an inhibition of polyphosphoinositide turnover by direct binding of the antibiotic to these lipids.Subject Classification: [43]65.20.

ISSN:0001-4966    

DOI:10.1121/1.380929

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Neurons in the anteroventral cochlear nucleus of the cat respond to combination tones of the formsf2−f1andf1−n(f2−f1), wherenis a small positive integer 1, 2, 3,.... The most easily observed combination tones aref2−f1and 2f1−f2. In general, a combination tone is effective if three conditions are fulfilled: (1) the combination‐tone frequency must fall within the pure‐tone response area of the neuron; (2) the intensity levels of the primaries must be appropriate; and (3) the separation of the primary frequencies cannot be unduly large. For any form of combination tone, a combination‐tone response area could be plotted by fixingf1at some level and varyingf2in small steps. The actual frequency of the combination tone could be determined from the timing of the discharges for all neurons whose discharges are phase locked. The combination‐tone response areas indicate that the response to a given form of combination tone is optimal when the combination frequency is at or near the best frequency of the neuron. Moreover, the combination‐tone response areas are similar in width to the pure‐tone response area of the neuron. These findings suggest that the neuron responds to combination tones as if such tones were actually delivered to the ear. It was further found that the combination‐tone frequencies that activate the neuron may be several octaves below the frequencies of the two primaries that produce the combination tone. Combination‐tone threshold and suprathreshold studies show that the combination‐tone level increases with decreasing separation of the two stimulus components. Levels of the combination tones expressed in equivalent decibels of SPL increase approximately proportionately with stimulus level (L1=L2) for bothf2−f1and 2f1−f2. Furthermore, for both these combination tones, the combination‐tone level as a function ofL2(L1fixed) shows a peaked curve with the maximum occurring whenL2is about equal toL1. The types of combination tones encountered and the effects of variations in stimulus frequency are in accord with psychophysical findings. The effect of stimulus level on combination tone level is in agreement with psychophysical observations for 2f1−f2but seems to disagree with most psychophysical data forf2−f1at higher stimulus frequencies. The results suggest that a marked nonlinearity is involved in cochlear processing, at least in the 40‐ to 90‐dB‐SPL range.Subject Classification: [43]65.56, [43]65.42, [43]65.40.

ISSN:0001-4966    

DOI:10.1121/1.380954

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Single‐fiber responses were recorded from the auditory nerves of kanamycin‐treated gerbils whose cochleas were subsequently processed for histological examination. On the basis of their abnormal responses to inferred trapezoidal displacements of the basilar membrane, the contacted fibers were classified according to that direction of basilar‐membrane deflection that was associated with their excitation. A frequency–distance map was constructed for the gerbil’s cochlea with the help of cochlear‐microphonic recordings and was used to infer the location of the hair cells innervated by the contacted fibers. Our correlations indicate that fibers innervating cochlear regions substantially depleted of outer hair cells were abnormal and were scala‐vestibuli excitatory. Furthermore, fibers innervating cochlear regions containing full or nearly full complements of both inner and outer hair cells were either abnormal and scala‐tympani excitatory, or were normal. These response polarities are consistent with the previously proposed polarity‐opposition model of interaction between inner and outer hair cells in the cochlea.Subject Classification: [43]65.28, [43]65.35, [43]65.40, [43]65.42, [43]65.59.

ISSN:0001-4966    

DOI:10.1121/1.380955

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

It is conjectured that the design of the cochlea is influenced by two conflicting requirements: (1) the cochlea should act as a precise frequency analyzer and (2) waves propagating along the basilar membrane should be transmitted without reflections. Accurate frequency analysis is possible only if the mechanical properties of the cochlea change rapidly with distance along the basilar membrane. Reflections of waves traveling on the basilar membrane will be negligible, however, only if these same mechanical properties change slowly. A compromise between these two requirements is possible if a loss constant δ related to the sharpness of response of the basilar membrane to a pure tone is related to the numberNof wavelengths of the wave on the basilar membrane [N/(δ)1/2?1]. Furthermore, if sizable changes in the displacement occur only over distances larger than the width of a hair cell, then δ must be larger than the ratio of the widthwof a hair cell to the distancedalong the basilar membrane over which the characteristic frequency changes by an octave [δ≳4N(2δ)1/2w/d]. These remarks are made explicit in a transmission‐line model of cochlear mechanics. A simple closed‐form solution of the equations, which agrees with a numerical solution, is given. The solution is compared with Mössbauer measurements of basilar membrane motion. Agreement with experiment is good ifNand δ are chosen appropriately. These values are consistent with both of the conjectured relations and indicate that δ is the same order of magnitude as its lowest possible value.Subject Classification: [43]65.26, [43]65.35.

ISSN:0001-4966    

DOI:10.1121/1.380956

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Behavioral observations of communication interaction patterns were gathered for traditional and ’’poster paper’’ presentations at the 89th Meeting of the Society (7–11 April 1975, Austin, Texas). Affective reactions of poster paper authors and audience members were also surveyed. The overall response to poster sessions was very positive, suggesting continuation of the new mode of technical communication. Poster paper authors were somewhat more positive in their responses than other participants. Although poster sessions produced much more verbal interaction, patterns of interaction did not appear to differ from those observed in traditional presentations. Several problems particular to poster sessions were identified and suggestions for improvement are offered.Subject Classification: [43]05.50; [43]10.85.

ISSN:0001-4966    

DOI:10.1121/1.380957

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

The present study investigates the effect on auditory stream segregation of the duration of silent gaps between items of a repeating sequence of sine tone stimuli. While previous investigators had shown that gaps reduced the tendency for items to segregate, the present experiment showed that this was not the case; rather, in adjusting tone durations for stream segregation thresholds, subjects simply compensated for increased gap duration, keeping the total time (tone duration plus gap duration) constant.Subject Classification: [43]65.75, [43]65.54, [43]65.68.

ISSN:0001-4966    

DOI:10.1121/1.380925

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP