摘要:

Wave activity in response to tonal stimuli was recorded in the superior‐olivary complex of anesthetized cats. A rapid and a slow phase of adaptation were observed. The intensity‐amplitude curves were found to approximate power functions, with an average exponent of 0.34 for an 800‐cps stimulus. The intensity‐amplitude functions for stimuli between 200 and 2400 cps tended to form families of curves with maximum amplitudes between 500 and 1000 cps. Some factors inducing variability were discussed in detail. Comparison of superior‐olive activity with eighth‐nerve activity as described in published reports suggested that auditory information is transmitted through the cochlear nuclei to accessory nucleus in essentially an unmodified form.

ISSN:0001-4966    

DOI:10.1121/1.1909437

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP

摘要:

The spread σ in the final settings of repeated adjustment processes is often taken equal to (or at any rate proportional to) the difference limendas found by a method of forced choice. A detailed investigation into the adjustment process shows that this is not necessarily correct. In principle,σ = (ξd)12, where ξ is the (average) move length in the adjustment process. This implies that σ is proportional to the square root of the difference limen if σ is constant. Normally, however, the subject intuitively chooses ξ roughly equal to13d, so that σ∼dholds in most practical cases. These ideas are applied to binaural frequency discrimination of sinusoids, the duration of which is variable.

ISSN:0001-4966    

DOI:10.1121/1.1909439

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP

摘要:

Eight male subjects were exposed for 3 min to a 4000‐cps fatigue tone at 40 dB SL. Each subject was tested under four task conditions: mental arithmetic (MA), written long division (LD), threshold determination (TD) on a 500‐cps tone, and reverie (REV). Temporary threshold shifts (TTS) were computed by comparing pre‐ and post‐fatigue thresholds. MA produced significantly more TTS than any other condition and LD resulted in greater shifts than REV. Amount of auditory fatigue can vary with the type of mental activity performed by the subject.

ISSN:0001-4966    

DOI:10.1121/1.1909441

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP

摘要:

In an effort to supply widespread cutaneous stimulation and thus make possible systematic study of the limits of spatial discrimination through this channel, there has been devised a multiple contactor system permitting application of vibratory signals to 10 bodily loci simultaneously. Patterns comprising from 1 to 9 stimuli were presented in successive pairs, the subject's task being to report whether the patterns were perceived as “same” or “different.” Members of pairs were separated by 500 msec and burst duration was 200 msec. Two synchronized Western Union tape transmitters presented 20 programs of 50 pairs of patterns, 500 “same” and 500 “different” pairs being randomly intermixed in the 1000 presentations. A pilot experiment, in which many types of pattern changes were explored, revealed errors to be associated with (a) relative pattern complexity (large numbers of vibrators) and (b) high degree of communality (many elements in common). A formal experiment, involving a stratified sample with all combinations of numbers of loci and degrees of communality represented equally, verified the preliminary finding, and permitted, in addition, separation of the two factors apparently responsible. The relation between errors and communality, with number of stimulus positions held constant, proves to be an intimate one; confusions between patterns arise when there is relatively large overlap of elements in the patterns to be discriminated. A supplementary analysis, directed at whether particular receptive areas may be especially prone to error, shows no single locus, of the 10 employed, contributing to error production more than would be dictated by chance.

ISSN:0001-4966    

DOI:10.1121/1.1909443

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP

摘要:

The masking produced by two, equal‐intensity sinusoids on a signal, a third sinusoid located midway in frequency between the two maskers, is measured as a function of the frequency separation between the two maskers. Three signal frequencies are used 250, 1000, and 4000 cps. At small frequency separations, the detectability of the signal is independent of center frequency and simply dependent on the frequency separation of the two maskers. As larger frequency separations are approached, the masking suddenly diminishes and this larger critical frequency separation, which is frequency‐dependent, is approximately the width of the envelope of excitation on the basilar membrane when excited by a sinusoid. The interpretation of these results in terms of a simple energy detector followed by a simple integrator is discussed.

ISSN:0001-4966    

DOI:10.1121/1.1909445

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP

摘要:

Acoustic clicks were presented through earphones to the two ears of anesthetized cats, and the electrical response activity of single nerve cells in the accessory nucleus of the superior olive was studied. Stimulus parameters investigated included interaural time difference, interaural intensity difference, and average intensity. Attention was concentrated on cells that were excited by stimulation of the contralateral ear and inhibited by stimulation of the ipsilateral ear. The experimental results are incorporated into van Bergeijk's model for binaural interaction, for which it is postulated that localization judgments are obtained on the basis of a comparison of the amounts of response activity in the two accessory nuclei. The model yields predictions that are in agreement with results from human psychophysics. The model predicts that the virtual image should be lateralized toward the side receiving prior or more intense stimulation. A time‐intensity trading relationship that is in agreement with results from “centering” experiments is derived. The model predicts minimum detectable changes in interaural time difference of 5–10 μsec and minimum detectable changes in interaural intensity difference of 0.1–0.5 dB.

ISSN:0001-4966    

DOI:10.1121/1.1909447

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP

摘要:

Certain laboratory studies show that it is necessary only to hear up to 1500, or perhaps 2000, cps for normal word‐list reception. However, many patients with normal hearing up to 2000 cps but deficiencies at higher frequencies have noticeable difficulty with everyday speech. The discrepancy may arise since ordinary speech is often distorted and/or masked, conditions not usually included in speech‐reception studies. Discrimination scores (DS) for sentence material were collected on 52 sensorineural hypoacusics, the speech being distorted by having talkers wear nose clamps, by speed, interruptions, and reverberations. When the mean DS from these four distortions was averaged with the DS for undistorted speech, to create “50% distorted speech,” a condition assumed to represent everyday listening, the important acuities were at 1000, 2000, and 3000 cps. The formula for predicting everyday speech should then utilize the simple average hearing loss at these three frequencies. The Pearsonrbetween this predictor and the DS for 50% distorted speech was 0.74. Multiple‐correlation frequency‐weighting techniques are inferior to simple averaging across audiometric frequencies for theoretical reasons and because of the almost insurmountable problem of collecting a truly representative sample of hearing‐loss patterns. These results confirm those of Kryter, Williams, and Green, who found the region 2000–4000 cps to be the important predictor for reception of loud speech heavily masked by noise.

ISSN:0001-4966    

DOI:10.1121/1.1909449

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP

摘要:

Initial information is presented on temporary threshold shifts in chinchilla as measured by behavioral audiometry. Data are presented for two animals after selected exposures to either a12‐or 1 oct band of high‐frequency noise.

ISSN:0001-4966    

DOI:10.1121/1.1909451

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP

摘要:

The gain in sensitivity of the middle‐ear‐muscle acoustic reflex with binaural, as opposed to monaural, exaltation was studied in awake cats. Measurements were obtained with electrodes permanently implanted on the round‐window membrane and in the muscles themselves. Summation at reflex threshold occurred only with tones of similar frequency and was most marked at low frequencies. For binaural tones considerably above reflex threshold, summation was most marked for the most dissimilar frequencies measured—1 and 8 kc/sec.

ISSN:0001-4966    

DOI:10.1121/1.1909453

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP

摘要:

When a pulse is presented from one position in space near in time to the beginning of a tone burst coming from another position in space, the tone burst may be perceived to be displaced toward the pulse. Measurements of displacement effects are given for various angles of separation of sources and duration of tone. A related type of displacement effect occurs that involves the perceived displacement of one pulse toward another in space when the two pulses are presented with small time separations between them. Another type of effect has been discovered, more closely related to yon Békésy's concept of funneling, in which a pulse appears to be funneled into the spatial location of another that precedesorfollows it by a small time interval. A “place” model is presented to help to explain these effects.

ISSN:0001-4966    

DOI:10.1121/1.1909456

出版商:Acoustical Society of America    

年代:1965

数据来源: AIP