Masked auditory thresholds, critical ratios, and scales of the basilar membrane of the housemouse (Mus musculus)

Summary1.Masked auditory thresholds were determined for the housemouse (Mus musculus, outbred strain NMRI) between 1 kHz and 80 kHz and for four noise spectrum levels.2.Critical ratios (K, K1) after Fletcher (1940), which represent bands of summated sound evaluation, were calculated. For frequencies (f) below 15 kHz critical ratios (CR-bands) remain constant (K = 35 dB;K1 = 3162 Hz). Above 15 kHz the relation between CR-bands andf can be expressed by the following functions:K = 13.27·Ig f−19.87;K1 = 0.456·f −2836.3.From these functions the width in kHz and the number of CR-bands in the acoustic system of the mouse could be derived. The ear ofMus musculus is able to form maximally 10 CR-bands between 0.8 kHz and 115.4 kHz.4.The width and number of CR-bands could be used to calculate a function for frequency distribution along the basilar membrane of the mouse, or to estimate fitting factors for Greenwood's (1961) equation respectively. The following function is proposed to be the best approximation:f = 3350·(100.21x−1),x = distance from the helicotrema.5.Equidistant scales for the basilar membrane ofMus musculus are constructed.6.The comparison of data on man, cat, and mouse shows that the CR-bands of these mammals are equal to a width of 0.67 mm on all respective basilar membranes. Thus accuracy of sound evaluation in mammals is directly proportional to the length of the respective basilar membranes.

[1]  E. Zwicker,et al.  Das Ohr als Nachrichtenempfänger , 1967 .

[2]  Charles S. Watson,et al.  Masking of Tones by Noise for the Cat , 1959 .

[3]  C. S. Johnson.  Masked tonal thresholds in the bottlenosed porpoise. , 1968, The Journal of the Acoustical Society of America.

[4]  D N Elliott,et al.  Frequency discrimination and masking effectiveness. , 1968, The Journal of the Acoustical Society of America.

[5]  D. D. Greenwood.  Critical Bandwidth and the Frequency Coordinates of the Basilar Membrane , 1961 .

[6]  E. de Boer,et al.  Masking and Discrimination , 1966 .

[7]  E. Zwicker,et al.  Subdivision of the audible frequency range into critical bands , 1961 .

[8]  Bertram Scharf.  Comments on “Masking and Discrimination” [C. E. Bos and E. de Boer, J. Acoust. Sec. Am. 39, 708–715 (1066)] , 1966 .

[9]  Günter Ehret,et al.  Frequency and intensity difference limens and nonlinearities in the ear of the housemouse (Mus musculus) , 1975, Journal of comparative physiology.

[10]  G. Békésy,et al.  Experiments in Hearing , 1963 .

[11]  E. Zwicker,et al.  A MODEL OF LOUDNESS SUMMATION. , 1965, Psychological review.

[12]  S. S. Stevens,et al.  The Masking of Pure Tones and of Speech by White Noise , 1950 .

[13]  B. Scharf.  Complex sounds and critical bands. , 1961, Psychological bulletin.

[14]  George Gourevitch.  Detectability of Tones in Quiet and in Noise by Rats and Monkeys , 1970 .

[15]  S. S. Stevens,et al.  Critical Band Width in Loudness Summation , 1957 .

[16]  John A. Swets,et al.  On the Width of Critical Bands , 1962 .

[17]  J MEAD,et al.  Mechanical properties of lungs. , 1961, Physiological reviews.

[18]  G. Ehret.  Age-dependent hearing loss in normal hearing mice , 1974, Naturwissenschaften.

[19]  G. Gourevitch.  AUDITORY MASKING IN THE RAT. , 1965, Journal of the Acoustical Society of America.

[20]  H. Markl,et al.  Die Hörschwelle der Maus (Mus musculus) , 1973 .