A morphometric study of the cochlea of the little brown bat (<i>Myotis lucifugus</i>)

Ramprashad, Fred; Landolt, Jack P.; Money, K. E.; Clark, Diana; Laufer, Jerry

doi:10.1002/jmor.1051600306

Cited by 23 publications

(18 citation statements)

References 30 publications

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“…The thickening of the pars pectinata in the rabbit is similar to that reported in the cat (Cabezudo 1978), in Microchiroptera (lkeda andYokote 1939;Pye 1966u, 1966bPye 1966u, , 1967Henson 1970;Hall 1969;Ramprashad et ul. 1978;Ramprashad 1979), in the house mouse (Ehret and Frankenreiter 1977), and in Heteromyidae (Pye 1965;Webster and Webster 1977). In Microchiroptera, the greatest thickening occurs within the basal coil.…”

Section: Initial Increases In Height With the Maximal Values In Similarmentioning

confidence: 97%

“…1979). Morphometric studies of the microchiropteran cochlea suggested that the frequencies used for echolocation coincided with a region of the basilar membrane in which morphological discontinuities occur (Bruns 1976a, 19766;Ramprashad et al 1979). Furthermore, Ehret and Frankenreiter (1977) have indicated that although the house mouse (Mus rnusc.ulus) is maximally sensitive to 15 kHz, the frequency of 50 kHz also occurs within a region of morphological discontinuity in the basilar membrane.…”

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confidence: 94%

“…Comparative aspects of the changes in width of the basilar membrane The variation in the width of the basilar membrane has been measured in several mammals: e.g., in the human (Guild 1927;Wever 1938), in the guinea pig (Fernandez 1952), in the cat (Cabezudo 1978), in the heteromyid rodent (Pye 1965;Webster and Webster 1977), in the house mouse (Ehret and Frankenreiter 1977), in some Cetacea (Wever et ul. 197 1, 1972), in some Microchiroptera (Pye 1966a(Pye , 1966b(Pye , 1967Bruns 1976a;Henson 1978;Ramprashad et al 1979), and in the two-toed sloth (Ramprashad et al 1983). These studies have shown that in general, the basilar membrane increases in width between the base and the apex.…”

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confidence: 97%

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Morphometric study of the cochlea of the rabbit (Oryctulagus cuniculus)

Ramprashad¹,

Landolt²,

Money³

et al. 1984

Can. J. Zool.

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1984. Morphometric study of the cochlea of the rabbit ( Orw-rulngus tunic-ulus ). Can. J . Zool . 62: 2476 -248 1 .A detailed morphometric study of the cochleae in four rabbits (0ryc~rultrgu.s c~unic~u1u.s) was made from graphic reconstructions of serial sections. Morphometric changes studied along the length of the cochlea were ( i ) the cross-sectional areas of the scalae vestibuli, tympani. and media, ( i i ) the width of the basilar membrane. (iii) the cross-sectional area and thickness of the basilar membrane, and ( i v ) the density of the bipolar ganglion cells innervating the organ of Corti. Changes in the cross-sectional areas of the scalae tympani and vestibuli were similar, both decrease from the cochlear base to 1.2 mm, increase to maximum values of 1.4 mm' at 3.0 mm. and decrease to 0.4 mm' at 4.3 mm. The cross-sectional area of the scala media remained unchanged. Three distinct morphometric changes were observed in the width and cross-sectional area of the basilar membrane. Firstly, there is a steep increase from the basal end to 3.2 mm. secondly a gradual increase from 3.2 to 8.5 mm, and thirdly, the greatest values occurred between 8.5 and 9.

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Section: Initial Increases In Height With the Maximal Values In Similarmentioning

confidence: 97%

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confidence: 94%

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confidence: 97%

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Morphometric study of the cochlea of the rabbit (Oryctulagus cuniculus)

Ramprashad¹,

Landolt²,

Money³

et al. 1984

Can. J. Zool.

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“…It is, therefore, interesting to note that the hearing range of the little brown bat is from 1 to 150 kHz and that the Boettcher cells in that animal are distributed throughout 90% of the length of the cochlea. Ramprashad et al (1979) showed that Greenwood's (1961) equation may be used to plot the relative position of maximum amplitude of vibration along the length of the basilar membrane for frequencies within the range of hearing of the little brown bat. Figure 10, which is a plot of this equation, shows that even though the frequency 2 kHz may be represented within a broad region of the curve, i.e., between 4.8 and 5.1 mm, the calculations indicate that the position of maximum amplitude for 2-kHz sound waves is approximately 5.1 mm from the basal end of the cochlea.…”

Section: Height Of Boettcher Cellsmentioning

confidence: 99%

“…The hearing range of that mammal varies from 1 to 32 kHz in Curve showing the theoretical frequency of vibration which is mapped along the length of the cochlea using Greenwood's (1961) formula for Myotis Zucifugus (reproduced from Ramprashad et al, 1979). Note air, while underwater it ranges from 0.7 to 100 kHz Ronald, 1971, 1972).…”

Section: Height Of Boettcher Cellsmentioning

confidence: 99%

Distribution and size of Boettcher cells in the little brown bat, rabbit, and other species

Ramprashad

Money²,

Landolt³

et al. 1983

Anat. Rec.

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The distribution and size of Boettcher cells were determined from serial sections of the temporal bones of four little brown bats and six rabbits. In addition, one harp seal and one two-toed sloth were examined. In the little brown bat, the heights of the Boettcher cells measured 4-8 micron and they were found throughout much of the length of the cochlea. There were four rows in most of the lower basal coil, five rows in the upper basal coil, and four rows in the middle coil. In the rabbit there were nine rows in the basal coil and 12 rows in the middle coil. The heights of the Boettcher cells were approximately 14 micron in the rabbit. In the two-toed sloth, Boettcher cells were sparsely distributed along the basal coil; similarly, in the harp seal, Boettcher cells were confined solely to the basal coil, where there were only three rows, which measured approximately 18 micron in height. The distribution and size of Boettcher cells in the rabbit and the little brown bat were compared to those in other mammalian species.

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Neuromorphometric features and dimensional analysis of the vestibular end organ in the little brown bat (Myotis lucifugus)

Ramprashad

Landolt²,

Money³

et al. 1980

J of Comparative Neurology

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Neuromorphometric parameters of the vestibular system were determined from serial sections of temporal bones from four little brown bats. Well-developed eminentiae cruciatae project from the cristae ampullares of the anterior and posterior membranous ampullae. A total of 4,500 bipolar ganglion cells were enumerated within the vestibular ganglion. The widths of the cell somas varied from 2.5 to 20 micrometers, with 70% of them having widths between 5.0 and 12.5 micrometers. Two maxima were observed in a curve of ganglion cell density as a function of the length of the ganglion. The first maximum indicated a density of 4,800 cells per mm2 at a length 0.20 from the apex of the ganglion (in the pars dorsalis); the second, a density of 4,750 cells per mm2 at 0.38 mm (in the pars ventralis). The morphometric parameters studied were the radii of curvature of the semicircular ducts, the cross-sectional diameters of the semicircular canals and ducts, the dimensions of the cristae ampullares and their membranous ampullae, and dimensions pertaining to the statoconial organs. Surface areas (measured from graphic projections) were determined as 0.098 mm2 and 0.016 mm2 and hair cell count 500 and 1,300 cells for the saccular and utricular maculae, respectively. The radii of curvature of the three semicircular ducts, R, were dissimilar, with the anterior duct having the largest radius (R = 0.91 mm) and the posterior duct the smallest one (R = 0.69 mm). The average cross-sectional diameters of the anterior, lateral, and posterior ducts were measured as 0.11 mm, 0.14 mm, and 0.13 mm, respectively. Some of the morphological parameters were used to ascertain information regarding the dynamics of semicircular--canal function. In particular, the coefficients theta and II in the torsion pendulum model (Steinhausen, '31; Egmond et al., '49), and the time constants xi L congruent to II/delta and xi S congruent to theta/II of the torsion pendulum model were estimated for the little brown bat from these parameters. Where appropriate, comparisons were made to time constants obtained for other species.

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A morphometric study of the cochlea of the little brown bat (Myotis lucifugus)

Cited by 23 publications

References 30 publications

Morphometric study of the cochlea of the rabbit (Oryctulagus cuniculus)

Morphometric study of the cochlea of the rabbit (Oryctulagus cuniculus)

Distribution and size of Boettcher cells in the little brown bat, rabbit, and other species

Neuromorphometric features and dimensional analysis of the vestibular end organ in the little brown bat (Myotis lucifugus)

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