Analysis Tools
behavior/neurological
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• when dropped into a tank of water, most homozygous mice spiral immediately downward and require rescuing
(J:49524)
• a small number of homozygotes could keep the nose but not the tail out of water; a few others could sometimes find the water surface but occasionally required rescuing
(J:49524)
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hearing/vestibular/ear
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• mice do not appear to have any hearing loss; ABR threshold determination shows similar levels compared to controls for all sound pressure levels tested
• histological analysis shows a grossly normal appearance of the middle ear and the bony and membranous labyrinths
• the sensory epithelia and otoconial membranes appear similar to controls; the otolithic membrane is visible over the surface of the maculae and there is no significant difference in the density of hair cells in the saccular and utricular maculae
• the cochlear duct, including the sensory and suppporting cells, cochlear nerve fibers and the tectorial membrane all appear similar to controls
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• complete absence of otoconia from the saccule and the utricle is observed at 3-5 weeks of age as well as E17.5 and newborn homozygous mice
(J:49524)
• in the rare mice that show a partial ability to swim, either otoconia are completely absent, or one or more giant otoconia are seen in the saccule
(J:49524)
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• absent vestibular nerve compund action potentials in response to linear acceleration at 9 and 16 pulses/s
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nervous system
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• morphometric analysis of the total vestibular ganglion volume and total cellular volume shows that mutants have reduced levels and developed slower than controls in the first 12 days of postnatal life
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