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However, it is possible that the high-frequency reversal borders also contain broadly tuned subpopulations of neurons, functioning to integrate a wide range of ultra- sonic sensory input for both the A1 and AAF. Researchers sometimes avoid probing these regions near the borders to prevent “contamination” from the accidental recording of neurons from neighboring regions (Carrasco et al., 2015). Due to this precaution, studies may fail to record from the neurons with the highest characteristic frequencies, lim- iting our understanding of the cortical representation of ultrasonic stimuli in cats and other terrestrial mammals.
Conclusion
Ultrasound is essential to the lives of many animals, evi- denced by the magnitude of cortical space allocated specifically for ultrasound in some species. Despite the biological importance of ultrasound, researchers might have been underestimating the ultrasonic hearing abilities of many terrestrial mammals. It is therefore also possible that the extent of the ultrasonic abilities of some terrestrial mammals, as discussed in this article, has not yet been conclusively established. Until this matter is clarified, the location in the brain where these frequencies are encoded also remains uncertain. Further investigations may elu- cidate uncertainties in our understanding of the role of ultrasonic frequencies in auditory neuroscience as a whole.
References
Arch, V. S., and Narins, P. M. (2008). “Silent” signals: Selective forces acting on ultrasonic communication systems in terrestrial vertebrates. Animal Behav- iour 76, 1423-1428. https://doi.org/10.1016/j.anbehav.2008.05.012.
Bajo, V. M., Nodal, F. R., Bizley, J. K., Moore, D. R., and King, A. J. (2006). The ferret auditory cortex: descending projections to the inferior colliculus. Cerebral Cortex 17, 475-491. https://doi.org/10.1093/cercor/bhj164.
Bizley, J. K., Nodal, F. R., Nelken, I., and King, A. J. (2005). Functional organization of ferret auditory cortex. Cerebral Cortex 15, 1637-1653. https://doi.org/10.1093/cercor/bhi042.
Brown, K. A., Buchwald, J. S., Johnson, J. R., and Mikolich, D. J. (1978). Vocalization in the cat and kitten. Developmental Psychobiology 11, 559-570. https://doi.org/10.1002/dev.420110605.
Carovac, A., Smajlovic, F., and Junuzovic, D. (2011). Application of ultrasound in medicine. Acta Informatica Medica 19(3), 168-171. https://doi.org/10.5455/aim.2011.19.168-171.
Carrasco, A., and Lomber, S. G. (2010). Reciprocal modulatory influ- ences between tonotopic and nontonotopic cortical fields in the cat. Journal of Neuroscience 30, 1476-1487. https://doi.org/10.1523/JNEUROSCI.5708-09.2009.
Carrasco, A., Kok, M. A., and Lomber, S. G. (2015). Effects of core audi- tory cortex deactivation on neuronal response to simple and complex acoustic signals in the contralateral anterior auditory field. Cerebral Cortex 25, 84-96. https://doi.org/10.1093/cercor/bht205.
Costalupes, J. A. (1983). Temporal integration of pure tones in the cat. Hear- ing Research 9, 43-54. https://doi.org/10.1016/0378-5955(83)90133-8.
Dent, M. (2017). Animal psychoacoustics. Acoustics Today 13(3), 19-26.
Dunlap, A. G., and Liu, R. C. (2018). Rodent ultrasonic vocalization as a window into auditory cortical processing and plasticity. In S. M. Brudzynski (Ed.), Handbook of Behavioral Neuroscience. Academic Press, London, UK, pp. 83-93.
Ehret, G. (1974). Age-dependent hearing loss in normal hearing mice. Natur- wissenschaften 61, 506-507. https://doi.org/10.1007/BF00622976.
Ehret, G., and Romand, R. (1981). Postnatal development of absolute auditory thresholds in kittens. Journal of Comparative and Physiolog- ical Psychology 95, 304-311. https://doi.org/10.1037/h0077770.
Elliott, D. N., Stein, L., and Harrison, M. J. (1960). Determination of absolute‐intensity thresholds and frequency‐difference thresh- olds in cats. Journal of the Acoustical Society of America 32, 380-384. https://doi.org/10.1121/1.1908071.
Farley, S. D., Lehner, P. N., Clark, T., and Trost, C. (1987). Vocalizations of the Siberian ferret (Mustela eversmanni) and com- parisons with other mustelids. Journal of Mammalogy 68, 413-416. https://doi.org/10.2307/1381487.
Fritz, J. B., Elhilali, M., David, S.V., and Shamma, S. A. (2007). Does attention play a role in dynamic receptive field adaptation to chang- ing acoustic salience in A1? Hearing Research 229(1-2), 186-203. https://doi.org/10.1016/j.heares.2007.01.009.
Gerken, G. M., and Sandlin, D. (1977). Auditory reaction time and absolute threshold in cat. Journal of the Acoustical Society of America 61, 602-606. https://doi.org/10.1121/1.381306.
Gerken, G. M., Saunders, S. S., Simhadri-Sumithra, R., and Bhat, K. H. V. (1985). Behavioral thresholds for electrical stimulation applied to auditory brain- stem nuclei in cat are altered by injurious and noninjurious sound. Hearing Research 20, 221-231. https://doi.org/10.1016/0378-5955(85)90027-9.
Gourbal, B. E. F., Barthelemy, M., Petit, G., and Gabrion, C. (2004). Spectrographic analysis of the ultrasonic vocalisations of adult male and female BALB/c mice. Naturwissenschaften, 91(8), 381-385. https://doi.org/10.1007/s00114-004-0543-7.
Hall, A. J., and Lomber, S. G. (2015). High-field fMRI reveals tono- topically-organized and core auditory cortex in the cat. Hearing Research 325, 1-11. https://doi.org/10.1016/j.heares.2015.03.003.
Harvey, G., Gachagan, A., and Mutasa, T. (2014). Review of high- power ultrasound-industrial applications and measurement methods. IEEE Transactions on Ultrasonics Ferroelectrics, and Frequency Con- trol, 61(3), 481-495. https://doi.org/10.1109/TUFFC.2014.2932.
Heffner, H. E. (1983). Hearing in large and small dogs: Absolute thresholds and size of the tympanic membrane. Behavioral Neurosci- ence 97(2), 310-318. https://doi.org/10.1037/0735-7044.97.2.310.
Heffner, R. S., and Heffner, H. E. (1982). Hearing in the elephant (Ele- phas maximus): Absolute sensitivity, frequency discrimination, and sound localization. Journal of Comparative and Physiological Psychol- ogy 96(6), 926-944. https://doi.org/10.1037/0735-7036.96.6.926. Heffner, R. S., and Heffner, H. E. (1985). Hearing range of the domestic cat. Hear- ing Research 19, 85-88. https://doi.org/10.1016/0378-5955(85)90100-5.
Heffner, R. S., Koay, G., and Heffner, H. E. (2001). Audiograms of five species of rodents: Implications for the evolution of hearing and the perception of pitch. Hearing Research 157(1-2), 138-152. https://doi.org/10.1016/S0378-5955(01)00298-2.
Hofer, M. A., Shair, H. N., and Brunelli, S. A. (2001). Ultrasonic vocal- izations in rat and mouse pups. Current Protocols in Neuroscience 17(1), 8.14.1-8.14.16. https://doi.org/10.1002/0471142301.ns0814s17.
Hofstetter, K. M. and Ehret, G. (1992). The auditory cortex of the mouse: connections of the ultrasonic field. Journal of Comparative Neurology 323, 370-386. https://doi.org/10.1002/cne.903230306.
Jensen, J. A. (2007). Medical ultrasound imaging. Progress in Biophys- ics and Molecular Biology 93(1-3), 153-165. https://doi.org/10.1016/j.pbiomolbio.2006.07.025.
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