عنوان

The Ability of Hamsters (Mesocricetus auratus) to Use the Binaural Phase Cue to Localize Sound

Number

TLpq2322825137

.Language of Text, Soundtrack etc

انگلیسی

Title Proper

The Ability of Hamsters (Mesocricetus auratus) to Use the Binaural Phase Cue to Localize Sound

General Material Designation

[Thesis]

First Statement of Responsibility

Cumming, John Freeman, IV

Name of Publisher, Distributor, etc.

The University of Toledo

Date of Publication, Distribution, etc.

2019

Specific Material Designation and Extent of Item

49

Dissertation or thesis details and type of degree

M.A.

Body granting the degree

The University of Toledo

Text preceding or following the note

2019

Text of Note

There are two binaural cues for localizing sound in the horizontal plane: the difference in the time of arrival of a sound at the two ears (binaural time-difference cue) and the difference in the intensity of a sound at the two ears (binaural intensity-difference cue). When localizing pure tones, the binaural time-difference cue is often referred to as a binaural phase-difference cue, with the sound reaching the two ears expressed as a phase difference (i.e., the difference in the phase of a sine wave at the two ears). Previous studies concerning the neural basis of sound localization have shown that damage to auditory cortex in carnivores and primates abolishes their ability to perceive the location of a sound in space (e.g., Neff, Fisher, Diamond & Yela, 1956; Heffner, 2004), whereas damage to auditory cortex in laboratory rats has little effect on their ability to localize sound (Kavanagh & Kelly, 1986). One possible explanation for this species difference is that rodents, in general, do not use auditory cortex for sound localization. Another is that auditory cortex is necessary for sound localization in animals that use the binaural time-difference cue, such as carnivores and primates, but not in animals that do not use that cue, such as rats (Wesolek, Koay, Heffner & Heffner, 2010). The goal of this study was to determine which of these two explanations is correct by identifying a rodent that used the binaural time-difference cue so that future studies might determine whether damage to auditory cortex affected its ability to localize sound. Thus, this study was to investigate whether hamsters (Mesocricetus auratus) use the binaural time-difference cue by determining their ability to localize low-frequency tones presented from loudspeakers located 30° to the left and right of their midline (60° total separation)-a task that requires the ability to use the binaural time-difference cue. If they could, then they could be studied to determine if the sound-localization ability of a rodent that uses the binaural time cue is affected by ablation of auditory cortex (as are carnivores and primates). The hamsters' ability to localize low frequencies from 125 Hz to 2 kHz, as well as a 4-kHz carrier tone modulated at 250 and 500 Hz, demonstrated their ability to use the binaural phase-difference cue. The hamsters were also able to localize high-frequency pure tones where the binaural phase-difference cue was ambiguous, demonstrating that they could use the binaural intensity-difference cue. Even though the binaural phase-difference cue was estimated to be physically unambiguous up to 9.175 kHz at ± 30°, the hamsters were only able to use the cue up to 2.4 kHz. Additionally, although binaural intensity differences were estimated to only be available above 13.902 kHz, the hamsters were able to use the cue far below this at 5.6 kHz. Although it was found that hamsters do use both binaural cues, the length of time required to train and test them, coupled with their relatively short lifespan of 2 years, makes them unsuitable for the behavioral study of the effect of cortical lesions on sound localization. However, these results contribute to a larger body of comparative localization research, adding to the sample of small rodents known to use the binaural time-difference cue.

Acoustics

Behavioral sciences

Biophysics

Experimental psychology

Psychobiology

Zoology

Cumming, John Freeman, IV

Electronic name

p

[Thesis]

276903

a

Y