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On the processing of vowels in the mammalian auditory system

The mammalian auditory system generates representations of the physical world in terms of auditory objects. To decide which object class a particular sound belongs to, the auditory system must recognise the patterns of acoustic components that form the acoustic “fingerprint” of the sound’s auditory class. Where in the central auditory system such patterns are detected and what form the neural processing takes that underlies their detection are unanswered questions in sensory neurophysiology. In the research conducted for this thesis I used artificial vowel sounds to explore the neural and perceptual characteristics of auditory object recognition in rats. I recorded cortical responses from the primary auditory cortex (A1) in anaesthetised rats and determined how well the spiking responses, evoked by artificial vowels, resolve the spectral components that define vowel classes in human perception. The recognition of an auditory class rests on the ability to detect the combination of spectral components that all member sounds of the class share. I generated and evaluated models of the integration by A1 responses of the acoustic components that define human vowels classes. The hippocampus is a candidate area for neural responses that are specific to particular object classes. In this thesis I also report the results of a collaboration during which we investigated how the hippocampus responds to vowels in awake behaving animals. Finally, I explored the processing of vowels behaviourally, testing the perceptual ability of rats to discriminate and classify vowels and in particular whether rats use combinations of spectral components to recognise members of vowel classes. For the behavioural training I built a novel integrated housing and training cage that allows rats to train themselves in auditory recognition tasks. Combining the results and methods presented in this thesis will help reveal how the mammalian auditory system recognises auditory objects.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:581204
Date January 2013
CreatorsHoney, Christian
ContributorsSchnupp, Jan
PublisherUniversity of Oxford
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Sourcehttp://ora.ox.ac.uk/objects/uuid:9931670b-2cec-423a-bfcf-013f17a2b206

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