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Modulation of activity in the auditory pathway by the auditory cortex| old_uid | 5944 |
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| title | Modulation of activity in the auditory pathway by the auditory cortex |
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| start_date | 2009/01/12 |
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| schedule | 11h-12h30 |
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| online | no |
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| summary | It is generally acknowledged that the act of listening is more than a process of passively hearing sounds. We bring to listening, experience of the world and our own predispositions and we are able to concentrate our listening efforts to select specific information from the incoming sounds. It is often assumed that these top down aspects of listening are mediated via the descending auditory nervous system. Alongside the complex ascending auditory system there is an equally complex descending system that provides the framework through which auditory centres all the way up to the auditory cortex are able to modulate the flow of incoming information. Certainly, attention considerably modifies the amount of activation of the auditory cortex and must also thereby alter the feedback to the lower centres. We have begun to study the function of these descending pathways by using a technique that allows us to reversibly inactivate the cortex in an animal model. We have shown widespread influences of the cortical output in the auditory thalamus and auditory midbrain. Even using a rather crude cortical inactivation technique, we have revealed a range of effects some of which appear to selectively affect inputs to these nuclei that arrive from the two ears. As a consequence we have shown that at least some of the sensitivity to binaural cues is under cortical control. It is not too much of a stretch of the imagination to suggest that such mechanisms might be involved in spatial attention to sound or at the very least in plasticity to localization cues. More recently we have been studying the effect that inactivation of the cortex has on the functioning of the cochlea. We have found changes in the threshold and amplitude of the cochlear potentials. While this is most likely the result of the cortex modulating the activity of the brainstem reflex circuits our results are currently not entirely consistent with this hypothesis. |
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| responsibles | Waszak |
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