Cascading Oscillators in Decoding Speech: Reflection of a Cortical Computation Principle
Technical Report,01 Sep 2011,31 Aug 2016
Trustees Of Boston University Boston United States
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Motivated by the possible role of brain rhythms in cortical function, we postulate a cortical computation principle by which decoding is performed within a time-varying window structure, synchronized with the input on multiple time scales. The windows are generated by a segmentation process, implemented by an array of cascaded oscillators. Correct segmentation is a critical prerequisite for correct decoding, and segmentation is correct as long as the oscillators successfully track the input rhythms. Syllabic segmentation utilizes flexible oscillators operating in the theta range 39Hz by tracking the input syllabic rhythms, and prosodic segmentation is driven by flexible oscillators in the delta range0.53 Hz, tracking prosodic rhythms. A model TEMPO was developed which is capable of explaining a variety of psychophysical and neuroimaging data difficult to explain by current models of speech perception, but emerging naturally from the architecture of the model. The key properties that enable such accountability are i the capability of the oscillators to track and stay locked to the input rhythm, and ii the cascaded nature of the oscillators within the array.
- Voice Communications