Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6032182 | NeuroImage | 2012 | 13 Pages |
Feedback connections among auditory cortical regions may play an important functional role in processing naturalistic speech, which is typically considered a problem solved through serial feed-forward processing stages. Here, we used fMRI to investigate whether activity within primary auditory cortex (PAC) is sensitive to the perceived clarity of degraded sentences. A region-of-interest analysis using probabilistic cytoarchitectonic maps of PAC revealed a modulation of activity, in the most primary-like subregion (area Te1.0), related to the intelligibility of naturalistic speech stimuli that cannot be driven by stimulus differences. Importantly, this effect was unique to those conditions accompanied by a perceptual increase in clarity. Connectivity analyses suggested sources of input to PAC are higher-order temporal, frontal and motor regions. These findings are incompatible with feed-forward models of speech perception, and suggest that this problem belongs amongst modern perceptual frameworks in which the brain actively predicts sensory input, rather than just passively receiving it.
⺠Abstract linguistic information modulates activity within primary auditory cortex. ⺠This effect is specific to degraded speech that is potentially intelligible. ⺠Reflects increased perceptual clarity resulting from knowledge-based cues. ⺠Is consistent with interactive, not feed-forward, accounts of speech perception.