title: Human auditory cortex is sensitive to the perceived clarity of speech.
abstract: 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.
authors.affiliation: Centre for Neuroscience Studies, Queen's University, Kingston ON, Canada. conorwild@gmail.com
authors.forename: Conor J
authors.initials: CJ
authors.lastname: Wild
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Davis
authors.forename: Ingrid S
authors.initials: IS
authors.lastname: Johnsrude
mesh_terms: D000293:Adolescent; D000328:Adult; D001303:Auditory Cortex / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D013060:Speech; D013067:Speech Perception / Q000502:physiology*; D055815:Young Adult