Task-dependent decoding of speaker and vowel identity from auditory cortical response patterns

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Abstract

Selective attention to relevant sound properties is essential for everyday listening situations. It enables the formation of different perceptual representations of the same acoustic input and is at the basis of flexible and goal-dependent behavior. Here, we investigated the role of the human auditory cortex in forming behavior-dependent representations of sounds. We used single-trial fMRI and analyzed cortical responses collected while subjects listened to the same speech sounds (vowels /a/, /i/, and /u/) spoken by different speakers (boy, girl, male) and performed a delayed-match-to-sample task on either speech sound or speaker identity. Univariate analyses showed a task-specific activation increase in the right superior temporal gyrus/sulcus (STG/STS) during speaker categorization and in the right posterior temporal cortex during vowel categorization. Beyond regional differences in activation levels, multivariate classification of single trial responses demonstrated that the success with which single speakers and vowels can be decoded from auditory cortical activation patterns depends on task demands and subject's behavioral performance. Speaker/vowel classification relied on distinct but overlapping regions across the (right) mid-anterior STG/STS (speakers) and bilateral mid-posterior STG/STS (vowels), as well as the superior temporal plane including Heschl's gyrus/sulcus. The task dependency of speaker/vowel classification demonstrates that the informative fMRI response patterns reflect the top-down enhancement of behaviorally relevant sound representations. Furthermore, our findings suggest that successful selection, processing, and retention of task-relevant sound properties relies on the joint encoding of information across early and higher-order regions of the auditory cortex.
Original languageEnglish
Pages (from-to)4548-4557
Number of pages10
JournalJournal of Neuroscience
Volume34
Issue number13
DOIs
Publication statusPublished - 26 Mar 2014

Keywords

  • auditory cortex
  • fMRI decoding
  • speech
  • voice
  • vowels
  • TEMPORAL-LOBE
  • LANGUAGE COMPREHENSION
  • RECEPTIVE-FIELDS
  • CHILDRENS VOICES
  • HUMAN BRAIN
  • SPEECH
  • CORTEX
  • PERCEPTION
  • ACTIVATION
  • SOUNDS

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