An investigation of place and voice features using fMRI-adaptation

• fMRI-adaptation used to investigate featural properties of speech encoding.
• Feature-level encoding found in mid- and posterior-STG/STS bilaterally.
• Changes in place and voicing elicit spatially discrete representations.
• Findings supported in single-subject and group-level analysis.

A widely accepted view of speech perception holds that in order to comprehend language, the variable acoustic signal must be parsed into a set of abstract linguistic representations. However, the neural basis of early phonological processing, including the nature of featural encoding of speech, is still poorly understood. In part, progress in this domain has been constrained by the difficulty inherent in extricating the influence of acoustic modulations from those which can be ascribed to the abstract, featural content of the stimuli. A further concern is that group averaging techniques may obscure subtle individual differences in cortical regions involved in early language processing. In this paper we present the results of an fMRI-adaptation experiment which finds evidence of areas in the superior and medial temporal lobes which respond selectively to changes in the major feature categories of voicing and place of articulation. We present both single-subject and group-averaged analyses.