Subcortical and cortical neural correlates of individual differences in temporal auditory acuity

Abstract

Parsing complex auditory scenes requires the activation and coordination of many neuronal centers, both in subcortical and cortical portions of the auditory pathway. Several studies have demonstrated that even normal-hearing listeners exhibit a range of abilities on various auditory tasks. Previous work in our lab suggests this variability may be due, in part, to degraded temporal encoding of supra-threshold stimuli at the level of the brainstem. A family of studies has shown that musical experience is correlated with differences in brainstem encoding as well as long-term plasticity in the cortex, results that provide the intriguing possibility that training may influence supra-threshold sound encoding. Here we explore methods for measuring subcortical and cortical neural activity in response to complex stimuli using electroencephalography (EEG). Subjects were tested in a passive mismatch negativity (MMN) paradigm using musical chords and tones. Brainstem frequency following responses (FFRs), a measure of subcortical temporal coding acuity, were measured in the same subjects using click trains. Finally, the same subjects performed a spatial selective attention task. These three measures were compared across the subject population to look for orderly relationships between brainstem coding, cortical response strength, and perceptual ability on an attentionally demanding task. © 2013 Acoustical Society of America.