Left frontal eye field encodes sound locations during passive listening

Previous studies reported that auditory cortices (AC) were mostly activated by sounds coming from the contralateral hemifield. As a result, sound locations could be encoded by integrating opposite activations from both sides of AC (opponent hemifield coding). However, human auditory where pathway also includes a series of parietal and prefrontal regions. It was unknown how sound locations were represented in those high-level regions during passive listening. Here, we investigated the neural representation of sound locations in high-level regions by voxel-level tuning analysis, regions-of-interest-level (ROI-level) laterality analysis, and ROI-level multivariate pattern analysis. Functional magnetic resonance imaging data were collected while participants listened passively to sounds from various horizontal locations. We found that opponent hemifield coding of sound locations not only existed in AC, but also spanned over intraparietal sulcus, superior parietal lobule, and frontal eye field (FEF). Furthermore, multivariate pattern representation of sound locations in both hemifields could be observed in left AC, right AC, and left FEF. Overall, our results demonstrate that left FEF, a high-level region along the auditory where pathway, encodes sound locations during passive listening in two ways: a univariate opponent hemifield activation representation and a multivariate full-field activation pattern representation.

Automated summary

This study investigated the neural representation of sound locations in high-level regions using various analysis methods. The results showed that besides the auditory cortices, regions such as the intraparietal sulcus, superior parietal lobule, and frontal eye field were also activated to different extents by sound locations. Additionally, both hemispheres of the auditory cortices and the left frontal eye field exhibited a multivariate pattern representation of sound locations.