Cerebral Representation of Sound Localization Using Functional Near-Infrared Spectroscopy

Xuexin Tian; Yimeng Liu; Zengzhi Guo; Jieqing Cai; Jie Tang; Fei Chen; Hongzheng Zhang

doi:10.3389/fnins.2021.739706

Cerebral Representation of Sound Localization Using Functional Near-Infrared Spectroscopy

Front Neurosci. 2021 Dec 14:15:739706. doi: 10.3389/fnins.2021.739706. eCollection 2021.

Authors

Xuexin Tian¹, Yimeng Liu¹, Zengzhi Guo², Jieqing Cai¹, Jie Tang^{1

3

4

5}, Fei Chen², Hongzheng Zhang^{1

4}

Affiliations

¹ Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
² Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, China.
³ Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.
⁴ Hearing Research Center, Southern Medical University, Guangzhou, China.
⁵ Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou, China.

Abstract

Sound localization is an essential part of auditory processing. However, the cortical representation of identifying the direction of sound sources presented in the sound field using functional near-infrared spectroscopy (fNIRS) is currently unknown. Therefore, in this study, we used fNIRS to investigate the cerebral representation of different sound sources. Twenty-five normal-hearing subjects (aged 26 ± 2.7, male 11, female 14) were included and actively took part in a block design task. The test setup for sound localization was composed of a seven-speaker array spanning a horizontal arc of 180° in front of the participants. Pink noise bursts with two intensity levels (48 dB/58 dB) were randomly applied via five loudspeakers (-90°/-30°/-0°/+30°/+90°). Sound localization task performances were collected, and simultaneous signals from auditory processing cortical fields were recorded for analysis by using a support vector machine (SVM). The results showed a classification accuracy of 73.60, 75.60, and 77.40% on average at -90°/0°, 0°/+90°, and -90°/+90° with high intensity, and 70.60, 73.6, and 78.6% with low intensity. The increase of oxyhemoglobin was observed in the bilateral non-primary auditory cortex (AC) and dorsolateral prefrontal cortex (dlPFC). In conclusion, the oxyhemoglobin (oxy-Hb) response showed different neural activity patterns between the lateral and front sources in the AC and dlPFC. Our results may serve as a basic contribution for further research on the use of fNIRS in spatial auditory studies.

Keywords: auditory cortex (AC); cerebral cortex; dorsolateral prefrontal cortex (dlPFC); functional near-infrared spectroscopy (fNIRS); sound localization; spatial hearing.