Otsuka Asuka, Yumoto Masato, Kuriki Shinya, Hotehama Takuya, Nakagawa Seiji
Biomedical Research Institute, The National Institute of Advanced Industrial Science and Technology (AIST), Osaka, Japan; Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Clin Neurophysiol. 2016 Jan;127(1):790-802. doi: 10.1016/j.clinph.2015.05.002. Epub 2015 May 11.
This study aimed to capture the neuronal frequency characteristics, as indexed by the auditory steady-state response (ASSR), relative to physical characteristics of constant sound pressure levels (SPLs). Relationship with perceptual characteristics (loudness model) was also examined.
Neuromagnetic 40-Hz ASSR was recorded in response to sinusoidally amplitude-modulated sweep tones with carrier frequency covering the frequency range of 0.1-12.5kHz. Sound intensity was equalized at 50-, 60-, and 70-dB SPL with an accuracy of ±0.5-dB SPL at the phasic peak of the modulation frequency. Corresponding loudness characteristics were modeled by substituting the detected individual hearing thresholds into a standard formula (ISO226:2003(E)).
The strength of the ASSR component was maximum at 0.5kHz, and it decreased linearly on logarithmic scale toward lower and higher frequencies. Loudness model was plateaued between 0.5 and 4kHz.
Frequency characteristics of the ASSR were not equivalent to those of SPL and loudness model. Factors other than physical and perceptual frequency characteristics may contribute to characterizing the ASSR.
The results contribute to the discussion of the most efficient signal summation for the generation of the ASSR at 0.5kHz and efficient neuronal processing at higher frequencies, which require less energy to retain equal perception.
本研究旨在获取以听觉稳态反应（ASSR）为指标的神经元频率特征，相对于恒定声压级（SPL）的物理特征。还研究了与感知特征（响度模型）的关系。
记录对载波频率覆盖0.1 - 12.5kHz频率范围的正弦调幅扫频音的神经磁40Hz ASSR。在调制频率的相位峰值处，声强在50、60和70dB SPL下进行均衡，精度为±0.5dB SPL。通过将检测到的个体听力阈值代入标准公式（ISO226:2003(E)）来模拟相应的响度特征。
ASSR成分的强度在0.5kHz时最大，并在对数尺度上向低频和高频方向线性下降。响度模型在0.5至4kHz之间呈平稳状态。
ASSR的频率特征与SPL和响度模型的频率特征不同。除了物理和感知频率特征之外的因素可能有助于表征ASSR。
这些结果有助于讨论在0.5kHz产生ASSR时最有效的信号总和以及在较高频率下有效的神经元处理，在较高频率下保持同等感知所需的能量较少。
