Fuglsang Søren A, Märcher-Rørsted Jonatan, Madsen Kristoffer H, Frantzen Ditte H, Encina-Llamas Gerard, Sørensen Charlotte, Dyrby Tim B, Dau Torsten, Hjortkjær Jens, Siebner Hartwig R
Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital-Amager and Hvidovre, Copenhagen, Denmark.
Hearing Systems Section, Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, Denmark.
Imaging Neurosci (Camb). 2024 Jul 17;2. doi: 10.1162/imag_a_00238. eCollection 2024.
Age-related alterations in the auditory system have been suggested to affect the processing of temporal envelope amplitude modulations (AM) at different levels of the auditory hierarchy, yet few studies have used functional magnetic resonance imaging (fMRI) to study this noninvasively in humans with high spatial resolution. In this study, we utilized sparse-sampling fMRI at 3 Tesla (3T) to investigate regional blood oxygenation level-dependent (BOLD) responses to AM noise stimuli in 65 individuals ranging in age from 19 to 77 years. We contrasted BOLD responses to AM noise stimuli modulated at 4 Hz or 80 Hz with responses to unmodulated stimuli. This allowed us to derive functional measures of regional neural sensitivity to the imposed AM. Compared with unmodulated noise, slowly varying 4 Hz AM noise stimuli elicited significantly greater BOLD responses in the left and right auditory cortex along the Heschl's gyrus (HG). BOLD responses to the 80 Hz AM stimuli were significantly greater than responses to unmodulated stimuli in putatively primary auditory cortical regions in the lateral HG. BOLD responses to 4 Hz AM stimuli were significantly greater in magnitude than responses to 80 Hz AM stimuli in auditory cortical regions. We find no discernible effects of age on the functional recruitment of the auditory cortex by AM stimuli. While the results affirm the involvement of the auditory cortex in processing temporal envelope rate information, they provide no support for age-related effects on these measures. We discuss potential caveats in assessing age-related changes in responses to AM stimuli in the auditory pathway.
听觉系统中与年龄相关的变化被认为会在听觉层级的不同水平上影响时间包络幅度调制（AM）的处理，但很少有研究使用功能磁共振成像（fMRI）以高空间分辨率对人类进行非侵入性研究。在本研究中，我们利用3特斯拉（3T）的稀疏采样fMRI，调查了65名年龄在19岁至77岁之间的个体对AM噪声刺激的局部血氧水平依赖（BOLD）反应。我们将对4赫兹或80赫兹调制的AM噪声刺激产生的BOLD反应与对未调制刺激的反应进行了对比。这使我们能够得出局部神经对施加的AM的敏感性的功能测量值。与未调制的噪声相比，缓慢变化的4赫兹AM噪声刺激在沿赫氏回（HG）的左右听觉皮层中引发了明显更大的BOLD反应。在外侧HG中假定的初级听觉皮层区域，对80赫兹AM刺激的BOLD反应明显大于对未调制刺激的反应。在听觉皮层区域，对4赫兹AM刺激的BOLD反应在幅度上明显大于对80赫兹AM刺激的反应。我们没有发现年龄对AM刺激引起的听觉皮层功能募集有明显影响。虽然结果证实了听觉皮层参与处理时间包络率信息，但它们没有为年龄对这些测量值的影响提供支持。我们讨论了评估听觉通路中对AM刺激反应的年龄相关变化时的潜在注意事项。
