Functional magnetic resonance imaging measurements of sound-level encoding in the absence of background scanner noise
Functional magnetic resonance imaging measurements of sound-level encoding in the absence of background scanner noise
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DOI：
10.1121/1.1345697
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发表时间：
2001-04-01
影响因子：
2.4
通讯作者：
Bowtell, RW
中科院分区：
文献类型：
--
作者：
Hall, DA;Haggard, MP;Bowtell, RW
在神经影像数据中可以看到声级对听觉皮层激活的影响。然而，皮质对强烈的环境扫描噪声和声刺激带宽的响应等因素都会影响对这种声级效应的精确量化和解释。本研究使用时间“稀疏”成像来减少扫描仪噪声的影响。为了实现对激励带宽的控制，对跨带宽声级匹配的三种方案进行了比较：分量级、均方根功率和响度。响度匹配的计算基于 Moore 和 Glasberg 报告的模型 [Acta Acust. 82, 335-345 (1996)]。使用功能磁共振成像 (fMRI) 对 10 名听力正常的志愿者进行扫描，同时聆听以 66 至 91 dB SPL 之间的六种不同声级呈现的 300 Hz 音调以及以 65 至 85 dB SPL 呈现的复合谐波音调 (F-0=186 Hz)。这个声级范围涵盖了声级匹配的所有三个基础。相对于安静基线条件，由八个音调条件中的每一个诱发的颞上回的激活被量化为范围和强度。声级对纯音的激活程度有微小但显着的影响，但对谐波复合音没有影响，而它对两种类型刺激的响应幅度都有显着影响。对于纯音的整个级别，响应幅度作为声级的函数线性增加。无论声级的匹配方案如何，谐波复合音比纯音产生更大的激活，这表明带宽对听觉激活模式的影响比声级更大。然而，当数据跨刺激类别折叠时，范围和幅度与响度尺度（以方测量）显着相关，但与强度尺度（以 SPL 测量）显着相关。因此，当皮质对其他刺激属性（例如刺激类别）的反应是主要关注点时，我们建议将响度公式作为匹配声级以控制响度效应的最合适基础。 (C) 2001 年美国声学学会。
Effects of sound level on auditory cortical activation are seen in neuroimaging data. However, factors such as the cortical response to the intense ambient scanner noise and to the bandwidth of the acoustic stimuli will both confound precise quantification and interpretation of such sound-level effects. The present study used temporally ''sparse'' imaging to reduce effects of scanner noise. To achieve control for stimulus bandwidth, three schemes were compared for sound-level matching across bandwidth: component level, root-mean-square power and loudness. The calculation of the loudness match was based on the model reported by Moore and Glasberg [Acta Acust. 82, 335-345 (1996)]. Ten normally hearing volunteers were scanned using functional magnetic resonance imaging (fMRI) while listening to a 300-Hz tone presented at six different sound levels between 66 and 91 dB SPL and a harmonic-complex tone (F-0=186 Hz) presented at 65 and 85 dB SPL. This range of sound levels encompassed all three bases of sound-level matching. Activation in the superior temporal gyrus, induced by each of the eight tone conditions relative to a quiet baseline condition, was quantified as to extent and magnitude. Sound level had a small, but significant, effect on the extent of activation for the pure tone, but not for the harmonic-complex tone, while it had a significant effect on the response magnitude for both types of stimulus. Response magnitude increased linearly as a function of sound level for the full range of levels for the pure tone. The harmonic-complex tone produced greater activation than the pure tone, irrespective of the matching scheme for sound level, indicating that bandwidth had a greater effect on the pattern of auditory activation than sound level. Nevertheless, when the data were collapsed across stimulus class, extent and magnitude were significantly correlated with the loudness scale (measured in phons), but not with the intensity scale (measured in SPL). We therefore recommend the loudness formula as the most appropriate basis of matching sound level to control for loudness effects when cortical responses to other stimulus attributes, such as stimulus class, are the principal concern. (C) 2001 Acoustical Society of America.