Auditory Neuroscience Laboratory, Bilingualism and Psycholinguistics Research Group, Department of Communication Sciences, Institute for Neuroscience, Department of Neurobiology and Physiology, and Department of Otolaryngology, Northwestern University, Evanston, Illinois 60208.
J Neurosci. 2013 Oct 30;33(44):17221-31. doi: 10.1523/JNEUROSCI.2102-13.2013.
Despite the prevalence of poverty worldwide, little is known about how early socioeconomic adversity affects auditory brain function. Socioeconomically disadvantaged children are underexposed to linguistically and cognitively stimulating environments and overexposed to environmental toxins, including noise pollution. This kind of sensory impoverishment, we theorize, has extensive repercussions on how the brain processes sound. To characterize how this impoverishment affects auditory brain function, we compared two groups of normal-hearing human adolescents who attended the same schools and who were matched in age, sex, and ethnicity, but differed in their maternal education level, a correlate of socioeconomic status (SES). In addition to lower literacy levels and cognitive abilities, adolescents from lower maternal education backgrounds were found to have noisier neural activity than their classmates, as reflected by greater activity in the absence of auditory stimulation. Additionally, in the lower maternal education group, the neural response to speech was more erratic over repeated stimulation, with lower fidelity to the input signal. These weaker, more variable, and noisier responses are suggestive of an inefficient auditory system. By studying SES within a neuroscientific framework, we have the potential to expand our understanding of how experience molds the brain, in addition to informing intervention research aimed at closing the achievement gap between high-SES and low-SES children.
尽管全球贫困现象普遍存在，但对于早期社会经济逆境如何影响听觉大脑功能，人们知之甚少。社会经济地位较低的儿童接触语言和认知刺激环境的机会较少，而接触环境毒素（包括噪音污染）的机会较多。我们推断，这种感官匮乏会对大脑处理声音的方式产生广泛影响。为了描述这种匮乏如何影响听觉大脑功能，我们比较了两组听力正常的人类青少年，他们就读于同一所学校，年龄、性别和种族相匹配，但母亲的教育水平不同，这与社会经济地位（SES）相关。除了较低的文化水平和认知能力外，来自母亲教育程度较低背景的青少年的神经活动比他们的同学更嘈杂，这反映在没有听觉刺激时的活动增加。此外，在母亲教育程度较低的群体中，对语音的神经反应在重复刺激下更加不稳定，对输入信号的保真度较低。这些较弱、更可变和更嘈杂的反应表明听觉系统效率低下。通过在神经科学框架内研究 SES，我们有可能扩展对经验如何塑造大脑的理解，此外还可以为旨在缩小高 SES 和低 SES 儿童之间成就差距的干预研究提供信息。
