Briley Paul M, Summerfield A Quentin
Department of Psychology, University of York, York, UK.
Neurobiol Aging. 2014 Mar;35(3):633-44. doi: 10.1016/j.neurobiolaging.2013.08.033. Epub 2013 Oct 1.
One of the principal auditory disabilities associated with older age is difficulty in locating and tracking sources of sound. This study investigated whether these difficulties are associated with deterioration in the representation of space in the auditory cortex. In psychophysical tests, half of a group of older (>60 years) adults displayed spatial acuity similar to that of young adults throughout the frontal horizontal plane. The remaining half had considerably poorer spatial acuity at the more peripheral regions of frontal space. Computational modeling of electroencephalographic responses to abrupt location shifts demonstrated marked differences in the spatial tuning of populations of cortical neurons between the older adults with poor spatial acuity on the one hand, and those with good spatial acuity, as well as young adults, on the other hand. In those with poor spatial acuity, cortical responses contained little information with which to distinguish peripheral locations. We demonstrate a clear link between neural responses and spatial acuity measured behaviorally, and provide evidence for age-related changes in the coding of horizontal space.
与老年相关的主要听觉障碍之一是难以定位和追踪声源。本研究调查了这些困难是否与听觉皮层中空间表征的退化有关。在心理物理学测试中，一组老年（>60岁）成年人中有一半在整个额部水平面的空间敏锐度与年轻人相似。其余一半在额部空间的更外围区域的空间敏锐度明显较差。对位置突然变化的脑电图反应进行的计算建模表明，一方面，空间敏锐度较差的老年人与空间敏锐度良好的老年人以及年轻人相比，皮层神经元群体的空间调谐存在显著差异。在空间敏锐度较差的人群中，皮层反应几乎不包含用于区分外围位置的信息。我们证明了神经反应与行为测量的空间敏锐度之间存在明确联系，并为水平空间编码中与年龄相关的变化提供了证据。
