Gao Fei, Zhang Jiping, Sun Xinde, Chen Liang
School of Life Science, Institute of Cognitive Neuroscience, and Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China.
Physiol Behav. 2009 Jun 22;97(3-4):369-73. doi: 10.1016/j.physbeh.2009.03.004. Epub 2009 Mar 16.
Most people are exposed daily to some level and duration of environmental noise. The aim of the present study was to determine the effect of postnatal exposure to a moderate level of noise on sound level processing by neurons in the primary auditory cortex of rats in adulthood. The cortical neuron response to sound stimuli was investigated in three groups of rats. Two groups, either in the critical period of postnatal hearing development or in adulthood, were exposed to 80 dB SPL interrupted white noise for 8 h/day for 2 weeks. The control group consisted of adult rats that were not exposed to the white noise. Seven weeks later, the minimum threshold, the first spike latency, the dynamic range and the slope of the rate-level functions of cortical neuron response to a sound stimulus were determined. The cortical neurons in young rats exposed to the noise had a significantly higher minimum threshold, a longer first spike latency, a shorter dynamic range and a bigger slope in rate-level functions compared with the control group. The group in which adult rats were exposed to the white noise, however, did not have a significant change of sound level processing by the auditory cortical neurons. These results demonstrated that young rats were more susceptible to noise exposure affecting the cortical neuron processing of sound levels.
大多数人每天都会在一定程度和时长上接触环境噪声。本研究的目的是确定出生后暴露于中等强度噪声对成年大鼠初级听觉皮层神经元声音水平处理的影响。在三组大鼠中研究了皮层神经元对声音刺激的反应。两组大鼠，一组处于出生后听力发育的关键期，另一组处于成年期，每天暴露于80 dB SPL的间断白噪声中，持续8小时，共2周。对照组由未暴露于白噪声的成年大鼠组成。7周后，测定了皮层神经元对声音刺激反应的最小阈值、首次放电潜伏期、动态范围和放电率-声级函数的斜率。与对照组相比，暴露于噪声的幼鼠皮层神经元具有显著更高的最小阈值、更长的首次放电潜伏期、更短的动态范围和更大的放电率-声级函数斜率。然而，成年大鼠暴露于白噪声的组中，听觉皮层神经元对声音水平的处理没有显著变化。这些结果表明，幼鼠更容易受到噪声暴露的影响，从而影响皮层神经元对声音水平的处理。
