Bowen G Peter, Lin Daniel, Taylor Merritt K, Ison James R
Department of Brain and Cognitive Sciences, Meliora Hall, University of Rochester, Rochester, NY 14627, USA.
Cereb Cortex. 2003 Aug;13(8):815-22. doi: 10.1093/cercor/13.8.815.
Temporal acuity for acoustic transients in rats with bilateral auditory cortex lesions (n = 6) was compared with that of sham-surgery control rats (n = 4), using a standard gap-detection method. A comparison of sensitivity to quiet gaps in noise and dark gaps in light tested for a cross-modal effect of the lesion. The groups were compared also in their sensitivity to noise offset, to noise increments, and to noise pulses presented in quiet. Stimulus detection was assessed with the startle reflex modification procedure, which uses changes in reflex expression caused by stimuli presented immediately before reflex elicitation as the objective evidence for their detection. There were no group differences in sensitivity to noise offset, noise pulses, or dark gaps in light. In contrast, the lesion reduced sensitivity to noise increments and eliminated gap detection. These deficits were maintained for 1 month and only partially recovered 2 months after surgery. The data indicate that the auditory cortex is critically important for temporal acuity in hearing, and suggest that its contribution to gap detection is to enhance the salience of noise increments at the end of the gap.
采用标准的间隙检测方法，将双侧听觉皮层损伤大鼠（n = 6）的听觉瞬态时间分辨力与假手术对照大鼠（n = 4）进行比较。比较了噪声中安静间隙和光中暗间隙的敏感度，以测试损伤的跨模态效应。还比较了两组对噪声抵消、噪声增量以及安静环境中呈现的噪声脉冲的敏感度。通过惊吓反射修正程序评估刺激检测，该程序将在惊吓反射引发前立即呈现的刺激所引起的反射表达变化作为其检测的客观证据。两组在对噪声抵消、噪声脉冲或光中暗间隙的敏感度上没有差异。相比之下，损伤降低了对噪声增量的敏感度并消除了间隙检测能力。这些缺陷持续了1个月，术后2个月仅部分恢复。数据表明，听觉皮层对听力的时间分辨力至关重要，并表明其对间隙检测的作用是增强间隙末端噪声增量的显著性。
