Shechter Barak, Depireux Didier A
Department of Anatomy and Neurobiology, School of Medicine, University of Maryland, 20 Penn St., HSF II Rm. S251, Baltimore, MD 21201, USA.
Hear Res. 2006 Nov;221(1-2):91-103. doi: 10.1016/j.heares.2006.08.002. Epub 2006 Sep 18.
Driven by previous reports of adaptation to persistent stimuli in other brain regions, we investigated adaptive effects in the Primary Auditory Cortex of awake non-behaving ferrets (Mustela putorius furo). Electrophysiological data was obtained in response to the presentation of auditory gratings with a structured spectro-temporal envelope of varying bandwidth which had repeated transitions between low and high modulation depths. The responses were analyzed in terms of the evoked spike rates and in terms of the degree of phase locking to the modulation. We found two populations of cells, both of which showed adaptation in the traditional sense. For one population, we also found a second order of adaptation--i.e., adaptation of the adaptation. This suggests the existence of at least two coding strategies which differ in the weight placed on sensory context.
受先前关于其他脑区对持续刺激适应性的报道的驱动，我们研究了清醒但不活动的雪貂（白鼬）初级听觉皮层中的适应性效应。通过呈现具有不同带宽的结构化频谱-时间包络的听觉光栅来获取电生理数据，该光栅在低调制深度和高调制深度之间有重复转换。从诱发的峰值率和对调制的锁相程度方面对反应进行了分析。我们发现了两类细胞，它们在传统意义上都表现出适应性。对于其中一类细胞，我们还发现了二阶适应性——即适应性的适应性。这表明至少存在两种在对感觉环境的权重上有所不同的编码策略。
