Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084, China.
Neuroscience. 2011 May 5;181:163-74. doi: 10.1016/j.neuroscience.2011.01.060. Epub 2011 Feb 1.
Stimulus specific adaptation (SSA) is known as a decrease of neuronal response to stimuli that are commonly presented than those rarely occurred. Previous studies have shown that SSA occurs at different levels of auditory pathway, from inferior colliculus (IC), auditory thalamus to auditory cortex (AC). In this study, we further investigated the properties of SSA in rat IC using oddball paradigm. We found that SSA existed even at a lower repetition rate (1 Hz), besides at relatively higher rates (≥2 Hz) shown in previous studies. We also analyzed the temporal dynamics of adaptation to the entire stimulus sequence. Global and local components were found in the response process. These components include a long-term adaptation during the entire oddball sequence, a short-term increase of responses to common stimuli after rare ones and the effects of stimulus history on current response. By fitting a linear model regarding stimulus local history and global probability, we found both of them affect IC neuronal responses. Our study further supports the existence of SSA in IC and provides detailed properties of the neural processing of novelty detection at midbrain level.
刺激特异性适应（Stimulus Specific Adaptation，SSA）是指神经元对经常出现的刺激的反应性降低，而对很少出现的刺激的反应性增强。先前的研究表明，SSA 发生在听觉通路的不同水平，从下丘（inferior colliculus，IC）、听觉丘脑到听觉皮层（auditory cortex，AC）。在这项研究中，我们使用Oddball 范式进一步研究了大鼠 IC 中的 SSA 特性。我们发现，SSA 不仅存在于先前研究中显示的相对较高的重复率（≥2 Hz），而且在较低的重复率（1 Hz）下也存在。我们还分析了对整个刺激序列适应的时间动态。在响应过程中发现了全局和局部成分。这些成分包括整个Oddball 序列期间的长期适应、稀有刺激后对常见刺激的短期增加以及刺激历史对当前响应的影响。通过拟合一个关于刺激局部历史和全局概率的线性模型，我们发现它们都影响 IC 神经元的响应。我们的研究进一步支持了 IC 中 SSA 的存在，并提供了中脑水平新颖性检测的神经处理的详细特性。
