Department of Neurology, University of Minnesota, Minneapolis, MN, USA.
Cerebellum. 2010 Dec;9(4):598-602. doi: 10.1007/s12311-010-0203-8.
The unique anatomical and electrophysiological features of the inferior olive and its importance to cerebellar function have been recognized for decades. However, understanding the exact function of the inferior olive has been limited by the general lack of correlation between its neural activity and specific behavioral states. Electrophysiological studies in animals showed that the inferior olive response to sensory stimuli is generally invariant to stimulus properties but is enhanced by unexpected stimuli. Using functional magnetic resonance imaging in humans, we have shown that the inferior olive is activated when subjects performed a task requiring perception of visual stimuli with unpredictable timing (Xu et al. J Neurosci 26(22):5990-5995, 2006, Liu et al. J Neurophysiol 100(3):1557-1561, 2008). In the current study, subjects were scanned while passively perceiving visual and tactile stimuli that were rendered unpredictable by continuously varying interstimulus intervals (ISIs). Sequences of visual stimuli and tactile stimuli to the right hand were presented separately within the same scanning session. In addition to the activation of multiple areas in the cerebellar cortex consistent with previous imaging studies, the results show that both tactile and visual stimulation with variable ISIs were effective in activating the inferior olive. Together with our previous findings, the current results are consistent with the electrophysiological studies in animals and further support the view that the inferior olive and the climbing fiber system primarily convey the temporal information of sensory input regardless of the modality.
橄榄核的独特解剖学和电生理学特征及其对小脑功能的重要性已经被认识了几十年。然而，由于橄榄核的神经活动与特定行为状态之间缺乏普遍相关性，因此对其确切功能的理解一直受到限制。动物的电生理研究表明，橄榄核对感觉刺激的反应通常不受刺激特性的影响，但对意外刺激有增强作用。我们使用功能磁共振成像在人类中进行的研究表明，当被试执行需要感知具有不可预测时间的视觉刺激的任务时，橄榄核会被激活（Xu 等人，J Neurosci 26(22):5990-5995, 2006，Liu 等人，J Neurophysiol 100(3):1557-1561, 2008）。在当前的研究中，被试在被动感知视觉和触觉刺激时进行扫描，这些刺激通过连续变化的刺激间间隔（ISIs）变得不可预测。在同一个扫描会话中，分别呈现了针对右手的视觉刺激和触觉刺激的序列。除了与以前的成像研究一致的小脑皮层多个区域的激活外，结果还表明，具有可变 ISIs 的触觉和视觉刺激都能有效地激活橄榄核。与我们之前的发现一起，当前的结果与动物的电生理研究一致，并进一步支持了这样一种观点，即橄榄核和 climbing 纤维系统主要传递感觉输入的时间信息，而与感觉模态无关。
