Department of Psychology, University of Iowa, Iowa City, Iowa 52242, USA.
Learn Mem. 2010 Feb 13;17(2):80-5. doi: 10.1101/lm.1572710. Print 2010 Feb.
The conditioned stimulus (CS) pathway that is necessary for visual delay eyeblink conditioning was investigated in the current study. Rats were initially given eyeblink conditioning with stimulation of the ventral nucleus of the lateral geniculate (LGNv) as the CS followed by conditioning with light and tone CSs in separate training phases. Muscimol was infused into the medial pontine nuclei (MPN) after each training phase to examine conditioned response (CR) retention to each CS. The spread of muscimol infusions targeting the MPN was examined with fluorescent muscimol. Muscimol infusions into the MPN resulted in a severe impairment in retention of CRs with the LGNv stimulation and light CSs. A less severe impairment was observed with the tone CS. The results suggest that CS information from the LGNv and light CSs is relayed to the cerebellum through the MPN. Retrograde tracing with fluoro-gold (FG) showed that the LGNv and nucleus of the optic tract have ipsilateral projections to the MPN. Unilateral inputs to the MPN from the LGNv and nucleus of the optic tract may be part of the visual CS pathway that is necessary for visual eyeblink conditioning.
本研究旨在探讨视觉延时眨眼条件反射所必需的条件刺激（CS）通路。在初始阶段，通过刺激外侧膝状体（LGNv）作为 CS 对大鼠进行眨眼条件反射训练，然后在单独的训练阶段中用光和音 CS 进行条件反射训练。在每个训练阶段后，将 muscimol 注入内侧脑桥核（MPN），以检查对每个 CS 的条件反应（CR）保持情况。用荧光 muscimol 检查针对 MPN 的 muscimol 输注的扩散情况。MPN 内的 muscimol 输注导致对 LGNv 刺激和光 CS 的 CR 保持严重受损。用音 CS 观察到较轻的损伤。结果表明，来自 LGNv 和光 CS 的 CS 信息通过 MPN 传递到小脑。逆行示踪荧光金（FG）显示，外侧膝状体核和视束核具有同侧投射到 MPN。来自外侧膝状体核和视束核的 MPN 的单侧输入可能是视觉眨眼条件反射所必需的视觉 CS 通路的一部分。
