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Title: 大鼠前额叶皮层中时间感知的编码机制
Author: 徐敏
Degree Level: 博士
Issued Date: 2009-09-01
Degree Grantor: 中国科学院上海生命科学研究院
Place of Degree Grantor: 上海生命科学研究院
Supervisor: 蒲慕明
Keyword: 大鼠 ; 前额叶皮层 ; 时间感知 ; 比例模型 ; 工作记忆
Alternative Title: Representation of Interval Timing by Temporally Scalable Firing Pattern in Prefrontal Cortex
Major: 神经生物学
Abstract: 时间是客观存在的一个基本维度,认知活动中非常重要的一个方面是对时间的感知,然而目前我们对时间感知过程中的神经生物学机制却知之甚少。在时间间隔相关的任务中,实验对象必须保持一个从计时开始提示信号起始的工作记忆来编码时间的推移,并且在到达任务要求时间时,做出必要抉择并执行任务要求的相应动作。我们知道前额叶皮层在工作记忆和抉择过程中发挥着至关重要的作用。已有的研究工作表明,前额叶皮层中的神经元表现出与记忆或者抉择相关的活动,然而对于时间间隔在前额叶皮层中是如何编码的这一问题却没有被很好的解答。我们目前的研究结果表明,在计时过程中,大鼠前额叶皮层中许多神经元的活动都受到调制。更有趣的是,在包含两个不同时间间隔的计时任务中,单一神经元呈现出相似的活动模式,并且这种活动模式可以在时间维度上被线性拉伸或者压缩来适应行为任务所要求的不同计时长度。在行为任务中,大鼠计时行为中的偏差也跟神经元活动的变化有关,并且这种变化也符合上述在时间维度上的线性比例关系。除此之外,在可卡因引起的时间感知紊乱实验中,我们也观察到前额叶皮层神经元的活动模式,在时间维度上被线性压缩的现象。综上所述,我们的研究表明,前额叶皮层神经元的活动模式可以在时间维度上,以计时时间为比例因子被线性的拉伸或压缩,并且这种比例模型可能是与时间隔间相关的计时行为中普遍存在的一个规则。
English Abstract: Perception of time on the order of seconds (interval timing) is an essential component of cognition, but little is known about the neural mechanism for time perception. In interval timing-related tasks, the animal is required to maintain working memory of the elapsed time from past events and make decisions about when to anticipate future sensory events or to execute motor actions. The prefrontal cortex (PFC) is known to be crucial for working memory and decision making. Although many PFC neurons exhibit memory- and decision-related activity, how interval timing is encoded in PFC neural activity is not yet well understood. Here we show that in rats trained to estimate timing on the order of seconds, many PFC neurons exhibit sustained spiking activity with a variety of temporal profiles of firing rate modulation. Interestingly, in tasks involving different timing, each neuron exhibited the same modulation profile that was temporally scaled by a factor linearly proportional to the task timing. The behavioral variability across trials within each task is also correlated with the inter-trial variability of the temporal scaling factor. Furthermore, cocaine intake, which caused a significant change in timing perception at the behavioral level, led to a corresponding change in the temporal scaling of PFC firing rate modulation. Together, these results point to temporally scalable firing rate modulation as a general mechanism for the neural representation of interval timing during animal behavior.
Language: 中文
Content Type: 学位论文
URI: http://ir.sibs.ac.cn/handle/331001/2390
Appears in Collections:神经所(总)_学位论文

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Recommended Citation:
大鼠前额叶皮层中时间感知的编码机制.徐敏[d].中国科学院上海生命科学研究院,2009.20-25
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