Okinawa Institute of Science and Technology, 12-22 Suzaki, Uruma-shi, Okinawa, Japan,
Cogn Neurodyn. 2009 Mar;3(1):39-46. doi: 10.1007/s11571-008-9068-7. Epub 2008 Oct 24.
In a recent experimental paper Lee et al. (Neuron 51:639-650, 2006) showed that the firing patterns of CA1 complex-spike neurons gradually shifted forward across trials toward prospective goal locations within a recording session over multiple trials. Here we propose a simple model of this result based on the phenomenon of awake sequence reverse replay (Foster and Wilson, Nature 440(7084):615-617, 2006) which occurs when the animal pauses at the reward location. The model is based on the CA3-CA1 anatomy with modulation of CA3-CA1 synaptic plasticity by feedback from CA3 projecting CA1 interneurons. Sequence replays, which are generated in CA3 by removal of subcortical inhibition on CA1 interneurons, are recoded into the synaptic weights of individual CA1 cells. This produces spatially extended CA1 firing fields, whose response provides a value function on experienced paths toward goal locations. Simulations show that the CA1 firing fields show positive movement in center of mass toward reward locations over many trials with negative shift in first few trials, and development of positive skew.
在最近的一篇实验论文中，Lee 等人（Neuron 51:639-650, 2006）表明，在多次试验中，在一个记录会话中，CA1 复合尖峰神经元的发射模式逐渐向前转移，朝着预期的目标位置。在这里，我们基于清醒序列反向重放（Foster 和 Wilson，自然 440(7084):615-617, 2006）的现象提出了一个简单的模型，当动物在奖励位置暂停时，就会出现这种现象。该模型基于 CA3-CA1 的解剖结构，通过来自投射到 CA1 中间神经元的 CA3 的反馈来调制 CA3-CA1 突触可塑性。序列重放由 CA1 中间神经元的皮质下抑制的去除在 CA3 中产生，被重新编码到单个 CA1 细胞的突触权重中。这产生了空间扩展的 CA1 发射场，其响应提供了朝向目标位置的经验路径的价值函数。模拟表明，CA1 发射场在多次试验中表现出向奖励位置的质心正向移动，在前几次试验中出现负向移动，并出现正偏斜。
