Dynamic synchrony of firing in the monkey prefrontal cortex during working-memory tasks
Dynamic synchrony of firing in the monkey prefrontal cortex during working-memory tasks
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DOI：
10.1523/jneurosci.2423-06.2006
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发表时间：
2006-10-04
影响因子：
5.3
通讯作者：
Takahashi, Susumu
中科院分区：
文献类型：
--
作者：
Sakurai, Yoshio;Takahashi, Susumu
工作大脑中神经元之间的同步放电被推断为反映了细胞组装的编码，细胞组装动态地改变它们的大小和功能连接来编码各种信息。因此，如果同步放电反映了细胞组装编码，那么它应该表现出动态变化，这种变化取决于正在处理的任务和事件以及神经元之间的距离。通过使用独特的尖峰分选和多神经元记录方法，我们研究了这种动态的同步性在前额叶皮层的猴子，而他们连续执行两个任务，其中工作记忆的刺激持续时间或颜色是必需的。在1405对神经元中，有48%的神经元在执行任务时表现出同步放电。几乎有一半的神经元对表现出固定的同步性，并且在两项任务中不断地一起发射。然而，一些神经元对表现出任务依赖性的同步，只出现在一个任务。此外，其他神经元对显示事件-任务依赖的同步，出现在刺激或保留期间的任务，但期间显示同步的任务之间的变化。固定的同步和任务依赖的同步主要观察到相邻的神经元之间的尖峰时间的变化不大，事件任务依赖的同步，相反，更经常检测到远距离神经元之间的尖峰时间的变化比其他两种类型的同步。这些结果表明，一些紧密相邻的神经元具有动态和尖锐的同步性，以代表某些情况（任务），而一些遥远的神经元则表现出更动态和不稳定的同步放电，以代表工作记忆中正在处理的快速变化的事件。
Synchronized firing among neurons in the working brain is inferred to reflect coding by cell assemblies, which dynamically change their sizes and functional connections to encode various information. It therefore follows that, if synchronized firing reflects cell-assembly coding, it should show dynamic changes that depend on the tasks and events being processed and on the distance between the neurons. By using unique spike-sorting and multi-neuronal recording methods, we investigated such dynamics of synchrony in the prefrontal cortex of monkeys while they were successively performing two tasks in which working memory for either stimulus duration or color was required. Forty-eight percent of 1405 neuronal pairs showed firing synchrony during the performance of the tasks. Almost half of such neuronal pairs showed fixed synchrony and constantly fired together in both tasks. However, some neuronal pairs showed task-dependent synchrony that appeared in only one of the tasks. Moreover, the other neuronal pairs showed event-task-dependent synchrony that appeared during stimulus or retention periods in the tasks, but the periods showing synchrony varied between the tasks. Fixed synchrony and task-dependent synchrony were mostly observed among neighboring neurons and showed little variation of spike timings; the event-task-dependent synchrony, in contrast, was more often detected among distant neurons with larger variation of spike timings than the other two types of synchrony. These results suggest that some closely neighboring neurons have dynamic and sharp synchrony to represent certain situations (tasks), whereas some distant neurons show more dynamic and unstable synchronous firing to represent quickly changing events being processed in working memory.