Division of Systems Neuroscience, Tohoku University Graduate School of Life Sciences, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan.
Neurosci Res. 2010 Jun;67(2):162-71. doi: 10.1016/j.neures.2010.02.011. Epub 2010 Mar 1.
The flexibility of the behavior of humans and other primates comes from the cognitive capability to use different behavioral modes depending on the contextual information. To investigate the neural mechanism of such a cognitive function, we trained monkeys to participate in a repeated category-outcome reversal. To perform the task efficiently, they had to explore and remember the relevant rule, i.e., which group of stimuli was associated with which outcome, and apply that rule to the visual cue in order to predict an outcome and select a response correctly. We recorded single-unit activity from the prefrontal cortex, including dorsolateral/ventrolateral prefrontal cortex and orbitofrontal cortex, and found that many neurons in these areas showed rule-dependent changes in activity during the trial and during the inter-trial-interval. The time period when a high proportion of neurons started to show rule-dependent activity was the precue period, and the typical activity pattern at that time was sustained and increasing firing towards the onset of the cue ("anticipatory" precue activity). The results indicate that the prefrontal cortex is involved in maintaining rule information in the short-term memory within and between trials and that the rule information is anticipatorily activated towards the onset of the task-relevant cue.
人类和其他灵长类动物行为的灵活性来自于认知能力，可以根据上下文信息使用不同的行为模式。为了研究这种认知功能的神经机制，我们训练猴子参与重复的类别-结果反转任务。为了高效地完成任务，它们必须探索和记住相关规则，即哪组刺激与哪种结果相关联，并将该规则应用于视觉提示，以便预测结果并正确选择反应。我们记录了来自前额叶皮层（包括背外侧/腹外侧前额叶皮层和眶额皮层）的单个神经元活动，并发现这些区域的许多神经元在试验过程中和试验间间隔期间表现出与规则相关的活动变化。大量神经元开始表现出与规则相关的活动的时间段是前提示期，此时的典型活动模式是朝着提示的出现持续且增加的放电（“预期”前提示活动）。结果表明，前额叶皮层参与在试验内和试验间保持短期记忆中的规则信息，并且规则信息在任务相关提示出现时被预期激活。
