Functional roles of the prefrontal cortex in updating behavioral rules

为了研究前额叶皮质在多步骤行为规划中的参与，我们记录了一只猴子执行路径规划任务时，背外侧前额叶皮质的神经元活动，这需要规划多步光标移动才能达到目标。实验开始时，动物每只胳膊都拿着两个机械手，每个姿势都有。然后，一个光标出现在迷宫中。一秒钟后，一个目标在迷宫中呈现了1秒，然后关闭了。一秒钟后，一个障碍出现了。然后，在进一步延迟1秒后，给猴子一个GO信号，然后要求猴子通过控制两个机械手将光标移动到指示的目标。为了分离手部运动和光标方向，我们训练猴子使用3种不同的手部光标分配或规则来执行这项任务。在这项研究中，我们分析了d…期间的神经元活动。在发出GO信号之前有更多的延迟期，以了解PF神经元是否反映即将到来的手的运动或光标的方向。在Pre-Go活动的Pf神经元中，大多数Pf神经元的活动与即将到来的光标方向有关。部分PF神经元表现出与第一光标方向相关的活动变化。另一个PF神经元为了一个最终目标选择性地显示出活动变化。相比之下，只有少量的PF神经元反映了手部动作的选择。我们的数据表明，前额叶皮质参与计划光标方向或手部运动的结果，而不是计划运动本身。在延迟期内，影响神经元活动的决定因素是即刻和最后的行为，而不是即将到来的动作的运动属性。我们的数据表明，前额叶皮质参与了前瞻记忆中最终目标的表征和从最终目标到即刻亚目标的转换，而不是感觉运动转换。较少

To investigate the involvement of the prefrontal cortex in multi-step behavioral planning, we recorded neuronal activity from the dorsolateral prefrontal cortex while a monkey performed a path-planning task, which required planning of multiple steps of cursor movements to reach goals. A trial began when the animal held two manipulanda given for each arm, at each holding position. Then a cursor was presented in a maze. One second later a goal was presented in the maze for 1s and then turned off. One second later, an obstacle was presented. Then after a further delay of 1s, a GO-signal was given to the monkey and then the monkey was required to move the cursor to the instructed goal by controlling the two manipulanda. To dissociate hand-movements and cursor-directions, we trained the monkey to perform this task with 3 different hand-cursor assignments or rules.Neuronal activity was recorded from the dorsolateral prefrontal cortex. In this study, we analyzed neuronal activity during the d … More elay period before the GO-signal to know whether the PF neurons reflected forthcoming hand movements or cursor directions. Among PF neurons with pre-GO activity, a majority of PF neurons showed activity related to forthcoming cursor directions. Some PF neurons showed activity changes related to the first cursor direction. Another PF neurons showed activity changes selectively for a final goal. In contrast, only a small number of PF neurons reflected the choice of hand movements. Our data demonstrated that the prefrontal cortex is involved in planning cursor directions or the outcome of hand movements, rather than planning the movement itself. The immediate and final behavioral was the decisive factor that influence neuronal activity during the delay period rather than the motor attributes of the forthcoming action. Our data suggest that the prefrontal cortex is involved in representation of final goal in prospective memory and transformation from final goal to immediate sub-goal rather than sensorimotor transformation. Less