Neurosciences Institute, 10640 John Jay Hopkins Dr., San Diego, CA 92121, USA.
J Neurophysiol. 2012 May;107(9):2393-407. doi: 10.1152/jn.01012.2011. Epub 2012 Feb 8.
Goal-directed behaviors require the consideration and expenditure of physical effort. The anterior cingulate cortex (ACC) appears to play an important role in evaluating effort and reward and in organizing goal-directed actions. Despite agreement regarding the involvement of the ACC in these processes, the way in which effort-, reward-, and motor-related information is registered by networks of ACC neurons is poorly understood. To contrast ACC responses to effort, reward, and motor behaviors, we trained rats on a reversal task in which the selected paths on a track determined the level of effort or reward. Effort was presented in the form of an obstacle that was climbed to obtain reward. We used single-unit recordings to identify neural correlates of effort- and reward-guided behaviors. During periods of outcome anticipation, 52% of recorded ACC neurons responded to the specific route taken to the reward while 21% responded prospectively to effort and 12% responded prospectively to reward. In addition, effort- and reward-selective neurons typically responded to the route, suggesting that these cells integrated motor-related activity with expectations of future outcomes. Furthermore, the activity of ACC neurons did not discriminate between choice and forced trials or respond to a more generalized measure of outcome value. Nearly all neural responses to effort and reward occurred after path selection and were restricted to discrete temporal/spatial stages of the task. Together, these findings support a role for the ACC in integrating route-specific actions, effort, and reward in the service of sustaining discrete movements through an effortful series of goal-directed actions.
目标导向行为需要考虑和付出体力。前扣带皮层（ACC）似乎在评估努力和奖励以及组织目标导向行为方面发挥着重要作用。尽管人们一致认为 ACC 参与了这些过程，但 ACC 神经元网络如何记录与努力、奖励和运动相关的信息仍知之甚少。为了对比 ACC 对努力、奖励和运动行为的反应，我们在一项反转任务中对大鼠进行了训练，在该任务中，轨道上选择的路径决定了努力或奖励的水平。努力表现为需要攀爬才能获得奖励的障碍物。我们使用单细胞记录来确定努力和奖励引导行为的神经相关物。在结果预期期间，记录的 52%的 ACC 神经元对获得奖励的特定路径作出反应，而 21%的神经元对努力作出前瞻性反应，12%的神经元对奖励作出前瞻性反应。此外，努力和奖励选择神经元通常对路径作出反应，这表明这些细胞将与未来结果相关的运动相关活动与预期相结合。此外，ACC 神经元的活动不能区分选择和强制试验，也不能对更一般的结果价值衡量标准作出反应。几乎所有对努力和奖励的神经反应都发生在路径选择之后，并且仅局限于任务的离散时间/空间阶段。这些发现共同支持 ACC 在整合特定于路径的动作、努力和奖励以维持通过一系列费力的目标导向动作的离散运动中的作用。
