Department of Psychological and Brain Sciences, Texas A&M University, 515 Coke Street, College Station, TX, 77843-4235, USA.
Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, USA.
Cogn Affect Behav Neurosci. 2019 Jun;19(3):568-585. doi: 10.3758/s13415-019-00689-0.
During voluntary task selection, a number of internal and external biases may guide such a choice. However, it is not well understood how reward influences task selection when multiple options are possible. To address this issue, we examined brain activation in a voluntary task-switching paradigm while participants underwent fMRI (n = 19). To reinforce the overall goal to choose the tasks randomly, participants were told of a large bonus that they would receive at the end of the experiment for making random task choices. We also examined how occasional, random rewards influenced both task performance and brain activation. We hypothesized that these transient rewards would increase the value of the just-performed task, and therefore bias participants to choose to repeat the same task on the subsequent trial. Contrary to expectations, transient reward had no consistent behavioral effect on subsequent task choice. Nevertheless, the receipt of such rewards did influence activation in brain regions associated with reward processing as well as those associated with goal-directed control. In addition, reward on a prior trial was found to influence activation during task choice on a subsequent trial, with greater activation in a number of executive function regions compared with no-reward trials. We posit that both the random presentation of transient rewards and the overall task bonus for random task choices together reinforced the goal to choose the tasks randomly, which in turn influenced activation in both reward-related regions and those regions involved in abstract goal processing.
在自愿任务选择过程中，许多内部和外部的偏见可能会影响这种选择。然而，当有多种选择时，奖励如何影响任务选择还不是很清楚。为了解决这个问题，我们在一项自愿任务转换范式中检查了大脑的激活情况，同时参与者接受了 fMRI（n=19）。为了强化随机选择任务的总体目标，参与者被告知在实验结束时会获得一大笔奖金，用于随机选择任务。我们还研究了偶尔的随机奖励如何影响任务表现和大脑激活。我们假设这些短暂的奖励会增加刚刚执行的任务的价值，因此会促使参与者在下一个试验中选择重复相同的任务。与预期相反，短暂的奖励对后续任务选择没有一致的行为影响。然而，这种奖励的获得确实会影响与奖励处理以及与目标导向控制相关的大脑区域的激活。此外，在前一次试验中获得奖励会影响随后试验中任务选择期间的激活，与无奖励试验相比，许多执行功能区域的激活增加。我们假设，短暂奖励的随机呈现以及随机任务选择的整体任务奖金共同加强了随机选择任务的目标，这反过来又影响了与奖励相关的区域和参与抽象目标处理的区域的激活。
