Nakao Takashi, Osumi Takahiro, Ohira Hideki, Kasuya Yukinori, Shinoda Jun, Yamada Jitsuhiro
Japan Society for the Promotion of Science (JSPS), Japan.
Neurosci Lett. 2009 Jul 31;459(1):30-4. doi: 10.1016/j.neulet.2009.04.056. Epub 2009 May 4.
Life choice (e.g. occupation choice) often includes situations with two or more possible answers. How does the brain respond to such conflict-ridden situations? We investigated whether the dorsal anterior cingulate cortex (dACC) evaluates the degree of conflict between possible answers. Additionally, we investigated whether the medial prefrontal cortex (MPFC) or the medial temporal lobe (MTL) has a function in behavior selection with plural possible answers. We used an occupational choice task (e.g. which occupation do you think you could do better?-dancer or chemist) with two possible answers and a word-length task (e.g. which word is longer?-dentist or comedian) that has a correct answer. The conflicts in each task were manipulated. Results showed that the dACC and the MTL were activated when the conflict during occupational choice was large, and that the MPFC and posterior cingulate cortex were activated more in the occupational choice task than in the word-length task. Our results show that the dACC evaluates the degree of conflict between possible answers, and that the MTL, MPFC, and posterior cingulate cortex have a function in behavior selection without an objective correct answer. It is thought that the MTL functions to reduce conflict when a large-conflict is detected in the dACC. Furthermore, the MPFC and posterior cingulate are thought to have a function of biasing any of the plural answers in behavior selection without an objective answer.
生活选择（如职业选择）往往包含有两个或更多可能答案的情况。大脑如何应对这种充满冲突的情况呢？我们研究了背侧前扣带回皮质（dACC）是否会评估可能答案之间的冲突程度。此外，我们还研究了内侧前额叶皮质（MPFC）或内侧颞叶（MTL）在面对多个可能答案时的行为选择中是否发挥作用。我们使用了一个职业选择任务（例如，你认为自己能做得更好的职业是什么——舞者还是化学家），该任务有两个可能答案，以及一个有正确答案的词长任务（例如，哪个词更长——牙医还是喜剧演员）。每个任务中的冲突都经过了操控。结果显示，当职业选择中的冲突较大时，dACC和MTL会被激活，并且在职业选择任务中，MPFC和后扣带回皮质的激活程度比在词长任务中更高。我们的研究结果表明，dACC会评估可能答案之间的冲突程度，并且MTL、MPFC和后扣带回皮质在没有客观正确答案的行为选择中发挥作用。据认为，当在dACC中检测到较大冲突时，MTL的功能是减少冲突。此外，MPFC和后扣带回被认为在没有客观答案的行为选择中具有偏向多个答案中的任何一个的功能。
