Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea.
Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon 34141, Korea.
Proc Natl Acad Sci U S A. 2021 Nov 30;118(48). doi: 10.1073/pnas.2111145118.
We studied the brain mechanisms underlying action selection in a social dilemma setting in which individuals' effortful gains are unfairly distributed among group members. A stable "worker-parasite" relationship developed when three individually operant-conditioned rats were placed together in a Skinner box equipped with response lever and food dispenser on opposite sides. Specifically, one rat, the "worker," engaged in lever-pressing while the other two "parasitic" rats profited from the worker's effort by crowding the feeder in anticipation of food. Anatomically, c-Fos expression in the anterior cingulate cortex (ACC) was significantly higher in worker rats than in parasite rats. Functionally, ACC inactivation suppressed the worker's lever-press behavior drastically under social, but only mildly under individual, settings. Transcriptionally, GABA receptor- and potassium channel-related messenger RNA expressions were reliably lower in the worker's, relative to parasite's, ACC. These findings indicate the requirement of ACC activation for the expression of exploitable, effortful behavior, which could be mediated by molecular pathways involving GABA receptor/potassium channel proteins.
我们研究了个体努力获得的不公平分配在社会困境情境下影响行为选择的大脑机制。当三只单独进行操作性条件反射训练的老鼠被放在一个斯金纳箱中，箱子的两边分别配备了杠杆和食物分配器时，就会形成一种稳定的“工人-寄生虫”关系。具体来说，一只老鼠“工人”会按压杠杆，而另外两只“寄生虫”老鼠则会通过在饲料器前拥挤，预期食物的到来，从工人的努力中获益。在解剖学上，前扣带皮层（ACC）中的 c-Fos 表达在工鼠中显著高于寄生虫鼠。在功能上，ACC 的失活在社交环境下极大地抑制了工人的杠杆按压行为，而在个体环境下则只有轻微的抑制作用。在转录水平上，相对于寄生虫的 ACC，工人的 ACC 中 GABA 受体和钾通道相关信使 RNA 的表达明显降低。这些发现表明，ACC 的激活是表现可剥削性、努力行为的必要条件，这可能通过涉及 GABA 受体/钾通道蛋白的分子途径来介导。
