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, GABAA 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 GABAA receptor/potassium channel proteins.
:We described for the production of cloud-free satellite sea surface temperature(SST) data around Northeast Asian using NOAA AVHRR(Advanced Very High Resolution Radiometer) SST data during 1990-2005. As a result of Markov model, it was found that the value of Markov coefficient in the strong current region such as Kuroshio region showed smaller than that in the weak current. The variations of average SST and regional difference of seasonal day-to-day SST in spring and fall were larger than those in summer and winter. In particular, the distribution of the regional difference appeared large in the vicinity of continental in spring and fall. The difference of seasonal day-to-day SST was also small in Kuroshio region and southern part of East Sea due to the heat advection by warm currents.
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