Department of Physiology, University of Cambridge, Cambridge CB2 3DY, UK.
Cereb Cortex. 2010 Jul;20(7):1668-75. doi: 10.1093/cercor/bhp236. Epub 2009 Nov 10.
Central serotonin is implicated in a variety of emotional and behavioral control processes. Serotonin depletion can lead to exaggerated aversive processing and deficient response inhibition, effects that have been linked to serotonin's actions in the amygdala and orbitofrontal cortex (OFC), respectively. However, a direct comparison of serotonin manipulations within the OFC and amygdala in the same experimental context has not been undertaken. This study compared the effects of infusing the serotonin neurotoxin, 5,7-dihydroxytryptamine into the OFC and amygdala of marmosets performing an appetitive test of response inhibition. Marmosets had to learn to inhibit a prepotent response tendency to choose a box containing high-incentive food and instead choose a box containing low-incentive food, to obtain reward. OFC infusions caused long-lasting reductions in serotonin tissue levels, as revealed at postmortem, and exaggerated prepotent responses. In contrast, the significantly reduced prepotent responses following amygdala infusions occurred at a time when serotonin tissue levels had undergone considerable recovery, but there remained residual reductions in extracellular serotonin, in vivo. These opposing behavioral effects of serotonin manipulations in the same experimental context may be understood in terms of the top-down regulatory control of the amygdala by the OFC.
中枢血清素参与了多种情绪和行为控制过程。血清素耗竭可导致厌恶加工过度和反应抑制不足，这些效应分别与血清素在杏仁核和眶额皮质（OFC）中的作用有关。然而，在相同的实验背景下，对 OFC 和杏仁核内的血清素操纵进行直接比较尚未进行。本研究比较了在执行反应抑制的奖赏性测试时，将 5,7-二羟基色胺注入狨猴的 OFC 和杏仁核中对其产生的影响。狨猴必须学会抑制选择包含高激励性食物的盒子的强烈反应倾向，而是选择包含低激励性食物的盒子来获得奖励。OFC 注射会导致组织内的血清素水平长期下降，如死后所揭示的那样，并使优势反应过度。相比之下，杏仁核注射后优势反应显著减少发生在血清素组织水平已经恢复相当大的时间点，但在体内，细胞外血清素仍有残留减少。在相同的实验背景下，血清素操纵的这些相反的行为效应可以根据 OFC 对杏仁核的自上而下的调节控制来理解。
