Brand Matthias, Grabenhorst Fabian, Starcke Katrin, Vandekerckhove Marie M P, Markowitsch Hans J
Department of Physiological Psychology, University of Bielefeld, Bielefeld, Germany.
Neuropsychologia. 2007 Mar 25;45(6):1305-17. doi: 10.1016/j.neuropsychologia.2006.09.021. Epub 2006 Oct 27.
Various neuropsychological studies have shown that decision-making deficits can occur in a wide range of patients with brain damage or dysfunctions. Decisions under ambiguity, as measured with the Iowa Gambling Task, primarily depend on the integrity of the ventromedial prefrontal cortex and the amygdala, as well as on further brain regions such as the somatosensory cortex. However, little is known about the specific role of these structures in decisions under risk measured with tasks that offer explicit rules for gains and losses and winning probabilities, for example, the Game of Dice Task. We aimed to investigate the potential role of the amygdala for decisions under risk. For this purpose, we examined three patients with Urbach-Wiethe disease--a rare syndrome associated with selective bilateral mineralisation of the amygdalae. Neuropsychological performance was assessed with the Iowa Gambling Task (decisions under ambiguity), the Game of Dice Task (decisions under risk), and an extensive neuropsychological test battery focussing on executive functions. Furthermore, previous studies found relationships between generating skin conductance responses and deciding advantageously in the Iowa Gambling Task. Accordingly, we recorded skin conductance responses during both decision tasks as a measure of emotional reactivity. Results indicate that patients with selective amygdala damage have lower scores in both decisions under ambiguity and decisions under risk. Decisions under risk are especially compromised in patients who also demonstrate deficits in executive functioning. In both gambling tasks, patients showed reduced skin conductance responses compared to healthy comparison subjects. The results suggest that deciding advantageously under risk conditions involves both the use of feedback from previous trials, as required by decisions under ambiguity, and in addition, executive functions.
多项神经心理学研究表明，决策缺陷可能出现在广泛的脑损伤或功能障碍患者中。用爱荷华赌博任务测量的模糊情境下的决策，主要取决于腹内侧前额叶皮层和杏仁核的完整性，以及体感皮层等其他脑区。然而，对于这些结构在通过提供收益、损失和获胜概率的明确规则的任务（例如掷骰子任务）测量的风险决策中的具体作用，我们知之甚少。我们旨在研究杏仁核在风险决策中的潜在作用。为此，我们检查了三名患有乌尔巴赫-维特病的患者，这是一种与双侧杏仁核选择性矿化相关的罕见综合征。使用爱荷华赌博任务（模糊情境下的决策）、掷骰子任务（风险决策）以及侧重于执行功能的广泛神经心理测试组来评估神经心理表现。此外，先前的研究发现，在爱荷华赌博任务中产生皮肤电导率反应与做出有利决策之间存在关联。因此，我们在两项决策任务中记录了皮肤电导率反应，作为情绪反应性的一种测量指标。结果表明，选择性杏仁核损伤的患者在模糊情境下的决策和风险决策中的得分都较低。在执行功能也有缺陷的患者中，风险决策尤其受到损害。在两项赌博任务中，与健康对照受试者相比，患者的皮肤电导率反应均降低。结果表明，在风险条件下做出有利决策既需要利用模糊情境下的决策所要求的来自先前试验的反馈，此外还需要执行功能。
