Hogeveen Jeremy, Hauner Katherina K, Chau Aileen, Krueger Frank, Grafman Jordan
Cognitive Neuroscience Laboratory, Rehabilitation Institute of Chicago, Chicago, IL, USA.
Department of Physical Medicine and Rehabilitation.
Cereb Cortex. 2017 Feb 1;27(2):1401-1408. doi: 10.1093/cercor/bhv317.
Apathy is defined by reduced goal-directed behavior, and is common in patients with damage to the ventromedial prefrontal cortex (vmPFC). Separately, in neuroeconomics research, the vmPFC has been shown to play a role in reward processing-namely, in "stimulus valuation," or the computation of the subjective reward value of a stimulus. Here, we used a sample of patients with focal brain lesions (N = 93) and matched healthy controls (N = 21) to determine whether the association between vmPFC damage and increased apathy is driven by impaired valuation. An auction task was used to measure valuation, and apathy was assessed via caregiver ratings of patients' day-to-day behavior. Lesion-symptom mapping identified the locus of impaired valuation in the vmPFC, and patients with damage to this region demonstrated increased apathy relative to patients with damage to dorsomedial prefrontal cortex (dmPFC), patients with damage to other brain regions, and healthy controls. Critically, the association between vmPFC damage and apathy was mediated by impaired valuation, with no effect as a function of dmPFC damage. Our results implicate a valuation-based mechanism underlying the relationship between vmPFC integrity and apathy, bridging findings from both the clinical literature and neuroeconomics research.
冷漠被定义为目标导向行为减少，在腹内侧前额叶皮层（vmPFC）受损的患者中很常见。另外，在神经经济学研究中，vmPFC已被证明在奖励处理中发挥作用——即在“刺激评估”中，或对刺激的主观奖励价值进行计算。在这里，我们使用了一组局灶性脑损伤患者（N = 93）和匹配的健康对照者（N = 21）来确定vmPFC损伤与冷漠增加之间的关联是否由评估受损所驱动。使用拍卖任务来测量评估，并通过照顾者对患者日常行为的评分来评估冷漠程度。病变-症状映射确定了vmPFC中评估受损的位置，与背内侧前额叶皮层（dmPFC）受损的患者、其他脑区受损的患者以及健康对照者相比，该区域受损的患者表现出更高的冷漠程度。至关重要的是，vmPFC损伤与冷漠之间的关联是由评估受损介导的，而与dmPFC损伤无关。我们的结果表明，vmPFC完整性与冷漠之间的关系存在一种基于评估的机制，将临床文献和神经经济学研究的结果联系起来。
