Penn Frontotemporal Degeneration Center and Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
eNeuro. 2019 Sep 26;6(5). doi: 10.1523/ENEURO.0488-18.2019. Print 2019 Sep/Oct.
The primary function of language is to communicate-that is, to make individuals reach a state of mutual understanding about a particular thought or idea. Accordingly, daily communication is truly a task of social coordination. Indeed, successful interactions require individuals to (1) track and adopt a partner's perspective and (2) continuously shift between the numerous elements relevant to the exchange. Here, we use a referential communication task to study the contributions of perspective taking and executive function to effective communication in nonaphasic human patients with behavioral variant frontotemporal dementia (bvFTD). Similar to previous work, the task was to identify a target object, embedded among an array of competitors, for an interlocutor. Results indicate that bvFTD patients are impaired relative to control subjects in selecting the optimal, precise response. Neuropsychological testing related this performance to mental set shifting, but not to working memory or inhibition. Follow-up analyses indicated that some bvFTD patients perform equally well as control subjects, while a second, clinically matched patient group performs significantly worse. Importantly, the neuropsychological profiles of these subgroups differed only in set shifting. Finally, structural MRI analyses related patient impairment to gray matter disease in orbitofrontal, medial prefrontal, and dorsolateral prefrontal cortex, all regions previously implicated in social cognition and overlapping those related to set shifting. Complementary white matter analyses implicated uncinate fasciculus, which carries projections between orbitofrontal and temporal cortices. Together, these findings demonstrate that impaired referential communication in bvFTD is cognitively related to set shifting, and anatomically related to a social-executive network including prefrontal cortices and uncinate fasciculus.
语言的主要功能是交流——也就是说，让个体对特定的思想或想法达到相互理解的状态。因此，日常交流确实是一项社会协调任务。事实上，成功的互动需要个体（1）跟踪并采用伙伴的视角，（2）不断在与交流相关的众多元素之间转换。在这里，我们使用参考交流任务来研究换位思考和执行功能对非失语症额颞叶痴呆（bvFTD）患者有效沟通的贡献。与之前的工作类似，任务是为对话者识别目标对象，该目标对象嵌入在一系列竞争对手中。结果表明，与对照组相比，bvFTD 患者在选择最佳、精确的反应方面存在障碍。神经心理学测试将这种表现与心理定势转移相关联，但与工作记忆或抑制无关。后续分析表明，一些 bvFTD 患者的表现与对照组相当，而第二组临床匹配的患者组表现明显更差。重要的是，这些亚组的神经心理学特征仅在定势转移方面有所不同。最后，结构 MRI 分析将患者的损伤与眶额叶、内侧前额叶和背外侧前额叶皮质的灰质疾病相关联，所有这些区域以前都与社会认知有关，并且与定势转移有关。补充的白质分析表明，钩束与眶额叶和颞叶皮质之间有投射。综上所述，这些发现表明，bvFTD 中参考交流的障碍在认知上与定势转移有关，在解剖学上与包括前额叶皮质和钩束在内的社会执行网络有关。
