Département d'Études Cognitives, École Normale Supérieure-PSL, Paris, France; Institut Mondor de Recherche Biomédicale, Inserm U955, Equipe E01 Neuropsychologie Interventionnelle, Créteil, France; Université Paris-Est Créteil, Faculté de Médecine, Créteil, France; Université Paris Cité, LaPsyDÉ, CNRS, Paris, France.
Département d'Études Cognitives, École Normale Supérieure-PSL, Paris, France; Institut Mondor de Recherche Biomédicale, Inserm U955, Equipe E01 Neuropsychologie Interventionnelle, Créteil, France; Université Paris-Est Créteil, Faculté de Médecine, Créteil, France; AP-HP, Centre de Référence Maladie de Huntington, Service de Neurologie, Hôpital Henri Mondor-Albert Chenevier, Créteil, France.
Cortex. 2023 Sep;166:91-106. doi: 10.1016/j.cortex.2023.04.016. Epub 2023 Jun 1.
The classical neural model of language refers to a cortical network involving frontal, parietal and temporal regions. However, patients with subcortical lesions of the striatum have language difficulties. We investigated whether the striatum is directly involved in language or whether its role in decision-making has an indirect effect on language performance, by testing carriers of Huntington's disease (HD) mutations and controls. HD is a genetic neurodegenerative disease primarily affecting the striatum and causing language disorders. We asked carriers of the HD mutation in the premanifest (before clinical diagnosis) and early disease stages, and controls to perform two discrimination tasks, one involving linguistic and the other non-linguistic stimuli. We used the hierarchical drift diffusion model (HDDM) to analyze the participants' responses and to assess the decision and non-decision parameters separately. We hypothesized that any language deficits related to decision-making impairments would be reflected in the decision parameters of linguistic and non-linguistic tasks. We also assessed the relative contributions of both HDDM decision and non-decision parameters to the participants' behavioral data (response time and discriminability). Finally, we investigated whether the decision and non-decision parameters of the HDDM were correlated with brain atrophy. The HDDM analysis showed that patients with early HD have impaired decision parameters relative to controls, regardless of the task. In both tasks, decision parameters better explained the variance of response time and discriminability performance than non-decision parameters. In the linguistic task, decision parameters were positively correlated with gray matter volume in the ventral striatum and putamen, whereas non-decision parameters were not. Language impairment in patients with striatal atrophy is better explained by a deficit of decision-making than by a deficit of core linguistic processing. These results suggest that the striatum is involved in language through the modulation of decision-making, presumably by regulating the process of choice between linguistic alternatives.
经典的语言神经模型是指涉及额叶、顶叶和颞叶区域的皮质网络。然而，纹状体下区病变的患者会出现语言困难。我们通过测试亨廷顿病（HD）突变携带者和对照组，来研究纹状体是否直接参与语言，或者其在决策中的作用是否通过对语言表现的间接影响。HD 是一种主要影响纹状体并导致语言障碍的遗传性神经退行性疾病。我们要求 HD 突变携带者在症状前（临床诊断前）和早期疾病阶段，以及对照组执行两项辨别任务，一项涉及语言刺激，另一项涉及非语言刺激。我们使用分层漂移扩散模型（HDDM）分析参与者的反应，并分别评估决策和非决策参数。我们假设与决策障碍相关的任何语言缺陷都将反映在语言和非语言任务的决策参数中。我们还评估了 HDDM 决策和非决策参数对参与者行为数据（反应时间和辨别力）的相对贡献。最后，我们研究了 HDDM 的决策和非决策参数是否与脑萎缩相关。HDDM 分析表明，早期 HD 患者的决策参数相对于对照组受损，与任务无关。在两项任务中，决策参数比非决策参数更好地解释了反应时间和辨别力表现的方差。在语言任务中，决策参数与腹侧纹状体和壳核的灰质体积呈正相关，而非决策参数则没有。纹状体萎缩患者的语言障碍可以通过决策缺陷而不是核心语言处理缺陷来更好地解释。这些结果表明，纹状体通过决策的调节参与语言，可能通过调节语言替代物之间选择的过程来实现。
