Theory of mind (ToM) deficit is a frequent finding in subjects with neurological and psychiatric conditions. While a number of brain regions play a role in ToM, to date the contribution of the diffuse projection systems is less understood.

Here, we explored the topographical and neurochemical bases of ToM using multi-tracer molecular imaging and quantitative electroencephalography (qEEG) in a group of 30 drug-naïve, de novo Parkinson's Disease (PD) patients (mean age 73.39 ± 8.93 years, 11 females).

ToM was assessed using the “Reading the Mind in the Eyes Task” (RMET), while general cognition with the MMSE.

We acquired FDG-PET images (as a marker of regional neurodegeneration), I-123 Ioflupane Single Photon Emission Computed Tomography (123 I-FP-CIT-SPECT, as a marker of dopaminergic impairment in the basal ganglia and in the cortex and as a proxy marker of serotoninergic deafferentation in the thalamus), and qEEG recordings (using the Theta/Alpha power ratio as marker of cholinergic deafferentation).

PD presented with a significantly worse RMET score compared to 60 controls (20.7 ± 5.5 vs 27.5 ± 3.0 p = .001) while there was no difference between the two groups in age, education or MMSE.

The voxel-wise analysis of total RMET score and regional metabolism showed a positive correlation in the superior temporal gyrus and in the insula. Among the proxy markers of dopaminergic degeneration, serotoninergic and cholinergic deafferentation, ToM presented only an inverse correlation with 123 I-FP-CIT thalamic specific binding ratio (SBR) values -a proxy serotoninergic marker-which remained significant after correction for FDG metabolism in the areas associated with ToM. On the other hand, MMSE only correlated with qEEG posterior Theta/Alpha power.

These findings point to the presence of a specific cortical and neurochemical signature of ToM in PD, to the independence of ToM from general cognition, and suggest possible therapeutic targets to treat social cognition deficits.

心理理论（ToM）缺陷是神经病和精神病患者的常见发现。尽管许多大脑区域在ToM中起作用，但迄今为止，对弥漫投影系统的贡献还知之甚少。

在这里，我们探讨的汤姆地形和神经化学基地一组30未用药的使用多示踪分子成像和定量脑电图（定量脑电图），从头帕金森病（PD）患者（平均年龄73.39±8.93年，女11 ）。

在使用MMSE进行一般认知的同时，使用“阅读眼神任务”（RMET）评估了ToM。

我们获取了FDG-PET图像（作为区域神经变性的标志），I-123碘氟烷单光子发射计算机断层扫描（123 I-FP-CIT-SPECT），作为基底神经节，皮质和皮质中多巴胺能障碍的标志。丘脑中5-羟色胺能脱除咖啡因的代理标记和qEEG记录（使用Theta / Alpha功率比作为胆碱能脱除咖啡因的标记）。

与60个对照组相比，PD的RMET评分显着更差（20.7±5.5 vs 27.5±3.0 p  = .001），而两组的年龄，学历或MMSE均无差异。

总RMET得分和区域代谢的体素分析显示，颞上回和岛状岛呈正相关。在多巴胺能变性，5-羟色胺能和胆碱能脱除咖啡因的代用标记中，ToM仅与123 I-FP-CIT丘脑特异性结合比（SBR）值（代用5-羟色胺能标记）呈负相关，在校正FDG代谢后仍显着与ToM相关的区域。另一方面，MMSE仅与qEEG后角Theta / Alpha功率相关。

这些发现指向PD中ToM的特定皮质和神经化学特征的存在，表明ToM与一般认知的独立性，并暗示了可能的治疗靶标来治疗社会认知缺陷。