We have previously shown that activity and connectivity within and between the action observation and mentalizing brain systems reflect the degree of positive dimensions expressed by social interactions such as cooperativity and affectivity, respectively. Here we aim to extend this evidence by investigating the neural bases of processing negative dimensions of observed interactions, such as competition and affective conflict, possibly representing a benchmark for different pathological conditions.

In this fMRI study 34 healthy participants were shown pictures depicting interactions characterized by two crossed dimensions, i.e. positively- vs. negatively- connotated social intentions mainly expressed in terms of motor acts vs. mental states, i.e. cooperative, competitive, affective and conflicting interactions.

We confirmed the involvement of the action observation and mentalizing networks in processing intentions mainly expressed through motor acts (cooperative/competitive) vs. mental states (affective/conflicting), respectively. Results highlighted the selective role of the left pSTS/TPJ in decoding social interactions, even when compared with parallel actions by non-interacting individuals. Its right-hemispheric homologue displayed stronger responses to negative than positive social intentions, regardless of their motor/mental status, and decreased connectivity with the medial prefrontal cortex (mPFC) when processing negative interactions. The resulting mPFC downregulation by negative social scenes might reflect an adaptive response to socio-affective threats, via decreased mentalizing when facing negative social stimuli.

This evidence on the brain mechanisms underlying the decoding of real complex interactions represents a baseline for assessing both the neural correlates of impaired social cognition, and the effects of rehabilitative treatments, in neuro-psychiatric diseases or borderline conditions such as loneliness.

我们之前已经表明，行动观察和心理化大脑系统内部和之间的活动和连通性分别反映了社会互动所表达的积极维度的程度，例如合作性和情感性。在这里，我们旨在通过调查处理观察到的相互作用的负面维度的神经基础来扩展这一证据，例如竞争和情感冲突，可能代表不同病理状况的基准。

在这项f MRI 研究中，向 34 名健康参与者展示了描绘以两个交叉维度为特征的互动的图片，即积极- 与消极-主要以运动行为与心理状态表达的社会意图，即合作、竞争、情感和冲突的互动.

我们证实了动作观察和心理化网络分别参与处理主要通过运动行为（合作/竞争）与心理状态（情感/冲突）表达的意图。结果强调了左侧 pSTS/TPJ 在解码社交互动中的选择性作用，即使与非互动个体的平行动作相比也是如此。无论他们的运动/精神状态如何，其右半球同系物对消极社会意图的反应都比积极的社会意图更强，并且在处理消极互动时与内侧前额叶皮层 (mPFC) 的连接性降低。负面社会场景导致的 mPFC 下调可能反映了对社会情感威胁的适应性反应，通过在面临负面社会刺激时减少心理化。

这一关于解码真实复杂相互作用的大脑机制的证据代表了评估社会认知受损的神经相关性以及康复治疗在神经精神疾病或孤独等边缘状况中的影响的基线。