<p>Social interactions in the context of cooperation and competition are the most important type of human activity, determining people’s well-being and success in life. The neural bases of this activity and the role of personality-related individual characteristics have received insufficient study. In particular, no data have been published on the relationship between neuroticism and individual differences in cerebral activity during cooperative and competitive interactions – the aim of the present work was to fill this gap. fMRI data were recorded during the performance of tasks in individual, cooperative, and competitive modes and were analyzed using inter-subject representational similarity analysis. The analysis results show that in people predisposed to emotional instability, social interactions, both in the context of cooperation and in the context of competition, are associated with greater tension, which is apparent in the activity of the social centers of the brain and the centers regulating emotion and attention. This can potentially lead to accumulation of the consequences of social stress and the emergence of symptoms of mental health disorders.</p>