All vertebrate brains contain a dense matrix of thin fibers that release serotonin (5-hydroxytryptamine), a neurotransmitter that modulates a wide range of neural, glial, and vascular processes. Perturbations in the density of this matrix have been associated with a number of mental disorders, including autism and depression, but its self-organization and plasticity remain poorly understood. We introduce a model based on reflected Fractional Brownian Motion (FBM), a rigorously defined stochastic process, and show that it recapitulates some key features of regional serotonergic fiber densities. Specifically, we use supercomputing simulations to model fibers as FBM-paths in two-dimensional brain-like domains and demonstrate that the resultant steady state distributions approximate the fiber distributions in physical brain sections immunostained for the serotonin transporter (a marker for serotonergic axons in the adult brain). We suggest that this framework can support predictive descriptions and manipulations of the serotonergic matrix and that it can be further extended to incorporate the detailed physical properties of the fibers and their environment.

中文翻译：

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血清素轴突作为分数布朗运动路径：洞察区域密度的自组织

所有脊椎动物的大脑都含有致密的细纤维基质，可以释放血清素（5-羟色胺），这是一种调节广泛的神经、神经胶质和血管过程的神经递质。该矩阵密度的扰动与许多精神疾病有关，包括自闭症和抑郁症，但其自组织和可塑性仍然知之甚少。我们引入了一个基于反射分数布朗运动（FBM）的模型，这是一种严格定义的随机过程，并表明它概括了区域血清素纤维密度的一些关键特征。具体来说，我们使用超级计算模拟将纤维建模为二维类脑域中的 FBM 路径，并证明所得的稳态分布近似于对血清素转运蛋白（血清素能轴突的标记）进行免疫染色的物理大脑切片中的纤维分布。成人大脑）。我们建议该框架可以支持血清素能基质的预测描述和操作，并且可以进一步扩展以纳入纤维及其环境的详细物理特性。