Kebiri Hamza, Delavari Farnaz, Van De Ville Dimitri, Jorge João, Cuadra Meritxell Bach
CIBM - Center for Biomedical Imaging, Lausanne, Switzerland.
Department of Radiology, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.
Imaging Neurosci (Camb). 2025 Jul 24;3. doi: 10.1162/IMAG.a.87. eCollection 2025.
The thalamus is a central component of the brain that is involved in a variety of functions, from sensory processing to high-order cognition. Its structure and function in the first weeks of extrauterine life, including its connections to different cortical and subcortical areas, have not yet been widely explored. Here, we used functional magnetic resonance imaging data of 588 newborns during natural sleep from the developing Human Connectome Project to study the functional organization of the thalamus from 37 to 44 post-conceptual weeks. We introduce : K-means for Nuclei in Infant Thalamus. The framework employs a highly granular vector space of 40 features, each corresponding to functional connectivity to a brain region, using clustering and uncertainty quantification through bootstrapping to delineate thalamic units. Although the different clusters showed common patterns of increased connectivity to the superior temporal gyrus, the parietal, and the frontal cortex, implying an expected decrease in specialization at that age, they also show some specificity. That is, a pulvinar unit was identified, similar to the adult thalamus. Ventrolateral motor and medial salience units were also highlighted. The latter appeared around 41 weeks of age, while the former showed at least from 37 weeks, but had a decrease in relative volume through age, replaced mostly by a dominant dorsal thalamic unit. We also observed an increase in clustering robustness and in hemispheric bilateral symmetry with age, suggesting more specialized functional units. We also found a burst in global thalamic connectivity around 41 weeks. Finally, we demonstrate the benefits of this method in terms of granularity compared to the more conventional winner-takes-all approach.
丘脑是大脑的一个核心组成部分，参与从感觉处理到高级认知等多种功能。其在宫外生活最初几周的结构和功能，包括其与不同皮质和皮质下区域的连接，尚未得到广泛研究。在此，我们使用了来自人类连接组计划（Human Connectome Project）的588名新生儿自然睡眠期间的功能磁共振成像数据，来研究孕龄37至44周时丘脑的功能组织。我们引入了“婴儿丘脑核团的K均值聚类法”。该框架采用了一个由40个特征组成的高粒度向量空间，每个特征对应于与一个脑区功能连接，通过聚类和自展法进行不确定性量化来描绘丘脑单元。尽管不同的聚类显示出与颞上回、顶叶和额叶皮质连接增加的共同模式，这意味着该年龄段的专业化程度预期会降低，但它们也表现出一些特异性。也就是说，识别出了一个类似于成人丘脑的枕核单元。腹外侧运动和内侧显著性单元也得到了突出显示。后者在约41周龄时出现，而前者至少从37周龄时就已出现，但相对体积随年龄增长而减小，主要被占主导地位的背侧丘脑单元所取代。我们还观察到，随着年龄增长，聚类稳健性和半球双侧对称性增加，这表明功能单元更加专业化。我们还发现，在41周龄左右丘脑的整体连接性出现了激增。最后，我们证明了与更传统的赢家通吃方法相比，该方法在粒度方面的优势。
