楔前叶的解剖结构和白质连接。
Anatomy and white-matter connections of the precuneus.
机构信息
Centre for Minimally Invasive Neurosurgery, Suite 19, Level 7 Prince of Wales Private Hospital, Barker Street, Randwick, Sydney, NSW, 2031, Australia.
Cingulum Health, Sydney, NSW, Australia.
出版信息
Brain Imaging Behav. 2022 Apr;16(2):574-586. doi: 10.1007/s11682-021-00529-1. Epub 2021 Aug 26.
Purpose Advances in neuroimaging have provided an understanding of the precuneus'(PCu) involvement in functions such as visuospatial processing and cognition. While the PCu has been previously determined to be apart of a higher-order default mode network (DMN), recent studies suggest the presence of possible dissociations from this model in order to explain the diverse functions the PCu facilitates, such as in episodic memory. An improved structural model of the white-matter anatomy of the PCu can demonstrate its unique cerebral connections with adjacent regions which can provide additional clarity on its role in integrating information across higher-order cerebral networks like the DMN. Furthermore, this information can provide clinically actionable anatomic information that can support clinical decision making to improve neurologic outcomes such as during cerebral surgery. Here, we sought to derive the relationship between the precuneus and underlying major white-mater bundles by characterizing its macroscopic connectivity. Methods Structural tractography was performed on twenty healthy adult controls from the Human Connectome Project (HCP) utilizing previously demonstrated methodology. All precuneus connections were mapped in both cerebral hemispheres and inter-hemispheric differences in resultant tract volumes were compared with an unpaired, corrected Mann-Whitney U test and a laterality index (LI) was completed. Ten postmortem dissections were then performed to serve as ground truth by using a modified Klingler technique with careful preservation of relevant white matter bundles. Results The precuneus is a heterogenous cortical region with five major types of connections that were present bilaterally. (1) Short association fibers connect the gyri of the precuneus and connect the precuneus to the superior parietal lobule and the occipital cortex. (2) Four distinct parts of the cingulum bundle connect the precuneus to the frontal lobe and the temporal lobe. (3) The middle longitudinal fasciculus from the precuneus connects to the superior temporal gyrus and the dorsolateral temporal pole. (4) Parietopontine fibers travel as part of the corticopontine fibers to connect the precuneus to pontine regions. (5) An extensive commissural bundle connects the precuneus bilaterally. Conclusion We present a summary of the anatomic connections of the precuneus as part of an effort to understand the function of the precuneus and highlight key white-matter pathways to inform surgical decision-making. Our findings support recent models suggesting unique fiber connections integrating at the precuneus which may suggest finer subsystems of the DMN or unique networks, but further study is necessary to refine our model in greater quantitative detail.
目的
神经影像学的进展使人们对楔前叶(PCu)在视觉空间处理和认知等功能中的作用有了一定的了解。虽然 PCu 以前被确定为高级默认模式网络(DMN)的一部分,但最近的研究表明,为了解释 PCu 促进的各种功能(例如情节记忆),可能需要对该模型进行可能的分离。改进的 PCu 白质解剖结构模型可以证明其与相邻区域的独特大脑连接,从而为其在整合高级大脑网络(如 DMN)中的信息方面的作用提供额外的清晰度。此外,这些信息可以提供具有临床操作性的解剖学信息,以支持临床决策,从而改善神经学结果,例如在大脑手术期间。在这里,我们试图通过描述其宏观连通性来确定 PCu 与潜在的主要白质束之间的关系。
方法
我们利用先前展示的方法,对人类连接组计划(HCP)中的 20 名健康成年对照进行了结构束追踪。在两个大脑半球中都绘制了所有 PCu 连接,并通过非配对、校正的曼-惠特尼 U 检验比较了结果束体积的半球间差异,并完成了侧性指数(LI)。然后进行了 10 次尸体解剖,作为使用改良的克林格勒技术进行的地面实况,该技术小心地保存了相关的白质束。
结果
楔前叶是一个具有五个主要连接类型的异质皮质区域,这些连接类型在双侧都存在。(1)短联络纤维连接楔前叶的回和连接楔前叶到顶叶上回和枕叶。(2)扣带回束的四个不同部分连接楔前叶到额叶和颞叶。(3)从中线的中间纵束从楔前叶连接到颞上回和背外侧颞极。(4)脑桥皮质纤维作为脑桥皮质纤维的一部分行进,连接楔前叶到脑桥区域。(5)广泛的连合束连接双侧楔前叶。
结论
我们总结了楔前叶的解剖连接,作为理解楔前叶功能的一部分,并强调了告知手术决策的关键白质通路。我们的发现支持了最近的模型,即提示在楔前叶处进行独特的纤维连接,这可能提示 DMN 或独特网络的更精细的子系统,但需要进一步的研究来更详细地完善我们的模型。