Arrigo Alessandro, Mormina Enricomaria, Calamuneri Alessandro, Gaeta Michele, Marino Silvia, Milardi Demetrio, Anastasi Giuseppe Pio, Quartarone Angelo
Department of Biomedical Sciences and Morphological and Functional Images, University of Messina, Messina, Italy.
Department of Biomedical Sciences and Morphological and Functional Images, University of Messina, Messina, Italy; Department of Neurology - Icahn School of Medicine, New York, Mount Sinai, USA.
Neuroscience. 2017 Feb 20;343:346-354. doi: 10.1016/j.neuroscience.2016.12.016. Epub 2016 Dec 18.
The limbic system has a central role for the integration of several cognitive and visceral functions through an extended network of connections involving the hippocampus and the amygdala. A number of studies performed in humans have been dedicated to the investigation of supratentorial limbic pathways by means of non-invasive MRI approaches, such as DTI. However, detection of possible limbic connections involving the brainstem and the spinal cord is still missing. Subtentorial limbic pathways have been previously studied in animals by means of invasive approaches, including viral tracing. The detection of limbic connections with the brainstem and the spinal cord has raised several new hypotheses regarding the interaction between the central nervous system and the periphery of the body. We investigated subtentorial limbic connections in twenty-one healthy humans by means of probabilistic constrained spherical deconvolution tractography. Our connectivity analysis showed, for both the hippocampus and the amygdala, a high probability of connections with the midbrain, pons, and bulb. Moreover, hippocampal and amygdalar pathways reaching the cervical spinal cord were also detected. Quantitative evaluation of diffusion parameters was also performed. Findings of the present study are in agreement with the literature and provide the first report of possible limbic connections between the brainstem and the spinal cord in human brain. Since these pathways might also have important implications both in physiological and pathological contexts, further studies should be conducted in order to confirm our data as well as to define functional features of these brain connections.
边缘系统通过包括海马体和杏仁核在内的广泛连接网络，在整合多种认知和内脏功能方面发挥着核心作用。在人类中进行的多项研究致力于通过非侵入性MRI方法（如扩散张量成像，DTI）来研究幕上边缘通路。然而，涉及脑干和脊髓的可能边缘连接的检测仍然缺失。此前在动物中通过包括病毒示踪在内的侵入性方法研究了幕下边缘通路。与脑干和脊髓的边缘连接的检测提出了一些关于中枢神经系统与身体外周之间相互作用的新假设。我们通过概率约束球面去卷积纤维束成像技术，对21名健康人类的幕下边缘连接进行了研究。我们的连通性分析表明，对于海马体和杏仁核来说，与中脑、脑桥和延髓建立连接的可能性很高。此外，还检测到了到达颈脊髓的海马体和杏仁核通路。我们还对扩散参数进行了定量评估。本研究结果与文献一致，并首次报道了人类大脑中脑干与脊髓之间可能存在的边缘连接。由于这些通路在生理和病理情况下可能也具有重要意义，因此应进行进一步研究以证实我们的数据，并确定这些脑连接的功能特征。
