Natbrainlab, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, King's College London, UK.
Cortex. 2012 Feb;48(2):273-91. doi: 10.1016/j.cortex.2011.12.001. Epub 2011 Dec 13.
Advances in our understanding of sensory-motor integration suggest a unique role of the frontal lobe circuits in cognition and behaviour. Long-range afferent connections convey higher order sensory information to the frontal cortex, which in turn responds to internal and external stimuli with flexible and adaptive behaviour. Long-range connections from and to frontal lobes have been described in detail in monkeys but little is known about short intralobar frontal connections mediating local connectivity in humans. Here we used spherical deconvolution diffusion tractography and post-mortem dissections to visualize the short frontal lobe connections of the human brain. We identified three intralobar tracts connecting: i) posterior Broca's region with supplementary motor area (SMA) and pre-supplementary motor area (pre-SMA) (i.e., the frontal 'aslant' tract - FAT); ii) posterior orbitofrontal cortex with anterior polar region (i.e., fronto-orbitopolar tract - FOP); iii) posterior pre-central cortex with anterior prefrontal cortex (i.e., the frontal superior longitudinal - FSL faciculus system). In addition more complex systems of short U-shaped fibres were identified in the regions of the central, pre-central, perinsular and fronto-marginal sulcus (FMS). The connections between Broca and medial frontal areas (i.e. FAT) and those between the hand-knob motor region and post-central gyrus (PoCG) were found left lateralized in a group of twelve healthy right-handed subjects. The existence of these short frontal connections was confirmed using post-mortem blunt dissections. The functional role of these tracts in motor learning, verbal fluency, prospective behaviour, episodic and working memory is discussed. Our study provides a general model for the local connectivity of the frontal lobes that could be used as an anatomical framework for studies on lateralization and future clinical research in neurological and psychiatric disorders.
我们对感觉运动整合的理解的进展表明，额叶回路在认知和行为中具有独特的作用。长程传入连接将高级感觉信息传递到额叶皮层，额叶皮层则通过灵活和适应性的行为对外界和内部刺激做出反应。在猴子中已经详细描述了来自和到额叶的长程连接，但对于介导人类局部连接的额叶内短程连接知之甚少。在这里，我们使用球型去卷积扩散轨迹和尸体解剖来可视化人类大脑的短额叶连接。我们确定了三个连接额叶内区域的短程连接束：i）后 Broca 区与辅助运动区（SMA）和前辅助运动区（pre-SMA）（即额叶“斜向”束 - FAT）；ii）后眶额皮质与前极区（即额眶极束 - FOP）；iii）后中央前回与前前额叶（即额叶上纵束 - FSL 纤维束系统）。此外，在中央回、中央前回、岛周回和额缘沟（FMS）区域还确定了更复杂的短 U 形纤维系统。在一组 12 名健康的右利手受试者中，发现 Broca 和内侧额叶区域之间的连接（即 FAT）以及手部运动区和中央后回之间的连接偏向左侧。使用尸体解剖钝性解剖确认了这些短程连接的存在。讨论了这些束在运动学习、言语流畅性、前瞻性行为、情景和工作记忆中的功能作用。我们的研究提供了一个额叶局部连接的通用模型，可以作为研究偏侧化和未来神经和精神障碍临床研究的解剖学框架。
