Herbet Guillaume, Zemmoura Ilyess, Duffau Hugues
Department of Neurosurgery, Gui de Chauliac Hospital, Montpellier University Medical Center, Montpellier, France.
INSERM-1051, Team 4, Saint-Eloi Hospital, Institute for Neurosciences of Montpellier, Montpellier, France.
Front Neuroanat. 2018 Sep 19;12:77. doi: 10.3389/fnana.2018.00077. eCollection 2018.
The inferior longitudinal fasciculus (ILF) is a long-range, associative white matter pathway that connects the occipital and temporal-occipital areas of the brain to the anterior temporal areas. In view of the ILF's anatomic connections, it has been suggested that this pathway has a major role in a relatively large array of brain functions. Until recently, however, the literature data on these potential functions were scarce. Here, we review the key findings of recent anatomic, neuromodulation, and neuropsychological studies. We also summarize reports on how this tract is disrupted in a wide range of brain disorders, including psychopathologic, neurodevelopmental, and neurologic diseases. Our review reveals that the ILF is a multilayered, bidirectional tract involved in processing and modulating visual cues and thus in visually guided decisions and behaviors. Accordingly, sudden disruption of the ILF by neurologic insult is mainly associated with neuropsychological impairments of visual cognition (e.g., visual agnosia, prosopagnosia, and alexia). Furthermore, disruption of the ILF may constitute the pathophysiologic basis for visual hallucinations and socio-emotional impairments in schizophrenia, as well as emotional difficulties in autism spectrum disorder. Degeneration of the ILF in neurodegenerative diseases affecting the temporal lobe may explain (at least in part) the gradual onset of semantic and lexical access difficulties. Although some of the functions mediated by the ILF appear to be relatively lateralized, observations from neurosurgery suggest that disruption of the tract's anterior portion can be dynamically compensated for by the contralateral portion. This might explain why bilateral disruption of the ILF in either acute or progressive disease is highly detrimental in neuropsychological terms.
下纵束（ILF）是一条长程联合白质通路，它将大脑的枕叶和颞枕叶区域与颞叶前部区域连接起来。鉴于ILF的解剖学连接，有人提出这条通路在一系列相对较多的脑功能中起主要作用。然而，直到最近，关于这些潜在功能的文献数据还很稀少。在这里，我们回顾了近期解剖学、神经调节和神经心理学研究的关键发现。我们还总结了关于这条神经束在多种脑部疾病（包括精神病理、神经发育和神经疾病）中如何被破坏的报告。我们的综述表明，ILF是一条多层双向神经束，参与处理和调节视觉线索，从而参与视觉引导的决策和行为。因此，神经损伤导致ILF突然中断主要与视觉认知的神经心理学损害（如视觉失认、面孔失认和失读症）有关。此外，ILF的中断可能构成精神分裂症中视觉幻觉和社会情感障碍以及自闭症谱系障碍中情感困难的病理生理基础。影响颞叶的神经退行性疾病中ILF的退化可能（至少部分地）解释了语义和词汇获取困难的逐渐出现。尽管ILF介导的一些功能似乎相对偏向一侧，但神经外科手术的观察结果表明，该神经束前部的中断可以由对侧部分动态补偿。这可能解释了为什么在急性或进行性疾病中ILF的双侧中断在神经心理学方面具有高度危害性。
