Middle Longitudinal Fasciculus in the Human Brain from Fiber Dissection

Although the middle longitudinal fasciculus (MdLF) is not part of the insular lobe, it penetrates the temporal operculum, which is manipulated or partially removed during surgical approaches to the insula. We present a comprehensive description of that fascicle and its anatomical relationships with neighboring structures that have been described in previous chapters. It has been hypothesized that MdLF plays a role in attention and language processing; however studies with peroperative subcortical electrostimulation or temporal lobectomies did not demonstrate permanent language deficits following resection of its anterior segment. The MdLF has close relationships to adjacent bundles, such as the arcuate fasciculus and the inferior fronto-occipital fasciculus that are required to be recognized and differentiated for adequate interpretation of tractography images and surgical planning.