Functional brain mapping,connectivity and plasticity applied to the surgery of supra-tentorial low-grade gliomas

Hugues Duffau

Abstract：Surgery appears currently a treatment of choice in several brain lesions, especially tumors, on condition that the resection is the largest possible. However, due to the infiltrative behaviour of many tumors, in particular (low-grade) gliomas, to the frequent location within eloquent areas, and because of an interindividual anatomo-functional variability, functional mapping methods are used to taylor the resection according to cortico-subcortical functional boundaries. Consequently, in addition to the preoperative functional neuroimaging for the surgical planning, intraoperative electrical stimulations can be used during resection, eventually under local anesthesia on awake patient iflanguage and other cognitive functions need to be mapped. Indeed, this is an easy, accurate,reliable and safe technique of detection of both cortical and subcortical structures essential for the function. Thus, stimulations have boundaries, allowing to optimize the quality of lesion removal while minimizing the risk to induce a permanent postoperative neurological deficit (i.e. to optimize the ratio: benefit / risk). Moreover, intraoperative stimulations can be combined with peri-operative functional neuroimaging methods (fMRI, PET, MEG, DTI), before and after surgery, in order to improve the reliability of the pre-operative planning, but also with the goal to better understand both the short-term and long-term plasticity mechanisms associating functional cortical reshaping and connectivity changes-due initially to the tumor growth, then to its surgical resection.Finally, modelisations of such phenomena may help to improve the planning of future surgeries.