Intraoperative functional remapping unveils evolving patterns of cortical plasticity

Area of Science:

• Neuroscience
• Neurosurgery
• Neuroimaging

Background:

• Diffuse low-grade gliomas (DLGG) are slow-growing brain tumors that induce adaptive changes in brain architecture, serving as a model for studying neuroplasticity.
• Repeated surgeries are often necessary for DLGG due to tumor recurrence, providing opportunities to observe brain reorganization over time.
• Direct electrostimulation (DES) mapping is crucial during awake surgeries to identify and preserve critical brain areas.

Purpose of the Study:

• To characterize the dynamic patterns of cortical reorganization in patients with DLGG undergoing sequential neurosurgeries.
• To generate probabilistic neuroplasticity maps illustrating brain rearrangements at both population and individual levels.
• To investigate the implications of these dynamic changes for re-operation strategies.

Main Methods:

• Analysis of a large dataset (2082 cortical sites) from 101 DLGG patients who underwent two DES-guided surgeries, typically years apart.
• Creation of probabilistic neuroplasticity maps using a multi-step approach, integrating data in Montreal Neurological Institute (MNI) space.
• Application of voxel-wise and parcel-wise analyses, along with clustering and statistical tests (e.g., Fisher's exact test, TFCE) to identify significant cortical changes.

Main Results:

• Probabilistic maps revealed significant potential for evolving reorganization in areas including the supplementary motor area (SMA), dorsolateral prefrontal cortex (dlPFC), ventral premotor cortex (vPMC), and superior temporal gyrus (STG).
• Parcel-wise analysis confirmed reorganization potential in the dlPFC and precentral gyrus.
• Clustering analyses identified topological migration of functional sites, particularly in language and motor areas, with dynamic changes confirmed at the individual level.

Conclusions:

• DLGG induces continuing, dynamic rearrangements of the cerebral cortex, highlighting the brain's remarkable neuroplasticity.
• Understanding these evolving cortical patterns is critical for planning and optimizing re-operation strategies in DLGG patients.
• The findings offer valuable insights into the long-term functional adaptation of the brain in response to chronic lesions.