Brain function may be preserved within brain tumors, according to outcomes from invasive cortical stimulation mapping and non-invasive neuroimaging studies. However, there was still a need for a non-invasive method to properly and fully identify individual-specific functional networks in the entire brain, particularly in brain regions within and surrounding tumors. The researchers sought to create a clinically relevant technique for functional mapping regions within tumored brains for a study. They used resting-state functional magnetic resonance imaging (rsfMRI) to build an individual-specific applicable network parcellation technique that efficiently captured active networks within and around tumors in 20 patients. Using invasive cortical stimulation and task response, the study group tested the accuracy of the value maps. They discovered that around 33.2% of the tumoral mass was functionally active, with solid functional connections to non-tumor brain areas. Invasive cortical stimulation mapping was used to validate available networks surrounding malignancies. The investigators’ method identified intratumoral sensorimotor networks with different cortico-cerebellar connection patterns and was compatible with hand movement elicited fMRI task activations. Furthermore, certain patients’ cognitive networks discovered in the tumor mass revealed long-distance and scattered functional connectivity. The non-invasive mapping of individual-specific available networks with rsfMRI was a promising new tool for identifying regions with preserved functional connectivity within and around brain tumors. It could be used as a supplement to presurgical planning for patients undergoing tumor resection surgery.