Inside a Programmer's Brain: Dissociating Code and Language Comprehension Networks Using a Novel fMRI-ESM Protocol

Code comprehension and natural language share structural similarities but engage partially distinct neural systems. While language predominantly recruits the classical perisylvian language network, code comprehension has been linked to the multiple-demand system, associated with mathematical thinking and problem solving. We report the case of a professional software engineer with an IDH-mutant astrocytoma in the left middle frontal gyrus, a region where these networks converge. To address the potential risk of impairing computer programming abilities during surgery, we implemented a personalized protocol combining fMRI and intraoperative electrical stimulation mapping (ESM), extending the standard language assessment with a Code comprehension task. Intraoperative mapping identified sites in the left inferior frontal cortex that were functionally relevant to the Code comprehension task but were not identified during standard object-naming mapping. Complete tumor resection was achieved while preserving these critical regions, with the patient showing intact post-operative language and programming performances. This single case study suggests that individualized Code comprehension mapping may identify functionally relevant sites not detected by standard object-naming mapping, supporting the potential clinical value of tailored fMRI-ESM protocols for preserving higher-order cognitive functions in neurosurgical patients.