Separating the forest from the palm trees: Individual variation in a presurgical language mapping task

Area of Science:

• Neuroimaging
• Cognitive Neuroscience
• Neurosurgery

Background:

• Language mapping in neurosurgery is challenged by practice mismatches between pre-surgical and intra-operative evaluations.
• Functional MRI (fMRI) tasks are increasingly used for intra-operative assessment in awake neurosurgery patients.
• Evaluating task reliability is crucial for aligning these mapping practices.

Purpose of the Study:

• To evaluate the reliability of a functional MRI version of the semantic association task, the Pyramids and Palm Trees Task (PPTT).
• To characterize fMRI activation reliability across individuals, test-retest sessions, and different scanner cohorts using a consistency mapping approach.
• To support the alignment of pre- and intra-operative language mapping in neurosurgical patients.

Main Methods:

• fMRI data acquired during an adapted PPTT in 15 healthy controls and 54 pre-surgical glioma patients.
• Utilized threshold-weighted overlap mapping (TWOM) to assess inter-individual variability, test-retest variability, and between-scanner reliability.
• Compared standard and advanced fMRI acquisitions across Siemens Prisma and Verio scanners.

Main Results:

• Task-related activations within the core language network demonstrated high consistency across individuals and test-retest sessions.
• Variable activations were observed in specific brain regions, correlating with atypical language dominance or semantic processing differences.
• Overlap mapping effectively visualized individual variations in neural processing.

Conclusions:

• The PPTT effectively engaged widespread brain networks, including semantic processing regions.
• Overlap mapping is a valuable tool for visualizing individual neural processing variations.
• This approach supports better alignment between pre-operative and intra-operative language mapping for neurosurgery.