A Comprehensive Analysis of Inconsistencies in the Brain's Conventional Ex Vivo Mechanical Experiments

In 2020, a review titled Fifty Shades of Brain: A Review on the Mechanical Testing and Modeling of Brain Tissue was published, offering a comprehensive overview of brain mechanics. While this work stands out for its insightful analysis of brain mechanics, there are certain points it did not fully address, as well as key areas that require more detailed examination. The goal of this review is not merely to summarize and report on previous studies but to highlight discrepancies in the root causes of the extensive data reported in the literature. By examining the wide-ranging data, the progression of research over six decades, and the knowledge developed during this period, we aim to identify the sources of these discrepancies and propose feasible directions for future research. Additionally, while micromechanical models have attracted significant attention in recent years, we provide evidence to emphasize that, despite their advantages, these models are not yet reliable enough to replace conventional mechanical experiments and macro-scale models. By compiling, visualizing, and analyzing data from the past six decades and integrating challenging issues into a cohesive framework, this approach provides a more actionable analysis. It simplifies navigation through the field and equips researchers with a clearer understanding of its historical progression, challenges, and opportunities.