Mechanical contribution of the pia-arachnoid complex to brain tissue revealed by large deformation indentation

The pia-arachnoid complex (PAC) tissue plays a vital role in upholding the physiological functionality of brain tissue and bolstering its capacity to withstand detrimental loads. However, the mechanical attributes of the PAC tissue remain inadequately comprehended and insufficiently explored. This investigation acquired the indentation response of the PAC tissue through large deformation dynamic indentation. The mechanical significance in the face of external loads of the PAC tissue was elucidated through the combination of finite element simulation and experiment. The findings demonstrated that the PAC tissue can augment the cortex’s shear modulus and damping ratio, fortifying the brain tissue’s resistance against deformation. Additionally, the outcomes revealed that the PAC tissue can curtail the maximum stress and strain within the brain tissue by 40% and 53%, respectively, when subjected to substantial local deformation. Furthermore, the PAC tissue can impede strain propagation to the cerebral cortex during relaxation. This inquiry furnished a fundamental dataset for characterizing the dynamic mechanical properties within finite element simulations and experimental explorations involving brain tissue.