A benchtop system to assess cortical neural interface micromechanics

A benchtop brain tissue-microelectrode insertion model system was developed to aid in improving the design of cortical neural interfaces. The model partially mimics the in vivo environment via the use of human cadaver brain specimens (nspecimen = 6), or agar gel exposed to physiologically relevant mechanical oscillations. 150 lpm diameter stainless-steel microelectrode wires (TS = 600 MPa) implanted 3.0 cm within fixed human primary auditory cortex (ntrial > 10) experienced 133 +/- 8 and 64 +/- 4 mN of peak and steady axial forces. When subjected to a 3 Hz, 3-mm vertical oscillation, dynamic force amplitudes (ntrial > 10) of 148 +/- 10 mN were measured. The model system allows the study and comparison of static and dynamic forces and their mechanical influences on proposed implanted microelectrode structures.