RT Journal Article SR Electronic T1 Mechanical flexibility reduces the foreign body response to long-term implanted microelectrodes in rabbit cortex JF bioRxiv FD Cold Spring Harbor Laboratory SP 058982 DO 10.1101/058982 A1 H S Sohal A1 G J Clowry A1 A Jackson A1 A O’Neill A1 S N Baker YR 2016 UL http://biorxiv.org/content/early/2016/06/14/058982.abstract AB Micromotion between the brain and implanted electrodes is a major contributor to the failure of invasive microelectrodes. Movements of the electrode tip cause recording instabilities while spike amplitudes decline over the weeks/months post-implantation due to glial cell activation caused by sustained mechanical trauma. We compared the glial response over a 26-96 week period following implantation in the rabbit cortex of microwires and a novel flexible electrode. Horizontal sections were used to obtain a depth profile of the radial distribution of microglia, astrocytes and neurofilament. We found that the flexible electrode was associated with decreased gliosis compared to the microwires over these long indwelling periods. This was in part due to a decrease in overall microgliosis and enhanced neuronal density around the flexible probe, especially at longer periods of implantation.