Markers of BBB Leakiness Correlate with Single Unit Recording Performance in High Density Penetrating Electrode Arrays Implanted Chronically in Rat Motor Cortex

摘要

We found that recording performance for center electrodes degraded to significantly lower SNR values compared to electrodes located at the edge of the 4×4 array. Moreover, this was related to greater BBB leakage near center electrodes, as evidenced by increased presence of IgG. BBB leakage may then lead to an unfavorable environment for neuronal function, increasing the distance between the recording site and the nearest healthy neuron and lowering the SNR as well as remodeling tissue. The FBR to the UEA was similar to single microwire or single shank planar electrodes except for the formation of a cavity of tissue loss in more superficial cortex. Such cavities have been reported in experimentally-induced infarction of multiple blood vessels in close proximity [3]. The presence of cavities in stab wound injured animals confirms that vascular injury is the most likely mechanism responsible for these areas of tissue loss. The architecture of the UEA, which has numerous closely-spaced microelectrodes inserted simultaneously into cortex similar to other devices of its type, has a much greater potential for vascular damage than single shank devices. Electrodes located near cavities performed poorly, which is unsurprising considering cavities were devoid of neural tissue markers. Together, these results suggest that strategies to reduce BBB leakage and vascular damage would improve the chronic recording function of high density intracortical microelectrode arrays.