Chronic recordings from the rat spinal cord descending tracts with microwires

This study investigated the feasibility of chronically recording descending signals from the rat spinal cord using microwire electrodes. Eight 25μm diameter Pt-Ir microwires were implanted in the dorsolateral rubrospinal tract (RST) bilaterally at the c5 level in each of the four adult Long Evans rats trained for food reach-to-grasp task. Signal stability was assessed by calculating the signal-to-noise ratio (SNR) and mean signal amplitude during the four week recording period. The results of ANOVA did not suggest significant difference between sessions for any of the electrodes, indicating stability. Immunohistology suggested minimal tissue response to these microwires during the four week implant period. The results of this study show that microwire electrodes can be used for short-term chronic recordings of signals from the descending motor tracts in experimental animals.