Electrode Implants

Following ICMS and ET-1 lesion procedures, skull screws (Pan Head Phillips head machine Screws, 0-80 thread, 1/8’’ length, stainless steel, McMaster-Carr, Elmhurst, IL) were placed in the six screw holes to ground the electrodes and to act as an anchor for dental acrylic applied to the skull. Two 16-channel microwire arrays (Tucker-Davis Technologies; 16 shank, 2x8 electrode, 50 µm wire diameter, 45° tip angle, 250 µm electrode spacing, 500 µm row spacing) were implanted in the RFA contralateral to the reaching forelimb (i.e., ipsilesional RFA) and CFA ipsilateral to the reaching forelimb (i.e., contralesional CFA). Online recording of activity from the microelectrode arrays was used to determine a depth with high neuronal firing on the majority of channels as the array was lowered into place with a mechanical micro-drive (at a depth ~1,550 µm perpendicular to the cortical surface). A quick-curing polymer was used (Kwik-Cast, WPI, Sarasota, FL) to cover the cortex, fix the arrays in place, and seal the cranial opening. Dental acrylic was then used to add additional anchoring to the skull by adhering to the stainless steel screws placed in the skull. The acrylic also served as an additional protective barrier over the polymer.