To begin, secure the micro-drive on a head cap. Secure all three screws on the micro-drive system. Using the screw control on the micro-drive, lower the silicon probe, making one turn every 1 to 2 seconds until units are observed at the array tip.
Once the neurons are observed, retract the one turn of the micro-drive to decrease the electrode's speed of entry as it moves through the Silastic and dura into the cortical tissue. Slowly continue to drive the array into the cortex, advancing 4 to 6 turns over 20 to 30 minutes until neurons are evenly distributed across the length of the probe. Then slowly retract the array by 1 to 2 turns to reduce the pressure on the tissue.
After the recording is complete, slowly retract the array from the cortex at a speed similar to the initial insertion. Once no more neurons are visible on the probe, retract the array more quickly until it returns to the fully retracted starting position. After removing the probe from the recording chamber, soak it in contact lens solution for 20 minutes to clean off any tissue or blood.
Place the probe in alcohol for one minute to remove the contact lens solution and allow the electrode to dry. The spike sorted array data obtained through Kilosort revealed that the principle component features of selected spikes in a cluster were distinct from background spikes, confirming the recording's stability over time. The reliability of the X-Y positioning demonstrated a 70.8%overlap in mean RF locations between two sessions a week apart.
Precise retina topic space movements were observed in a series of recording sessions crossing the MT and MTC borders using minor positioning changes.
