Figure 1.  (SchematicOverviewTetrode v2.pdf)

Begin making the tetrode by cutting a 50 cm long electrode wire [overview #1].  Fold the electrode wire in half and pull with slight force on both ends [overview #2]. Fold the wire pair to make a bundle of four electrode wires on one end and a loop on the other end.  Cut the bundle so the four tips are virtually in the same position [overview #3].  Clip the four electrodes together with an alligator clip, and then place the loop over a stable horizontal metal bar.  Turn the alligator clip 80 times clockwise, then 40 times counter clockwise [overview #4].  Heat the twisted electrode wire using a hot-air gun set to approximately 800 degrees Fahrenheit.  Perform this heating process from 3 different angles around the tetrode.  Cut the tetrode tip and the loop. [overview #5].  Bend the four non-bonded wire strands so they do not stick together and place them in a box [overview #6].  To install the tetrode, push the tip of the tetrode down the 30 gage polyimide tubing of a micro-drive.  Connect the four non-bonded wires of the tetrode using gold pins to the connector board.  Cut the tetrode to the desired length using a pair of serrated scissors [overview #7].  Plate gold particles onto the electrode tips to condition the tetrode for chronic in-vivo recording [overview #8].  It may be more effecient to load the tetrodes in one step, and plate them all afterwards [overview #9].  Measure out two grounds and strip off the insulation as shown [overview #10].  Connect the ground wires to the connector board [overview #11].  Place the protective cone over the drive-array, snaking the ground wires through the bottom hole of the cone.  Take one ground wire and connect it to the cone using one of the three cone fastening screws [overview #12].

Figure 2a,b (Tetrode Install)
Slide the tetrode into the 30 gage polyimide tubing and connect the tetrode wires to the connector board.

Figure 3 (Tetrode Grouping)
You may want to group adjacent tetrodes according to their target location in the brain (Please label one group CA1, the other CA3, and the other Cortex).

Figure 4 (Electrodes in Brain)
The final position of the tetrodes in the brain may look something
like this.  When you cut the tetrodes, make sure to the tetrode is long enough to reach its pre-determined destination.

Figure 5. (scissors)
Here is an example of the serrated scissors that we use to cut the tetrodes before gold plating.

Figure 6. (Rat with Implant)
A rat implanted with a completed multi-electrode micro-drive array.

