Conical thumbtack electrode

 Conical thumbtack electrode

This epoxy-fixed electrode made of platinum-iridium leads is suitable for conducting intracortical signals with permanent implantation (even for a period of one year). A silicone disc limits the penetration depth of the electrode and secures its position. Wires running in a silicone tube allow the connector to be secured separately from the implantation site, thus providing a long-lasting chronic measurement option for the researcher when installed.

The electrode is not suitable for piercing the puncture. At the electrode lead points 16 or 24, at a platinum-iridium wire thickness of 40 microns, the diameter of the polyimide tube is 0.4-0.5 mm. These sizes are typical, but smaller sizes are possible. The end of the electrode is cylindrical and sealed with an epoxy resin hemisphere.

Electrode materials:

• The outer surface of the electrode is typically a 400 or 500 micron diameter polyimide tube, but can be made of even thinner ones.

• Lead points: platinum-iridium wire. Diameter: 40 microns, but can also be made of 15, 20, 25 micron wire.

• Synthetic resin binder: implant grade epoxy resin.

• Cable: medical grade one component silicone rubber coating

• Silicone disc fitting to the surface of the cortex: implant-grade silicone sheet, diameter between 3 and 10 mm typical

• Connector: Omnetics, Precidip, etc. different types.