Electrode electrode. In a vacuum tube or a semiconductor having polarity (diodes, electrolytic capacitors) the anode is the positive (+) electrode and the cathode the negative (−). The electrons enter the device through the cathode and exit the device through the anode. Many devices have other electrodes to control operation, e.g., base, gate, control grid. In a three-electrode cell, a counter electrode, also called an auxiliary electrode, is used only to make a connection to the electrolyte so that a current can be applied to the working electrode. The counter electrode is usually made of an inert material, such as a
Chronic electrode implant that glial encapsulation, i.e. gliosis, insulates the electrode from nearby neurons, thereby hindering diffusion and increasing impedance, extends the distance between the electrode and its nearest target neurons, or creates an inhibitory environment for neurite extension, thus repelling regenerating neural processes away from recording sites"”. Either activated astrocytes or buildup of cellular debris from cell death around the electrode would act to insulate the recording sites from other, active neurons. Even very small increases in the separation between the electrode and local nerve population can insulate the electrode completely, as electrodes must be within 100 um to get a signal.