What is considered the depolarizing pole for SSEP stimulation?

In the context of Somatosensory Evoked Potentials (SSEP) stimulation, the depolarizing pole refers to the electrode configuration that causes depolarization of the neural elements, which then leads to the generation of action potentials. The cathode serves this role, as it is the site where negative charge is accumulated, leading to depolarization when stimulation occurs. When the cathode is placed near the nerve or area of interest, it effectively generates the necessary electrical field that triggers the depolarization and subsequent response in the sensory pathway being evaluated.

Understanding the functionality of the electrodes is crucial in SSEP studies, as the placement and polarity can significantly influence the quality and characteristics of the neural responses being measured. In contrast, the anode, ground electrode, or neural origin do not serve this specific depolarizing function in the same way. The anode is more associated with hyperpolarization and does not lead to the generation of action potentials in this context, while the ground electrode ensures electrical stability but does not play a role in stimulating neural activity directly. The neural origin refers to where neural activity begins following stimulation but is not itself an electrode or stimulation component. Therefore, recognizing the cathode as the depolarizing pole is fundamental in