Nerve degeneration or central blocking may explain anodic pulse dominance

Evidence

Our reasoning was based on the observation that spiral ganglion neurons degenerate over time in deafened animals and that this degeneration first affects the peripheral processes (Koitchev et al. 1982 ; Cazals et al. 1983 ). If this degeneration is responsible for the higher anodic sensitivity, we hypothesized that the effect of polarity would change over time. … An alternative explanation for the higher anodic sensitivity at high current levels comes from a model of the implanted guinea-pig cochlea (Frijns et al. 1996 ). This model predicts that cathodic stimulation should elicit action potentials at the periphery of the neurons but that above a certain current level, the propagation of these action potentials may be blocked by the hyperpolarization produced more centrally on the fibers. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2273

Categorization

• XREF: Ties into the reader’s broader theme of how neural degradation alters stimulation responses, echoing deafness-and-neural-plasticity threads elsewhere in the library.