Cathodic pulses are more efficient in animals but anodic pulses in humans

Evidence

Animal recordings performed at the level of the auditory nerve usually show longer latencies and lower thresholds for cathodic than for anodic stimulation (e.g., Miller et al. 1999 ). This observation is consistent with theoretical models of extracellular electrical stimulation of the nerve showing that a cathodic current produces a larger depolarization and elicits action potentials more peripherally than an anodic current of the same level (Rattay 1989 ). In past years, studies performed with human CI listeners have shown different results. While at hearing threshold, no consistent difference between polarities has been observed, a large number of studies have reported that anodic stimulation is more effective than cathodic stimulation at suprathreshold levels (Macherey et al. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2273

Categorization

• XREF: Connects to the reader’s neuroscience-of-hearing corpus on electrode-neuron interaction and polarity mechanisms, and the general puzzle of species differences in neural stimulation.
• QUESTION: Why would cathodic stimulation beat anodic in animal cochleas but lose to it in human cochleas at suprathreshold levels? Worth chasing the mechanism.