Species differences in final nerve geometry may drive the polarity reversal

Evidence

If neural degeneration had an effect on polarity sensitivity, we would expect the polarity effect to increase over time and to reach positive values when fibers are degenerated. This does not seem to be the case as the level difference between polarities rather tends to decrease right after deafening for several subjects and then to remain roughly constant. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2309 (#complicates, via linked claim)

If neural degeneration had an effect on polarity sensitivity, we would expect the polarity effect to increase over time and to reach positive values when fibers are degenerated. This does not seem to be the case as the level difference between polarities rather tends to decrease right after deafening for several subjects and then to remain roughly constant. … Although the polarity effect is opposite in sign for the two species, it is interesting to note that its magnitude is similar for RPS and for TRI. For RPS-IPG, the smaller effect obtained psychophysically may be due to the fact that the delayed long, low-amplitude phase contributed to perception whereas it did not contribute to the neural responses recorded here. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2311 (#contradicts, via linked claim)

Categorization

• XREF: connects to: Polarity effect magnitude is similar in guinea pigs and humans but reversed in sign; Pulse polarity effects on neural response differ significantly across pulse shapes; Neural degeneration does not increase polarity sensitivity following deafening — Dijk, Pim van, Physiology, Psychoacoustics and…, 2311 (+3 more)

Related

• Polarity effect magnitude is similar in guinea pigs and humans but reversed in sign (similarity 0.93)
• Pulse polarity effects on neural response differ significantly across pulse shapes (similarity 0.93)
• Neural degeneration does not increase polarity sensitivity following deafening (similarity 0.93)
• Spiral ganglion degeneration does not progressively increase polarity sensitivity (similarity 0.92)
• Cochlear implant input-output responses can reverse polarity preference at high levels (similarity 0.90)
• Neural degeneration alone does not explain polarity sensitivity differences in cochlear implants (similarity 0.89)
• Neural degeneration over time does not flip cathodic-anodic stimulation efficiency in deafened guinea pigs (similarity 0.88)
• Neural degeneration does not drive the anodic sensitivity seen in humans (similarity 0.86)
• Asymmetric pulse shapes amplify polarity sensitivity beyond symmetric pulses (similarity 0.84)
• Polarity effect magnitude is similar across guinea pigs and human cochlear implant users (similarity 0.84)
• Neural degeneration does not alter CI pulse polarity sensitivity over time (similarity 0.83)
• Polarity effect magnitude is similar across species even though its direction is reversed. (similarity 0.81)
• Nerve degeneration or central blocking may explain anodic pulse dominance (similarity 0.80)
• Never degeneration of neural peripheral processes may explain human anodic stimulation preference (similarity 0.79)
• Nerve degeneration may flip polarity sensitivity toward anodic dominance in implant users. (similarity 0.79)

Broader Connections

• Neural degeneration alone does not explain polarity sensitivity differences in cochlear implants #complicates (0.85) — Dijk, Pim van, Physiology, Psychoacoustics and…, 2309
• Neural degeneration does not increase polarity sensitivity following deafening #contradicts (0.80) — Dijk, Pim van, Physiology, Psychoacoustics and…, 2311
• Spiral ganglion degeneration does not progressively increase polarity sensitivity #contradicts (0.80)
• Cochlear implant input-output responses can reverse polarity preference at high levels #expands (0.75)
• Pulse polarity effects on neural response differ significantly across pulse shapes #expands (0.70)