Morphometric classification and spatial organization of spiral ganglion neurons in the human cochlea: consequences for single fiber response to electrical stimulation.
Bottom Line: Furthermore, we found evidence of a spatial arrangement of perikarya and their accordant nuclei along the cochlea spiral.Cathodic stimulation was found to induce stronger variations of spikes while also leading to the lowest thresholds and longest latencies.Therefore, anodic stimulation leads to a more uniform excitation profile among SGCs with different cell body size.
Affiliation: Innsbruck Medical University, Department of Otorhinolaryngology, Laboratory for Inner Ear Biology, Anichstrasse 35, Innsbruck, Austria.Show MeSH
Mentions: When the soma-electrode distance is 0.5 mm, the cathodic threshold increases with soma diameter monotonically from −171 μA to −393 μA, always initiating the AP at compartment 13. Contrarily, the anodic threshold decreases monotonically from 174 μA to 162 μA with a constant IS at compartment 27. For the biphasic pulses of E3, the thresholds as well as the IS changes with varying soma diameter. When stimulated with biphasic cathodic first pulses, the thresholds again increase with cell size. The values range from −451 μA to −954 μA, although the slope of the curve decreases for diameters larger than 19.07 μm correlating with the change of IS from compartment 13 to 27 (compare top panel of Fig. 8). For biphasic anodic first pulses, this change appears already for diameters above 11.64 μm. As a result, the threshold values ascend steeply at first from 611 μA to 654 μA, but then again decrease to 635 μA (compare bottom panel of Fig. 8).
Affiliation: Innsbruck Medical University, Department of Otorhinolaryngology, Laboratory for Inner Ear Biology, Anichstrasse 35, Innsbruck, Austria.