Afferent and efferent innervation of the cat cochlea: Quantitative analysis with light and electron microscopy

摘要: The purpose of the present study was to describe longitudinal and radial gradients cochlear innervation in cat. To this end, afferent efferent terminals both inner (IHC) outer hair cell (OHC) regions were reconstructed from serial ultrathin sections at six eight locations, respectively, corresponding roughly octave intervals characteristic frequency (CF). Analysis IHCs showed (1) number fibers per IHC rises 10 0.25 kHz region a maximum 30 locus; (2) branching is essentially restricted apical 1.0 point; (3) there are significant differences synaptic-body morphology for synapses on different sides IHC, known threshold rate spontaneous activity. With respect area, we found that numerous vesicle-filled contacting every examined; however, those with obvious synaptic specialization confined most regions; same numbers fiber all locations; each location, modiolar side (corresponding high-threshold afferents) significantly more than pillar side. OHC clear rise 3 base 15 apex, no systematic as function row, bodies synapse common only locus. Counts OHCs revealed maximal (9 OHC) between 6 24 striking decrease terminal counts first- third-row OHCs. Ultrastructural data compared quantitatively light-microscopic analysis cochleas immunostained (with antibody synaptophysin) reveal vesiculated terminals.