Figure 6.
Refinement of the AIS was partially blocked by bilateral otocysts deprivation. A, Immunostainings of myelin marker (MAG, top) and dorsal surface of brainstems (bottom) from normal (left) and deprived (right) animals at E21. Note that the auditory nerve is identified as MAG-immunopositive fibers (top, red arrowheads) and white bundles (bottom, green arrowheads) only in normal animals. M, Medial; V, ventral; VIII, auditory nerve; NM, nucleus magnocellularis. B, Immunostainings of Nav channels (red, arrowheads) after labeling of NL neurons (green) in deprived animals. C, Immunostainings of ankyrinG (red, middle) and either Nav1.6 (top) or Nav1.2 (bottom, green, left) were made in deprived animals of E21 and overlaid (right). Note that the AIS was immunopositive to Nav1.6 (arrowheads), but not to Nav1.2. D–F, Length (D-P, D) and proximal (P-S, E) and distal (D-S, F) positions of the AIS. G, Correlation between length (D-P) and proximal position (P-S) of the AIS. Light blue columns and circles are from control animals of the same age (Fig. 3B–D; E21). Blue and red fitted lines are for control and deprived animals, respectively. Note that length was apparently longer and negative correlation was reduced in deprived animals. H, Action potentials in response to depolarizing current steps of 3 nA (red or blue) and the threshold current (gray) in deprived animals. Spikes at the high CF (left) and the low CF (middle) were overlaid after alignment at the threshold (right, arrowheads). I, Correlation between the rise time and amplitude of action potentials still remained after otocyst deprivation. *p < 0.05; **p < 0.01.