Figure 10. Effects of oligodendrocyte hyperpolarization on axonal conduction in the alveus and LTP induction at destination synapses. A, Top, Schematic drawing showing the stimulating (S) and recording (R) electrodes for recording CAPs. Bottom left, Changes in CAP amplitude induced by yellow light illumination for 30 s, starting at 0 min (yellow bar), expressed as a percentage of the mean CAP amplitude during the 8 min period before light pulse delivery (n = 12). The white squares and light yellow triangles are the data without photostimulation in PLP-ArchT mice (n = 6) and with photostimulation in control wild-type mice (n = 5), respectively. Bottom right, Summary histograms for the change in CAP amplitude at 1–3 or 28–30 min, the periods are indicated by the black bars, with no stimulation or after photostimulation for the indicated time, expressed as a percentage of the mean CAP amplitude during the 8 min period before yellow light pulse delivery. B, Top, Schematic drawing showing the stimulating (S) and recording (R) electrodes for recording EPSCs from subicular bursting neurons. Bottom left, Changes in EPSC amplitude induced by yellow light illumination for 30 s, starting at 0 min (yellow bar), expressed as a percentage of the mean EPSC amplitude during the 10 min period before light pulse delivery (n = 6). The white circles are the data without photostimulation (n = 5). Bottom right, Summary histograms for the change in EPSC amplitude at 1–3 or 28–30 min, the periods are indicated by the black bars, with no stimulation or after photostimulation for the indicated time, expressed as a percentage of the mean EPSC amplitude during the 10 min period before yellow light pulse delivery. C, Schematic drawing showing the stimulating (S) and recording (R) electrodes for recording EPSCs from subicular neurons and yellow light illumination (yellow jagged arrow; top left), and the protocol for photostimulation and electrical theta burst stimulation for the induction of LTP (top right). Changes in EPSC amplitude induced by theta burst stimulation (15 or 20 bursts) in the absence (15 bursts, n = 7; 20 bursts, n = 6; middle left) and presence (15 bursts, n = 5; 20 bursts, n = 5; middle right) of yellow light illumination expressed as a percentage of the mean EPSC amplitude during the 10 min period before theta burst stimulation. Yellow light illumination was initiated at 5 s before first burst stimulation and terminated at 25 s after the end of the last (15th or 20th) burst, as indicated by the yellow bar. Bottom, Left, Changes in EPSC amplitude induced by theta burst stimulation in the presence (15 bursts, n = 4; 20 bursts, n = 5) of yellow light illumination in PLP-ArchT mice with Dox treatment. Bottom, Right, Summary histograms for the change in EPSC amplitude at 35–40 min after theta burst stimulation with or without photostimulation in PLP-ArchT mice or with photostimulation in PLP-ArchT mice with Dox treatment, expressed as a percentage of the mean EPSC amplitude during the 10 min period before yellow light pulse delivery. *p < 0.05 (two-way ANOVA).