Figure 2

M-8324 altered rates of sound-evoked and spontaneous spike in AI in vivo. (A) Experimental procedures. (B) Identification of putative excitatory (red) and inhibitory (blue) neurons based on their spike waveforms, while light gray dots between the blue and red dots were excluded from data analysis. (C) Example receptive fields during “before drug” (upper) and “after drug” (lower) trials for the same recording site in AI. Each pixel in the plot represents the average number of spikes evoked by a sound stimulus at a particular frequency and intensity level. (D) (Left) Examples of an increase in the frequency of spontaneous spiking in inhibitory neurons concomitant with a decrease in excitatory neurons after 100 µM M-8324 infusion. (Right) Population results and time course of changes in spontaneous spiking in excitatory and inhibitory neurons. (E) (Left) An increase in the sound-evoked spike frequency in inhibitory neurons concomitant with a decrease in excitatory neurons after 100 µM M-8324 infusion. (Right) Population and time course of changes. Neurons were the same as in (D). (F) A significant increase of SNR in excitatory neurons but no change for inhibitory neurons. (G) A significant increase in the E/I ratio for both spontaneous spiking (left) and sound-evoked responses (right). For excitatory cells, N = 95 cells/8 mice (vehicle), 73 cells/6 mice (M-8324 30 µM), 114 cells/9 mice (M-8324 100 µM). For inhibitory neurons, N = 28 cells/8 mice (vehicle), 19 cells/6 mice (M-8324 30 µM), 46 cells/9 mice (M-8324 100 µM). Data are presented as the mean ± SEM. * represent significance versus vehicle group.