Figure 4.

AlstR-mediated inhibition of excitatory neuronal population activity in an Emx1-Cre: AlstR mouse slice. (A1) Time series data of VSD imaging of photostimulation-evoked activity in S1 cortex in normal ACSF. The color scale codes VSD signal amplitude expressed as standard deviation (SD) multiples above the mean baseline. The site of photostimulation between layers 4 and 5a can be identified by the laser excitation artifact (purple) in the first frame, which is also indicated by the white arrowhead. Color-coded excitatory activity is superimposed on the background slice image. (A2) The time course of VSD signal (in the percent change of pixel intensity [ΔI/I%]) from the region of interest (ROI) indicated by the small rectangle in the first image frame in (A1). The arrowhead point the downward signal deflection caused by the laser excitation artifact. (B1) Time series of network activity in the same slice in the presence of the AL peptide, with excitatory response being clearly reduced compared to control. (B2) The time course of VSD signal (in the percent change of pixel intensity [ΔI/I%]) from the ROI indicated by the small rectangle in the first image frame in (B1). (C1) Time series of network activity in the same slice after the washout of the AL peptide. (C2) The time course of VSD signal (in the percent change of pixel intensity [ΔI/I%]) from the ROI indicated by the small rectangle in the first image frame in (C1).