Ploting 3D matrix on different planes

Hello every body, I have a question, sorry if it looks very simple. I have data like x=1:Nx, y=1:Ny, z=1:Nz and Ez(1:Nx,1:Ny,1:Nz). I'm going to plot Ez at planes x=floor(Nx/2) and floor(3Nx/4) and y=floor(Ny/5). Any help is appreciated.