You have to create three column vectors from your data to use them with plot3, and they all have to be equal length. This replicates the row and column sizes to be equal to the number of elements in the array, and plots them. That’s the only way I can think of to do what you describe. It has the virtue of running, but I have no idea if it does what you want:
emg_recording = randi(9,6,8);
X = repmat([1:size(emg_recording,1)]', size(emg_recording,2), 1);
Z = repmat([1:size(emg_recording,2)]', size(emg_recording,1), 1);
Y = emg_recording(:);
figure(1)
plot3(X, Y, Z)
grid on
xlabel('Rows')
ylabel('Cell Value')
zlabel('Columns')
