Now this in turn will usually cause changes to the membrane permeability of the postsynaptic cell and that in turn will generate some type of signal that will be passed down to the postsynaptic cell. And this is usually how the propagation of the electrical signal actually works along our nerve cell. And we'll discuss this in much more detail in the next several lectures. Now, the final important aspect of a neuron that I want to mention is the energy source that it actually uses. So neurons depend almost entirely on glucose for energy generation. However, the neuron cannot actually store much of the glucose in the form of glycogen inside the cell and the neuron cannot actually store much oxygen inside the cell either.