Pot = blocks your neurotransmitters to return back into the previous neuron, thus it effects the next neuron in the chain with added effects because there are more stimulants and only the "c?phalo-rachidian liquid" (or the LCR) is there to wash it out (also the outer cells that destroys neurotransmitters). Ah, the joy of biology em phased upon human behaviors for psychology students !
(From the class' power point, coll?ge Ahuntsic, Phillipe Courtemanche-Asselin)