All I know is that some drugs shut down certain parts of your brain (to supress feelings like depressions etc) and some do the opposite, and turn on certain parts of your brain.. fuck knows what weed does though.. but someone I dont think there are actual 'THC receptors' in your brain that are specifically there for that reason, THC just does stuff to your brain, i dunno, i sucked at biology, i was always high.. ironic, eh?