In this simulation of synapses, learners act out communication at the neural level by behaving as pre-synaptic vesicles, neurotransmitters, post-synaptic receptors, secondary messengers and re-uptake transporters. Neurotransmitters and receptors interact via “lock-and key” puzzle pieces (included). An adaptation of this activity includes modifying the learners' roles to illustrate the effect of drugs on the synapse.