Long-term depression, or LTD, is a process by which synaptic connections between neurons are weakened. Although the functions of LTD are not completely understood, it may be important to memory formation---perhaps by resetting previous synaptic changes to allow for new memories to be formed via long-term potentiation (LTP).?In this video, I discuss the best understood mechanism underlying LTD, which involves AMPA and NMDA glutamate receptors.