Long-lasting changes in the strength of synapses in the brain underlie many forms of learning and memory. Depending on the pattern of activation, synapses can show either long-term potentiation (LTP) or long-term depression (LTD). A provocative study now shows that a form of LTD may spread over considerable distances, and that this spread may even involve signals that travel backwards.
- Roger A. Nicoll
- Robert C. Malenka
