Long- and Short-term Memory Differences (1)

Professor Eric Kandel compares short-term memory, which involves the alteration of pre-existing proteins, and long-term memory, which involves new protein synthesis.

There are dramatic differences. Short-term memory involves alterations in pre-existing proteins. Long-term memory involves new protein synthesis. The way that happens is short-term memory involves recruitment of signaling pathways in the brain, like the cyclic AMP pathway and the calcium/calmodulin dependent kinase pathway. These activate enzymes - calmodulin dependent protein kinase, or the cyclic AMP dependent protein kinase. And they produce actions locally on the release machinery for transmitter control in the presynaptic terminal and on postsynaptic receptors. Long-term memory involves the movement of those signaling pathways into the nucleus to turn on gene expression, and that turning-on of gene expression gives rise to the growth of new synaptic connections. So, short-term memory involves alterations in pre-existing proteins, usually through protein phosphorylation and alteration in the strength of pre-existing connections. Long-term memory involves gene expression, new protein synthesis and the growth of new synaptic connections.