Synapse changes during learning

Professor Kenneth Kosik discusses changes in synapses that accompany long-term potentiation, which include enlarged dendritic spines.

Learning in the brain is very complicated; it involves a large amount of brain tissue. Scientists however, as reductionists, tend to want to narrow things down further and further to the level of cells and molecules. For that reason, we have begun to actually look at synapses during learning and memory. There is a physiological approach in which one can change the thresholds of synapses by repeatedly stimulating them, called long-term potentiation (LTP), that is thought to be a reductionist correlate at the single synapse level of learning. Now when LTP takes place at a synapse, there are a number of changes that take place there that have fascinated neurobiologists for many years. Among those changes are shape changes; that is, protrusions from the dendrites, that carry the synapse, called spines, will enlarge. Another feature of the change in synaptic threshold is that proteins begin to be translated locally at the synapse. This is an area of intense jnterest right now because those proteins, that are being translated locally in the synapse, involved in learning, are probably going to turn out to be critical mediators of this process.