Growth Molecules’ Role in Long-term Memory Formation

Findings from a study recently published in the journal Neuron demonstrate how a pair of growth factor molecules contribute to long-term memory formation. Growth factor molecules (GFs) are critical in the building of the brain from utero into adulthood. Through previous research, it has been established that GFs are “recycled,” starting from the brain-building function and later transitioning to “engineers” of long-term memories. In the current study, the research team examined GFs in Aplysia californica, the California sea slug. Aplysia is a model organism that is quite powerful for this type of research because its neurons are 10 to 50 times larger than those of higher organisms, such as vertebrates, and it possesses a relatively small network of neurons — characteristics that readily allow for the examination of molecular signaling during memory formation. Specifically, to produce a form of “threat memory,” called sensitization in a simple reflex system of Aplysia, the researchers presented the sea slugs with a pair of mild tail-shocks delivered 45 minutes apart — the first to instill a “molecular context” in the neurons of the reflex and the second to use that context to drive molecular mechanisms that are required to form a long-term memory — and then examined GF activity at two different time periods. Their results showed differences in the role of these two GF families across two dimensions: time and space. “These results give us a better understanding of memory’s architecture and, specifically, how molecules act as a network in creating long-term memories,” explained the paper’s senior author. To read more about this study, click here.