A new study identified the molecular mechanism that controls the strength of our memories. Neuronal connections in the brain are formed when memories are created and the gaps that form between two neuronal fibers are known as synapses. The research focuses on the molecules that are involved in strengthening the chemical signals that cross synapses. The paper describing the findings is published in Cell Reports.
When messages in the form of chemical signals travel across a synapse connecting two neurons, a neurotransmitter is released on one side of the synapse and connects with its corresponding receptor on the other side of the gap. AMPA-type glutamate receptor has been identified by the research team as an important receptor that can move freely in and out of the synapse. "The idea is that when a synapse experiences signaling that could lead to a new memory, it needs to recruit new receptors," said Elva Diaz, associate professor of pharmacology at UC Davis and senior author on the paper. More receptors in the synapse means a stronger memory - just as bringing more fielders out of the dugout will mean more balls get caught.
The study explores what regulates receptor movement in the hippocampus—a part of the brain important to memory function. The protein, SynDIG4, was identified to interact with AMPA receptors and has the surprising ability to recruit other receptors from outside the synapse. Stronger memories seem to be formed when more receptors are present at the synapse. The research team observed that knockout mice lacking in SynDIG4 protein could not complete a maze navigation which is simple memory test. These mice seem to have no short-term memory. The next step for the team is to conduct in vivo and in vitro studies to learn exactly how SynDIG4 works in controlling synaptic response.