The neuroscientist explains how our mind produces memories and why they actually alter our DNA.

Question: How do our brains create memories?

Ottavio Arancio:  Okay, the neurological process includes a series of chemical reactions at the level of the synapse and this series of reactions leads to changes in the connection of the synapses, changes that include both the…   How would you say?  Changes in the receptors that are located at the synapses such that these receptors respond in a different way and changes in the release of neurotransmitters of the synapses and eventually changes at the level of the morphology of the synapse, such that the synaptic response becomes much stronger. And even in addition to that for this memory to last longthere have to be changes in the…  at the level of the genes that are part of our DNA and that are long-lasting, so there are genetic changes with formation of new proteins in the cells that will leave its, you know, like sign, its change over there, as plastic changes, like as more protein and new proteins formed at the synapse. 

You see, memory passes through several processes, several points and first you memorize something, then you consolidate this something, then you can recall it when you need to remember, then you can reconsolidate it.  It’s a process which has several steps or phases.

Question: Why are we occasionally unable to recall a particular memory?

Ottavio Arancio: I'll bet that it depends on the particular moment in which you are trying to recall that memory and certain processes that no longer happen in the brain or they are blocked.  Some chemical reactions occur and they interfere or do not occur and interfere with this process of recalling in a certain moment and then one you know has the chance then to remember it, maybe because you make an association with something at the moment that has to like…  You know if you associate something with a particular odor as an example and then that odor comes then the memory comes up.  It’s just those are tricks also to remember.

Question: Do our senses affect memory particularly strongly?

Ottavio Arancio: Well, I mean, obviously I bet that smell is much more important for a dog than for humans—although there are humans who exercise their sense of smell and probably much better than I am to remember using smell.  I mean there is differences between sense as a way of learning according to people and we are not the same. It’s like a door that some people is more open one door than another, so or and so they use one particular way more than others, so there are differences, but if we accept through the way in which the memory gets in the chemical process that once those things get in they are very, very similar inside the brain.  They are very, very similar for different, we’ll call input of memory coming different ways, through different mechanisms and they’re very similar in humans and they are very similar between different animals.