Fonseca Lab | Understand how the brain knows the good from the bad: the neuron perspective

[Left to right: Natália Madeira, Ana Drumond, Rosalina Fonseca]

Natália Madeira, PhD Student from the from Cellular and Systems Neurobiology Lab led by Rosalinda Fonseca, published an article in the journal Cerebral Cortex entitled "Temporal Gating of Synaptic Competition in the Amygdala by Cannabinoid Receptor Activation " (full article here).

In brief, Rosalina Fonseca talks about this article:

What were you trying to understand and what is the main discovery of this work?
We know that memories evolve in time, in a very dynamic fashion. Consider this example: when one eats a candy bar, we expected to be good due to prior experiences. If it is not, then the brain is faced with a conflict. Should one update the prior information and render all candy bars as bad? Or should we store this particular event as unique and consider that this particular candy bar is not good? Or simply forget that we have ever tasted a bad candy bar? This may seem simple questions, but we do not know the rules that determine whether information is lost, updated or stored in a separate event. Given that single neurons, the unitary elements of neuronal networks, are already capable of making such decisions, in this work, we set out to determine the rules by which events occurring at particular neuronal connections, called synapses, interact with prior information, that is, with prior synaptic events. Our goal was to set out a conceptual model that could be predictive of one’s behavior when faced with conflicting information.

What discoveries led you to the research described in your publication?
We looked at individual neurons and recorded their responses to particular stimulation patterns. We found a fundamental role of time in association or discrimination of separate events and that the sequence of events is also important.

Why is this important?
Building on our cellular information we have now a detailed model that we can test at the behavioral level. And that is exactly what we are doing! We can now know whether the time interval between bad and good events determine whether they will get associated or discriminated. Going back to candy bars, our aim is to understand how a bad and a good candy bar get discriminated. We have also built some insights regarding the molecular players that may be key determinants in associating or discriminating memories.

What questions remain to be asked?
Of course, our final goal is to be able to prevent over generalization of fear, a pathological setting in which subjects are no longer able to distinguish bad from neutral or good events. This is exactly what happens in post-traumatic stress disorder. If we understand how events get associated in time, and the molecular players involved in this generalization we can prevent the progression of post-traumatic stress disorders as well as revert it once it has been established.

This article has been recommended in Faculty Opinions as being of special significance in its field by Faculty Member Sajikumar Sreedharan. Read Dr Sreedharan's recommendation here.

Find out more about Cellular and Systems Neurobiology Lab.

Written by