How emotions change over time

Our emotions change over time. This may seem obvious, but understanding precisely these variations, their dynamics and the brain regions involved is of major importance from a therapeutic perspective. Emotional variation is a key characteristic in many mental health disorders such as depression, post-traumatic stress or borderline personality disorders.

What happens when you get emotional? And how does it evolve over time? Research on the dynamics of emotions is relatively recent. The different methodologies developed made it possible to highlight two main phases in the dynamics of emotions. First, the onset of emotion, which can be brutal or progressive, is referred to as the degree of "explosivity" of the emotion. Then the emotional compensation phase, that is, the intensification or attenuation of the emotion over time, assessed by its degree of "accumulation".

The brain bases of these two phases and their possible variations over time remain to be elucidated. Recent studies have identified areas of the brain involved in the delivery of emotions such as the medial prefrontal cortex, amygdala and insula.

But how does the activity of these different brain regions vary during different phases of an emotional experience?

To find out, researchers from Paris Brain Institute, KU Leuven and Maastricht University carried out an experiment on 31 participants.

They asked them to write several short texts on personal topics such as their dreams or aspirations. These texts were then read by judges who deduced from them the personalities of the participants. In fact, all participants received the same negative or neutral feedback on their personalities, regardless of their texts. Researchers then asked participants to read and reflect on these returns for 90 seconds and to report on the emotional changes experienced over time. In parallel, their brain activity was recorded by functional MRI, which allows real-time observation of the activation of different brain regions.

Researchers were thus able to study the brain regions involved in explosivity and the accumulation of emotional responses following a negative social experience, which is known to generate emotional responses that last for a long time and thus allow the two phases to be clearly differentiated.

The results show that the emotion triggering and compensation phases are the two main components of emotional changes over time and are associated with distinct regions in the brain. Differences in the explosiveness of the onset of emotion are related to activity in the median prefrontal cortex. This region is supposed to be involved in one’s perception of oneself. Here, its activation could therefore reflect the difference between the judges’ assessment and the participants’ idea of themselves. Differences in accumulation are related to the activation of the posterior part of the insula, a region known to play a key role in the integration of emotional cues.

This is the first study to show that the activity of brain regions that orchestrate the emotional response varies over time. It thus underlines the importance of taking this temporal dimension into account in order to understand the cerebral bases of the evolution of emotions, from triggering to intensification or attenuation, following a process of social exclusion. These findings may have implications for treatment of mental health disorders.