For some people a single small irritation can wreck their entire day, while others can swiftly shake off minor problems and move on. A new study led by researchers from the University of Miami is suggesting persistent activity in the amygdala could be why some people are unable to quickly move on from momentary negative experiences.
"The majority of human neuroscience research looks at how intensely the brain reacts to negative stimuli, not how long the brain holds on to a stimulus," explains Aaron Heller, psychologist and senior author on the new study. "We looked at the spillover – how the emotional coloring of an event spills over to other things that happen. Understanding the biological mechanisms of that is critically important to understanding the differences in brain function, daily emotions, and well-being.”
The new research examined data from a massive longitudinal study called MIDUS (Midlife in the United States), an ongoing study that follows thousands of subjects tracking their general health and well-being.
Data from 52 MIDUS participants were investigated looking at correlations between self-evaluated measures of psychological well-being, daily affective experiences and fMRI scans. The researchers were particularly interested in associations between negative affect and persistent activity in the amygdala, a brain region known to process subjective emotional experiences.
The fMRI experiments involved showing participants images that were either positive or negative, mixed with images of neutral facial expressions. In some subjects, neural activity in the amygdala in response to negative images persisted longer than others.
Interestingly, the researchers detected a correlation between more persistent left amygdala activation in response to negative images and more frequent negative emotions in their daily lives. Essentially, those subjects with persistent activity in the left amygdala following negative stimuli were more likely to have generally negative emotional outlook.
"It may be that for individuals with greater amygdala persistence, negative moments may become amplified or prolonged by imbuing unrelated moments that follow with a negative appraisal," the researchers write in the newly published study. "This brain-behavior link between left amygdala persistence and daily affect can inform our understanding of more enduring, long-term evaluations of well-being."
Looking more closely at the longitudinal data from the small cohort the researchers suggest this specific kind of persistent amygdala activity could effectively predict a person’s subjective psychological well-being seven years later.
Niki Puccetti, lead author on the study, says a compelling next step for the research may be investigating whether this kind of acute persistent amygdala activation in the face of a negative image could predict whether someone is likely to develop major depression or anxiety in the future.
"It might be the case that they're showing even greater persistence and that's something that can tell us about why they might be more likely to go on to develop a psychiatric disorder," adds Puccetti.
While it obviously is no surprise that those individuals who fixate on small, fleeting negative moments may be more generally unhappy than those who can quickly move on from life’s little frustrations, the compelling findings identify a neurophysiological mechanism underpinning this psychological behavior.
The new study was published in the journal jNeurosci.
Source: University of Miami