Heightened connectivity between two brain networks is associated with anger and aggression

People who engage in more physical aggression are more likely to have overconnectivity between the brain’s default network and attentional networks, according to a new study published in Psychiatry Research: Neuroimaging. The findings shed some new light on the relationship between brain architecture and emotional health.

“There has been quite a bit of work looking at patterns of brain activity that may be associated with cognitive ability, and many studies have examined how differences in factors like reading ability, IQ, or attention might be encoded in the brain,” explained Jeff Anderson, the corresponding author of the study and a professor of radiology and imaging sciences at the University of Utah.

“But there is very little information on how differences in our brains might translate into behaviors associated with emotional health and well-being. We took advantage of a large public dataset to look for associations between differences in functional brain architecture across this population and whether this might predict emotional health.”

The researchers analyzed data from 1,003 subjects in the Human Connectome Project, an initiative of the National Institutes of Health that collected high-quality neuroimaging and behavioral data from healthy young adults.

The data set includes information about brain connectivity in each individual, using two distinct magnetic resonance imaging (MRI) approaches.

One, called resting-state functional connectivity, is based on spontaneous fluctuations in functional MRI signals that occur in a complex pattern in space and time throughout the gray matter of the brain. Another, called diffusion imaging, provides information about the long-distance “wiring” — the anatomical pathways traversing the brain’s white matter.

The Human Connectome Project also collected a number of other measurements, including but not limited to the subjects’ ages, IQs, and emotional health.

Based on this data, the researchers found evidence that a particular pattern of functional connectivity was associated with physical aggressiveness.

“Many factors related to emotional health and well-being are complex and do not map onto specific differences in the brain. But we did find that attitudes of anger and aggression were associated with crosstalk between two networks in the brain,” Anderson told PsyPost.

“One of these networks, the default network, is active when we are thinking to ourselves or reflecting on our inner feelings. The other is active when we’re paying attention to the outside world.”

“When these two networks are too closely connected, it can lead to intrusive stimuli interrupting our thoughts, or not being able to shut off the voice in our head when we’re trying to pay attention to something outside of ourselves. Our results suggest that this configuration may be more associated with attitudes relating to anger,” Anderson said.

The study examined correlational data, preventing the researchers from making inferences about the direction of causality. How the increased connectivity between the two regions translates into behavior is still unclear.

“We don’t know if the differences in brain connectivity cause heightened feelings of anger and aggression, or if these differences in the brain are a reflection of experience and training throughout life. We also don’t know yet whether this pattern of connections in the brain may be a marker for people trying to improve feelings of anger or aggression in their lives,” Anderson said.

“Could it be that mental exercises like mindfulness that focus on sustaining activity in the default network or attention network might help to mitigate unwanted feelings of anger through this mechanism? These are important future ideas to test.”

Despite the limitations, the ongoing advances in mapping the functional connections of the brain are producing more and more insights into the underlying mechanisms of our emotions.

“It is exciting after so many years studying brain health and function using imaging that we are now getting to the point where deeply meaningful questions about emotional health may finally be studied,” Anderson remarked.

“There are now powerful techniques that can resolve very subtle differences in the brain and begin to understand why we wrestle with different emotional challenges, and how we might be able to manage them most effectively.”

The study, “Functional connectivity of emotional well-being: Overconnectivity between default and attentional networks is associated with attitudes of anger and aggression“, was authored by Fiona L. Weathersby, Jace B. King, J. Chancelor Fox, Amy Loret, and Jeffrey S. Anderson.