Is your salience network turning you into a worrywart?

Neuroimaging studies, such as functional magnetic resonance imaging (fMRI) scans (which look at brain activity) and cognitive neuroscience (which evaluates human behavior) have demonstrated that brain regions don’t work in isolation. Quite the contrary! Far flung gray matter tracts wired together by white matter cellular cables (axons) assemble into functional connectivity patterns and brain networks (neural circuits).

One such circuit called the Salience Network (SN). The SN links the front part of the insular cortex (part of the brain responsible for sensory processing, self-awareness, and emotional guidance of social behavior) to the front part of the cingulate cortex (part of the brain involved in motivation, error detection, reward prediction, and pain perception)

The SN has been related to the detection and integration of emotional and sensory stimuli. In plain English, the SN makes sure the emotionally charged sights, sounds, smells and tastes that come into your life are properly assessed and well integrated in your thought processes, so they don’t drive you bonkers. The SN also provides for enhanced attention to the environment during periods of threat or opportunity. Additionally, the SN may super-charge your memory, reduce anxiety and stress and deliver a high octane productivity boost.

Sounds pretty awesome, right? So, how can the SN bias your brain?

Cognitive biases, shaped by evolution and experience, prioritize efficiency, emotional relevance, and pattern recognition. Cognitive biases can be great shortcuts, which often help you arrive at the best decision quickly and efficiently (sparing precious brain power for deep thinking (like what’s for lunch)). On the flip side, cognitive biases can lead to skewed perceptions and decisions.

The SN is evolutionarily designed to detect emotionally significant stimuli and direct attention, which may lead to biases like the availability heuristic. The availability heuristic is a mental shortcut where people judge the likelihood or frequency of an event based on how easily examples come to mind. If something is vivid, recent, or emotionally charged, it feels more common or probable, even if that perception or belief isn’t statistically true. For example, after seeing news about plane crashes, you might overestimate the risk of flying, despite it being safer than driving. The availability bias relies on memory accessibility rather than objective data, often leading to biased judgments such as overestimating events (good or bad) that only have a tiny likelihood of happening.

Worse yet, an overactive SN can turn you into a worrywart by ramping up an underlying proclivity towards negativity bias. Negativity bias is the psychological tendency for people to give more weight to negative experiences, emotions, or information than to positive or neutral ones. It means negative events or stimuli often have a stronger impact on our thoughts, feelings, and behaviors than positive ones of equal intensity. For example, a single criticism might stick with you longer than multiple compliments.

This bias likely evolved to help humans survive by prioritizing threats and dangers in their environment. It influences memory (we recall negative events more vividly), decision-making (we may avoid risks due to fear of negative outcomes), and attention (we notice negative stimuli faster).

It shows up in daily life—like dwelling on a bad day at work more than a good one or being more affected by negative news. While useful for survival, it can skew perceptions, increase stress, or contribute to pessimism if unchecked.

Scientists from Phoenix, Arizona elucidated the underlying neuroanatomy of the SN which may lead to this undue pessimism: On its own, the anterior insula processes bodily sensations (interoception) and integrates them with cognitive and emotional information, contributing to self-awareness and the sense of "how we feel." When the insula functions as part of the SN (that is, together with the anterior cingulate cortex) emotional processing, decision-making, and time perception become part of the calculus.

Under these circumstances, the insula can amplify negative emotional responses to salient cues, skewing risk assessment. What’s more, an inaccurate cerebral representation of the body's state may alter conscious awareness, leading to inordinate anxiety and depression (in other words the maladaptive SN makes you a worrywart).

In the worst of cases, a SN relying on a damaged insular cortex may lead to a host of problems. Argentine researchers reviewed medical literature regarding the clinical effects of insular damage in humans, highlighting the insula's role in integrating sensory, emotional, and cognitive functions. Damage to the insula can lead to diverse deficits, including impaired emotional processing (e.g., difficulty recognizing emotions), disrupted interoceptive awareness (e.g., altered perception of pain or bodily states), and impaired decision-making. It also affects social cognition, such as empathy, and can contribute to neurological and psychiatric symptoms, including those seen in frontotemporal dementia, stroke, and addiction.

Wow, when the SN isn’t working right, things can really go sideways. What can I do to diminish my reliance on the SN?

Well, if you want to banish the SN from the decision making process, you’ve got to get less (yes, less) in tune with what’s going on inside your body. They don’t call it a gut decision for nothing! German scientists delineated which type of person is more prone to making decisions based on the SN rather than rely on the less emotional frontal lobes. The researchers investigated how interoceptive awareness—the ability to perceive internal bodily signals, such as heartbeats—influences brain activity during decision-making. Using fMRI, the study examined 30 volunteers who performed a decision-making task involving risky choices. Interoceptive awareness was measured via heartbeat perception.

The researchers reported that people with higher interoceptive awareness showed increased activation in the component brain regions of the SN (insula and anterior cingulate cortex) which are associated with processing bodily signals and decision-making. On the other hand, individuals with lower interoceptive awareness exhibited greater activation in the prefrontal cortex (essentially the brain's executive center, overseeing various aspects of behavior and thought), suggesting reliance on cognitive control rather than bodily cues.

So, now you know all about how the SN affects your decision making!

Want to learn why your Default Mode Network is racist? Check out https://brain2mind.substack.com/p/is-your-default-mode-network-racist