New research in mice sheds light on how the brain understands what is important – and what isn’t

The sound of a fire alarm tells us to get out quickly to not get hurt, while the sight of a gas station sign can signal a chance to refuel.

In everyday life, we learn to link cues we sense with what they mean, helping us avoid danger or find what we need. But how does the brain sort and prioritize all these cues and their significance to quickly guide our reactions to what we see, hear, feel and sense?

Following new research in mice, scientists hope to be closer to answering this question.

“A sensory cue, like the sound of an alarm, can be more or less attention-grabbing, feel positive or negative, and feel more or less important or motivating for us to act, depending on what outcome we associate with it. These aspects help define the significance we assign to environmental stimuli and are key to driving behavior and decision-making. But how the brain organizes this information to guide appropriate behaviors remains unclear,” explains Assistant Professor Daniel Jercog from the Department of Neuroscience at the University of Copenhagen.

A new study in mice led by Daniel Jercog in collaboration with an international team of researchers investigates how a specific brain area organizes these aspects as they responded to emotionally significant stimuli.

The researchers saw that neurons would activate in patterns that follow a certain structure and that the structure was defined by the importance that the mice attributed to the stimuli.

“Those patterns show us that the brain sorts the different aspects that define emotional stimuli into separate channels – and that these channels run independently and simultaneously. This likely lets the brain handle these signals without mixing them, allowing it to evaluate this information in parallel, which in turn could help guide decisions more efficiently,” says Daniel Jercog.

The researchers saw that three characteristics of external stimuli were represented in this area of the brain independently – think of it as three separate channels:

‘Salience’ describes how attention-grabbing a sensory cue is, ‘valance’ refers to whether it is perceived as good or bad, while ‘value’ characterizes how important it feels or how motivating it is.

“For instance, a sound from a potential predator has negative valence, is highly salient and the mouse would likely assign high value to it. This way, the sound quickly grabs the mouse’s attention and drives it to run and hide to not get hurt,” says Daniel Jercog.

Potential implications for mental health research

In order to understand what happens when this information is processed, the researchers examined the neural activity in the brain of mice as they responded to specific sounds that they associated with more or less positive or negative outcomes.

They found that neurons in the brain’s prefrontal cortex would activate in response to the sounds and that the neurons would follow patterns depending on their associated outcome. This allowed the researchers to map how the brain handles this information.

While the present study only looks at how mice respond to external stimuli, such research could be an important first step to better understand the cognitive processing of emotional stimuli in the human brain – but more research is needed.

Eventually, the scientists hope that their research can have implications for mental health research.

“In humans, the prefrontal cortex is also the machinery behind everyday choices: Do I go for it? Do I steer clear? Is this worth my effort? But what happens when those evaluations of significance misfire? For instance, overestimating threats can be associated with anxiety, overestimating rewards with addiction, while underestimating rewards can occur in depression,” says Daniel Jercog, adding:

“If our prefrontal cortex also keeps value, salience and valence on separate channels to drive behavior, it gives us a clearer target for better understanding and eventually helping conditions that are often associated with prefrontal cortex dysfunctions. This perspective may ultimately inform new roads towards more precise approaches to treatment.”

Read the study “Prefrontal neural geometry of associated cues guides learned motivated behaviors”: https://www.nature.com/articles/s41586-025-09902-2