Where does your mind go when it aimlessly drifts? Do you remember a blissful beach vacation? Morbidly contemplate your own death? Relive an awkward encounter?
Such idle thoughts can light up different parts of the brain, creating a map of our emotional activity even when we’re supposedly relaxing, researchers at Duke University found in a new study.
Their research, published Wednesday in the journal PLOS Biology, show how distinct emotional brain states can emerge even without external stimuli, such as a love song that tugs at your heart strings or a horror flick that fills you with dread.
The research team had previously studied brain activity patterns that reflect feelings stirred up by movies or music. But Wednesday’s study is the first to map brain patterns in people at rest.
“It’s getting to be a bit like mind-reading,” Kevin LaBar, the study’s lead author and a psychology professor at Duke Institute for Brain Sciences, said in a press release.
“This study gets us one step closer to having objective measures of specific emotions in the brain,” he later told Mashable by phone.
“Typically, we measure emotions based on self-reporting, and that kind of data can be unreliable,” he noted. “The ’emotion’ world is really trying to get other more biologically-based markers for identifying when people are in specific emotional states, like happiness or sadness or fear.”
Using functional magnetic resonance imaging (fMRI), LaBar and his research team scanned the brains of 21 university students, who were encouraged to let their minds wander. Every 30 seconds, participants responded to questions about their current emotional state.
Brain activity data for each participant was collected every two seconds, and researchers compared each of these individual scans to seven different patterns of brain activity: content, amusement, surprise, fear, anger, sadness, or neutral.
The team tested to see whether the seven brain maps of emotions emerged spontaneously as participants rested in the fMRI scanner without any outside disruptions, LaBar said.
“Earlier studies have shown that functional MRI can identify whether a person is thinking about a face or house,” he said in the statement. “Our study is the first to show that specific emotions like fear and anger can be decoded from these scans as well.”
A separate study by Carnegie Mellon University researchers used fMRI to identify patterns of brain activity that aligned not with emotions, but the distinct mental stages we go through as we solve challenging math problems.
A group of 80 participants first practiced using specific strategies to solve math problems and then moved under the fMRI scanner. Participants then answered a series of target problems and received feedback, with answers turning green if correct and red if incorrect.
Neuroimaging data revealed four stages of cognition: encoding, planning, solving and responding, according to the July study published in the journal Psychological Science.
“How students were solving these kindsof problems was a total mystery to us until we applied these techniques,” John Anderson, the study’s lead researcher and a psychological scientist at Carnegie Mellon, said in a press release.
“Now, when students are sitting there thinking hard, we can tell what they are thinking each second,” he added.
LaBar, the Duke professor, said the new maps of emotional states published this week could help guide research into people who struggle with emotional awareness or interpersonal relationships. The maps could also be used in clinical trials to test the effectiveness of emotions-regulating treatments.
He said the researchers next plan to study how emotions fluctuate on a moment-to-moment basis. For instance, a person without depression or anxiety might return to a neutral emotional state fairly quickly after experiencing fear or sadness. Someone with depress, by contrast, may remain stuck in a cycle of negative emotions.
Wednesday’s study “is a second step” toward using the emotional brain maps in a clinically validated way, LaBar told Mashable.
“We’re on our way to identifying these emotional markers, but there are other steps we need to do to help demonstrate the reliablity of these maps over time,” he added.