Stanford Study Reveals Brain Activity Patterns ‍Behind ⁤Emotions

⁣Updated May ⁣30,⁢ 2025
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Emotions, though frequently enough elusive, are crucial for navigating daily life.They influence decisions and ‍actions,⁢ but⁤ can be detrimental if prolonged or inappropriate. Now, Stanford Medicine researchers are shedding light⁣ on ‍the brain activity underlying emotional responses, possibly paving the way for a better understanding of neuropsychiatric disorders.

A study published in Science on May 29 details how⁣ investigators mapped brainwide neuronal processing related ‍to emotional responses‍ triggered by mildly unpleasant sensory experiences. The research indicates that these ‍brain activity features are ⁣shared across mammals, including humans and mice.

Karl deisseroth, professor of bioengineering and of psychiatry and ⁤behavioral sciences at⁢ Stanford, led the collaborative research effort. Senior co-authors ⁤include Carolyn Rodriguez,Vivek ‍Buch,and Paul⁤ Nuyujukian. Lead co-authors⁤ are Isaac Kauvar,Ethan Richman,and Tony Liu.

The research was part of Stanford Medicine’s ⁢Human Neural Circuitry ‍program, which aims to understand the human brain’s inner workings in both healthy and diseased ⁢states.

While this study focused ⁢on negative sensory experiences,⁤ Deisseroth believes the observed brainwide⁢ activity pattern may also apply ⁢to positive experiences.

Deisseroth noted the mammalian brain’s⁤ large size allows for ‍a richer ⁤mental life. Though, he added that the brain must integrate sensory data, goals, and‍ physiological ‍needs to make accurate decisions. Emotions, he suggests, may ⁣integrate information to guide behaviour, requiring interaction among brain structures.

Richman⁣ added that tuning the timescale⁢ of this communication could be notable for⁢ typical brain function.Disruptions in the stability ⁣of these brainwide communication patterns could contribute to emotional ‍dysfunction in neuropsychiatric disorders.

To pinpoint key signals,the Stanford team ⁢used an evolutionary approach,screening neural activity in both mice and humans.They looked for activity patterns ⁤induced by the same stimuli, measurable⁤ in⁤ the ⁣same way, synchronized with behaviors, and blocked by the same interventions.

kauvar said ⁤this approach allowed the team to focus on shared principles between mice and humans.

The researchers used air puffs, similar to those used in eye exams, as the‍ stimulus. Participants described the puffs as “annoying”‍ or “unpleasant.” Repeated puffs led to an increasing feeling of annoyance.

Deisseroth⁤ noted that repeated negative events are⁤ critically importent for the brain to consider when‍ guiding future⁢ behavior.

Brain ⁤activity was recorded in patients at Stanford Hospital who had electrodes implanted in ⁤their ⁤brains for seizure treatment. These patients volunteered⁢ for ⁢the study.

Subjects consistently blinked reflexively in response to each puff. They also exhibited additional eye squinting or rapid blinks, a quantifiable response to the unpleasant stimulus.

The researchers observed ⁤a two-phase pattern of brain activity. The first phase, lasting about 200 ⁤milliseconds, showed a spike of activity broadcasting the air puff throughout the brain. The second phase, lasting about 700 milliseconds,‍ was localized to⁤ circuits ‍associated with emotion.

The⁢ same experiment was conducted in mice, revealing a similar ‍two-phase pattern.Repeated ⁤air puffs‍ induced ⁤a negative emotional state in the mice, reducing their willingness to seek rewards.

The team then used ketamine, an FDA-approved antidepressant, to test the importance of‍ the ⁤persistent activity⁤ pattern. Ketamine is known to cause dissociation, reducing ‍emotional responses to stimuli.

Deisseroth said that ketamine recipients are ⁢aware of sensory experiences⁢ but frequently enough lack typical emotions about them.

After administering ketamine to human subjects, the scientists found that the negative⁢ emotion caused ‍by the air‍ puffs was greatly inhibited.

One participant said the air puff “felt entertaining,” while another⁣ described ⁣it as ⁣”little⁤ whispers on my eyeballs.”

The ⁢human ‍subjects also did not show self-protective behavior, keeping their eyes open between puffs. The same effect was observed ‍in mice.

Ketamine sped up the decay of the slower,second phase of post-eye-puff brain activity,effectively sharpening the brain’s response. This suggests that the persistent second⁤ phase is strongly linked to emotional state,according ⁢to Kauvar.

The team also⁢ found that ketamine⁢ accelerated the “intrinsic time scale” ⁢of⁣ brain activity, even without the air puff.This effect was ⁤reversible.

Deisseroth said that dissociative medication ⁤may render the stabilizing ‍phase of⁣ brain activity so ephemeral that information cannot be properly integrated across the brain, ⁣including ⁤to build an⁣ emotional state.

What’s next

These findings suggest that tunable ⁤timing properties ⁣in brain activity could offer clues for understanding and potentially treating neuropsychiatric disorders. Further research could explore how altered brain‍ activity patterns contribute to conditions like schizophrenia,PTSD,and autism spectrum disorder.