Brains generate a body of feeling.

Emotions ranging from the thrill of victory to the agony of defeat--this is an Olympic year, after all--engage structures throughout the brain that keep tabs on the body's current status, such as a racing heartbeat, flushed cheeks, and churning guts. That, at least, is the implication of a study in the October NATURE NEUROSCIENCE.

Each basic emotion activates a unique brain network that extends far beyond the limbic system, the inner-brain areas that researchers have often viewed as the seat of emotion, contends a team of neuroscientists led by Antonio R. Damasio of the University of Iowa College of Medicine in Iowa City.

Damasio's group asked 41 men and women to think about personal events marked either by happiness, sadness, anger, or fear. Physiological measures, such as large changes in heart rate, established the onset of an emotion. Positron emission tomography (PET) scans then monitored blood flow changes in each volunteer's brain as markers of neural activity.

Inducing emotions in this way--by introspection--substantially affected brain areas that receive signals from internal organs, muscles, and skin, the scientists say. They suggest that the work underscores Damasio's theory that bodily reactions precede a person's awareness of a specific emotion.