BRAINnet ~ media releases

Why can a piece of music make us burst into tears, or physically tense up? How can a whiff of a familiar smell make the feeling of being with a loved one, or at a favourite place, flood back so realistically? 

A Sydney neuroscientist, Dr Lea Williams, has used the latest brain scanning technology to unravel this link between our brains and emotions. 

``A lot happens subconsciously, and we've never had access to it before this," she says. 

Her findings support the idea that humans have a unique ability to store memories of emotional states. She says the physical reactions triggered by a song or smell are caused by a feedback loop between three key areas: the body, a primitive part of our brains known as the amygdala, and the frontal brain area that makes us rational beings. 

``We're calling it the network for feeling," she says. 

In the first study of its kind, she has identified such a feeling network by examining people's brain activity and physical sensations simultaneously. 

Dr Williams, of the University of Sydney, has used a technique called functional magnetic resonance imaging, or fMRI, to find the brain areas activated when people experience fear, anger and disgust. 

``Our collaborators in London have also looked at happy emotions," she says, adding that the brain does not appear to be as hard wired for positive feelings as for negative ones. 

A picture of an angry face is all it takes to evoke fear and activate the brain's primitive limbic system, of which the almond-sized amygdala is a key bit. 

This happens even when the image is flashed up too quickly for people to consciously see it. It also happens very fast, as Dr Williams's studies measuring electrical brain activity have shown. 

The limbic system is critical in balancing our desires for both survival and pleasure, she says. ``It tries to keep us out of danger, as well as give us our emotional rewards." 

It plays a big role in gambling and drug addiction, which are disturbances in the reward mechanism. And Dr Williams believes this ``emotional brain" also subtly biases most of our normal thinking and behaviour. 

Her experiments at BRAINnet at Westmead Hospital are done in collaboration with centre director Dr Evian Gordon, Dr Tony Peduto and Professor Richard Bryant. 

Their novel approach has been to study the physical manifestations of emotions, such as sweating and high heart rate, at the same time as brain activity. 

Dr Williams found that when people react physically to fear, only two parts of their brain, the amygdala and the medial frontal region, were activated. 

This is in keeping with a theory by an American neurologist, Dr Antonio Damasio, that memories of the physical changes caused by strong emotions are stored in this frontal region. 

Sounds, smells or tastes can trigger the stored body states, and set off the emotional limbic system. ``Damasio calls it an `as if' experience," says Dr Williams. 

These as if' experiences could be as subtle as an unconscious tensing of your muscles when you walk into the boss's office, because your brain has stored away emotional memories from a previous bad meeting. 

The Sydney team is testing the effects of sounds, like screams, while their University College London colleagues plan to test tastes and smells. 

Dr Williams has already found differences in the emotion-related brain activity of people with schizophrenia, and has started a study of people with post-traumatic stress disorder, and borderline personalities. 

She will be giving a free public lecture at the University of Sydney on Wednesday night (inquiries 9351 5268).

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