Too strong a sense of 'self' may not good for you, but this may help to understand and ease anxiety disorders, writes Jane Qiu.
What is the feeling of fear and what causes it? We see a vicious dog running at us and our brain instantly sounds the alarm, making our heart and lungs race. We feel afraid. For Aristotle and Plato, fear was above all a physical reaction. William James, the founding father of modern psychology, proposed in 1884 that we experienced emotions such as fear as a result of our bodily sensations.
This theory of emotion has been taken as a truism. Now a study led by Dr Ray Dolan, published in this month's Nature Neuroscience, has provided some scientific evidence to support it.
Dr Dolan was born in Galway and is now the chairman of department of neuropsychiatry and neuropsychology at the Institute of Cognitive Neuroscience, University College London.
He conjectured that if the theory of emotion was correct then the more we were aware of our bodily sensations the stronger the emotions we experienced. To test this, he asked subjects to perform the so-called heartbeat detection task. In each trial, the subjects heard a sequence of notes, each triggered by their own pulse. In half of the trials, the notes were delivered immediately.
In the other half, each note was delivered with a short delay. The subjects were to judge the timing of their own heartbeats relative to the feedback notes. After the task, they were asked to report how they felt.
Dr Dolan found that people who judged their heartbeats accurately had the tendency to report negative feelings such as anxiety and depression. Positive emotions, however, were not affected.
He also identified the part of the brain that mediated such a link. While the subjects were doing the task, their brain was scanned by functional magnetic resonance imaging to spot the active region. Dr Dolan found that a part of the brain called the right anterior insula was responsible for translating bodily sensations into conscious, emotional feelings.
"People who are more aware of their bodily responses have richer emotional lives," says Dr Hugo Critchley who conducted the experiments. "Higher levels of awareness are necessary for better control of these responses.
"But paying attention to your bodily responses may also predispose worries," suggests Dr Critchley. "In fact, people with anxiety disorders often focus on bodily responses and experience them more intensely.
"The right anterior insula is not the only region of the brain that can detect bodily functions. But it is the only one where this detection is available to conscious, emotional feelings."
In other words, the right anterior insula lies at the interface between the "heart" and the "mind", and could be the gateway to consciousness. But there is still a missing link. What makes our heart and lungs race in the first place when we see a vicious dog? Scientists believe that this has to do with our previous experience and knowledge of what is dangerous and threatening. Babies do not react with fear in the same situation. Fear is a learned process.
This learning process involves our body associating two stimuli, that is, the sight of a vicious dog and the racing of the heart and lungs. This is the classical conditioning response that was famously illustrated by Russian physiologist Ivan Pavlov at the turn of the 20th century. Pavlov flashed a light to a dog and then presented him with a meal. After a few repetitions, the sight of light itself was enough to make the dog salivate.
Humans learn in the same way. This is a basic mechanism that the brain has evolved to detect causal relationships in the environment in order to make the correct predictions in terms of hunting for food and avoiding dangers. Once we have learned that vicious dogs are dangerous, our body would react automatically when we see a vicious dog. It is these bodily reactions that give us the conscious feeling of fear.
Consciousness is the great unsolved puzzle in neuroscience, a puzzle being challenged by a better understanding of the functional processes involved.