Science: A wheel of fear in our head

Jerome Burne hears of the dramatic insights into the working of emotion yielded by a study of rats

THERE are certain things you do not expect to find in the briefcase of a heating engineer. One of these is a book on the neuranatomy of the emotions. But had you sneaked a peep inside the briefcase of Derek Goldsmith, any time in the last year you would have seen a well-thumbed copy of The Emotional Brain by Joseph LeDoux.

But Goldsmith, now retired and rich having sold the business, wasn't just a unexpected fan of cutting-edge brain research. So impressed is he by the product, that he has bought himself some research. He has given pounds 250,000 to the London School of Economics to fund a three-year programme to develop LeDoux's ideas. "I'm hoping we may have a breakthrough in understanding schizophrenia," he says.

Goldsmith is not the only one raving about The Emotional Brain, to be published here later this month (Weidenfeld & Nicolson). Our own most media-friendly brain scientist Dr Susan Greenfield predicts it will inspire a "sea-change in the way we think about emotions" and in the States it has already prompted a radical shake-up of the neurosciences.

"The emotions have always had a bad press," says LeDoux, a professor at the Centre for Neural Science at New York University. "Plato saw them as wild horses who had to be controlled by the charioteer of reason, Christianity regarded them as a fertile source of sin and recently cognitive science has constructed a model of how the brain works that largely ignores them." But that is beginning to change.

Previous researchers, he believes, have made the mistake of treating the emotions as if they were a single system. "Articles and text books on the brain all talk about the limbic system as the emotional centre of the brain," says LeDoux, "but that's just wrong, for all sorts of reasons. Just as there's no perception centre, we process sights and sounds in different parts of the brain. I suspect that each of the basic emotions has its own system and pathways." So LeDoux set out to map the anatomy of fear, a phenomenon common to all vertebrate species.

The world of brain research has become so high-tech, with brain scanners showing neurones lighting up in brilliant colours, that the tools he used have a distinctly old-fashioned feel to them. Rats in a cage, electric shocks, painstaking trial-and-error removal of minute bits of brain and a fluorescent orange dye to show where the nerve pathways end up. But, combined with an awful lot of patience, they were enough.

The end result was a far clearer picture of where fear is handled in the brain and some surprises. The hub of the system is the amygdala - two tangles of neurones, shaped like an almond and about the size of a chick pea, near the centre of the brain. "We found that it has connections to planning centres, action centres and the hormone system," says LeDoux. "It's the centre of a wheel of fear."

Rats with the amygdala removed will saunter nonchalantly past a cat, when normally they would freeze, their heart rate would soar and their fur would stand on end. Most interesting, LeDoux discovered a previously unsuspected route from the senses, in this case the auditory system, direct to the amygdala. "This was important," he explains, "because for at least 100 years many psychologists believed that for us to register a sight or a sound as frightening we had to be aware of it consciously. What this shows is that you can be frightened of something without knowing what it is."

The value of this back door route is speed. A message from one of the senses, say the sound of a twig snapping, can reach the amygdala in half the time it takes for the impulse to travel to the thinking judging part of the brain and then down to the amygdala. In the wild those few milliseconds could make the difference between life and death. But it's a route that can also lead us astray.

"That gut feeling you get that something is wrong may not be revealing an inner truth," says LeDoux, "but a demonstration of the way we are all slaves to past emotional learning." Another idea is that this fast, low road to the amygdala becomes the favoured one in certain disorders like post-traumatic shock syndrome when a single sight or sound can unleash a wave of terror. The slower high road via the cortex allows a more reasonable response. It is insights into psychiatric problems like those that has prompted giving to the cause of further research into the subject.

Even more intriguing is a finding that may lead to improved treatment for phobias. LeDoux's rats all learned a fear response by getting an electric shock that was linked with a sound. Normally rats, and humans in similar situations, gradually lose their fear of the sound on its own when it stops being followed by a shock. But one groups of rats never lost their fear.

Many of the rats had bits of their brain removed before being put in the cage with the sound and the shock. "Those who had damage to a part of the prefrontal cortex," says LeDoux, "never lost their fear response, no matter how many times they heard the sound on its own." It seems possible that people with an irrational fear they just cannot get rid of may also have a malfunction of their medial prefrontal cortex, the part of the brain involved with planning and judgement.

This improved mapping of the pathways of fear hold out the possibility of more effectively targeted drugs. At the moment pharmaceuticals like Valium and Prozac act very crudely. Valium damps down the whole brain, which is why you often feel sleepy as well as less anxious, while Prozac boosts serotonin everywhere. "It should be possible to find the genes that code for cells in the amygdala and use that to deliver a drug directly there and nowhere else," says LeDoux.

Of course this work is only a beginning, as LeDoux is the first to admit. "Someone else is going to have to trace what is going on with the other emotions like anger or love," he says.

What LeDoux has done, brilliantly or disastrously depending on your point of view, is to side-step one of the biggest issues for psychology. When we talk about our everyday emotions we mean feelings - the rush that goes with anger, that tight sinking feel of fear - but it is precisely these subjective feelings that he has ignored."From an evolutionary perspective fear, or any emotion, is a system that has evolved to improve an animals chance of survival," he says. "Being consciously aware of those messages is a later add-on." Fear still does its job, even if you aren't conscious of it. In fact many of our fear responses initially take place at an unconscious level." LeDoux has found a way to get a handle on an emotion, without having to tackle the insoluble problem of consciousness.

Have you tried new the Independent Digital Edition apps?
Life and Style
ebookNow available in paperback
ebooks
ebookA delicious collection of 50 meaty main courses
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

SPONSORED FEATURES

ES Rentals

    iJobs Job Widget
    iJobs General

    Recruitment Genius: Project Assistant

    £17000 per annum: Recruitment Genius: They are a leading company in the field ...

    Recruitment Genius: DBA Developer - SQL Server

    £30000 - £35000 per annum: Recruitment Genius: This is an exciting opportunity...

    Recruitment Genius: Office Manager

    £26041 - £34876 per annum: Recruitment Genius: There has never been a more exc...

    Recruitment Genius: Travel Customer Service and Experience Manager

    £14000 - £17000 per annum: Recruitment Genius: The fastest growing travel comp...

    Day In a Page

    Blairites be warned, this could be the moment Labour turns into Syriza

    Andrew Grice: Inside Westminster

    Blairites be warned, this could be the moment Labour turns into Syriza
    HMS Victory: The mystery of Britain's worst naval disaster is finally solved - 271 years later

    The mystery of Britain's worst naval disaster is finally solved - 271 years later

    Exclusive: David Keys reveals the research that finally explains why HMS Victory went down with the loss of 1,100 lives
    Survivors of the Nagasaki atomic bomb attack: Japan must not abandon its post-war pacifism

    'I saw people so injured you couldn't tell if they were dead or alive'

    Nagasaki survivors on why Japan must not abandon its post-war pacifism
    Jon Stewart: The voice of Democrats who felt Obama had failed to deliver on his 'Yes We Can' slogan, and the voter he tried hardest to keep onside

    The voter Obama tried hardest to keep onside

    Outgoing The Daily Show host, Jon Stewart, became the voice of Democrats who felt the President had failed to deliver on his ‘Yes We Can’ slogan. Tim Walker charts the ups and downs of their 10-year relationship on screen
    RuPaul interview: The drag star on being inspired by Bowie, never fitting in, and saying the first thing that comes into your head

    RuPaul interview

    The drag star on being inspired by Bowie, never fitting in, and saying the first thing that comes into your head
    Secrets of comedy couples: What's it like when both you and your partner are stand-ups?

    Secrets of comedy couples

    What's it like when both you and your partner are stand-ups?
    Satya Nadella: As Windows 10 is launched can he return Microsoft to its former glory?

    Satya Nadella: The man to clean up for Windows?

    While Microsoft's founders spend their billions, the once-invincible tech company's new boss is trying to save it
    The best swimwear for men: From trunks to shorts, make a splash this summer

    The best swimwear for men

    From trunks to shorts, make a splash this summer
    Mark Hix recipes: Our chef tries his hand at a spot of summer foraging

    Mark Hix goes summer foraging

     A dinner party doesn't have to mean a trip to the supermarket
    Ashes 2015: With an audacious flourish, home hero Ian Bell ends all debate

    With an audacious flourish, the home hero ends all debate

    Ian Bell advances to Trent Bridge next week almost as undroppable as Alastair Cook and Joe Root, a cornerstone of England's new thinking, says Kevin Garside
    Aaron Ramsey interview: Wales midfielder determined to be centre of attention for Arsenal this season

    Aaron Ramsey interview

    Wales midfielder determined to be centre of attention for Arsenal this season
    Community Shield: Arsene Wenger needs to strike first blow in rivalry with Jose Mourinho

    Community Shield gives Wenger chance to strike first blow in rivalry with Mourinho

    As long as the Arsenal manager's run of games without a win over his Chelsea counterpart continues it will continue to dominate the narrative around the two men
    The unlikely rise of AFC Bournemouth - and what it says about English life

    Unlikely rise of AFC Bournemouth

    Bournemouth’s elevation to football’s top tier is one of the most improbable of recent times. But it’s illustrative of deeper and wider changes in English life
    A Very British Coup, part two: New novel in pipeline as Jeremy Corbyn's rise inspires sequel

    A Very British Coup, part two

    New novel in pipeline as Jeremy Corbyn's rise inspires sequel
    Philae lander data show comets could have brought 'building blocks of life' to Earth

    Philae lander data show comets could have brought 'building blocks of life' to Earth

    Icy dust layer holds organic compounds similar to those found in living organisms