·
Love on the brain
· Butterflies in the stomach...The
pain of a broken heart...They are staples of romantic fiction. But what does
science have to say?
Falling
in love is not as simple as it seems, but it is very quick.
Those
intense over-powering feelings of being truly, madly, deeply in love are the
result of complex and rapid brain activity.
Being in
love – or more precisely being in an emotional state of intense longing for
union with another, involving chemical, cognitive, and goal-directed behavioural
components – is a pretty complicated affair.
According
to new research, it's not a basic emotion, as some thought, but a highly
complex and businesslike process involving 12 areas of the brain working
together to produce and sustain that magic moment. And researchers have
discovered that the first brain activity specific to love starts within one
fifth of a second of being smitten.
According
to a new study, The Neuroimaging of Love, brain regions with decidedly
unromantic names, like the dorsolateral middle frontal gyrus and the anterior
cingulate, as well chemicals like nerve growth factor, dopamine and oxytocin,
are all involved in orchestrating these feelings of love. Some of these areas
are those that are also active when people are under the influence of
euphoria-inducing drugs – suggesting that falling in love may have a similar
effect on the brain as using cocaine.
"Although
many emotion theories have included love as a basic emotion, love is more than
that," says Dr Stephanie Ortigue who led the study. "Love includes
basic emotions and also complex emotions, goal-directed motivations, body
image, appraisal and cognition." Passionate love, long the exclusive
domain of poets, writers and artists, is increasingly being studied by scientists.
At the
heart of the research is functional magnetic resonance imaging, or fMRI, a
relatively new tool that is used to spot brain activity. The harder an area of
the brain works, the greater the amount of oxygen it consumes. The fMRI scan
detects the increase in blood flow needed to supply that oxygen. It has been
used in a number of areas, from the study of brain disorders to lie detection.
By identifying areas of the brain involved in, for example, pain or anxiety it
can also help in the development of new therapies that target those areas.
One of
the new growth areas is its use in pinpointing areas of the brain involved in
particular mental processes, especially emotions and behaviour, including sex
drive, and love.
Mapping
the course of true love through the brain is not simply an academic exercise.
Understanding the brain networks that are activated during love may help
clinicians to better understand relationship problems and sexual behaviours. It
may, provide doctors, psychologists, and therapists with new treatments for
couples suffering from love addiction, love deprivation, or rejection in love.
"The
better our understanding of love, the greater our respect for the significance
and potency of its role in mental and physical health," says Dr Ortigue.
In fMRI
love research, scans are taken of the brains of men and women volunteers after
they have been shown visual stimuli related to their partner or loved one. The
results are then analysed to see where the action is within the brain. Six fMRI
studies have now been carried out on love, involving scans taken of 120 people,
and Dr Ortigue and colleagues at Syracuse and Western Virginia universities,
and the University Hospital of Geneva, have analysed the results to piece
together a love map of the brain.
In one of
the experiments, 17 men and women described as being truly, deeply, and madly
in love with their partner had their brains scanned while looking at a picture
of the partner for 17 seconds. The scans showed that there was increased
activity in the caudate nucleus and putamen areas of the brain, which are
associated with the brain chemical dopamine and with sensations of euphoria and
reward. There was also activity in other dopamine areas, the same regions that
are active in people using cocaine.
Increased
activity was also seen in the post-erior hippocampus, an area involved in
memory and mental associations. There was activity too in areas processing
emotions and rewards, but there was a drop in activity in areas associated with
anxiety and fear.
Overall,
Dr Ortigue's analysis shows that passionate love involves brain areas involved
in emotion, motivation, reward, social cognition, attention, and
self-representation or body image.
Activity
in these areas leads to changes in the levels of a number of chemicals in the
besotted brain, including increases in dopamine, oxytocin, adrenaline,
vasopressin, and a decrease of serotonin, which results in the classic love
symptoms, like obsessively thinking about the beloved, craving for a union with
him or her, euphoria, and greater energy.
Dopamine
is associated with feelings of euphoria, motivation, motor activity, desire,
craving and addiction, while adrenaline heightens an indivual's attention, and
boosts short-term memory, hyperactivity, and goal-oriented behaviour. It is
also adrenaline which gets the heart racing.
The
importance of dopamine has been shown in a number of animal studies. When a
female prairie vole was paired with a male, dopamine levels went up 50 per
cent. Levels of oxytocin, (the so-called "cuddle hormone", released
in response to stimuli including skin-to-skin contact) likewise go up, as do
levels of vasopressin, both promoting relationship bonding. When the female
vole was injected with a drug that blocks the activity of dopamine, she lost
interest in him.
Nerve
growth factor of NGF is involved too. Researchers at the University of Pavia in
Italy measured blood levels of NGF in 58 men and women who had recently fallen
in love, and two control groups. Blood levels of NGF were significantly higher
in those who were in love.
The
highest levels were seen in men and women who had just fallen in love, compared
to those in longer standing relationships. The researchers also found that the
higher the levels of NGF, the greater the intensity of the relationship. Both
these findings suggest that NGF may be involved in the very early stages of the
love.
"Our
data demonstrate for the first time that circulating levels of nerve growth
factor are elevated among people in love, suggesting an important role for this
molecule in the 'social chemistry' of humans," say the researchers.
Researchers
at Rutgers University in the US have also looked at romantic love and brain
activity. Their view is that romantic love is one of three primary brain
systems that evolved in avian and mammalian species to direct reproduction.
The
suggestion is that sex drive evolved to motivate individuals to seek a range of
mating partners, while attraction and romantic love evolved to motivate them to
prefer and pursue specific partners, and attachment evolved to motivate them to
remain together long enough to complete parenting responsibilities.
The
researchers, who have also carried out work on people rejected in love, say
that the power of love is greater than sex drive alone.
Romantic
love is evidently stronger than the sex drive, because when one's sexual
overtures are rejected, people do not kill themselves or someone else. Instead,
abandoned lovers sometimes stalk, commit suicide or homicide or fall into a
clinical depression.
The
collection of brain areas that are active in passionate or romantic love appear
to be unique to that particular kind of love, with research showing that
maternal and unconditional love involve other areas.
A study
at the University of Montreal into unconditional love shows that brain regions
not implicated in romantic and maternal love, including BA 13 and BA 32, were
activated.
"As
in the case of romantic love and maternal love, the rewarding nature of
unconditional love facilitates the creation of strong emotional links between
humans. Such robust emotional bonds may critically contribute to the
preservation of the human species," say the researchers.
Dr
Ortigue and her colleagues believe that there are 12 areas of the brain
involved in passionate love – the caudate nucleus/putamen, thalamus, ventral
tegmental area, insula, anterior cingulate, posterior hippocampus, occipital,
occipito-temporal/fusiform region, angular gyrus/temporo-parietal junction,
dorsolateral middle frontal gyrus, superior temporal gyrus, and the precentral
gyrus.
But what
happens first, what is the trigger for that torrent of cerebral activity? A new
study to be published shortly by Dr Ortigue offers some clues. The researchers
used a high-density electroencephalogram or EEG to measure the volume of
electrical activity among brain cells.
The
results reveal that when people were shown names of loved ones, electrical
activity was swift. Activity spiked very quickly at a pre-conscious level, or
within 200 milliseonds, in one of those 12 separate areas of the brain, the
angular gyrus.
This area
is involved in the processing of visual images, sounds, language comprehension,
metaphors, and bodily self-representation. People with brain damage to this
area suffer a number of classic symptoms, including depression, poor memory,
frustration, poor relationships, belligerence, difficulty with metaphors, and
disorders of bodily self representation.
These
tentative results suggest that that the brain responds to the stimulus of the
soon-to-adored one in less time that it takes to blink. Romantics, who have
long propagated the idea of love at first sight, may have been right after all.
[original author unknown]
