Love Deactivates Brain Areas For Fear, Planning, Critical Social Assessment
June 17, 2004 02:39 AM
FuturePundit: Brain Love Archives
Brain Articles: By Randall Parker
Source : http://www.futurepundit.com/archives/002183.html
Accessed : Feb. 10, 2010
Love Deactivates Brain Areas For Fear, Planning, Critical Social Assessment
Andreas Bartels and Semir Zeki of the Welcome Department of Imaging Neuroscience,
University College London have found using Functional Magnetic Resonance Imaging
(fMRI) that love turns down activity in some areas of the brain in part so that we will not
see flaws in the object of our affections.
However the key result was that it's not just that certain shared areas of the brain are
reliably activated in both romantic and maternal love, but also particular locations are
deactivated and it's the deactivation which is perhaps most revealing about love.
Among other areas, parts of the pre-frontal cortex – a bit of the brain towards the front
and implicated in social judgment – seems to get switched off when we are in love and
when we love our children, as do areas linked with the experience of negative emotions
such as aggression and fear as well as planning. The parts of the brain deactivated form a
network which are implicated in the evaluation of trustworthiness of others and basically
critical social assessment.
The scientists recruited mothers and used pictures of their children as well as pictures of
other people and watched how the women responded to the pictures. The researchers also
reanalysed data they had previously collected for previously published research involving
women in love.
We are fools for love because love disables our ability to do critical social assessment.
He said: "Our research enables us to conclude that human attachment employs a pushpull
mechanism that overcomes social distance by deactivating networks used for critical
social assessment and negative emotions, while it bonds individuals through the
involvement of the reward circuitry explaining the power of love to motivate and
exhilarate."
Bartels has the full text of the research paper on his web site. When we fall in love we
become blinded to faults and at the very same time we become flooded with rewarding
feelings.
Romantic and maternal love are highly rewarding experiences. Both are linked to the
perpetuation of the species and therefore have a closely linked biological function of
crucial evolutionary importance. Yet almost nothing is known about their neural
correlates in the human. We therefore used fMRI to measure brain activity in mothers
while they viewed pictures of their own and of acquainted children, and of their best
friend and of acquainted adults as additional controls. The activity specific to maternal
attachment was compared to that associated to romantic love described in our earlier
study and to the distribution of attachment-mediating neurohormones established by other
studies. Both types of attachment activated regions specific to each, as well as
overlapping regions in the brain’s reward system that coincide with areas rich in oxytocin
and vasopressin receptors. Both deactivated a common set of regions associated with
negative emotions, social judgment and ‘mentalizing’, that is, the assessment of other
people’s intentions and emotions. We conclude that human attachment employs a push–
pull mechanism that overcomes social distance by deactivating networks used for critical
social assessment and negative emotions, while it bonds individuals through the
involvement of the reward circuitry, explaining the power of love to motivate and
exhilarate.
Maternal and romantic love share a common and crucial evolutionary purpose, namely
the maintenance and perpetuation of the species. Both ensure the formation of firm bonds
between individuals, by making this behavior a rewarding experience. They therefore
share a similar evolutionary origin and serve a similar biological function. It is likely that
they also share at least a core of common neural mechanisms. Neuro-endocrine, cellular
and behavioral studies of various mammalian species ranging from rodents to primates
show that the neurohormones vasopressin and oxytocin are involved in the formation and
main-tenance of attachment between individuals, and suggest a tight coupling between
attachment processes and the neural systems for reward (Carter, 1998; Insel and Young,
2001; Kendrick, 2000; Pedersen and Prange, 1979). This is confirmed by lesion, gene
expression and behavioral studies in mammals (Numan and Shee-han)
Perhaps it is not a coincidence that many lovers call each other "babe" and there is a great
deal of overlap between the brain's feelings of romantic and maternal love.
Note that regions rich with vasopressin receptors are involved in maternal and romantic
love. This brings us to another recent report where scientists have found that gene therapy
to deliver vasopressin receptor genes into the ventral pallidum part of the brain made
male meadow voles become uncharacteristically monogamous.
ATLANTA -- Researchers at the Yerkes National Primate Research Center of Emory
University and Atlanta's Center for Behavioral Neuroscience (CBN) have found
transferring a single gene, the vasopressin receptor, into the brain's reward center makes a
promiscuous male meadow vole monogamous. This finding, which appears in the June
17 issue of Nature, may help better explain the neurobiology of romantic love as well as
disorders of the ability to form social bonds, such as autism. In addition, the finding
supports previous research linking social bond formation with drug addiction, also
associated with the reward center of the brain.
In their study, Yerkes and CBN post-doctoral fellow Miranda M. Lim, PhD, and Yerkes
researcher Larry J. Young, PhD, of the Department of Psychiatry and Behavioral Sciences
at Emory University's School of Medicine and the CBN, attempted to determine whether
differences in vasopressin receptor levels between prairie and meadow voles could
explain their opposite mating behaviors. Previous studies of monogamous male prairie
voles, which form lifelong social or pair bonds with a single mate, determined the
animals' brains contain high levels of vasopressin receptors in one of the brain's principal
reward regions, the ventral pallidum. The comparative species of vole, the promiscuous
meadow vole, which frequently mates with multiple partners, lacks vasopressin receptors
in the ventral pallidum.
The scientists used a harmless virus to transfer the vasopressin receptor gene from prairie
voles into the ventral pallidum of meadow voles, which increased vasopressin receptors
in the meadow vole to prairie-like levels. The researchers discovered, just like prairie
voles, the formerly promiscuous meadow voles then displayed a strong preference for
their current partners rather than new females. Young acknowledges many genes are
likely involved in regulating lifelong pair bonds between humans. "Our study, however,
provides evidence, in a comparatively simple animal model, that changes in the activity
of a single gene profoundly can change a fundamental social behavior of animals within a
species."
According to previous research, vasopressin receptors also may play a role in disorders of
the ability to form social bonds, such as in autism. "It is intriguing," says Young, "to
consider that individual differences in vasopressin receptors in humans might play a role
in how differently people form relationships."
And, Lim adds, past research in humans has shown the same neural pathways involved in
the formation of romantic relationships are involved in drug addiction. "The brain process
of bonding with one's partner may be similar to becoming addicted to drugs: both activate
reward circuits in the brain."
The researchers' next step is to determine why there is extensive variability in behaviors
among individuals within a species in order to better understand the evolution of social
behavior.
Well, consider the possibilities. Want to solve the soaring divorce rate problem?
Bioengineer a virus to infect the population to deliver the vasopressin gene into the
ventral pallidum at the base of the brain. After years of ineffective moralizing and
countless social science studies the problem of disintegrating marriages would be solved.
Another possibility would be the use of such a gene therapy by someone who is in love to
make the object of their affections primed to fall in love. Of course, the lover
surreptiously treated with emotional brain engineering genetic therapy might fall in love
with the next person they accidentally bump into in the supermarket. So such a gene
therapy would not be foolproof once it becomes feasible.
But since love causes brain changes that have some similarities to what addictive drugs
do to the brain an argument can be made for the proposition that love is just another form
of addiction for which humans need an effective treatment that will end the craving.
Oxytocin and vasopression receptors show up only in the reward areas of the brain.
In their research, funded by the National Institute of Mental Health, Larry Young, PhD.,
associate professor of psychiatry and behavioral sciences at Emory University School of
Medicine and an affiliate scientist at Yerkes National Primate Research Center; graduate
student Miranda Lim; and Anne Murphy, PhD., associate professor of biology at Georgia
State University, examined the distribution of two brain receptors in the ventral forebrain
of monogamous prairie voles that have been previously tied to pair bond formation:
oxytocin (OTR) and vasopressin V1a receptor (V1aR). Using receptor audiographic
techniques, the scientists found that these receptors are confined to two of the brain's
reward centers, the nucleus accumbens and the ventral pallidum. V1aR receptors, which
are thought to be activated in the male vole brain during pair bond formation, were
confined largely to the ventral pallidum. OTR receptors, which play a crucial role in pair
bond formation in females, were found mainly in the nucleus accumbens.
Perhaps a person with more oxytocin and vasopressin receptors finds life to be more
rewarding in general. But are they more or less prone to drug addiction?
By Randall Parker at 2004 June 17 02:39 AM Brain Love
ARTICLE #2
Romantic Love Seen As Motivation Or Drive Rather Than Emotional State
May 31, 2005 11:29 AM
FuturePundit: Brain Love Archives
Brain Articles: By Randall Parker
Source : http://www.futurepundit.com/archives/002802.html
Accessed : Feb. 10, 2010
Romantic Love Seen As Motivation Or Drive Rather Than Emotional State
Functional Magnetic Resonance Imaging (fMRI) brain scans of people in the early stages
of romantic love show romantic love is less about emotions and more about rewards and
the parts of the brain that control motivation.
BETHESDA, Md. (May 31, 2005) – You just can't tell where you might find love these
days. A team led by a neuroscientist, an anthropologist and a social psychologist found
love-related neurophysiological systems inside a magnetic resonance imaging machine.
They detected quantifiable love responses in the brains of 17 young men and women who
each described themselves as being newly and madly in love.
The multidisciplinary team found that early, intense romantic love may have more to do
with motivation, reward and "drive" aspects of human behavior than with the emotions or
sex drive. Brain systems were activated that humans share with other mammals. So the
researchers think "early-stage romantic love is possibly a developed form of a
mammalian drive to pursue preferred mates, and that it has an important influence on
social behaviors that have reproductive and genetic consequences."
People in romantic love showed no consistent pattern of emotional activation in areas of
the brain known to govern emotions. But they did show consistent activation of brain
areas associated with motivation and goal-seeking mental states.
"Most of the participants in our study clearly showed emotional responses," noted Arthur
Aron of the State University of New York-Stony Brook, "but we found no consistent
emotional pattern. Instead, all of our subjects showed activity in reward and motivation
regions. To emotion researchers like me, this is pretty exciting because it's the first
physiological data to confirm a connection between romantic love and motivation
networks in the brain.
"As it turns out, romantic love is probably best characterized as a motivation or goaloriented
state that leads to various specific emotions, such as euphoria or anxiety," Aron
noted. "With this view, it becomes clearer why the lover expresses such an imperative to
pursue his or her beloved and protect the relationship."
Romantic love happens in the basal ganglia region of the brain.
Aron reported that, using functional magnetic resonance imaging (fMRI) and other
measurements, he and his colleagues found support for their two major predictions: (1)
early stage, intense romantic love is associated with subcortical reward regions rich with
dopamine; and (2) romantic love engages brain systems associated with motivation to
acquire a reward.
Brown explains some of these findings, commenting that "when our participants looked
at a photo of his/her beloved, specific activation occurred in the right ventral tegmental
area (VTA) and dorsal caudate body. These regions were significant compared to two
control conditions, providing strong evidence that these brain areas, which are associated
with the motivation to win rewards, are central to the experience of being in love."
Brown noted that "an important concept is that the caudate probably integrates huge
amounts of information, everything from early personal memories to one's personal
notions of beauty. Then, this brain region (and related regions of the basal ganglia) helps
to direct one's actions toward attaining one's goals. For neuroscientists," she said, "these
findings about the diverse regional functions of the basal ganglia in humans have
remarkable implications."
Romantic love happens on the right side of the brain while facial attraction happens on
the left side.
Another important discovery, Brown said, was that "to our surprise, the activation regions
associated with intense romantic love were mostly on the right side of the brain, while the
activation regions associated with facial attractiveness were mostly on the left.
"We didn't predict such a striking lateralization," Brown reported. "It is well known that
speech is largely a left-sided cortical function. But our data indicate that lateralization
also occurs in lower parts of the brain. Moreover, different kinds of rewards (in this case,
the "rush" of romantic love, compared with the pleasing experience of looking at a pretty
or handsome face) is also lateralized. These results give us a lot to think about how the
normal human brain learns and remembers and functions in general," Brown added.
Humans form attachments to each other using the same part of the brain that prairie voles
use for pair-bonding.
Another breakthrough, Brown noted, was that "we found several brain areas where the
strength of neural activity changed with the length of the romance. Everyone knows that
relationships are dynamic over time, but we are beginning to track what happens in the
brain as a love relationship matures."
Helen E. Fisher, a research anthropologist at Rutgers University, New Jersey, noted that
not only did the brain change as romantic love endured, but that some of these changes
were in regions associated with pair-bonding in prairie voles. The fMRI images showed
more activity in the ventral pallidum portion of the basal ganglia in people with longer
romantic relationships. It's in this region where receptors for the hormone vasopressin are
critical for vole pair-bonding, or attachment.
"Humans have evolved three distinct but interrelated brain systems for mating and
reproduction – the sex drive, romantic love, and attachment to a long term partner,"
Fisher said, "and our results suggest how feelings of romantic love might change into
feelings of attachment. Our results support what people have always assumed – that
romantic love is one of the most powerful of all human experiences. It is definitely more
powerful than the sex drive."
People consider rejection in love as more important than rejection for sex.
For instance, Fisher point out, "If someone rejects your sexual overtures, you don't harm
yourself or the other person. But rejected men and women in societies around the world
sometimes kill themselves or someone else. In fact, studies indicate that some 40% of
people who are rejected in love slip into clinical depression. Our study may also suggest
some of the underlying physiology of stalking behavior," she added.
Fisher sees love as a product of natural selection.
"Darwin and many of his intellectual descendants have studied the myriad physiological
ornaments that one sex of a species have evolved to attract members of the opposite sex,
like the peacock's fancy tail feathers that attract the peahen," Fisher noted. "But no one
has studied what happened in the brain of the viewer, the individual that becomes
attracted to these traits. Our study indicates what happens in the brain of the viewer as he
or she becomes physiologically attracted to these traits."
She added, "This brain system probably evolved for an important reason – to drive our
forebears to focus their courtship energy on specific individuals, thereby conserving
precious mating time and energy. Perhaps," she hypothesized, "even love-at-first-sight is
a basic mammalian response that developed in other animals and our ancestors inherited
in order to speed up the mating process."
What does the future hold for love? Greater knowledge of a phenomenon very often
brings with it the ability to manipulate and control it. I expect the development of drugs
and other treatments that cause people to fall in and out of love and to recover more
easily from lost love.
Some people will choose to immunize themselves from love by using treatments that
prevent the love process from developing in the first place. A person with history of heart
breaks might decide that the possibility of a new love is just too painful to bear. Or
someone who wants to devote their time to career might decide to innoculate themselves
from the risk of romantic distractions. Still others of a more cerebral sort will decide that
love is just a costly cognition distorting evolutionary vestige that they are best off
without.
The ability to manipulate love medically will inevitably lead to misuse via surreptious
reprogramming of the love state of others. Someone who wants to ditch their mate will be
tempted to surreptitiously deliver medicine that will cause the mate to fall out of love. Or
imagine the case where a suitor is rejected because the object of their love is in love with
someone else. Inevitably some suitors will look for ways to surreptiously deliver a
medical treatment that will cause the object of their love to fall out of love with someone
else and thereby open up the possibility of forming a new love bond with them.
Motives also exist to cause people to fall in love with each other. This might be done by
someone who has unrequited love for another. One can also very easily imagine members
of couples (married or otherwise) using love potions to revive flagging marriages by
returning their partner to an earlier state of love. But one can also imagine third parties
(e.g. parents wanting to form a dynastic alliance of some sort) deciding to secretly do this
as well.
The ability to surreptitiously cause people to fall in and out of love will inevitably lead to
suspicions by those falling in and out of love. Can they trust their feelings as legitimate?
Is pharmaceutically induced love less legitimate than natural love? If so, why? Will it be
possible to develop technologies that check for unnaturally induced feelings of love?
By Randall Parker 2005 May 31 11:29 AM Brain Love
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