We can now look inside brains to view their patterns of activity, measure biochemical changes that take place in different forms of love, explore diverse human experiences of love, and look for the evolutionary roots of love in other animals.
If the different forms of love have any common evolutionary beginning, where should we look? Maternal love seems a good place to start. Of all the forms of love, none seems as deep, strong, selfless or enduring as the love of a mother for her child, nor is any other bond so ubiquitous in the animal kingdom. Biologically this bond makes perfect sense. In any animal that must provide care for newborn offspring to survive, the bond is essential if that mother’s genes are to be passed on to the next generation.
“Of all forms of love, none seems as enduring as the love of a mother for her child”
How is that bond created? Much of what we know about the brain chemistry of bonding comes from studies of rodents. Whether they feel “love” we cannot say, but they will bitterly defend their young. This tendency seems directly triggered by motherhood: virgin female rats, or even pregnant ones, will avoid or attack pups, but just before giving birth their behaviour changes profoundly.
What makes newborn infants so special to their mothers? The critical link turns out to be the hormone oxytocin. Late in pregnancy, raised levels of oestrogen boost the number of receptors for oxytocin in parts of the brain. During birth, the physical stimulation of labour triggers the release of oxytocin and when the hormone hits those receptors it causes the mother to become addicted to those pups and their particular smell. “Addicted” might seem like a strong word, but the process of bonding to the newborn pups involves powerful activation of a system that carries reward information around the brain. It is this same dopamine reward circuit that can be artificially stimulated by drugs like cocaine and heroin.
The reward circuits originate near the base of the brain in the ventral tegmental area (VTA). Nerve fibres from here connect to the front of the brain, most importantly to the nucleus accumbens that lies just beneath the frontal cortex, where they release the neurotransmitter dopamine. Ultimately, it is in the cortex that reward information is coordinated with emotions and memories and where, in humans, subjective feelings are created, but it is the VTA that sends on the key information about the value of an activity and helps stamp it into memory.
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Oxytocin and vasopressin certainly seem important in human love. When Andreas Bartels and Semir Zeki at University College London scanned the brains of couples who had been together for several years while they looked at a picture of their partner, they found that activity rose in just those parts of the brain that are rich in receptors for these two hormones.
Oxytocin levels rise during orgasm in women and sexual arousal in men, as they do from touching and massage. Oxytocin also boosts trust, which is an important step in developing a loving relationship. In a laboratory investment game devised by neuro-economist Ernst Fehr at the University of Zurich in Switzerland, almost half the people playing the role of “investors” would hand over all their money to an anonymous trustee, with no guarantee of its return, if they sniffed an oxytocin spray beforehand.
At its height, romantic love certainly does seem to set the brain on fire. Helen Fisher’s team at Rutgers University scanned the brains of couples who were newly in love while they gazed at photos of their sweethearts. Activity soars in the brain’s reward system. That results, Fisher says, in “fierce energy, concentrated motivation to attain a reward, and feelings of elation, even mania - the core feelings of romantic love.”
Other areas linked with negative emotions and assessing other people’s intentions switch off. And they switch off too when mothers look at pictures of their babies. No wonder that love is blind and to love someone is, as François Mauriac wrote, “to be the only one to see a miracle invisible to others” (see a comic strip explaining what really goes on inside the brains of lovers, 200k file).
Not everything is the same in romantic and maternal love. Romantic love also includes activation of the hypothalamus, where the sex hormone testosterone is produced. Lust, the sexual part of love, is, unsurprisingly, switched on in romantic love but not in maternal love.
Overall, then, science tends to confirm what human experience teaches. The various forms of love - maternal, pair-bonded and romantic - are biologically related and have neurochemical circuitry in common.
But what about an even wider form of love - the religious love for God and humankind? Love that extends to strangers, outcasts and even to enemies, is central to the Christian message. Other religions stress love and compassion for fellow creatures too and Buddhism in particular has developed meditative practices intended to develop these feelings.
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First results also show that Tibetan Buddhist monks have unusual brain activity when they meditate on loving compassion: Richard Davidson at the University of Wisconsin-Madison found exceptionally high levels of integrated electrical activity during mediation, especially in the right prefrontal cortex. Curiously enough, separate experiments have shown that areas of the prefrontal cortex also light up when a mother gazes at a picture of her child.
Colbert on White House Press
April 30th, 2006 by 
Pocoju
Stephen Colbert spoke tonight at the dinner and lampooned pretty much everything he could think of and Helen Thomas. I used the second half of his performance because it included the Generals, Scalia, the Faux press briefing and as E&P reported:
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