Month: February 2008

Love is the most exalted and sublime of human emotions. It has inspired breathtaking works of art, journeys through continents and even the tragedies of war. Given its powerful hold on humanity it’s surprising that it’s been traditionally neglected by the brain sciences. In spite of this, a new dawn in romance research has begun to bud in recent years, and love has finally blossomed in the lab.

While romantic love has always been an obsession of the psychoanalysts, they were often creating little more than a new poetry of emotion, often beautiful, often bizarre, but rarely explaining more than their own metaphors.

Always a little late to the game, it wasn’t until the end of the 1990s that neuroscience fell head over heals for love. The first to become inspired by this new passion was, as if we needed to ask, an Italian.

Psychiatrist Donatella Marazziti and her colleagues measured levels of a protein that transports the neurotransmitter serotonin in the blood of 20 people who had recently fallen madly in love, 20 people with obsessive compulsive disorder (OCD) and 20 healthy comparison participants.

People with OCD experience intrusive, obsessive thoughts and are often described as having an ‘over-valued idea’ – an almost semi-delusional state where a particular thought becomes the focus of attention.

Marazziti, already an established OCD researcher, knew that serotonin had previously been linked both to obsessional thoughts and to sexual attraction, and wondered whether something similar might be going on in the early stages of romance.

She found that the group of patients with OCD and the recently love-struck were no different in terms of the serotonin transporter protein, suggesting the brain began to function markedly differently as love blossomed.

Although measuring the blood is a fairly crude way of looking at how the brain works, the researchers were struck by the similarities between these two states:

This aspect we believe underlies the obsessive pre-occupation so characteristic of the early stage of love (which, in rare instances, might persist for a lifetime of abstract idealization that leads to poetry and music dedicated to the love object). As far as we are aware, this is the first report of changes in the 5-HT [serotonin] transporter during a physiological state; it would suggest that being in love literally induces a state which is not normal – as indeed suggested by a variety of colloquial expressions used throughout the ages in different countries, all of which refer generally to falling ‘insanely’ in love or to being ‘lovesick’

Since this initial flirtation, love has become a hot topic in the neurosciences, with whole conferences dedicated to it and numerous scientific studies being published every year.

Perhaps unsurprisingly, the traditional connection between love and madness has not been dispelled by these recent studies.

In fact, a 2007 study that looked at new love in adolescents found so many striking similarities between the intensity of teenage romance and hypomania, a symptom of manic-depression, that the authors warned researchers to look out for the love-struck when conducting research with young people, so as not to bias their results.

Link to abstract of study of the serotonin transporter and romantic love.
Link to abstract of study on hypomania and adolescent love.

I’ve just found an interesting page on Wikipedia that discusses the concept of ‘emotional labour‘: where employees are expected to regulate their outward emotional reactions so they are consistent with the company’s goals, regardless of their internal feelings.

A classic ’emotional labour’ worker would be a shop assistant or a waitress, where the employee has to control their emotions and maintain a pleasant demeanour even when customers are being difficult, annoying or even abusive.

This concept was apparently first devised by the sociologist Arlie Hochschild in the book The Managed Heart.

However, a distinction is made between ‘surface acting’, where the display doesn’t need to match internal feelings at all (as when waitressing), and ‘deep acting’ where the employee is expected to genuinely feel the emotions (like in nursing).

Apparently, ‘surface acting’ jobs are associated with stress, feeling inauthentic and depression, while ‘deep acting’ jobs are associated with increased job satisfaction.

How well this is supported by empirical evidence is anyone’s guess, but it’s an interesting concept.

Link to Wikipedia page on ’emotional labour’.

How does the brain generate orgasm? It’s one of the most under-investigated human experiences but two articles, one in the LA Times and another in The Psychologist, discuss some of the key developments of recent years.

The LA Times article is a good description of some of the most interesting neuroscience studies in this developing field, but is a little uncritical in places.

Apparently “About 43% of women and 31% of men in the U.S. between ages 18 and 60 meet criteria for sexual dysfunctions, according to a 1999 report on the sexual behavior of more than 3,000 U.S. adults”.

This report was a research study published in the Journal of the American Medical Association that classified sexual dysfunction as reporting any one of the following during the last 12 months:

(1) lacking desire for sex; (2) arousal difficulties (ie, erection problems in men, lubrication difficulties in women); (3) inability achieving climax or ejaculation; (4) anxiety about sexual performance; (5) climaxing or ejaculating too rapidly; (6) physical pain during intercourse; and (7) not finding sex pleasurable

Almost all of which fall within the normal range of a year’s worth of regular sexual experiences, which probably explains why a third to almost half of people surveyed experienced at least one – but hardly a marker of a serious medical problem in itself.

There’s a much better article on orgasm in this month’s The Psychologist by Barry Komisaruk, Carlos Beyer and Beverly Whipple, authors of a recent book on ‘The Science of Orgasm’.

It looks at the research on the roles of neurotransmitters in orgasm, as well as what the brain scanning literature tells us about brain activity during sexual arousal and release.

Most interestingly, it has a good discussion of non-genital orgasm:

As reviewed in Komisaruk et al. (2006), there are published reports of orgasms elicited by stimulation also of lips, hand, knee and anus occurring during dreaming sleep, of phantom limbs, from electrical or chemical stimulation of the septum, amygdala or thalamus of the brain and of the spinal cord.

Orgasms have also been described by men and women when they suffer epileptic seizures that are triggered by specific activity (e.g. brushing the teeth: Chuang et al., 2004), or that occur spontaneously. While these epileptic orgasms are in some cases described as ‘unwelcome’ (Reading & Will, 1997), others describe them as pleasurable, one woman refusing anti-epileptic medication for that reason (Janszky et al., 2004)

We have measured autonomic and brain activity during orgasms that women have produced by thought alone. During the thought orgasms, the magnitude of the increases in heart rate, blood pressure, pain threshold, pupil diameter, and brain regions are similar to those that we observe during vaginal or cervical self-stimulation-induced orgasms (Whipple et al., 1992). It is not surprising that in those cases of thought-induced orgasms, the specific genital sensory thalamic and cortical, and specific limb-motoric regions, are not activated.

The article notes that a number of different nerve pathways may serve to communicate sensual stimulation to the brain, which may account for why different sites of stimulation can produce orgasm.

Link to LA Times article ‘Science of the orgasm’
Link the The Psychologist article on orgasm.

Full discloser: I’m an unpaid associate editor of The Psychologist.

A 61 year-old lady was admitted to a Florida hospital with florid hallucinations after suffering a stroke to her thalamus. She saw curious strangers and visitors with odd clothes, but rather unusually, the ones on the right always seemed pleasant and happy, whereas the ones on the left always seemed fearful and unsettling.

The case was reported in the journal Cognitive Neuropsychiatry and is of interest because the emotional content of the hallucinations seem to match the dominant emotion of the corresponding hemisphere of the brain.

[The patient] described the right visual hallucinations as consisting of “college age boys in colourful Hawaiian shirts” that “are too happy, talk too much”, and that are somewhat “too energetic”. The patient called them the “he-haw boys,” and reported that she could hear them talking.

The left visual hallucinations were described as “men in black religious clothes that make no noises.” The patient called them “the eye drillers”, and stated that “they look a hole right through you”. The patient provided vivid drawings of the hallucinations that accentuated the positive and negative associations she had with each hallucination. The patient provided vivid drawings of the hallucinations that accentuated the positive and negative associations she had with each hallucination.

This is not the first time that hallucinations have been reported to be differing in emotional tone depending on which side of space they appear.

This is likely due to the way emotion is processed in the brain.

Perception of negative emotions often relies largely on the right hemisphere, where positive emotions are processed by both the right and the left hemispheres. In fact, this pattern of brain response has been found in children as young as 10 months old.

The woman in this case report didn’t suffer damage to the hemispheres directly, but to the thalamus. This area is often called the brain’s relay station as it is extensively connected to hemispheres, so damage in this area can often mimic damage to the cortex.

Link to PubMed abstract of case report.