Lust and Love

Is it more than chemistry?

Gabriele Froböse, Rolf Froböse

• Publisher: Royal Society of Chemistry
• Year: 2015
• eBook ISBN: 9781782625506
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Higher Education

Philosophers have mused over them, poets have written about them and musicians have sung about them. Love, desire and passion will at some point touch everyone's life - yet they are little understood and some of the oldest mysteries of mankind. Why do people fall in love and what is love anyway? What makes people attractive? How do these emotions tie in with our physiology and how we have evolved? Lust and Love: Is it more than Chemistry? provides answers to some of these questions through the eyes of science. It takes a light hearted and entertaining approach in explaining the current scientific knowledge of why people are attracted to each other, from the first moments of meeting to how emotions change in a long lasting partnership. The book covers research from the fields of chemistry, biochemistry, neurology, psychiatry, psychology, physics and medicine while using the love story of a fictional couple to take the reader on a journey explaining the science. Additional topics on the 'tools of attraction', including the history of the lipstick, and the development of perfumes and aphrodisiacs, provide an absorbing insight into the subject. Medical treatments and conditions including contraception, erectile dysfunction and the climacteric phenomenon are also discussed. This engaging and unusual book is ideal for anyone interested in the science behind love, desire and passion.

CHAPTER 1

Mysteries of the Emotional Rollercoaster

Lovers close their eyes when they kiss,
because they want to see with their hearts.
Daphne du Maurier (Writer, 1907–1989)

1 A DAY IN THE LIFE OF BIANCA AND MICHAEL

Never before has Michael arrived at an airport so early. Today is a very special day. With a quick look at the monitor he finds out that the transatlantic flight he is waiting for will arrive at gate B14 in an hour.

On board that flight is Bianca, to whom he has been happily engaged for six months. Bianca, a medical student, has spent a large part of the summer holidays with relatives in the US, where she had an internship at a hospital, and she must have had many interesting experiences. For Michael, however, an IT engineer for a European electronics company, the separation appeared like an eternity. While he always kept himself busy, he hates to think of the long weekends spent alone.

“Well, in that case, I could have taken it slowly,” he mused by himself, “but never mind, better to be early at the airport than late.” The thought of getting stuck in traffic, while Bianca, with her suitcases in hand, might be looking for him in vain, makes him uncomfortable.

Strolling through the arrivals area, Michael checks one more time which exit Bianca will be taking coming from B14. He realises how his inner tension relaxes gradually and makes way for deeply felt joy. To pass the time, he takes a seat in the cafe called “Zeppelin,” allowing him a direct view at the monitor displaying the arrivals.

“I’ll have a chicken sandwich and a cup of coffee,” he tells the waiter and reaches for a newspaper. He scans the headlines, but only skips diagonally through the articles. He finds it hard to concentrate today. Only a feature about San Francisco holds his attention. “Her relatives live in Monterey,” he recalls. “Knowing her, she hasn’t been content with seeing the photos of Golden Gate Bridge.”

While Michael is busy eating, the monitor updates the “arrivals” information. The plane arrives a little earlier after all and will land in a few minutes, he realises. Nervously, he folds up the paper and signals the waiter. After paying the bill, he walks straight to the exit.

Excitedly, Michael observes the sliding door opening and closing at short intervals. Tanned tourists heavily loaded with suitcases and bags struggle through the waiting crowd. Businessmen with briefcases hurry past him, while a Japanese man is upset, apparently looking for somebody, and a group of three Arabs enjoy their small talk. Michael notices these figures only marginally, as he would the extras in a movie.

Suddenly his expression relaxes – Bianca comes through the door. She spots him immediately, leaves the trolley with the suitcase behind and runs towards him. Speechlessly, they sink into each other’s arms. When they kiss, Bianca has tears of joy in her eyes. Michael, noticing the familiar smell of her body, has only one thought on his mind: “We belong together!”

This short scene from the life of two young people should sound familiar to many of us. The unrest, tension, excitement, combined with longing, and then the unlimited joy after the encounter – who hasn’t experienced this rollercoaster of emotions in similar situations?

2 WHY OUR BRAIN PRODUCES “BUTTERFLIES”

Even though those two may be under the impression that the centre of their love is located in the heart, in reality it is only the brain that is responsible for the heartbeats and the “butterflies” in the tummy. “We do not think with the heart, but with the brain,” as the Greek physician Hippocrates, who lived on the island of Kos, stated around 400 BC – but he was way ahead of his time (Figure 1). Even though the organ which the Greek called “en kephale” (located in the head) had fascinated humankind from the beginnings, it was a long way to the understanding that only the brain is the source of our thoughts, feelings, sensations, and ultimately our consciousness.

Even our ancestors in prehistoric times must have been wondering about the source and location of consciousness. Thus, people in ancient cultures saw the head as the dwelling of evil spirits. As we know from skeletons found, some people of that era had holes carved in their skulls – apparently with the aim of curing maladies like “obsession,” although the success must have been dubious.

Figure 1 Hippocrates

Greek anatomists like Anaxagoras looked for the location of the mind in the human body and believed that the cavities in the brain contained the fluid which represented the breath of the mind. Around 500 BC, the Greek Alcmaeon of Croton conducted sections of animals and found out that nerves connect the sensory organs to the brain. He concluded that the brain contains the centre of sensory perception and thinking. However, he considered the brain to be a gland that secretes thoughts like the tear glands produce tears.

The Ancient Egyptians also connected human thought processes with the brain. Herophilus (335 BC) and Erasistratos (300 BC) were the first to break the taboo against dissections of human bodies. They found that people who had certain nerve paths cut, were no longer able to see. Thus they developed the concept of an interconnected system, of which the brain was the centre. To them, the brain was the seat of the soul and the central command of all thought processes.

The Roman physician Claudius Galenus had the opportunity to gain insights from numerous injured gladiators. With this work, he helped to establish the concept developed by the Egyptians that the brain is the centre of human thinking and memory. Aristotle, in contrast, held very different views. Unlike Hippocrates, he insisted on the view – still favoured by the romantically inclined – that human beings think with their hearts.

Eventually, the chamber model of Anaxagoras, which was improved over the centuries, remained victorious. Mediaeval philosophers turned it into a very vivid model, in which the first chamber of the brain serves perception and insight. The second chamber, according to the model, is for knowledge and judgement, while the third chamber is in charge of recording the results of the previous two chambers.

Figure 2 Leonardo da Vinci

LEONARDO DA VINCI: ARTIST AND RESEARCHER

When Leonardo da Vinci was born in 1452, Italy was about to leave the Dark Ages behind at a fast pace. Italy, and Florence in particular were at the centre of the intellectual life newly awakened during the Renaissance. This historical development, which had its beginnings in the learned circles of the humanist writers, was clearly connected with the progress made in the sciences, the changes in the clerical realm, and the emergence of economic structures.

Leonardo da Vinci (Figure 2) was the son of a respected notary. The father recognised the unusual talent of his son quite early on and supported him with all means at his disposal. Thus, young Leonardo at the age of 15 arrived at the atelier of the Florence master Verrocchio, and by 1472, at the age of just 20, he had already made his name among the painters of the city.

From about 1500, Leonardo da Vinci dedicated himself mainly to technical and scientific studies. In countless, very precise drawings of muscles, bones, and brains he tried to track down the laws of life and combine them in a cosmology including all phenomena of nature.

Even around 1490, Renaissance’s all-round genius, Leonardo da Vinci, drafted a preliminary “map of the mind,” which associated different mental functions with various areas of the brain divided in three parts.

Although Leonardo’s sketches of the brain are today only of historical interest, making place for a much more refined picture of the brain and its functions, our most intimate organ has yet to reveal many of its secrets. Even today, many aspects of brain function appear as blank spots on the map of scientific knowledge.

The French philosopher René Descartes (1596–1650) had a much more technical view, comparing the brain with a kind of machine. He imagined that a substance contained in the windings of the brain, which he called “pneuma,” is put under pressure by the excitation arising from the sensory organs and directed into the tube-like nerves by the pineal gland. Thus, the pneuma would travel to the muscles and make them move.

Franz Josef Gall (1758–1828) stirred up his contemporaries by asserting that certain actions of the brain can be felt through the skull. But only Paul Broca (1824–1880) and Carl Wernicke (1848–1905) provided scientific evidence showing that brain functions can be assigned to specific regions. For this purpose, the researchers had investigated a number of patients with language disorders. Between 1900 and 1920, Cecile and Oskar Vogt, along with Korbinian Brodman led this work to its logical consequence and drew the first detailed “architectural” maps of the cortex.

2.1 Mapping the Brain is Like Decoding the Genome

While the earlier thinkers believed that complex processes like learning or memory can each be confined to one particular area of the brain, today’s scientists assume that each brain activity involves various groups of cells that may be distant in space but are linked by nerve fibres. Researchers led by Karl Zilles at the Jülich Research Centre (Germany) have committed themselves to the task of localising these nodes and networks. Their ultimate goal – the complete mapping of all brain functions – is an extremely ambitious one and could be compared to the decoding of the human genome. It is already becoming obvious that the results of this research will throw up a multitude of new questions, which will keep generations of scientists busy.

It is beyond doubt that the brain is our central command which governs all body functions. This applies not only to simple behavioural patterns like eating, sleeping, drinking and heat regulation, but includes the more highly developed abilities of the human mind such as its gift for culture, music, art, science, and language. But it was only recently that researchers obtained insights into the molecular processes in the brain and decoded the first building blocks and processes of a hitherto unknown chemistry which controls all our thought processes – be they conscious or unconscious – and thus our entire emotional world including love. When Bianca and Michael ran towards each other at the airport, when they hugged and cuddled each other, these events triggered a whole cascade of chemical reactions in their brains.

2.2 The Universe Inside Bianca’s and Michael’s Heads

And yet, one should not imagine the brains of our protagonists as a simple chemical reactor. Because the brain would be completely useless if it wasn’t connected with the entire human body with an unimaginably complex network of wires. A mesh of around 380,000 nerve fibres, which would span the distance to the Moon if they were aligned end to end, ensures the smooth flow of information between the central command and all other areas of the human body.

It may sound unbelievable, but the hardware in our heads consists of around 100 billion nerve cells, and is thus comparable to the number of stars in the Milky Way. If we were to calculate the number of connections between these cells that would be possible in theory, the result would be absolutely mindboggling, as there are more possibilities than there are atoms in the entire Universe!

Werner Stangl, a professor at the institute for pedagogics and psychology of the Johannes Kepler University of Linz, Austria, goes even further and visualizes this unimaginably large number thus: “If the brain contains at least 15 billion cells, their connective possibilities could in theory store 210 billion pieces of information. If we wanted to write down this number at the rate of one figure per second, it would take us 90 years.”

This unique architecture allows the brain to do more than simply represent the information it acquires. Unlike a camera or a tape recorder, it has ingenious ways of data reduction. In other words, the brain separates unnecessary junk data by interpreting the signals recorded from the outside world within fractions of a second, and summarising them to form a personalised world. While Michael was waiting for Bianca at the airport, his brain received an incredible one million times more information than his consciousness processed.

THE AGEING BRAIN LOSES ONLY A SMALL NUMBER OF CELLS

According to Prof. Werner Stangl, we lose between 1,000 and 10,000 brain cells every day. “Even if we assume that a person loses 10,000 of their initial reservoir of 15 billion cells every day, they would have to reach an age of 410 years in order to lose just ten percent of their brain,” he calculates. This calculation clarifies that the capacity of the brain cannot be the limiting factor if the memory abilities decline with age. The reasons for the decay are usually found in the lack of training. When people are no longer challenged by their environment and their working life, when they no longer have to learn and the intellectual requirements are reduced, they must take measures themselves and train their brain. Only intellectual activity can ensure that new brain patterns and structures are formed. This way, the thinking and memory abilities can not only be conserved, they can even be enhanced in old age, says Stangl.

In order to better understand this remarkable process, which no computer can match, we shall have a closer look at the human brain. If Bianca and Michael represent the statistical average, her brain weighs around 1245 grams, and his 1375 grams. The largest part is the cerebrum, which has the size of a grapefruit. It consists of two different halves, the left and right hemispheres, which are, among other things, in charge of the physical functions of the body half located on the opposite side. The hemispheres are covered by the multiple folds and creases of the cerebral cortex. The cortex enables us to organise, remember, understand, to communicate and be creative, to invent and value things. The most complicated and remarkable part of the brain however, is the pea-sized hypothalamus, the “brain” of the brain, so to speak. It controls basic needs like eating, drinking, sleep, but also body temperature, pulse rate, hormones and sexuality. By a combination of electrical and chemical messages, the hypothalamus also controls the pituitary gland. The latt...

Table of contents

• Cover
• Title
• Copyright
• Preface
• Contents
• Chapter 1 Mysteries of the Emotional Rollercoaster
• Chapter 2 Two Networks of Nerves
• Chapter 3 Signals of Love
• Chapter 4 Tied Up with a Double Helix
• Chapter 5 Hormones–The Body’s Snailmail
• Chapter 6 Estrogen and Testosterone – Driving Our Emotional Lives
• Chapter 7 Oxytocin – the “Amuse-Gueule” Among Hormones
• Chapter 8 Dopamine – Casanova’s Double-Edged “Secret Weapon”
• Chapter 9 Serotonin – the Happy Messenger in the Blood
• Chapter 10 Phenylethylamine – the Stuff that Makes the Soul Jubilate
• Chapter 11 The Chemistry of Birth Control
• Chapter 12 Menopause: When the Hormone Supply Falters
• Chapter 13 Endogenous Opiates – the Chemistry of Euphoria
• Chapter 14 Chemistry for the Eye of the Beholder – Lipsticks through the Ages
• Chapter 15 Secret Scents of Seduction
• Chapter 16 Pheromones – Words in the Dialogue of Fragrances
• Chapter 17 The ABC of Aphrodisiacs
• Chapter 18 Viagra & Co
• Chapter 19 Epilogue: Returning from the Airport
• Further Reading
• Subject Index