I’m dead tired! The importance of sleep

Evelina Petitto

Everybody sleep2will agree that sleep is an important aspect of our life, important for our physical and mental health and also a great pleasure! It is so important that during our life we spend almost a third of our time sleeping. However, we still don’t really know why we do it… despite years of research about it, the true function of sleep is still uncertain. One of the main theories on sleep states that the brain needs it. The question then is how is sleeping useful to our brain? It is now proved that sleep helps in memory consolidation and, therefore, learning. A study published some years ago by Giulio Tononi (Wisconsin University) showed that during sleep the brain eliminates redundant and useless connections. Furthermore, a recent experiment by Robert Stickgold (Harvard University) showed that if students have the possibility of sleeping between two tests, they will perform better on the second one. While sleeping, the brain appears to repeat a pattern of neuronal activation that occurred when the person was last awake, as if it is trying to reinforce the traces of the information recently learnt. According to these findings, the purpose of sleep would be helping us to remember what is important whilst letting us forget what’s not. Sleep has physiological effects too; indeed, prolonged sleep deprivation can lead to death, as proven in experiments conducted by Rechtschaffen (University of Chicago). In these experiments, rats were sleep deprived by placing them on a disk suspended over a tank of water. If the rats fell asleep, they would fall in the water and wake up again. After two weeks, every rat was dead. However, necropsies on the animals didn’t find anything significantly wrong with them. All the organs and vital markers were not altered, and the only reason of death was exhaustion, that is lack of sleep.

PHYSIOLOGY OF SLEEP

The sleep-wake cycle is controlled by two internal influences: sleep homeostasis and circadian rhythms. Sleep, like other body conditions such as blood pressure and temperature, is under homeostatic control; in other words, the body maintains these parameters in a steady state. From the time we wake up, the homeostatic drive for sleep accumulates until late evening, when we will eventually fall asleep again. One neurotransmitter, adenosine, seems to be the sleep-inducing chemical. In fact, the level of adenosine rises consistently when someone is awake, resulting in an increasing need for sleep. Conversely, the level of adenosine decreases during the night, satisfying the need for sleep. Some drugs (like caffeine!) act on the adenosine receptor, disrupting this process to some extent. Circadian rhythms are cyclical changes occurring in a 24-hour period driven by the brain’s “biological clock”. This consists in a group of neurons in the hypothalamus, called the suprachiasmatic nucleus (SCN). The physiology and behaviour regulated in these cycles are synchronised to the external physical environment and social schedules. The strongest synchronising factors are light and darkness, the external stimuli that set the “biological clock” and determine when we need to fall asleep and wake up. Although we think of sleep as a period where we shut down, sleep is actually an active physiological process. There are two types of sleep: rapid eye movements (REM) and non REM (NREM) sleep, characterised by distinct brain activities. NREM sleep, characterised by a reduction in physiological activity, consists of 4 stages:

  • Stage 1: the transition from being awake to falling asleep – this is characterised by slow brain waves and diminished muscular activity.
  • Stage 2: period of light sleep where eye movements stop, brain waves become slower and spontaneous periods of muscle tone are mixed with periods of muscle relaxation.
  • Stages 3-4: these are characterised by slow brain waves known as delta-waves interspersed with small faster waves. Sleep is deep, with no eye movements and decreased muscle activity, although movement is possible.

REM sleep is a paradoxical change in brain activity: the brain is extremely active, its waves are fast and desynchronised, similar to those characteristic of the waking state. Breath becomes irregular, eyes moves rapidly and limb muscles become temporarily paralysed. This is the stage where most dreams occur. The role of each phase in overall health is still uncertain; however, striking a good balance between the phases appears to be crucial in achieving beneficial sleep. A complete sleep cycle lasts about 90-110 minutes, and is repeated from 4 to 6 times every night. The composition of each cycle is not constant during the night (REM sleep increases after each cycle), and also changes during the life of an individual, with children having significantly longer periods of REM sleep compared to adults.

SLEEP DEPRIVATION sleep3

Sleep deprivation, chronic or acute, is the condition of not having enough sleep. The short-term consequences of this condition are well-documented, including diminished cognitive performance, impaired memory and low levels of alertness. Prolonged periods of inadequate sleep have cumulative side effects. In one of the most extensive studies on human sleep deprivation, subjects were restricted to 6 hours of sleep per night for two weeks. Subsequently, in cognitive and motor tasks, they performed as poorly as subjects who were entirely deprived of sleep for two consecutive nights. In the long term, poor sleep habits negatively impact the functions of several organs (such as heart, lung and kidneys), on metabolism and weight control, immune responses, sensitivity to pain, as well as mood and cognitive functions. Sleep deprivation is also a risk factor for depression and substance abuse, and it has been linked to increased risk of diabetes, heart disease, obesity, and certain forms of cancer. Obviously, the consequences on humans of total sleep deprivations are not well documented, and our knowledge about this comes from only a few studies, world-record attempts and distressing stories like the one told by the psychotherapist John Schlapobersky, who was tormented with sleep deprivation: “I was kept without sleep for a week in all. I can remember the details of the experience, although it took place 35 years ago. After two nights without sleep, the hallucinations start, and after three nights, people are having dreams while fairly awake, which is a form of psychosis. By the week’s end, people lose their orientation in place and time — the people you’re speaking to become people from your past; a window might become a view of the sea seen in your younger days. To deprive someone of sleep is to tamper with their equilibrium and their sanity”. People who are left without sleep for long periods of time usually recover after a few days. So far, no human death has been attributed to forced or intentional wakefulness. However, some rare instances where humans are literally unable to sleep have ended in death. This is known as fatal familial insomnia (FFI), which is an extremely rare prion brain disease, which results in total inability to sleep, dementia and ultimately death, within a time frame of 7-36 months. The disease progresses from insomnia, hallucinations, temperature fluctuations, to complete loss of sleep, weight loss, dementia, irresponsiveness, and eventually to sudden death. These symptoms suggest that prolonged periods without sleep would end in death by disrupting critical functions such as those related to metabolism. The person becomes hypometabolic, and cannot appropriately manage energy intake and expenditure, so that the energy is wasted.

CONCLUSIONS

sleep4Sleep is a fundamental physiological function that serves vital roles to the organisms. All animals sleep, from birds to fish, and some of them can do it with one hemisphere at a time to maintain a certain level of alertness. Many sleep disorders can lead to mild sleep deprivation that will have negative repercussions on cognition and physical health. In the most severe cases, sleep deprivation can eventually cause dementia and death. It is therefore important that we take care of our sleep, keeping in mind that is not only the quantity that matters, but most importantly the quality of the sleep and in what sleep phase we are in when we wake up. That is the case of when we are forced to wake up and we end up feeling sleepy all day, opposed to when we naturally wake up, maybe at the same time of day, but feel great and full of energy. We can roughly calculate how much time we should sleep if we want to wake up in a better state by considering the length of the sleep phases. However, no matter what, I find myself agreeing with Wilson Mizner, who wisely said: “The right amount of sleep required by the average person is 5 minutes more”. Do you want to find out if you suffer from a sleep disorder? Take this simple test:

http://www.edinburghsleepcentre.com/sleep_disorders/online_questionnaire.htm

References:

http://ngm.nationalgeographic.com/2010/05/sleep/max-text http://sleepfoundation.org/sites/default/files/SleepWakeCycle.pdf https://en.wikipedia.org/wiki/Sleep_deprivation http://io9.com/can-you-die-from-sleep-deprivation-1684235719    

The Milwaukee Protocol and beyond: Is rabies really a death sentence?

Stuart Mather

Within the discipline of virology, rabies is pretty unanimously regarded as the world’s deadliest human virus. Most commonly transmitted from the bite of an infected dog, the virus begins to spread to the central nervous system (CNS), originally causing pain, fever, headache and a tingling sensation (known as paraesthesia), before leading in some ases to paralysis and coma, whilst in others developing the characteristic rage, hyperactivity and hydrophobia associated with the disease. In either instance, the result is almost certainly death – statistically, the case-fatality rate of symptomatic rabies infection is 100%.

1Fortunately, rabies is as preventable as it is fatal. Through human and canine vaccination, the number of cases of the virus has significantly decreased in many countries. Furthermore, the administration of post-exposure prophylaxis – or PEP – following suspected occurrences of infection is estimated to avoid hundreds of thousands of rabies-attributed deaths every year.

Nevertheless, rabies still circulates on every continent other than Antarctica, is endemic in 150 countries worldwide, with roughly 60,000 individuals succumbing to the disease annually. Why is this? One o2f the main obstacles to further reducing the public health burden of rabies is poor accessibility to the most resource-deprived areas of the world, typically in Africa and Asia. It is not straightforward to roll out mass vaccination schemes in these regions, and many potential rabies transmission events, such as dog or wild animal bites, are not promptly reported to local medical services. And once the virus fully manifests itself within a host and reaches the CNS, there are no licensed medical treatments available to prescribe.

So, is there any way to combat rabies when it’s in the full swing of infection? This blog post explores some of the evidence to suggest that being diagnosed with rabies is not necessarily always a death sentence.

First of all, it is important to acknowledge that rabies is probably one of the oldest infectious diseases known to man. Reports of the virus date back to as far as 2300 BC, where Babylonian dog owners in the ancient city of Eshnunna were severely fined for deaths caused by bites from their dogs. Rabies was then consistently documented in Ancient Greece by the philosophers Democritus and Aristotle, as well as being alluded to in Homer’s The Iliad. They even dedicated two Gods to the prevention and healing of rabies – Arisaeus and Artemis, respectively. Mesopotamian and Roman physicians detailed4 the symptoms of rabid dogs and developed a cleaning regimen for management of bite wounds. In the following 1500 years, the infection steadily spread throughout Arabia and Europe, causing notable outbreaks in Germany (13th century) and Spain (15th century) before wreaking havoc in Paris and finally reaching the shores of England by the 1730s. At a similar time, undoubtedly due to the emergence of the global empires, the growing merchant shipping industry and the slave trade, rabies emerged in the West Indies, Barbados and Mexico, before spreading in both directions throughout North and South America, on its way to becoming the globally ubiquitous virus we see today.

Although the literature throughout history clearly focuses on the death and devastation caused by rabies, it is highly likely that, on rare occasions, some individuals may survive the infection, whether that be because of a very strong and rapid immune response in the patient or exposure to a particularly weak strain of the virus. Certainly nowadays, researchers are well aware that some wild animals conquer rabies alone, without vaccination or medical intervention. After all, viruses must hijack host cellular machinery to replicate themselves and flourish, so a virus that decimates every single host it infects is not necessarily a successful virus, with respect to its own self-preservation and evolution. And rabies can definitely be described as ‘successful’!

Speculation aside, the5 first reported instance of a human surviving the full force of rabies (perhaps contrary to popular belief) is that of Matthew Winkler, a 6-year-old boy from Ohio, USA, during the Autumn of 1970. One night, a bat managed to get into Matthew’s bedroom through a hole in the attic and firmly bit his thumb. The father managed to catch the bat after hearing his son screaming and upon sampling it a few days later, public health officials declared the animal rabid, prompting paediatrician Dr John Stechschulte to initiate a course of rabies vaccine for the boy over a fortnight. However, in the following weeks, Matthew developed a fever, stiffness of the neck and left side, and slipped into a semi-comatose state. The vaccine had failed and rabies had taken hold. Rather than resign themselves to the fact that the patient would soon die, they opted to fight the disease based on the assumption that death may be brought about as a result of the ailment’s symptoms, as opposed to the presence of the virus itself. So if, for instance, the physicians could perform a tracheotomy when Matthew’s throat contracted, or prescribe anti-convulsants to prevent hyperactive twitching and spasming, then they may be able to stave off death long enough to give his immune system time to mount a response against the rabies virus, altering the outcome for the boy. Three months after being admitted, Matthew had recovered enough to be released from hospital on his 7th birthday, and has since gone on to live a life relatively unhindered by neurological complications.

Definitely the most famous and well-documented case of rabies survival is that of Jeanna Giese, the first person to have overcome rabies with no vaccination or PEP whatsoever prior to symptom development. Jeanna was 15 years old when she attended a regular church Mass in September 2004. During the service, a bat was circling overhead, getting increasingly near to the attendants before finally being knocked to the ground by a church usher. Out of compassion and a love of animals, Jeanna decided to pick the bat up and take it outside, sustaining a small bite to her index finger in the process. After cleaning and dressing the wound, her family thought nothing more of the incident. A few weeks later, Jeanna started complaining of double vision and tingling in her limbs; suffering from fatigue, nausea and fever. When her arms started to stiffen and jerk involuntarily and her speech slurred, she was hospitalised and tested for a number of neurological diseases. Every result came back negative. In desperation, Jeanna’s mother mentioned the recent bat bite, which was an important step in achieving a rabies diagnosis, and soon after Jeanna was transferred to the Children’s Hospital of Wisconsin, where she was referred to Dr Rodney Willoughby, an infectious diseases consultant.

Despite his expertise in the discipline, Dr Willoughby had never encountered a patient with rabies before, and as neither licensed treatments nor promising but unpublished approaches were available, the plan of action for combatting the infection was completely unclear. So with Jeanna’s condition rapidly declining, Rodney went back to basics and pored over old case files and publications, trying to find clues about how the disease’s progression could be halted. One point, highlighted several times in the literature, caught the doctor’s eye –rabies pathology does not primarily function by physically destroying neuronal cells or causing lesions in the brain an6d CNS, but rather by disrupting the controlled release of neurotransmitters, such as acetylcholine and serotonin. Dr Willoughby and his colleagues therefore decided to place Jeanna into an induced coma, which could suppress her neuronal activity and delay the progression of rabies symptoms, effectively buying time for her adaptive immune system to produce enough antibodies directed against the virus o overcome, or neutralise, the infection. While comatose, Jeanna was also prescribed ketamine and midazolam to further dampen brain function, as well as the antivirals ribavirin and amantadine. After six days, Jeanna displayed protective antibody levels against rabies and was brought out of the coma to begin her gradual recovery. She had to re-learn how to stand and walk, then regain fine motor skills and so on. A decade on, Jeanna has undergone a pretty complete recovery, now only unable to run and speak at full speed. She graduated from college in 2011 with a degree in Biology and got married in 2014.

Dr Willoughby’s innovative treatment approach was subsequently dubbed the ‘Milwaukee Protocol’. Despite this initial success story, the protocol is a controversial and divisive subject for medical professionals and scientists in the field. Since 2004, the treatment has been attempted approximately 35 times, with only 5 resulting in patient survival. It is also unsure whether these successes can be attributed to the protocol itself, or rather exposure to a low-pathogenic variant of the rabies virus coupled with a robust immune response from the patient. Furthermore, the location of the bite wound may play an influential role in the propensity for the patient to overcome the infection. Both Matthew Winkler and Jeanna Giese were bitten on a finger or thumb, meaning that the rabies virus would have to travel further along nerve cell axons before reaching the CNS (at a rate of 1-2cm per day), allowing a longer timespan for patient immune responses to develop.

More recently, in 2012, one study published in the American Journal of Tropical Medicine and Hygiene detailed new evidence suggesting that rabies infections in humans may not be as lethal as first thought, potentially revolutionising the way the virus is regarded clinically. Dr Amy T Gilbert of the Centers for Disease Control and Prevention led a serosurveillance study in two communities at risk of vampire bat bites in the Peruvian Amazon – this involved taking blood samples from a number of community members and assessing levels of rabies virus neutralising antibodies in their serum. Over half claimed to have previously been bitten by bats and remarkably, 11% of those tested carried rabies antibodies at levels sufficient to protect them from subsequent infection. Out of these seven seropositive individuals, only one had received the rabies vaccine, indicating that the remaining six people had been naturally exposed to the virus, with a non-fatal outcome. Potential alternative explanations for these findings could be that these people were infected with a virus highly related to rabies, which can induce the production of cross-reactive antibodies but which is not fatal to humans; or that they were exposed to a large enough dose of rabies to virus to elicit an immune response, but that viral replication did not occur. In any instance, if these individuals possess some inherent genetic resistance to rabies, being able to understand why may lead to novel treatment strategies.

Other interesting approaches to rabies therapy have also been studied. It seems logical to try and identify antiviral drugs for the treatment of rabies, and the two agents known to have activity against the virus are ribavirin and interferon-α. These have both shown promise as treatments in in vitro and animal model studies, but have failed to display beneficial effects when administered to human patients in early stages of clinical rabies. A major limitation to the use of these antivirals is that they often have to penetrate the blood-brain barrier to reach the primary sites of infection, meaning they can’t reach many of the rabies virions.

Another approach that seems more experimental is deliberate hypothermia. Body cooling has previously proven effective in trials involving cardiac arrest patients, and works by reducing metabolism, oxidative stress and inflammation in the brain. These effects could also be beneficial in the treatment of rabies, but have not undergone clinical trials at any phase as of yet.

The cases discussed in this blog prove that rabies can be survived, albeit very rarely, and offer hope that more successful treatment strategies may be developed in the future. For now, it retains its place on top of the list of deadliest human viruses, so the best plan of action to survive rabies is… don’t get rabies!

Check out these great resources for more information:

Images:

Excuse me, do I know you?

Evelina Petitto

prosopoagnosia

W.J. was a 51 years old man who became a shepherd after suffering several strokes. He had a peculiar ability: he could recognize and distinguish each one of his sheep; however, he could not recognise any of his family members, and most generally, he could not distinguish human faces.

Dr. P. was a music teacher. He couldn’t recognise his student by their faces, unless they spoke to him. Not only he failed to see faces, but he saw faces where there were none to see; for example he often mistook fire hydrants for children.

Can you imagine to wake up one morning and not be able to recognise the people around you, even those who are closely related to you? Yeah, it seems like the plot of a movie, however this is what people with prosopagnosia experience every day. Glenn Alperin, blogger for Psychology today uses a metaphor in his personal website (http://home.earthlink.net/~blankface/prosopagnosia.shtml) to describe this condition that afflicts him: “Imagine that every person has a camera inside their head. Every time they meet somebody for the first time, they take a picture with their camera, develop the picture, and file it away for future use. …For me, I take a picture with my camera, but I never store it away.”

Prosopagnosia, also known as face blindness, it’s the inability to recognize faces. Originally it was thought that this disorder was due to damage of certain brain areas as a consequence, for example, of a stroke. Now it is known that, although true in most cases, this is not always the case, and about 2% of the population suffer from congenital prosopagnosia.

The brain regions involved in this condition are the parts of the occipital and temporal lobes involved in perception and memory, and specifically a region of the temporal lobe called fusiform gyrus.

prosopo

The importance of this region for facial recognition has led to it being commonly known as the fusiform face area (FFA). There is a fusiform gyrus in both sides of the brain, but the one in the right hemisphere is what is usually associated with face processing.

There is evidence suggesting that fusiform gyrus damage tends to bring about difficulties in face perception and recognition, whilst damage to other areas of the temporal lobes is associated with difficulties accessing memories of faces. It has therefore been suggested that there are two subtypes of prosopagnosia, one affecting the way we perceive faces (apperceptive prosopagnosia), and the other affecting our memory for faces (associative prosopagnosia).

Congenital prosopagnosia, instead, manifest itself from early childhood, and is not associated to any specific brain damage. People with congenital prosopagnosia seem to fail to develop the visual mechanisms necessary for successful face recognition. There have been reports of families in which multiple members have the condition, suggesting a genetic link in some cases; this hypothesis has been also confirmed by studies of identical and non-identical twins.

So what goes wrong in the perception of faces by people with prosopagnosia? Do they perceive them normally? The answer to this question is yes, they don’t see faces in a distorted manner. However, they find it very difficult to use the visual information to recognise familiar faces.

Moreover, the process they use to analyse faces is different from the one used by other people. Research suggests that faces are processed in a unique way, differently to other types of objects. People with normal face recognition abilities appear to process faces ‘holistically’. This means that the face is processed as a whole, taking account of the relationship between features rather than focusing on the features themselves. Rather than processing faces as a whole, individuals with prosopagnosia seem to adopt a feature-by-feature strategy, in which faces are processed in a piecemeal manner and each feature is looked at in turn. Not only does this make face recognition a longer and more difficult process, but it also ignores the spatial relations between features – information that is critical for successful recognition.

Do you want to test your ability to recognise faces? Take this simple test: http://www.cbsnews.com/videos/do-you-have-trouble-recognizing-faces-take-a-test/

If you arbook2e interested to read about stories of patients suffering of prosopagnosia and other neuropsychological disorders, read this book: Oliver Sacks “The man who mistook his wife for a hat”.

Love: is it in our heart or in our head?

Evelina Petitto

Humans are social animals. In fact, our lives depend on other human beings, and from the early stages of our existence we can’t live without someone taking care of us: when we are children, our survival depends on the effort another human being puts in feeding, cleaning and relating to us. Our first experiences of the world are strictly connected to our carer, and the ways we learn how to interpret other’s signals of affection and behave in relationships are closely dependent on the first experiences we have.

HOW EARLY RELATIONSHIPS SHAPE OUR FUTURE ONES

baby

To have a normal psychological and social development, infants need to establish a relationship with at least one person. This is what in evolutionary psychology is called attachment, and its characteristics depend on how the parents (or the caregivers) respond to the behaviours and emotions of the child. Depending on the nature of these early responses, the child will develop a particular type of attachment, which later in life will shape his/her relationships in the terms of expectations and emotions.

The early types of attachments are four, and can be described as follow:

  • Secure: this is the ideal type of attachment, and is established when the caregiver responds to the child’s interaction in a consistent and sensitive manner. In this way, the child learns that the others can be trusted, and they use the caregiver as a secure base to explore and experience the world with a reasonable degree of autonomy.
  • Avoidant: if the carer is emotionally unavailable and insensitive or unaware of the needs of the child, the child will learn not to be dependent on someone else for his needs, and become fast a “little adult” who take care of himself.
  • Ambivalent/anxious: if the carer is not consistent in his responses to the child, alternating moments of appropriate responses and moments of intrusive or insensitive behaviours, the child won’t know what to expect in response to his needs. He will be suspicious and distrustful of the carers, but at the same time he will try to constantly get their attention crying and acting clingy.
  • Disorganised: this is the type of attachment developed by children with abusive carers. These children are caught in a terrible dilemma: they need the carer for their survival, but at the same time they are terrified by them, being the carers the source of their emotional and sometimes physical pain. These children usually resolve the impasse by dissociating from their selves, and as a result the disturbing experiences are removed from their conscious thoughts.

According to the type of attachment developed during the first year of our lives, we grow up with certain relationship assumptions regarding what we can and what we can’t expect from others. In adulthood, children who had a secure attachment to their carers will have a secure personality: they have a positive and strong sense of self, and desire close connections with others. In their relationships, they can find the right balance between independence and closeness.

Children who had an avoidant attachment will most likely grow up having a dismissive personality: they consider relationships and emotions as being unimportant, and tend to avoid stressful situations and conflicts by distracting themselves with superficial activities.

Children who had an ambivalent/anxious type of attachment will have a preoccupied personality: they are self-critical and insecure, and ask seek approval and reassurance from others. In relationships, the fear of being rejected makes them distrustful and worried, and they usually end up being overly dependent from their partners.

Finally, children who develop a disorganised attachment will likely have a fearful/avoidant personality: they desire relationships and are comfortable in them until they develop emotional closeness. At this point the feelings they repressed as children come to the surface, and they start experiencing them in the present without the awareness that they belong to the past. Instead of living in the present, they constantly re-live the old trauma.

Of course there is space for change, and people who developed an insecure type of attachment during childhood can grow into secure adults if faced with corrective secure experiences.

NEUROCHEMISTRY OF LOVE

Oftloveen, when we fall in love with someone, we say that there is a certain chemistry between us and the object of our love. Well, this isn’t completely wrong. In fact, our brain creates this feeling producing a variety of chemicals that characterise the different stages of romantic love.

Scientists have proposed that romantic love consists of 3 distinct phases, each of them different according to the chemical that our brain produces:

  1. Lust/romantic feelings

This stage is the first one, and corresponds to the period of time where the partner seems perfect and ideal. This is due to the fact that our brain is full of endorphins, and the two hormones that specifically drive this stage are testosterone and oestrogen (for both males and females).

  1. Physical attraction

This is the phase where you are “love sick”: you think about your partner all day long, lose appetite and need less sleep. It is controlled by three neurotransmitters: adrenaline, that activates stress responses; this is the reason why at the beginning of a relationship when you meet your loved one you heart rate increases, you sweat, and your mouth goes dry.

Dopamine, that stimulates the desire and reward system in our brain; it causes rushes of pleasure, and alters cognition (you day dream about your partner all day long), mood and sleep patterns (you sleep less). In a way, we can say that falling in love is the same thing than being addicted to cocaine!

Serotonin, whose effect in this stage of being in love is much similar to the one observed in obsessive compulsive disorder (OCD): this explains why people experiencing infatuation cannot think of anyone else. Serotonin also regulates appetite, sleep, memory, and mood, and plays a vital role in physical attraction.

  1. Emotional attachment

This stage includes commitment, partnership, the possibility of procreation, and can recognize both positive and negative traits towards the partner. This is the stage you and your partner will either work towards a healthy/loving relationship or decide to end all together. It is mostly driven by two hormones: oxytocin, also known as the cuddle hormone, is a powerful hormone released by males and females during orgasm, and it strengthens the bond between partners. The theory is the more sex and hugs a couple has, the stronger and deeper the connection between them becomes.

Vasopressin, an important hormone released after sex. Its effects are enhanced by testosterone, and it heightens one’s responsibility, monogamy, also giving them protective, jealous, and loyal feelings towards their partner.

So these are the responses that our brain has when it’s in love. Given all that (especially the involvement of the reward system at an early stage) love looks more like an addiction rather than a simple feeling or emotion. This is also confirmed by fMRI scans that show the activation of those areas responsible for drug addictions in the early stages of physical attraction: a new love produces chemical responses similar to opioids.

HOW DO WE FALL IN LOVE?

More than 20 years ago, the psychologist Arthur Aron could make two strangers fall in love in his lab. The way he did it was very simple: the subjects simply had to answer 36 questions that become more and more intimate one after another, and then staring at each other’s eyes for four minutes without saying a word.

The questions used in the experiment were:

  1. Given the choice of anyone in the world, whom would you want as a dinner guest?
  2. Would you like to be famous? In what way?
  3. Before making a phone call, do you ever rehearse what you’re going to say? Why?
  4. What would constitute a perfect day for you?
  5. When did you last sing to yourself? To someone else?
  6. If you were able to live to the age of 90 and retain either the mind or body of a 30-year old for the last 60 years of your life, which would you choose?
  7. Do you have a secret hunch about how you will die?
  8. Name three things you and your partner appear to have in common.
  9. For what in your life do you feel most grateful?
  10. If you could change anything about the way you were raised, what would it be?
  11. Take four minutes and tell your partner your life story in as much detail as possible.
  12. If you could wake up tomorrow having gained one quality or ability, what would it be?
  13. If a crystal ball could tell you the truth about yourself, your life, the future or anything else, what would you want to know?
  14. Is there something that you’ve dreamt of doing for a long time? Why haven’t you done it?
  15. What is the greatest accomplishment of your life?
  16. What do you value most in a friendship?
  17. What is your most treasured memory?
  18. What is your most terrible memory?
  19. If you knew that in one year you would die suddenly, would you change anything about the way you are now living? Why?
  20. What does friendship mean to you?
  21. What roles do love and affection play in your life?
  22. Alternate sharing something you consider a positive characteristic of your partner. Share a total of five items.
  23. How close and warm is your family? Do you feel your childhood was happier than most other people’s?
  24. How do you feel about your relationship with your mother?
  25. Make three true “we” statements each. For instance, “we are both in this room feeling…”
  26. Complete this sentence “I wish I had someone with whom I could share…”
  27. If you were going to become a close friend with your partner, please share what would be important for him or her to know.
  28. Tell your partner what you like about them: Be honest this time, saying things that you might not say to someone you’ve just met.
  29. Share with your partner an embarrassing moment in your life.
  30. When did you last cry in front of another person? By yourself?
  31. Tell your partner something that you like about them already.
  32. What, if anything, is too serious to be joked about?
  33. If you were to die this evening with no opportunity to communicate with anyone, what would you most regret not having told someone? Why haven’t you told them yet?
  34. Your house, containing everything you own, catches fire. After saving your loved ones and pets, you have time to safely make a final dash to save any one item. What would it be? Why?
  35. Of all the people in your family, whose death would you find most disturbing? Why?
  36. Share a personal problem and ask your partner’s advice on how he or she might handle it. Also, ask your partner to reflect back to you how you seem to be feeling about the problem you have chosen.

So why this simple experiment seems to work in making random people falling in love with each other? According to Dr. Markman, a professor of psychology at the University of Texas, this experiment “it’s almost like hypnosis in a way. If you think about falling in love, it’s really a willingness to lower barriers that normally inhibit us from getting to know each other.”

Indeed, many couples that took part to this experiment ended up in long term relationships, and one also got married!

CAN WE MEASURE LOVE?

There is a validated scale that can help us understand if someone is in love or not: the Passionate Love Scale (PLS). Created in 1986, this scale has been validated for adult and adolescent populations, and can be used for short term loves (7 months or less), as well as for long lasting relationships where the subjects claim they are still in love with their partner (although at this stage usually the scores drop a bit).

The short version of the PLS consists of 14 question, to which a person has to indicate his agreement from 1 (totally disagree) to 9 (totally agree).

PLS

Although it may look like this is a quiz taken by a teen magazine, it is actually a validated scale that scientists use to find subjects for their neurophysiological studies on love. You simply add up your results, and you can know how strong your love for your partner is…

Split brain: are we two brains and one mind?

Evelina Petitto

“Scientists have often wondered whether split brain patients, who have had the two hemispheres of their brain surgically disconnected, are ‘of two minds’” (Zilmer, 2001)

It is quite trivial to say: we only have one brain. However, our brain is composed of two hemispheres, each one specialised to perform certain tasks and process certain pieces of information. These two parts of the brain normally interact and cooperate in our everyday life, but what happens when they can’t communicate with each other?

This is what happens in the so called split brain patients, whose hemispheres are surgically disconnected with a procedure called corpus callosotomy. This procedure is usually undertaken as the last resort to treat severe epilepsy, and consists of the dissection of the corpus callosum, the structure in the brain where the connections between the two hemispheres are; as a result, the left and the right brain can process information and behave independently from each other. The consequences of the procedure can sometimes affect the everyday life of the patients, who can develop a split personality. For example, one of them reported her difficulties in completing tasks each one of us normally accomplishes without even thinking about it, such as choosing what to buy in a grocery store or getting dressed. In fact, this patient described how her left and right hand were competing with each other, each one of them trying to decide on its own what to do: she consciously wanted to buy something, reached it with her right hand to put it in the trolley, whilst the left hand put it back where it was on the shelf. Similarly, her left and right hands also choose different dresses to wear, and she often found herself wearing two or three outfits at once, before throwing everything on the bed and start to get dressed again. Another patient had difficulties in getting dressed too, with his hands not agreeing on what to do: one hand would button his shirt, the other would unbutton it. Another one, tried to strike his wife with his left hand, while the right hand grabbed the left to stop it. Although curious and fascinating, these disorders are quite rare among split brain patients, and tend to disappear with time.

Nonetheless, split brain patients have been very important for neuroscience. When tested in experimental settings, in fact, they appear to have two separate consciousnesses; in addition, they helped to prove that the two hemispheres of the brain have different specialisations. To understand the results of the experiments we will describe, it is important to have a general idea on how brain and body interact; the left part of our body is controlled by our right brain and vice versa. So, our right brain moves the muscles on the left and the left brain moves the muscles on the right; in the same way, sensitive information from the left part of our body are processed by the right brain and those from the right part are processed by the left brain. Our brain usually unifies the information it receives through the connections via the corpus callosum. However, in split brain patients this can’t happen, and the information processed in one hemisphere can’t be shared with the other one. So how do split brain patients perform in artificial settings able to stimulate only one hemisphere at a time?

The two main types of experiments performed on split brain patients are visual and tactile. In visual experiments, patients are presented with a series of visual stimuli in the left or in the right visual field (so that they couldn’t see them with both eyes) and are asked to ring a bell when they see a stimulus. All patients report correctly the fact that a stimulus is presented, however they can verbalise what they saw only when the stimulus is presented in the right visual field (and therefore processed by the left side of the brain). When the stimulus is presented in the left visual field, the patients simply respond that they didn’t see anything, despite the fact that they correctly rang the bell. When asked to choose a random object among others, however, they always choose the one correspondent to the stimulus presented (but without consciously knowing the reason), or, in the same way, they are able to draw it. It is to notice that both the choice of the object and the drawing have to be performed with the left hand. In fact, we can say that the right hand doesn’t know what the patient saw: the stimulus was presented to the left eye, the information processed in the right brain, and the right brain controls the left muscles of the body, that can activate to produce the according behaviour (pointing or drawing).

split

(from:Split brain: a tale of two halves. http://www.nature.com)

Similarly, in tactile experiments the patients hold an object with one hand without being able to see it. When the hand touching the object is the right one, patients can easily name what it is. On the contrary, when they touch the object with their left hand, the patients can’t say what is that they are touching. At the same time, however, they can choose with the left hand the object correspondent to the one they were touching among other distractive stimuli. These experiments importantly helped to prove that the left hemisphere is dominant for language and speech. Furthermore, they also point out another intriguing fact: although the two hemispheres behave independently and don’t communicate with each other, the patients don’t lose their unified sense of self. To explain this phenomenon, Gazzaniga (the pioneer investigator of split brain together with Perry) formulated the “interpreter theory”. When asked to explain with words actions performed by the left part of the body, split brain patients make up stories to justify their behaviour. In one example, the word “smile” was presented to the right hemisphere of a patient, and the word “face” was presented to the left hemisphere. When asked to draw what he saw, the patient drew a smiley face; asked why he drew that, the patient responded that nobody likes to see a sad face. Another time, the picture of a naked man was presented to the right hemisphere of a patient. The patient (who was a girl) started to laugh but she couldn’t explain why; she then said she was probably laughing because of the machine that projected the images. Even more significant for this theory are the results from a slightly more complex experiment. Two different pictures were projected at the same time, one to the left brain, the other to the right. The patient then has to point at the picture that has a connection with what they saw on the screen. In one of these experiments, the image of a winter scene was projected to the right hemisphere, while a chicken’s foot was presented to the left one. When asked to choose a picture, the left hand correctly chose a snow shovel, whilst the right hand correctly chose a chicken. But when the patient was asked about the reason his left hand was pointing at a shovel, he answered that the shovel is used to clean the chicken’s house. In other worlds, his left hemisphere, which didn’t have any access to what the right one had seen, observed what the left hand was doing and then tried to interpret that behaviour according to the information that it had. These experiments showed that the left brain is the interpreter and narrator of reality, what people use to order the information we receive and create narratives that give order and meaning to the word.

For more informations: https://www.youtube.com/watch?v=aCv4K5aStdU