Cheese, dreams and drugs

A common belief says that eating cheese causes vivid dreams or nightmares. However, I couldn’t find any support for the idea in the scientific literature except for one bizarre case study.

Although the case report really tells us nothing about the link between cheese and dreaming, it’s lovely to read because it’s from a bygone day where doctors could write into medical journals with their strange and idiosyncratic observations.

From a 1964 edition of the British Medical Journal:

I have lately seen a patient with moderate essential hypertension who because of various side-effects with other drugs was changed to pargyline, 25 mg every morning; this gave satisfactory control and within a fortnight the patient volunteered that he felt much less depressed, but was having nightmares.

Inquiry produced the fact that he habitually ate one or two ounces (30-60 g) of Cheddar cheese with his supper every evening. The nightmares were of a horrifying nature, and curiously they were concerned not with his immediate family or friends but with people such as his workmates, with whom he was not in any particular emotional relationship. He dreamt of one, terribly mutilated, hanging from a meat-hook. Another he dreamt of falling into a bottomless abyss. When cheese was withdrawn from his diet the nightmares ceased.

I am, etc. J. CHARLES SHEE, Bulawayo, S. Rhodesia.

The mentioned drug, pargyline, as well as being used for hypertension is in the same class of drugs more commonly used as antidepressants.

These are monoamine oxidase B inhibitors (MAOIs) which prevent the breakdown of the monoamine neurotransmitters serotonin, epinephrine and norepinephrine. However, they also prevent the breakdown of the chemical tyramine which occurs naturally in some foods, such as cheese, some soy bean products, processed meats and some fruit and nuts.

A build up of tyramine can cause an increase in blood pressure which can cause headaches, heart problems and increases the chance of stroke (blood vessel blockage or bleeds in the brain). Hence, people taking MAOI antidepressants have to avoid foods high in tyramine to prevent these potentially lethal side-effects.

Interestingly, the fact that the UK Prime Minister, Gordon Brown, was apparently avoiding similar foods led to internet rumours that he was on these antidepressants, which caused a media flap when the BBC questioned him about his mental health and use of “pills” to “get through”.

Link to PubMed entry for case study with full text option.

Inhabiting a robot hand

BBC News has a fascinating short video report of a robotic hand that is connected to the nerve fibres of an amputated arm and which allows the patient to actually feel touches with the robot fingers.

Although it doesn’t mention it in the report, the technology is from the SmartHand research group who are attempting to use knowledge about the cognitive neuroscience of action and body sensation to make fully integrated naturally controlled prosthetics.

There’s an interesting part of the video where the patient says “When I grab something tightly I can feel it in the finger tips, which is strange because I don’t have them anymore”.

In other words, despite the fact that the robot hand feeds touch information into the nerve fibres into the arm stump, the patient feels the sensations ‘in’ the robot fingers.

This is essentially the ‘rubber hand illusion‘ and the same research group demonstrated exactly this in a recent experiment where they induced touch sensations in a robot hand by stroking it and the stump simultaneously.

This is interesting because a recent study found that sensations in people with intact arms only transferred to a realistic looking rubber hand and not a wooden one, whereas this research team uses a obviously false robot limb.

The fact that touches transfer to an obviously false hand for someone with an amputation but not for people with intact limbs is interesting, because it suggests that brain’s remaining body-image ‘maps’ for the amputated hand may be being recruited to enhance the illusion.

Link to BBC News video report “New robotic hand ‘can feel'”.
Link to SmartHand project.

Hallucinations in sensory deprivation after 15 minutes

Photo by Flickr user Matthew McVickarSensory deprivation lasting only 15 minutes is enough to trigger hallucinations in healthy members of the public, according to a new study published in the Journal of Nervous and Mental Disease.

The researchers were interested in resurrecting the somewhat uncontrolled research done in the 50s and 60s where participants were dunked into dark, silent, body temperature float tanks where they subsequently reported various unusual perceptions.

In this study the researchers screening a large number of healthy participants using a questionnaire that asks about hallucinatory experiences in everyday life. On the basis of this, they recruited two groups: one of ‘high’ hallucinators and another of ‘low’ hallucinators.

They then put the participants, one by one, in a dark anechoic chamber which shields all incoming sounds and deadens any noise made by the participant. The room had a ‘panic button’ to stop the experiment but apparently no-one needed to use it.

They asked participants to sit in the chamber for 15 minutes and then, immediately after, used a standard assessment to see whether they’d had an unusual experiences.

After a twenty minute break, they were asked again about perceptual distortions to see if there were any difference when normal sensation was restored.

Hallucinations, paranoid thoughts and low mood were reported more often after sensory deprivation for both groups but, interestingly, people already who had a tendency to have hallucinations in everyday life had a much greater level of perceptual distortion after leaving the chamber than the others.

This study complements research published in 2004 that found that visual hallucinations could be induced in healthy participants just by getting them to wear a blindfold for 96 hours.

However, my attention was grabbed by the researchers use of a ‘panic button’. The effect of having a panic button in sensory deprivation experiments was specifically studied in 1964 by psychologists Martin Orne and Karl Scheibe. They also asked about hallucinations and compared two groups of people.

One group was met by researchers in white coats, given a medical examination and told to press a ‘panic button’ if they wanted out. The other was met by researchers in causal clothes, weren’t given medical checks, and told to knock on the window if they wanted the experiment to stop.

The actual sensory deprivation part was the same, but the group with the panic button reported many more hallucinations, likely owing to ‘demand characteristics’, or, in other words, their expectations of what might happen.

We also know that an increase in anxiety also increases the likelihood of hallucinations, and having a ‘panic button’ during an experiment, I suspect, is likely put most people a little more on edge.

So we can’t be sure that the effect was purely due to sensory deprivation, but it does chime with various other studies showing that when we reduce our normal sensations, the brain has a tendency to ‘fill in’ with hallucinations.

Link to PubMed entry for sensory deprivation study.

How many shrinks does it take to change a diagnosis?

With debates still raging over the new version of the psychiatrists’ diagnostic manual, the DSM-V, a selection of radical new diagnoses have been submitted which may give the committee pause for thought.

They have been carefully reviewed by Matthew Hutson over at Psychology Today and we include a couple so you can see how this paradigm shift in medical thinking may affect future practice:

Napoleon Complex

Antecedents: Being short, male; having a French accent.

Symptoms: Power-seeking. Attempting to compensate for small stature through aggression, tall hats.

Notes: Despite widespread misconception, Napoleon Bonaparte of France was of average height for his time. He was actually compensating for almost imperceivably asymmetrical nostrils.

Neapolitan Complex (also known as Tripolar Disorder)

Antecedents: Being Italian; nearly drowning in a vat of frozen dairy dessert.

Symptoms: Having a light side, a dark side, and a sickeningly rosy side. Wanting to be everything to everyone. Chronic brain freeze.

There’s plenty more in the full piece but on a more serious note, a short article in Psychiatric News reflects on one psychiatrist’s attempt to communicate with the DSM-V committee while finding that actually, much of it has already been decided.

Link to humorous diagnostic suggestions at Psychology Today.
Link to Psychiatric Times piece on ‘the DSM process’.

Around the brain in forty years

The latest edition of the Journal of Neuroscience has a fantastic collection of articles by leading neuroscientists who look back on the last 40 years of discoveries in brain research.

The collection is to celebrate the 40th anniversary of the Society for Neuroscience. As the articles make clear, the last four decades have seen a huge expansion in our knowledge of how the brain works and the Society asked leading lights in the field to reflect on this scientific revolution.

Memory and Brain Systems: 1969–2009 by Larry R. Squire [link]

Neurotransmitters, Receptors, and Second Messengers Galore in 40 Years by Solomon H. Snyder [link]

Four Decades of Neurodegenerative Disease Research: How Far We Have Come! by Anne B. Young [link]

A Paradigm Shift in Functional Brain Imaging by Marcus E. Raichle [link]

The Development of Developmental Neuroscience by Carol Mason [link]

The Biology of Memory: A Forty-Year Perspective by Eric R. Kandel [link]

Strictly speaking, they’re not all retrospectives. For example, while Larry Squire gives a whistle-stop tour through the last 40 years of the cognitive neuroscience of memory (and you’ll probably not read a better brief article in this area), Marcus Raichle takes the opportunity to look forward and is clearly enthusiastic about the ‘default network‘ which he is co-credited with discovering.

They’re all academic articles, so are not the most accessible if you’re not familiar with the scientific literature, but as brief guides to some of the major areas of neuroscience they’re fantastic and freely available online.

Science of slumber

Science News has a brilliant special issue on the ‘science of slumber’ that tackles sleep disorders, the mental impact of sleep deprivation, how sleep differs across species and the still mysterious question of why we need to sleep.

I found the article on two seemingly straightforward sleep disorders, insomnia and narcolepsy, the most interesting. They seem straightforward because they appear as a lack and an excess of sleep, but as the piece makes clear, they are still quite mysterious.

Insomnia is particularly interesting because having trouble sleeping happens to everyone at some point, so in itself, it’s not abnormal – meaning that research into what triggers it is unlikely to find anything striking.

Instead research has shifted to try and understand what prevents insomnia from resolving naturally so it becomes a chronic condition:

Sleeplessness may be brought on by traumatic events such as a death in the family, an illness such as cancer or anything else distressing, causing a person to lie awake at night with a racing mind. For a subset of people, though, insomnia has no prompting signal — a condition called primary insomnia.

Regardless of the trigger (or lack thereof), temporary insomnia has a nasty way of becoming a habit. Poor sleep habits can become ingrained. When trouble sleeping persists for three or four nights a week over several months, insomnia is considered chronic.

It may turn out that untangling the prompting signals of insomnia, as many sleep researchers attempt, is a fool’s errand, says Michael Perlis, director of the University of Pennsylvania’s Behavioral Sleep Medicine Program in Philadelphia. “The whole zeitgeist has changed,” he says. Most sleep researchers now agree that “once insomnia goes chronic, it stays that way,” regardless of the prompting signal, Perlis says. So rather than focusing on the immediate trigger for insomnia, many scientists are trying to figure out why it becomes chronic and how to prevent that from happening.

I also liked the short piece that briefly compares the amount of type of sleep between lots of different animals. It seems dolphins don’t have REM sleep. I wonder if that means that they lack or have very limited dreams?

Anyway, a great collection of articles and all freely available online.

Link to SciNews ‘Science of Slumber’ collection.

Neuroanthropology, a rough guide

There’s a comprehensive and compelling introduction to neuroanthropology over at the blog of the same name that outlines why we can’t fully understand the brain or culture while thinking of them as separate entities.

The Neuroanthropology blog is run by two of the main researchers in the field and this recent article was written to launch their recent conference ‘The Encultured Brain’.

The article is in-depth but accessible and clearly lays out the main ideas in the field, looking at the benefits to both brain science and cultural studies in a combined approach and noting where narrow thinking has dimmed our view of human nature.

The potential gains are enormous: a robust account of brains in the wild, an understanding of how we come to possess our distinctive capacities and the degree to which these might be malleable across our entire species. The applications of this sort of research are myriad in diverse areas such as education, cross-cultural communication, developmental psychology, design, therapy, and information technology, to name just a few. But the first step is the one taken here – by coming together, we can achieve significant advances in understanding how our very humanity relies on the intricate interplay of brain and culture.

Link to ‘Why Neuroanthropology? Why Now?’