Mind Hacks

An interesting case study from a 2002 edition of The Lancet of a man who suffered paralysis from drinking too much Earl Grey tea owing to the toxic effects of huge doses of bergamot oil – taken from orange rind and used as flavour:

A 44-year-old man presented in May, 2001, with muscle cramps. He had no medical history of note, but volunteered the fact that he had been drinking up to 4 L of black tea per day over the past 25 years. His preferred brand was GoldTeefix (Tekanne, Salzburg, Austria). Since this type of tea had given him occasional gastric pain, he changed to Earl Grey (Twinings & Company, London, UK), which he thought would be less harmful to his stomach. 1 week after the change, he noticed repeated muscle cramps for some seconds in his right foot. The longer he drank Earl Grey tea, the more intense the muscle cramps became. After 3 weeks, they also occurred in the left foot…

Earl Grey tea is composed of black tea and the essence of bergamot oil, an extract from the rind of bergamot orange (Citrus aurantium ssp bergamia), which has a pleasant, refreshing scent. Bergamot oil contains bergapten (5-methoxypsoralen), bergamottin (5-geranyloxypsoralen), and citropten (5,7-dimethoxycoumarin), which can be found in grapefruit juice, celery, parsnips, and Seville orange juice. Bergamot oil is a well-known UVA-induced photosensitiser with a strong phototoxic effect, and is used therapeutically in psoriasis, vitiligo, mycosis fungoides, and cutaneous lymphoma. Because of this side-effect, bergamot oil has been widely banned as an ingredient in cosmetics and tanning products. Bergamot oil also has a hepatotoxic effect and may cause contact-allergy. The adverse effects of bergamot oil in this patient are explained by the effect of bergapten as a largely selective axolemmal potassium channel blocker, reducing potassium permeability at the nodes of Ranvier in a time-dependent manner. This may lead to hyperexcitability of the axonal membrane and phasic alterations of potassium currents, causing fasciculations and muscle cramps.

In other words, it disrupts the way chemical flow through the membrane of the nerve fibre, causing the neurons that connect to the muscles to malfunction.

Link to DOI entry for the case study.

Not Exactly Rocket Science covers a fantastic study on how the structure of the brain changes as illiterate adults learn to read and write. The research was conducted on rather a novel group of participants. Most were ex-members of guerilla forces in Colombia that had recently put down their weapons to re-integrate in society.

Colombia has a sizeable program to rehabilitate ex-paramilitary ‘reinsertados’ that includes social support and education, as many have never attended school. As the researchers note, this sets up an interesting natural experiment:

After decades spent fighting, members of the guerrilla forces have begun re-integrating into mainstream Colombian society, introducing a sizeable population of illiterate adults who have no formal education. Upon putting down their weapons and returning to society, some had the opportunity to learn to read for the first time in their early twenties, providing the perfect natural situation for experiments investigating structural brain differences associated with the acquisition of literacy in the absence of other types of schooling or maturational development.

The researchers, led by neuroscientist Manuel Carreiras, recruited a group of ex-paramilitaries who could read less than five simple words on a Spanish reading and writing test, and compared them to a similar group who learnt to read and write from an early age.

The research team use MRI scans to compare differences in brain structure between the two groups to allow an insight into how brain anatomy changes to accommodate reading and writing.

While it is possible to do this with children, it is almost impossible to separate out which are the brain changes due specifically to acquiring literacy and which are just part of the massive changes that constantly take place as children develop.

The images above show the areas of the brain (in orange) where the structure was significantly different between literate and illiterate adults.

Rather neatly, these are also areas that have been identified in brain activation studies of reading and writing, and are known to be associated with visual perception, processing word sounds and dealing with the meaning of words.

Subsequent analyses showed that pathways the angular gyrus, a key language area, across each hemisphere were less developed in illiterate adults and were less active when the participants were asked to name objects.

A brilliantly innovative study, a good write-up from Not Exactly Rocket Science and perfectly timed for my arrival in Colombia.

Link to NERS on guerilla reading.
Link to summary of scientific paper.

There are a couple of excellent posts on Neurophilosophy covering recent studies that demonstrate the powerful effect of vision on the perception of physical sensations in our body.

The first covers an interesting study that found that looking directly at your hand reduces laser-induced pain compared to a condition where you are only looking at a visual substitute created with a mirror reflection of the other hand (akin to a mirror box set up).

The second post discusses the possibilities of taking advantage of the ‘rubber hand illusion‘ to allow us to feel like we’re physically inhabiting virtual bodies.

Numerous experiments have shown that we look at a rubber hand being touched simultaneously and in the same way as our real hand, the sensation seems to be located in the fake.

This new experiment attempted something similar but in virtual reality, demonstrating that a synchronised ‘touch’ could be perceived as arising from an avatar hand in a 3D computer generated environment.

While the same research team had demonstrated this effect before this new study showed how the effect could transfer, albeit more weakly, to a virtual arm controlled by a brain-computer interface driven solely from EEG readings.

Both of these studies demonstrate how vision is integrated with tactile information from the body to create our sense of body image, ownership and sensation and both get a great write-up from Neurophilosophy.

Link to Neurophilosophy post visual pain reduction.
Link to Neurophilosophy on the ‘virtual hand illusion’.

New Scientist has a fantastic issue on ‘strange journeys of the mind’ that has three great articles on the twilight zone of sleep, simulating psychopathology with hypnosis and laboratory-induced out-of-body experiences.

The piece on the hypnotic simulation of brain disturbances is fantastic, not least because it features two researchers I work with, Peter Halligan and David Oakley, who have done some of the seminal work in the area.

Essentially, the approach views hypnosis as a tool that allows researchers, with the co-operation of the participant, to temporarily alter mental states in a completely safe and reversible way.

Importantly, these alterations, such as blindness or paralysis, seem like they’re happening ‘on their own’ – which helps us understand conditions like conversion disorder, where these sorts of symptoms appear without any neurological damage but without the patient seeming to have any control over them.

The other article which blew me away was on recent studies suggesting that sleep and alertness are not two distinct states of consciousness and in some people with a dementia-like brain disorder the boundaries between sleep and wakefulness completely break down.

That this can happen contradicts the way we usually think about sleep, but it came as no surprise to Mark Mahowald, medical director of the Minnesota Regional Sleep Disorders Center in Minneapolis, who has long contested the dogma that sleep and wakefulness are discrete and distinct states. “There is now overwhelming evidence that the primary states of being are not mutually exclusive,” he says. The blurring of sleep and wakefulness is very clear in status dissociatus, but he believes it can happen to us all. If he is right, we will have to rethink our understanding of what sleep is and what it is for. Maybe wakefulness is not the all-or-nothing phenomenon we thought it was either.

Finally, the piece on out of body experiences covers the work of Swiss researchers who have been studying these states in people with brain disorder, and managing to induce them in volunteers in a number of inventive ways.

Three awesome articles, all worth your time, all open-access. Three cheers New Scientist.

Link to article on sleep states.
Link to article on hypnotic simulations.
Link to article on out-of-body experiences.

In what sounds like a plot from an animated sci-fi film, I’ve just found a remarkable study where Japanese researchers put a Yoga Master in a brain scanner and fired lasers at him because he claimed not to be able to feel pain while meditating.

It turns out that he showed significantly less brain activity in areas typically activated by pain when meditating.

Intracerebral pain processing in a Yoga Master who claims not to feel pain during meditation.

Eur J Pain. 2005 Oct;9(5):581-9.

Kakigi R, Nakata H, Inui K, Hiroe N, Nagata O, Honda M, Tanaka S, Sadato N, Kawakami M.

We recorded magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) following noxious laser stimulation in a Yoga Master who claims not to feel pain when meditating. As for background MEG activity, the power of alpha frequency bands peaking at around 10 Hz was much increased during meditation over occipital, parietal and temporal regions, when compared with the non-meditative state, which might mean the subject was very relaxed, though he did not fall asleep, during meditation.

Primary pain-related cortical activities recorded from primary (SI) and secondary somatosensory cortices (SII) by MEG were very weak or absent during meditation. As for fMRI recording, there were remarkable changes in levels of activity in the thalamus, SII-insula (mainly the insula) and cingulate cortex between meditation and non-meditation. Activities in all three regions were increased during non-meditation, similar to results in normal subjects. In contrast, activities in all three regions were weaker during meditation, and the level was lower than the baseline in the thalamus.

Recent neuroimaging and electrophysiological studies have clarified that the emotional aspect of pain perception mainly involves the insula and cingulate cortex. Though we cannot clearly explain this unusual condition in the Yoga Master, a change of multiple regions relating to pain perception could be responsible, since pain is a complex sensory and emotional experience.

I have an image of scientists shielding their eyes as lasers fail to penetrate the force field of the Yoga Master who serenely hovers a few inches above the ground, although I suspect that’s because I’ve read too many manga comics

Link to PubMed entry for study,