Ancient hallucinogenic ayahuasca ceremony

national_geographic_ayahuasca.jpgNational Geographic sent a reporter to take part in an ancient Peruvian shamanic ritual where the hallucinogenic plant ayahuasca is used.

The article describes the reporter’s account of what sounds like a profound and terrifying experience, and discusses the culture, traditions and interest from Western science that ayahuasca has inspired.

The taking of ayahuasca has been associated with a long list of documented cures: the disappearance of everything from metastasized colorectal cancer to cocaine addiction, even after just a ceremony or two. It’s thought to be nonaddictive and safe to ingest. Yet Western scientists have all but ignored it for decades, reluctant to risk their careers by researching a substance containing the outlawed DMT. Only in the past decade, and then only by a handful of researchers, has ayahuasca begun to be studied.

At the vanguard of this research is Charles Grob, M.D., a professor of psychiatry and pediatrics at UCLA’s School of Medicine. In 1993 Dr. Grob launched the Hoasca Project, the first in-depth study of the physical and psychological effects of ayahuasca on humans. His team went to Brazil, where the plant mixture can be taken legally, to study members of a native church, the Uni√£o do Vegetal (UDV), who use ayahuasca as a sacrament, and compared them to a control group that had never ingested the substance. The studies found that all the ayahuasca-using UDV members had experienced remission without recurrence of their addictions, depression, or anxiety disorders. In addition, blood samples revealed a startling discovery: Ayahuasca seems to give users a greater sensitivity to serotonin‚Äîone of the mood-regulating chemicals produced by the body‚Äîby increasing the number of serotonin receptors on nerve cells.

Link to article ‘Peru: Hell and Back’ with video clip (via MeFi)
Link to excellent Wikipedia page on ayahuasca.

Deep thoughts

NathW_LookUp.jpgI just found a couple of Flickr groups that have caught my imagination. The first is the ‘Brains‘ group for “fans of neuroscience, cognitive science, and other studies of how the mind and brain work”, and the second is ‘Deep Thoughts‘ which has some beautiful portraits of pensive people.

The Brains group is not without its striking images though, including this photo of ‘the apical tufts of 2 cortical layer V pyramidal cells’.

By combining the groups you can move from the level of biological action of the brain to the moment of intellectual discovery revealed on the face of the thinker.

Link to Flickr ‘Brains’ group.
Link to Flickr ‘Deep Thoughts’ group.

Illusions of taste

A curious comment just added to the discussion page of Wikipedia’s illusion entry has really got me thinking:

the beginning of the article claims that all human senses can be fooled. I’ve yet to expirence an illusion of taste/smell. i.e. something salty tasting sweet. it may follow that consumption is the ‘truest’ of human expirences… [sic] Andrew

The only example that I could find on PubMed suggests that we experience taste in areas of the mouth without taste receptors, because we are fooled by the touch sensations of the food in our mouths. I could find no similar ‘smell illusions’.

If anyone knows of any examples of taste or smell illusions I’d be very interested to hear about them.

UPDATE: There’s some great answers on the comments page. Keep ’em coming. Thanks!

Sleeping pill wakes brain-injured from coma-like state?

flat_pills.jpgControversial findings were recently published in the journal Neurorehabilitation suggesting that the insomnia drug zolpidem roused three severely brain-injured patients from the coma-like persistent vegetative state (PVS).

Zolpidem is better known by its trade name Ambien, and has also been in the news recently for causing unusual sleep behaviour such as sleep-driving.

The study published by Drs Ralf Clauss and Wally Nel reported on three patients diagnosed as being in PVS. All three were temporarily but reliably roused after being given the drug each morning over a period of 3 to 6 years.

It has been suggested, however, that the patients may not have genuinely been in PVS, as this state is thought to be misdiagnosed in up to 40% of cases.

Even if these patients were misdiagnosed, the results would still be interesting for those hoping to find an effective treatment for people who have chronic problems with arousal after brain-injury.

Furthermore, the fact that the treatment was consistent over such a long period is promising. Nevertheless, the drug will need to be tested in comprehensive clinical trials to show that the treatment is widely beneficial and the improvement in these patients was not due to person-specific factors.

Link to abstract of study.
Link to write-up from New Scientist.

2006-05-26 Spike activity

Quick links from the past week in mind and brain news:

spike.jpg

Mixing Memory looks at research on how much children believe from what they’re told.

Canine Epilepsy Guardian Angels! No really.

A strangely vague news story suggests that measuring ‘brainwaves’ (EEG / MEG?) explains how optical illusions trick the mind. More details gratefully received.

Smile! You’re on CogSci camera! Researcher aims to record every waking hour of his child’s first three years to study development of speech. More details at this pdf.

BPS Research Digest reports that the individual characteristics of therapists may have more influence on outcome than type of therapy.

Cognitive Daily reports on the immensely cool SNARC effect.

What would be the psychological strain of immortality?

Developing Intelligence picks up on a video lecture on the mathematics of visual hallucinations.

Japanese War Tuba Hack

Via badscience.net, the Japanese War Tuba Hack! (Or maybe we’ll call it “improve sound localisation by increasing interaural distance” or something).

Similarly the way your visual system calculates depth from the different images that your two eyes get, you use the difference in when sounds arrive at your ears to calculate their location. Bigger distance between the ears means bigger differences in arrival times, means more sensitivity in detecting sound location. How do you increase the distance between the ears? Ear horns! Don’t they look great?

itd_hack.jpg

More here and here

New brain scan detects ‘instant’ biological changes

LeBihan_diffusion_scan.jpgBrain Ethics have picked up on a new development in fMRI brain scanning technology that has the potential to detect fast changes in brain activity.

Research just published by neuroscientist Denis Le Bihan and his team has found that changes in brain activation can be detected by measuring water diffusion through neurons.

This type of water diffusion is thought to reflect the activity of the cells, but crucially, it seems it provides a more direct and quicker measure of brain activity than conventional methods.

The majority of fMRI studies use a measure of how oxygen-rich certain areas of the brain are, as it is well known that more active areas take more oxygen from the blood.

One disadvantage, is that this Brain Oxygen Level Dependent (BOLD) measure is relatively slow. It only seems to kick in 1-2 seconds after a brain area has been active and peaks up to 5 seconds later.

The new method from Le Bihan’s team has the potential to improve this process but there are still many unanswered questions, including exactly how the measure of water diffusion relates to the known activities of single neurons or synapses.

Link to ‘An fMRI revolution?’ from Brain Ethics.
Link to abstract of Le Bihan and colleagues’ study.