Breaking news from the BBC -Testosterone link to aggression 'all in the mind' Work in Nature magazine suggests the mind can win over hormones... Testosterone induces anti-social behaviour in humans, but only because of our own prejudices about its effect rather than its biological activity, suggest the authors. The researchers, led by Ernst Fehr of the University of Zurich, Switzerland, said the results suggested a case of "mind over matter" with the brain overriding body chemistry. "Whe........ Read more »
Eisenegger, C., Naef, M., Snozzi, R., Heinrichs, M., & Fehr, E. (2009) Prejudice and truth about the effect of testosterone on human bargaining behaviour. Nature. DOI: 10.1038/nature08711
When you drink alcohol and get drunk, are you getting drunk on alcohol?Well, obviously, you might think, and so did I. But it turns out that some people claim that the alcohol (ethanol) in drinks isn't the only thing responsible for their effects - they say that acetaldehyde may be important, perhaps even more so.South Korean researchers Kim et al report that it's acetaldehyde, rather than ethanol, which explains alcohol's immediate effects on cognitive and motor skills. During the metabolism of........ Read more »
Kim SW, Bae KY, Shin HY, Kim JM, Shin IS, Youn T, Kim J, Kim JK, & Yoon JS. (2009) The Role of Acetaldehyde in Human Psychomotor Function: A Double-Blind Placebo-Controlled Crossover Study. Biological psychiatry. PMID: 19914598
Brain maturation continues for longer than previously thought - well up until age 30. That's according to two papers just out, which may be comforting for those lamenting the fact that they're nearing the big Three Oh.This challenges the widespread view that maturation is essentially complete by the end of adolescence, in the early to mid 20s.Petanjek et al show that the number of dendritic spines in the prefrontal cortex increases during childhood and then rapidly falls during puberty - which p........ Read more »
Lebel C, & Beaulieu C. (2011) Longitudinal development of human brain wiring continues from childhood into adulthood. The Journal of neuroscience : the official journal of the Society for Neuroscience, 31(30), 10937-47. PMID: 21795544
Petanjek, Z., Judas, M., Simic, G., Rasin, M., Uylings, H., Rakic, P., & Kostovic, I. (2011) Extraordinary neoteny of synaptic spines in the human prefrontal cortex. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.1105108108
A news feature in Nature asks whether placebo controls are always a good idea: Why Fake It?
The piece looks at experimental neurosurgical treatments for Parkinson's, such as "Spheramine". This consists of cultured human cells, which are implanted directly into the brain of the sufferer. The idea is that the cells will grow and help produce dopamine, which is deficient in Parkinson's.
Peggy Willocks, a 44 year old teacher, took part in a trial of the surgery in 2000. She says it helped stave of........ Read more »
Katsnelson, A. (2011) Experimental therapies for Parkinson's disease: Why fake it?. Nature, 476(7359), 142-144. DOI: 10.1038/476142a
Via Dormivigilia, I came across a fascinating paper about a man who suffered from a severe lack of monoamine neurotransmitters (dopamine, serotonin etc.) as a result of a genetic mutation: Sleep and Rhythm Consequences of a Genetically Induced Loss of SerotoninNeuroskeptic readers will be familiar with monoamines. They're psychiatrists' favourite neurotransmitters, and are hence very popular amongst psych drug manufacturers. In particular, it's widely believed that serotonin is the brain's "happ........ Read more »
Smaranda Leu-Semenescu et al. (2010) Sleep and Rhythm Consequences of a Genetically Induced Loss of Serotonin. Sleep, 33(03), 307-314. info:/
Neuroskeptic readers will know that I'm a big fan of theories. Rather than just poking around (or scanning) the brain under different conditions and seeing what happens, it's always better to have a testable hypothesis.I just found a 2007 paper by Israeli computational neuroscientists Niv et al that puts forward a very interesting theory about dopamine. Dopamine is a neurotransmitter, and dopamine cells are known to fire in phasic bursts - short volleys of spikes over millisecond timescales - in........ Read more »
Niv Y, Daw ND, Joel D, & Dayan P. (2007) Tonic dopamine: opportunity costs and the control of response vigor. Psychopharmacology, 191(3), 507-20. PMID: 17031711
Absinthe is a spirit. It's very strong, and very green. But is it something more?I used to think so, until I came across this paper taking a skeptical look at the history and science of the drink, Padosch et al's Absinthism a fictitious 19th century syndrome with present impactAbsinthe is prepared by crushing and dissolving the herb wormwood in unflavoured neutral alcohol and then distilling the result; other herbs and spices are added later for taste and colour.It became extremely popular in th........ Read more »
Padosch SA, Lachenmeier DW, & Kröner LU. (2006) Absinthism: a fictitious 19th century syndrome with present impact. Substance abuse treatment, prevention, and policy, 1(1), 14. PMID: 16722551
"It's pretty painless. Basically you just need to lie there and make sure you don't move your head".This is what I say to all the girls... who are taking part in my fMRI studies. Head movement is a big problem in fMRI. If your head moves, your brain moves and all fMRI analysis assumes that the brain is perfectly still. Although head movement correction is now a standard part of any analysis software, it's not perfect.It may be a particular problem in functional connectivity studies, which attemp........ Read more »
Van Dijk, K., Sabuncu, M., & Buckner, R. (2011) The Influence of Head Motion on Intrinsic Functional Connectivity MRI. NeuroImage. DOI: 10.1016/j.neuroimage.2011.07.044
According to a new paper in the prestigous journal PNAS, High-field MRI reveals an acute impact on brain function in survivors of the magnitude 8.0 earthquake in China.The earthquake, you'll remember, happened on 12th May last year in central China. Over 60,000 people died. The authors of this paper took 44 earthquake survivors, and 32 control volunteers who had not experienced the disaster.The volunteers underwent a "resting state" fMRI scan; survivors were scanned between 13 and 25 days after ........ Read more »
Lui, S., Huang, X., Chen, L., Tang, H., Zhang, T., Li, X., Li, D., Kuang, W., Chan, R., Mechelli, A.... (2009) High-field MRI reveals an acute impact on brain function in survivors of the magnitude 8.0 earthquake in China. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.0812751106
When you smoke pot, you get stoned.Simple. But it's not really, because stoned can involve many different effects, depending upon the user's mental state, the situation, the variety and strength of the marijuana, and so forth. It can be pleasurable, or unpleasant. It can lead to relaxed contentment, or anxiety and panic. And it can feature hallucinations and alterations of thinking, some of which resemble psychotic symptoms.In Central nervous system effects of haloperidol on THC in healthy male ........ Read more »
Liem-Moolenaar, M., Te Beek, E., de Kam, M., Franson, K., Kahn, R., Hijman, R., Touw, D., & van Gerven, J. (2010) Central nervous system effects of haloperidol on THC in healthy male volunteers. Journal of Psychopharmacology. DOI: 10.1177/0269881109358200
A couple of months ago I pointed out that a Letter published in the American Journal of Psychiatry, critiquing a certain paper about antidepressants, made very similar points to the ones that I did in my blog post about the paper. The biggest difference was that my post came out 9 months sooner.Well, it's happened again. Except I was only 3 months ahead this time. Remember my post Clever New Scheme, criticizing a study which claimed to have found a brilliant way of deciding which antidepressan........ Read more »
Tsai AC. (2010) Unclear clinical significance of findings on the use of referenced-EEG-guided pharmacotherapy. Journal of psychiatric research. PMID: 20943234
A few months ago, I asked Why Do We Sleep?That post was about sleep researcher Jerry Siegel, who argues that sleep evolved as a state of "adaptive inactivity". According to this idea, animals sleep because otherwise we'd always be active, and constant activity is a waste of energy. Sleeping for a proportion of the time conserves calories, and also keeps us safe from nocturnal predators etc.Siegel's theory in what we might call minimalist. That's in contrast to other hypotheses which claim that s........ Read more »
Hobson JA, & McCarley RW. (1977) The brain as a dream state generator: an activation-synthesis hypothesis of the dream process. The American journal of psychiatry, 134(12), 1335-48. PMID: 21570
Hobson, J. (2009) REM sleep and dreaming: towards a theory of protoconsciousness. Nature Reviews Neuroscience, 10(11), 803-813. DOI: 10.1038/nrn2716
Irving Kirsch, best known for that 2008 meta-analysis allegedly showing that "Prozac doesn't work", has hit the headlines again.This time it's a paper claiming that something does work. Actually Kirsch is only a minor author on the paper by Kaptchuck et al: Placebos without Deception.In essence, they asked whether a placebo treatment - a dummy pill with no active ingredients - works even if you know that it's a placebo. Conventional wisdom would say no, because the placebo effect is driven by th........ Read more »
Kaptchuk, T., Friedlander, E., Kelley, J., Sanchez, M., Kokkotou, E., Singer, J., Kowalczykowski, M., Miller, F., Kirsch, I., & Lembo, A. (2010) Placebos without Deception: A Randomized Controlled Trial in Irritable Bowel Syndrome. PLoS ONE, 5(12). DOI: 10.1371/journal.pone.0015591
Wouldn't it be cool if you could measure brain activation with fMRI... right as it happens?You could lie there in the scanner and watch your brain light up. Then you could watch your brain light up some more in response to seeing your brain light up, and watch it light up even more upon seeing your brain light up in response to seeing itself light up... like putting your brain between two mirrors and getting an infinite tunnel of activations.Ok, that would probably get boring, eventually. But th........ Read more »
Hinds, O., Ghosh, S., Thompson, T., Yoo, J., Whitfield-Gabrieli, S., Triantafyllou, C., & Gabrieli, J. (2010) Computing moment to moment BOLD activation for real-time neurofeedback. NeuroImage. DOI: 10.1016/j.neuroimage.2010.07.060
In an unusual study with potentially revolutionary implications, Austrian biologists Wilkinson et al show evidence of Social learning in a non-social reptile.Social learning means learning to do something by observing others doing it, rather than by doing it yourself. Many sociable animal species, including mammals, birds and even insects, have shown the ability to learn by observing others doing things. It's often seen as a distinct form of cognition, separate to "normal" learning, which evolve........ Read more »
Wilkinson, A., Kuenstner, K., Mueller, J., & Huber, L. (2010) Social learning in a non-social reptile (Geochelone carbonaria). Biology Letters. DOI: 10.1098/rsbl.2010.0092
Deep-brain stimulation (DBS) is probably the most exciting emerging treatment in psychiatry. DBS is the use of high-frequency electrical current to alter the function of specific areas of the brain. Originally developed for Parkinson's disease, over the past five years DBS has been used experimentally in severe clinical depression, OCD, Tourette's syndrome, alcoholism, and more.Reports of the effects have frequently been remarkable, but there have been few scientifically rigorous studies, and th........ Read more »
Hamani, C., Diwan, M., Macedo, C., Brandão, M., Shumake, J., Gonzalez-Lima, F., Raymond, R., Lozano, A., Fletcher, P., & Nobrega, J. (2009) Antidepressant-Like Effects of Medial Prefrontal Cortex Deep Brain Stimulation in Rats. Biological Psychiatry. DOI: 10.1016/j.biopsych.2009.08.025
Is there a gene for long life?Boston-based group Sebastiani et al say they've found not one but two, in RNA Editing Genes Associated with Extreme Old Age in Humans and with Lifespan in C. elegans.They took 4 groups of "oldest old" people: from New England, Italy, and Japan, and American Ashkenazi Jews. All were aged 90 or more, and many of them were 100, centenarians. As control groups, they used random healthy people who weren't especially old. The total sample size was an impressive 2105 old v........ Read more »
Sebastiani P, Montano M, Puca A, Solovieff N, Kojima T, Wang MC, Melista E, Meltzer M, Fischer SE, Andersen S.... (2009) RNA editing genes associated with extreme old age in humans and with lifespan in C. elegans. PloS one, 4(12). PMID: 20011587
It's a cliché, but it's true - "schizophrenia genes" are the Holy Grail of modern psychiatry.Were they to be discovered, such genes would provide clues towards a better understanding of the biology of the disease, and that could lead directly to the development of better medications. It might also allow "genetic counselling" for parents concerned about their children's risk of schizophrenia.Perhaps most importantly for psychiatrists, the definitive identification of genes for a mental illness w........ Read more »
Purcell, S., & et Al. (2009) Common polygenic variation contributes to risk of schizophrenia and bipolar disorder. Nature. DOI: 10.1038/nature08185
Shi, J., & et Al. (2009) Common variants on chromosome 6p22.1 are associated with schizophrenia. Nature. DOI: 10.1038/nature08192
Schizophrenia is generally thought of as the "most genetic" of all psychiatric disorders and in the past 10 years there have been heroic efforts to find the genes responsible for it, with not much success so far.A new study reminds us that there's more to it than genes alone: Social Risk or Genetic Liability for Psychosis? The authors decided to look at adopted children, because this is one of the best ways of disentangling genes and environment.If you find that the children of people with schiz........ Read more »
Wicks S, Hjern A, & Dalman C. (2010) Social Risk or Genetic Liability for Psychosis? A Study of Children Born in Sweden and Reared by Adoptive Parents. The American journal of psychiatry. PMID: 20686186
It's always nice when a local boy makes good in the big wide world. Many British neuroscientists and psychiatrists have been feeling rather proud this week following the enormous amount of attention given to Professor David Nutt, formerly the British government's chief adviser on illegal drugs.Formerly being the key word. Nutt was sacked (...write your own "nutsack" pun if you must) last Friday, prompting a remarkable amount of condemnation. Critics included the rest of his former organisation, ........ Read more »
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