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- May 15, 2010
- 05:40 PM
- 740 views
Do It Like You Dopamine It
by Neuroskeptic in Neuroskeptic
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
- February 12, 2010
- 05:19 PM
- 739 views
Dope, Dope, Dopamine
by Neuroskeptic in Neuroskeptic
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
- March 8, 2010
- 03:45 PM
- 739 views
Life Without Serotonin
by Neuroskeptic in Neuroskeptic
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:/
- August 2, 2011
- 04:21 AM
- 738 views
The 30something Brain
by Neuroskeptic in Neuroskeptic
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
- September 1, 2011
- 03:06 AM
- 738 views
Men, Women and Spatial Intelligence
by Neuroskeptic in Neuroskeptic
Do men and women differ in their cognitive capacities? It's been a popular topic of conversation since as far back as we have records of what people were talking about.While it's now (almost) generally accepted that men and women are at most only very slightly different in average IQ, there are still a couple of lines of evidence in favor of a gender difference.First, there's the idea that men are more variable in their intelligence, so there are more very smart men, and also more very stupid on........ Read more »
Hoffman M, Gneezy U, & List JA. (2011) Nurture affects gender differences in spatial abilities. Proceedings of the National Academy of Sciences of the United States of America. PMID: 21876159
- March 20, 2010
- 03:00 PM
- 734 views
Absinthe Fact and Fiction
by Neuroskeptic in Neuroskeptic
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
- August 4, 2010
- 03:44 PM
- 732 views
Real Time fMRI
by Neuroskeptic in Neuroskeptic
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
- November 5, 2009
- 07:29 PM
- 723 views
The Politics of Psychopharmacology
by Neuroskeptic in Neuroskeptic
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 »
Nature. (2009) A drug-induced low. Nature, 462(7269), 11-12. DOI: 10.1038/462011b
Daniel Cressey. (2009) Sacked science adviser speaks out. Nature. info:/
- December 28, 2010
- 06:00 AM
- 723 views
When Is A Placebo Not A Placebo?
by Neuroskeptic in Neuroskeptic
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
- December 27, 2009
- 03:24 PM
- 721 views
The Genetics of Living To 100
by Neuroskeptic in Neuroskeptic
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
- July 27, 2011
- 03:27 AM
- 720 views
Brain Connectivity, Or Head Movement?
by Neuroskeptic in Neuroskeptic
"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
- April 7, 2010
- 08:48 AM
- 717 views
Why Do We Dream?
by Neuroskeptic in Neuroskeptic
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
- August 17, 2009
- 10:09 AM
- 716 views
Schizophrenia: The Mystery of the Missing Genes
by Neuroskeptic in Neuroskeptic
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
Stefansson, H., & et Al. (2009) Common variants conferring risk of schizophrenia. Nature. DOI: 10.1038/nature08186
- October 23, 2009
- 04:45 PM
- 714 views
Deep Brain Stimulation for Depressed Rats
by Neuroskeptic in Neuroskeptic
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
- October 20, 2010
- 05:38 AM
- 714 views
You Read It Here First...Again
by Neuroskeptic in Neuroskeptic
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
- August 9, 2010
- 01:33 PM
- 709 views
Zapping Memory Better in Alzheimer's
by Neuroskeptic in Neuroskeptic
Last month I wrote about how electrical stimulation of the hippocampus causes temporary amnesia - Zapping Memories Away.Now Toronto neurologists Laxton et al have tried to use deep brain stimulation (DBS) to improve memory in people with Alzheimer's disease. Progressive loss of memory is the best-known symptom of this disorder, and while some drugs are available, they provide partial relief at best.This study stems from a chance discovery by the same Toronto group. In 2008, they reported that st........ Read more »
Laxton AW, Tang-Wai DF, McAndrews MP, Zumsteg D, Wennberg R, Keren R, Wherrett J, Naglie G, Hamani C, Smith GS.... (2010) A phase I trial of deep brain stimulation of memory circuits in Alzheimer's disease. Annals of neurology. PMID: 20687206
- September 8, 2010
- 08:54 AM
- 706 views
Autistic Toddlers Like Screensavers
by Neuroskeptic in Neuroskeptic
Young children with autism prefer looking at geometric patterns over looking at other people. At least, some of them do. That's according to a new study - Preference for Geometric Patterns Early in Life As a Risk Factor for Autism.Pierce et al took 110 toddlers (age 14 to 42 months). Some of them had autism, some had "developmental delay" but not autism, and some were normally developing.The kids were shown a one-minute video clip. One half of the screen showed some kids doing yoga, while the ot........ Read more »
Pierce K, Conant D, Hazin R, Stoner R, & Desmond J. (2010) Preference for Geometric Patterns Early in Life As a Risk Factor for Autism. Archives of general psychiatry. PMID: 20819977
- October 29, 2009
- 04:12 PM
- 705 views
More Antidepressant Debates
by Neuroskeptic in Neuroskeptic
Six months ago, I asked What's The Best Antidepressant?, and I discussed a paper by Andrea Cipriani et al. The paper claimed that of the modern antidepressants, escitalopram (Lexapro) and sertraline (Zoloft) offer the best combination of effectiveness and mild side effects, and that sertraline has the advantage of being much cheaper.The Cipriani paper was a meta-analysis of trials comparing one drug against another. With a total of over 25,000 patients, it boasted an impressively large dataset, ........ Read more »
Ioannidis JP. (2009) Ranking antidepressants. Lancet, 373(9677), 1759. PMID: 19465221
Gartlehner, G., & Gaynes, B. (2009) Are all antidepressants equal?. Evidence-Based Mental Health, 12(4), 98-100. DOI: 10.1136/ebmh.12.4.98
- November 2, 2009
- 12:52 PM
- 703 views
Real vs Placebo Coffee
by Neuroskeptic in Neuroskeptic
Coffee contains caffeine, and as everyone knows, caffeine is a stimulant. We all know how a good cup of coffee wakes you up, makes you more alert, and helps you concentrate - thanks to caffeine.Or does it? Are the benefits of coffee really due to the caffeine, or are there placebo effects at work? Numerous experiments have tried to answer this question, but a paper published today goes into more detail than most. (It caught my eye just as I was taking my first sip this morning, so I had to blog ........ Read more »
Harrell PT, & Juliano LM. (2009) Caffeine expectancies influence the subjective and behavioral effects of caffeine. Psychopharmacology. PMID: 19760283
- October 19, 2009
- 12:20 PM
- 694 views
Antidepressant Sales Rise as Depression Falls
by Neuroskeptic in Neuroskeptic
Antidepressant sales are rising in most Western countries, and they have been for at least a decade. Recently, we learned that the proportion of Americans taking antidepressants in any given year nearly doubled from 1996 to 2005.The situation has been thought to be similar in the UK. But a hot-off-the-press paper in the British Medical Journal reveals some surprising facts about the issue: Explaining the rise in antidepressant prescribing.The authors examined medical records from 1.7 million Bri........ Read more »
Moore M, Yuen HM, Dunn N, Mullee MA, Maskell J, & Kendrick T. (2009) Explaining the rise in antidepressant prescribing: a descriptive study using the general practice research database. BMJ (Clinical research ed.). PMID: 19833707
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