- March 15, 2010
- 01:04 PM
- 7 views
Dyslexia and Brain Connectivity: Insights from Periventricular Nodular Heterotopia
by Livia in Reading and Word Recognition Research
Accessibility Level: Intermediate
One theory of dyslexia is that it stems from abnormal brain connectivity -- that faulty connections between different language areas result in reading difficulty. Now, some evidence from another condition offers some support for this theory.
Periventricular nodular heterotopia (PNH) is a neurological condition in which neurons don’t migrate to the correct
... Read more »
Chang, B., Katzir, T., Liu, T., Corriveau, K., Barzillai, M., Apse, K., Bodell, A., Hackney, D., Alsop, D., Wong, S.... (2007) A structural basis for reading fluency: White matter defects in a genetic brain malformation. Neurology, 69(23), 2146-2154. DOI: 10.1212/01.wnl.0000286365.41070.54
- March 15, 2010
- 01:01 PM
- 5 views
Hitting cancer’s Achilles’ heel
by Cancer Research UK in Cancer Research UK - Science Update
Like the mythical Greek hero Achilles, whose heel was his only vulnerable spot, we now know that cancer cells have certain weaknesses that we can exploit. The difficulty is finding them.
Today, new research from Professor Alan Ashworth and his team at The Institute of Cancer Research, who have already been involved in the exploitation of [...]... Read more »
Sarah A. Martin, Nuala McCabe, Michelle Mullarkey, Robert Cummins, Darren J. Burgess, Yusaku Nakabeppu, Sugako Oka, Elaine Kay, Christopher J. Lord, & Alan Ashworth. (2010) DNA Polymerases as Potential Therapeutic Targets for Cancers Deficient in the DNA Mismatch Repair Proteins MSH2 or MLH1. Cancer Cell. info:/10.1016/j.ccr.2009.12.046
- March 15, 2010
- 12:42 PM
- 8 views
Is Weight Loss Associated with Increased Risk of Early Mortality?
by Travis Saunders, MSc in Obesity Panacea
The current recommendations from major health organizations stipulate that if an individual has a BMI in the obese range (>30 kg/m2), they should be counseled to lose at least 5-10% of their body weight. This advice appears to make some sense given that increasing body weight is generally associated with heightened risk of various diseases, and that reduction of body weight usually improves levels of risk factors for disease (e.g blood pressure, triglycerides, etc). However, the literature has been much more complicated in terms of the effect of weight loss on risk of early mortality.
Adding to that literature is a recent study by Ingram and Mussolino published ahead of print last week in The International Journal of Obesity. In essence this recent study showed that weight loss of 15% or more was associated with an increased risk of death from all causes among overweight men and among overweight and obese women. Read the rest of this post... | Read the comments on this post...... Read more »
Ingram, D., & Mussolino, M. (2010) Weight loss from maximum body weight and mortality: the Third National Health and Nutrition Examination Survey Linked Mortality File. International Journal of Obesity. DOI: 10.1038/ijo.2010.41
- March 15, 2010
- 12:17 PM
- 7 views
Fumbling the Communication Baton in Patient Hand-offs
by Rob Mitchum in ScienceLife
As you may have gathered from various television dramas, medical residents work insane hours. A typical shift “on call” often means 30 straight hours on duty at the hospital, mostly spent on the time-intensive process of admitting new patients. People outside the medical profession often ask why such marathon shifts are necessary, and express surprise [...]... Read more »
Chang, V., Arora, V., Lev-Ari, S., D'Arcy, M., & Keysar, B. (2010) Interns Overestimate the Effectiveness of Their Hand-off Communication. PEDIATRICS, 125(3), 491-496. DOI: 10.1542/peds.2009-0351
- March 15, 2010
- 12:00 PM
- 4 views
The bizarre history of rangeland management research
by JL in Analyze Everything
As with the paper from last Friday, today's paper comes from "Ecological Restoration", one of the few journals that is delivered, in print, to our office. So yeah, I've been reading through it. This paper is by Sayre (2010; full cite below) and is basically about how the cultural and scientific beliefs of those living in the desert southwest have shaped the way that restoration has occurred ... Read more »
Sayre, N. (2010) Climax and "Original Capacity": The Science and Aesthetics of Ecological Restoration in the Southwestern USA. Ecological Restoration, 28(1), 23-31. DOI: 10.3368/er.28.1.23
- March 15, 2010
- 10:16 AM
- 13 views
How Loss Creates Depression And Growth
by Cole Bitting in Fable
The Creative Destruction of Loss: Can We Grow More Than We Wither?
Height is a trait: the taller the man, the greater the (evolutionary) fitness, at least to a certain point. The average height of a population closely approximates the optimal height. There is a distribution around this optimal norm: some are taller and some are shorter. Neuroticism,1 like height, is also a trait.
Language is an adaptation - an innate capacity baked into our DNA. Language skill is a trait, influenced by genetics but not uniform across the gene pool. Depressive behavior, like language, is an adaptation, and neuroticism is the equivalent to language skill or height.
The setting for depressive behavior is a low mood state.
Daniel Nettle:2
Low mood describes a temporary emotional and physiological state in humans, typically characterised by fatigue, loss of motivation and interest, anhedonia (loss of pleasure in previously pleasurable activities), pessimism about future actions, locomotor retardation, and other symptoms such as crying...3
Since the generic trigger of low mood is loss of or lack of access to some important resource, low mood may usefully be seen as an evolved suite of responses to unfavourable or adverse situations... Note that this does not mean that clinical depression itself represents adaptive behaviour... Low mood probably has multiple adaptive functions in unpropitious circumstances, subserved by its various different symptoms. [Italics mine]
Loss is one of the principal triggers of depressive behavior. In this analytical framework, what is loss? It is the loss of the abilities and resources necessary to live an optimal life. It is the loss of life fitness. The more we have lost, the greater our peril (we are more likely to die and less likely to have children). The loss of social status, for example, is a significant loss because it can imperil access to resources (e.g. food) and the ability to attract a suitable mate.
When we experience expected or readily manageable loss (of fitness), it is appropriate for our mood state to reflect the increased peril. With fewer resources, we have a more limited ability to risk fitness for possible reward. We must be cautious and the low mood state appropriately evokes congruent behaviors.
Daniel Nettle, again:
When the individual’s state is poor, a risky venture going wrong could push state down further into the danger area, and so behaviours with a small variance in payoff are preferred. When state is better, the individual can absorb potential failures and so is in a position to try out risky options that might just lead to a big payoff. Thus, to a very considerable extent, the model [for behavior responses to peril] supports existing views for the adaptive functions of low mood symptoms, and of positive emotions in general: when things are going quite badly, it is not the time to take risks, but as things improve, greater experimentation is warranted. [Economics would indicate such behavior is highly rational.]
One category of loss/limitation is the readily manageable, usually expected loss. During winter, for example, we lose access to new food. Because winter is expected, our contextual understanding accommodates our sensation-based experience. These sets of memories (contextual and sensation-based) are aligned and integrated. The event of loss - winter - matches our anticipation of loss. The level of distress is appropriate to the loss, and the salience of both is minimized because of the strength of the context. Put simply, the actual experience was as it was supposed to be.
Chris Brewin:4
According to dual representation theory, perception of a moderately stressful or emotionally salient event results in the creation of more enduring contextual memories [C-reps] and sensory-based memories [S-reps]...
In healthy individuals, the S-rep [sensation-based memory] for an extreme event is associated to a corresponding C-rep [contextual memory]. The association to the corresponding C-rep has two consequences: (a) allowing the event to be correctly integrated with its semantic and autobiographical context... and (b) allowing for increased top-down control.
What is context? Context is a set of beliefs, unchallenged assumptions, values, scripts, schemas, internal working models, biases, etc. Context is nothing less than the model of the world and how we most effectively and efficiently respond to it. We architect memories from a limited, biased sampling of new information and from the narrative and structural elements of already accepted ‘context.’
When the contextual and sensation-based memories of a loss have a strong correspondence (i.e. they are congruent), the consequent depressive behavior occurs without associated dissonance and the related neuroticism. However, if the winter were more severe than usual, we would not build contextual memories as efficiently. The surplus of sensation-base memories would cause dissonance - the sensation that something was not as it was supposed to be. Literally, we would have experience we could not account for: too much experience, too little understanding, an unnerving combination.
Neuroticism is our sensitivity to dissonance and the associated low mood state. If the winter was unexplainably severe, we would become neurotic - more focused on identifying behaviors to limit the loss of fitness, on developing improved understanding of the reasons for the severe winter.
Fresh insights allow us to create more viable contextual memories - better explanations - of the distressing loss. We come to associate the contextual memories with the sensory-based memories alleviating the distress and dissonance. In other words, as long as we are ill-at-ease, we seek better understanding. Similarly, understanding is relief.
We might conclude, ”The winter was severe because we did not pay tribute to the harvest god.” The accuracy of the belief is not relevant, rather the strength of the explanation is.
The losses which are associated with the greatest mental anguish are unexpected losses. The losses are inexplicable. They also destroy prior context, causing trauma.
Brewin et al.:5
Trauma generally involves a violation of basic assumptions connected with survival as a member of a social group. These include assumptions (not necessarily conscious ones) about personal invulnerability from death or disease, status in a social hierarchy, the ability to meet internal moral standards and achieve major life goals, the continued availability and reliability of attachment figures, and the existence of an orderly relation between actions and outcomes.
Trauma’s epistemic wounds are the means of destroying context. In the aftermath of these events, we have a limited array of contextual memories to match the many powerful, affect-laden, overwhelming sensation-based memories. In other words, without context, the sensation-based memories become intrusive imagery. We relive the trauma experiences rather than contextually re-experience them.
Chris Brewin (2010) again:
Normal encoding involves the creation of contextual memories [C-reps] and sensory-based memories [S-reps] with connections between the two. Pathological encoding involves relatively stronger S-reps [sensation-based memories], relatively weaker C-reps [contextual memories], and impaired connections between them.
Trauma causes Brewin’s “pathological encoding.” We failed, we were overwhelmed, we didn’t know what to do. We lost significant life fitness and don’t understand why. As a result, we continue to experience significant, persistent dissonance. We relive the associated images repeatedly and intrusively.
Given the heightened peril cause by the loss of life fitness, our mood drops and our behaviors change. We become neurotic. In other words, we are distressed by the loss, and we experience our depressive behaviors as the mental experienc... Read more »
NETTLE, D. (2004) Evolutionary origins of depression: a review and reformulation. Journal of Affective Disorders, 81(2), 91-102. DOI: 10.1016/j.jad.2003.08.009
Brewin, C., Gregory, J., Lipton, M., & Burgess, N. (2010) Intrusive images in psychological disorders: Characteristics, neural mechanisms, and treatment implications. Psychological Review, 117(1), 210-232. DOI: 10.1037/a0018113
Brewin, C., Dalgleish, T., & Joseph, S. (1996) A dual representation theory of posttraumatic stress disorder. Psychological Review, 103(4), 670-686. DOI: 10.1037/0033-295X.103.4.670
Nettle, D. (2009) An evolutionary model of low mood states. Journal of Theoretical Biology, 257(1), 100-103. DOI: 10.1016/j.jtbi.2008.10.033
Watkins, E. (2008) Constructive and unconstructive repetitive thought. Psychological Bulletin, 134(2), 163-206. DOI: 10.1037/0033-2909.134.2.163
Nettle, D. (2006) The evolution of personality variation in humans and other animals. American Psychologist, 61(6), 622-631. DOI: 10.1037/0003-066X.61.6.622
- March 15, 2010
- 09:50 AM
- 9 views
Tumour associated macrophages and survival in Hodgkins Lymphoma
by Sally Church in Pharma Strategy Blog
While reading my pile of mail on Friday, I realised that an interesting paper on Hodgkins Lymphoma (HL) appeared in the current edition of the New England Journal of Medicine (full reference below). The basics of the paper are that...... Read more »
Steidl C, Lee T, Shah SP, Farinha P, Han G, Nayar T, Delaney A, Jones SJ, Iqbal J, Weisenburger DD.... (2010) Tumor-associated macrophages and survival in classic Hodgkin's lymphoma. The New England journal of medicine, 362(10), 875-85. PMID: 20220182
DeVita, V., & Costa, J. (2010) Toward a Personalized Treatment of Hodgkin's Disease. New England Journal of Medicine, 362(10), 942-943. DOI: 10.1056/NEJMe0912481
Kunisch, E. (2004) Macrophage specificity of three anti-CD68 monoclonal antibodies (KP1, EBM11, and PGM1) widely used for immunohistochemistry and flow cytometry. Annals of the Rheumatic Diseases, 63(7), 774-784. DOI: 10.1136/ard.2003.013029
- March 15, 2010
- 09:30 AM
- 21 views
Pocket Science - a psychopath's reward, and the mystery of the shark-bitten fossil poo
by Ed Yong in Not Exactly Rocket Science
The rewarding side of being a psychopath
What goes on in the brains of psychopaths? They can seem outwardly normal and even charming, but tthese people typically show a lack of empathy, immoral behaviour and an impulsive streak. Joshua Buckholtz found that the last of these traits - impulsivity - may stem from a hyperactive reward system in the brain and unusually high levels of the signalling chemical dopamine.
When given small doses of amphetamines, people who come out as more impulsive on tests of psychopathy also released more dopamine in a part of their brain called the nucleus accumbens. This region plays many roles in feelings of reward, pleasure and addiction. This link between it and the impulsive side of psychopathy remained even after adjusting for other personality traits. Even the prospect of winning money, as opposed to a physical drug, triggered a hyperactive response from the nucleus accumbens.
When a psychopath imagines a future reward, the explosion of dopamine in their brain provides them with incredible motivation to get that reward. This extra motivation could underlie the increased drug use and the impulsive streaks that accompany the condition. It could even explain some of the antisocial behaviour - dopamine's most familiar as a chemical linked to feelings of reward and pleasure but studies in mice suggest that its presence in the nucleus accumbens is vital for aggression.
Previous research in this area has focused on the emotionally cold side of psychopathy, which may stem from problems in other parts of the brain like the amygdala, involved in emotions, and the ventromedial prefrontal cortex (vmPFC), involved in fear and risk. The impulsive side of the disorder has typically been overlooked but it predicts many of the problems associated with psychopathy, including drug abuse and violent criminal behaviour.
Reference: Nature Neuroscience http://dx.doi.org/10.1038/nn.2510
Image by Gregory R.Samanez-Larkin and Joshua W. Buckholtz
Why did the shark bite the poo?
The specimen on the right is a most unusual one. It's a coprolite, a piece of fossilised dung. That's not unique in itself; such specimens are often found and they tell us a lot about what extinct animals ate. But this one has a line of grooves running down its middle. They were made by a shark.
Stephen Godfrey and Joshua Smith found two such specimens in Maryland's Chesapeake Bay. The identity of the coprolites' maker is a mystery, but its chemical composition suggests that they were excreted by a meat-eating vertebrate. The identity of the biter is clearer. The duo poured liquid rubber into the grooves to make a model cast of the teeth that made them. These model teeth made it clear that the biter was a shark and the duo even managed to narrow its identity down to one of two species -a tiger shark, or Physogaleus, a close extinct relative.
Why would a shark bite a piece of dung? Tiger sharks are notorious for their ability to eat just about anything, but obviously, neither piece of dung was actually swallowed. No known shark eats poo for a living. The shark may have had an exploratory bite and didn't like what they tasted. But Godfrey and Smith's favourite explanation is that the bites were the result of collateral damage - the shark attacked an animal and during its assault, it happened to bite through the bowels. These specimens are the enduring remains of a battle between two predators, as suggested by this wonderful drawing in the paper by T Schierer of the Calvert Marine Museum.
Reference: Godfrey, S., & Smith, J. (2010). Shark-bitten vertebrate coprolites from the Miocene of Maryland Naturwissenschaften DOI: 10.1007/s00114-010-0659-x
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... Read more »
Godfrey, S., & Smith, J. (2010) Shark-bitten vertebrate coprolites from the Miocene of Maryland. Naturwissenschaften. DOI: 10.1007/s00114-010-0659-x
- March 15, 2010
- 09:28 AM
- 14 views
Sloppy Technicians and the Progress of Science
by Promega Corporation in Promega Connections
Entry 6 March 11, 2010 (from One Reader’s Journey through The Immortal Life of Henrietta Lacks)
Then, in 1953, a geneticist in Texas accidentally mixed the wrong liquid with HeLa and a few other cells, and it turned out to be a fortunate mistake. The chromosomes inside the cells swelled and spread out, and for the [...]... Read more »
Tjio JH, & Puck TT. (1958) THE SOMATIC CHOMOSOMES OF MAN. Proceedings of the National Academy of Sciences of the United States of America, 44(12), 1229-37. PMID: 16590337
BAIKIE AG, COURT-BROWN WM, BUCKTON KE, HARNDEN DG, JACOBS PA, & TOUGH IM. (1960) A possible specific chromosome abnormality in human chronic myeloid leukaemia. Nature, 1165-6. PMID: 13685929
FORD CE. (1960) Human cytogenetics: its present place and future possibilities. American journal of human genetics, 104-17. PMID: 13823894
PENROSE LS. (1962) Some clinical aspects of human cytogenetics. Postgraduate medical journal, 284-5. PMID: 14485139
Hsu, T.C.,. (1952) Mammalian Chromosomes In Vitro: I The Karyotype of Man. J. Heredity, 167-172. info:/
Kottler MJ. (1974) From 48 to 46: cytological technique, preconception, and the counting of human chromosomes. Bulletin of the history of medicine, 48(4), 465-502. PMID: 4618149
- March 15, 2010
- 09:23 AM
- 32 views
Surveying the gut microbiota, cross dressing chickens and more, in my Picks of the Week, from RB
by Alejandro Montenegro-Montero in MolBio Research Highlights
Another week has gone by and some very interesting molbio blog posts have been aggregated to Researchblogging.org. Every week [see my opening post on the matter], I'll select some blog posts I consider particularly interesting in the field of molecular biology [see here to get a sense of the criteria that will be used], briefly describe them and list them here for you to check out.Note that I'm ... Read more »
Qin, J., Li, R., Raes, J., Arumugam, M., Burgdorf, K., Manichanh, C., Nielsen, T., Pons, N., Levenez, F., Yamada, T.... (2010) A human gut microbial gene catalogue established by metagenomic sequencing. Nature, 464(7285), 59-65. DOI: 10.1038/nature08821
Vijay-Kumar, M., Aitken, J., Carvalho, F., Cullender, T., Mwangi, S., Srinivasan, S., Sitaraman, S., Knight, R., Ley, R., & Gewirtz, A. (2010) Metabolic Syndrome and Altered Gut Microbiota in Mice Lacking Toll-Like Receptor 5. Science. DOI: 10.1126/science.1179721
Zhao, D., McBride, D., Nandi, S., McQueen, H., McGrew, M., Hocking, P., Lewis, P., Sang, H., & Clinton, M. (2010) Somatic sex identity is cell autonomous in the chicken. Nature, 464(7286), 237-242. DOI: 10.1038/nature08852
- March 15, 2010
- 07:37 AM
- 12 views
An investigation into the effect of motivational climate on participant enjoyment of children’s athletics sessions
by PhD Blogger in Exercise Psychology
I thought today for some light relief I would post my undergrad dissertation. As I can actually read it and feel OK about it, i reckon its not too bad, it also got quite a good grade It can be downloaded in full here. Don't submit it as your own! That's cheating! Any questions email me!The study was based on the using TARGET framework to influence motivational climate in children coaching sessions, the abstract is below;Grounded in Achievement Goal Theory (Maehr & Nicholls, 1980: Nicholls, 1984: Dweck, 1986: Ames, 1984) and with a Social Cognitive Perspective (Bandura, 1986) the study investigated the effects of motivational climate on enjoyment ratings of children's athletics sessions. The rationale was to attempt to increase enjoyment by designing lesson plans which could utilize the reported benefits of a mastery motivational climate. It was postulated this may reduce drop out rates in children's physical activity classes. The children n=16 (10 boys and 6 girls) mean age 9.87 took part in two sessions. The researcher attempted to manipulate the motivational climate of the sessions using the TARGET framework, (Ames, 1992: Epstein, 1989) to design sessions with a mastery or performance motivational climate. The enjoyment rating of the children was measured after each session. The results indicated that the there was no significant difference in the enjoyment score rating of the two sessions.Ames, C. (1992). Classrooms: Goals, structures, and student motivation. Journal of Educational Psychology, 84 (3), 261-271 DOI: 10.1037//0022-0663.84.3.261... Read more »
Ames, C. (1992) Classrooms: Goals, structures, and student motivation. Journal of Educational Psychology, 84(3), 261-271. DOI: 10.1037//0022-0663.84.3.261
- March 15, 2010
- 07:00 AM
- 16 views
Quantifying the impact of land cover change on regional climate
by Rob Goldstein in Conservation Maven
Ecosystems can influence regional climate through biophysical regulation. Researchers test a method to help resource mangers quantify this ecosystem service and predict how land cover changes will affect climate...... Read more »
West, P., Narisma, G., Barford, C., Kucharik, C., & Foley, J. (2010) An alternative approach for quantifying climate regulation by ecosystems. Frontiers in Ecology and the Environment, 2147483647. DOI: 10.1890/090015
- March 15, 2010
- 06:30 AM
- 20 views
Should scientists be in control?
by Björn Brembs in bjoern.brembs.blog
The cliché scientist is often portrayed as the laborious worker slogging away days and nights in the lab. In contrast, the cliché for musicians or artists often comprises a bohemian lifestyle, full of parties, drugs and the occasional spurts of genius and frantic artistic expression. Reality, as always, is somewhere in-between. Artists need to work hard and laboriously to get something finished before the concert, recording or exhibition and scientists need to be creative and invest a lot of thought and effort into devising the new hypothesis or the clincher experiment. In his highly readable autobiography "Physics and Beyond" Werner Heisenberg of uncertainty-principle fame tells us that, when stuck with a complicated problem, he would have to leave the institute and spend time in nature, away from everything, waiting for the creative idea to solve the problem. In today's publish-or-perish scientific culture, such behavior is a young scientist's doom. Heisenberg received his Nobel Prize at the age of 31, an age where today's scientists barely get around towards their first or second postdoc and a tenured faculty position is still about a decade away, on average.It's been known for a very long time that creativity requires a so-called 'relaxed field', meaning an absence of outside stressor distracting from the thought processes at hand. I've written before about neurobiological research uncovering the biological basis for this requirement. Today I listened to a podcast from Radio National on the "Powerful Biology of Stress", which reminded me of that post. In the podcast, Bruce McEwen, one of the researchers the host, Natasha Mitchell, interviewed, mentioned research of one of his graduate students, Connor Liston. Connor Liston had conducted a series of experiments in rats which showed that when the animal, the rat, is challenged with a complex task in which it has to shift the meaning of cues that predict where a food reward is, if the task is difficult, having either a lesion of the prefrontal cortex which other people did, or chronic stress, reduces mental flexibility. Their ability to shift is not totally gone, it's just much slower and less efficient. Confirming much previous work, chronic stress reduces mental flexibility in rats and lesion studies pointed towards the prefrontal cortex. Connor Liston found that in the prefrontal cortex, under chronic stress these neurons are shrinking, the dendrites are shrinking and they're losing connections. So they are losing a very important input—it's a reversible process, if you stop the stress it will grow back. Chronic stress leads to dendritic pruning in the medial prefrontal cortex, which probably accounts for the loss in flexibility. So far, this research is interesting, but still on the level of the rat model system. How would this research translate into humans under chronic stress? Just over one year ago, Connor Liston published a study in PNAS about chronic stress in medical students who were preparing for their board exams. he used something called the perceived stress scale, which actually asks you questions about how much in control of your life you are in and what things are causing you to be stressed out. What he also did was to develop a human task which was very much like what he did with the rats, and they used functional brain imaging to define a circuit that was activated by this task. They could observe this circuit in these stressed students and they found that the more stressed out, the less efficient was the circuit, and they also showed an impairment on this behavioural task. While dendritic pruning cannot easily be studied in live human beings, it is tempting to speculate that also in humans this process takes place in our prefrontal cortex under chronic stress and causes you to fail in behavioral tests which require mental flexibility.This kind of research shows that not only were the old reports which connected creativity with what people at the time called 'a relaxed field' correct, we are now finding out what the neurobiological basis of this connection is. This research also demonstrates even more clearly how detrimental a stressful environment is for scientists: lacking the mental flexibility to think out of the box, to distance yourself from the problem at hand to maybe find the ingenious solution, stress postpones the progress of science. Forcing scientists into habits and grunt work, stress pushes science into dead ends and wasteful spending. Today, scientists finish their PhDs when they're just about to turn 30 and receive their first own grant in their 40s. During this decade, they live on short-term contracts and any failure to publish could mean the end of a life in science. For many 40-somethings, having been scientists for all their lives, never seen a company from the inside, a dry spell at any time in their career may mean the end to any middle-class life, with salaries being so low that no large savings would ever accrue. I'm not aware of any study investigating the reversibility of dendritic pruning after a decade of existential stress, but I'm willing to hazard a guess that a scientist's most formative years are not being used to their full potential by our current system and may even be detrimental for the final decades of a scientist's work. It is also conceivable that such existential stress incentivizes fraud and other misconduct in scientists who under normal circumstances would never be prone to such behavior.Interesting for my own research is the aspect that the critical factor deciding what is considered stress in these neurobiological studies, was whether or not the rats or humans had any control over their circumstances (restraint in rats and the exams in humans). My own research focuses on how the brain learns to control its circumstances and how it detects whether it is in control or not. Maybe one day my own research will contribute to a better understanding of how to contstruct a professional work-environment that fosters science, instead of stifling it.Liston, C., McEwen, B., & Casey, B. (2009). Psychosocial stress reversibly disrupts prefrontal processing and attentional control Proceedings of the National Academy of Sciences, 106 (3), 912-917 DOI: 10.1073/pnas.0807041106Radley, J. et al. (2005). Repeated Stress Induces Dendritic Spine Loss in the Rat Medial Prefrontal Cortex Cerebral Cortex, 16 (3), 313-320 DOI: 10.1093/cercor/bhi104... Read more »
Liston, C., McEwen, B., & Casey, B. (2009) Psychosocial stress reversibly disrupts prefrontal processing and attentional control. Proceedings of the National Academy of Sciences, 106(3), 912-917. DOI: 10.1073/pnas.0807041106
Radley, J. (2005) Repeated Stress Induces Dendritic Spine Loss in the Rat Medial Prefrontal Cortex. Cerebral Cortex, 16(3), 313-320. DOI: 10.1093/cercor/bhi104
- March 15, 2010
- 06:10 AM
- 9 views
Measles week, part I: Introduction
by iayork in Mystery Rays from Outer Space
Zhong Kui, a Chinese god, punishing two gods of measles (1862)
I’ve talked before about measles incidence and the effect of vaccination. Now I’m going to spend this whole week talking about measles deaths, because I ended up with more than I could cover in one or two posts. So this is Part I of a [...]... Read more »
Armstrong, G. (1999) Trends in Infectious Disease Mortality in the United States During the 20th Century. JAMA: The Journal of the American Medical Association, 281(1), 61-66. DOI: 10.1001/jama.281.1.61
- March 15, 2010
- 05:52 AM
- 39 views
How to Stop Smoking
by Neuroskeptic in Neuroskeptic
1. Don't smoke.2. See 1.This is essentially what Simon Chapman and Ross MacKenzie suggest in a provocative PloS Medicine paper, The Global Research Neglect of Unassisted Smoking Cessation: Causes and Consequences.Their point is deceptively simple: there is lots of research looking at drugs and other treatments to help people quit smoking tobacco, but little attention is paid to people who quit without any help, despite the fact that the majority (up to 75%) of quitters do just that. This is good news for the pharmaceutical industry and others who sell smoking-cessation aids, but it's not clear that it's good for public health.As they put it,despite the pharmaceutical industry’s efforts to promote pharmacologically mediated cessation and numerous clinical trials demonstrating the efficacy of pharmacotherapy, the most common method used by most people who have successfully topped smoking remains unassisted cessation ... Tobacco use, like other substance use, has become increasingly pathologised as a treatable condition as knowledge about the neurobiology, genetics, and pharmacology of addiction develops. Meanwhile, the massive decline in smoking that occurred before the advent of cessation treatment is often forgotten.Debates over drugs, or other treatments, tend to revolve around the question of whether they work: is this drug better than placebo for this disorder? Chapman and MacKenzie point out that even to frame an issue in these terms is to concede a lot to the medical or pathological approach, which may not be a good idea. Before asking, do the drugs work? We should ask, what have drugs got to do with this?Their argument is not that drugs never help people to quit; nor are they saying that tobacco isn't addictive, or that there is no neurobiology of addiction. Rather, they are saying that the biology is only one aspect of the story. The importance of drugs (and other stop-smoking aids like CBT), and the difficulty of quitting, is systematically exaggerated by the medical literature...Of the 662 papers [about "smoking cessation" published in 2007 or 2008], 511 were studies of cessation interventions. The other 118 were mainly studies of the prevalence of smoking cessation in whole or special populations. Of the intervention papers, 467 (91.4%) reported the effects of assisted cessation and 44 (8.6%) described the impact of unassisted cessation (Figure 1).... Of the papers describing cessation trends, correlates, and predictors in populations, only 13 (11%) contained any data on unassisted cessation.And although pharmaceutical industry funding of research plays a part in this, the fact that medical science tends to focus on treatments rather than on untreated individuals is unsurprising since this is fundamentally how science works:Most tobacco control research is undertaken by individuals trained in positivist scientific traditions. Hierarchies of evidence give experimental evidence more importance than observational evidence; meta-analyses of randomized controlled trials are given the most weight. Cessation studies that focus on discrete proximal variables such as specific cessation interventions provide ‘‘harder’’ causal evidence than those that focus on distal, complex, and interactive influences that coalesce across a smoker’s lifetime to end in cessation.Overall, it's an excellent paper and well worth a read in full (it's short and it's open access). Of course, it is itself only one side of the story and many in the tobacco control community will find it controversial. But I think Chapman and MacKenzie's is a point that needs to be made, and point applies to other areas of medicine, especially, although not exclusively, to mental health. This week, British social care charity Together told us thatSix out of ten of people have had at least one time in their life where they have found it difficult to cope mentally... stress (70%), anxiety (59%) and depression (55%) were the three most common difficulties encountered by the publicWhich was not still not quite as good as rivals Turning Point who last month saidThree quarters of people in the UK experience depression occasionally or regularly yet only a third seek helpThese were opinion surveys, not real peer-reviewed science, but they might as well have been: the best available science says that if you go and ask people, 50-70% of the population report suffering at least one diagnosable DSM-IV mental disorder in their lifetime, and that the majority receive no treatment at all. This leads to papers in major journals such as this one warning that "Depression Care in the United States" is "Too Little for Too Few."But we don't know whether these tens of millions of cases of untreated "mental illness" should be treated, because there is basically no research looking at what happens to such people without treatment. On the other hand, the very fact that they aren't treated, and yet manage to hold down jobs, relationships and so forth, suggests that the situation is not so bad.Of course we must never forget that depression and anxiety can be crippling diseases, but fortunately, such cases are at least comparatively rare. By using the word "depression" to cover everything from waking-up-at-4-am-in-a-suicidal-panic-melancholia to feeling-a-bit-miserable-because-something-bad-just-happened, it's easy to forget that while clinical depression is a serious matter, feeling a bit miserable is normal and resolves without any help 99% of the time. Even though there are no published scientific studies proving this, because it's not the kind of thing scientists study.Incidentally, this issue is a good reminder that there's no one big bad conspiracy behind everything. With smoking, Big Tobacco find themselves in direct opposition to Big Pharma, like in From Dusk Till Dawn when the psychopaths fight the vampires. With depression, the people who are quickest to decry the widespread use of antidepressants often seem to be the ones who are most keen on the idea that depression is common and under-treated, perhaps because it allows them to recommend their own favorite psychotherapy. Big Pharma hands the baton to Big Couch in the race to medicalize life.Chapman S, & MacKenzie R (2010). The global research neglect of unassisted smoking cessation: causes and consequences. PLoS medicine, 7 (2) PMID: 20161722... Read more »
Chapman S, & MacKenzie R. (2010) The global research neglect of unassisted smoking cessation: causes and consequences. PLoS medicine, 7(2). PMID: 20161722
- March 15, 2010
- 04:48 AM
- 19 views
Thirty years on - the babies judged negatively by their mothers
by Christian Jarrett in BPS Research Digest
If a mother has a negative perception of her baby when it's just one month old, there's a strong possibility that same baby will have attachment problems as an adult, thirty or forty years later. That's the claim of a longitudinal study that recommends screening new mothers to see if they have a negative perception of their child, so that any necessary action can be taken to stop the transmission of attachment problems from mother to child.Elsie Broussard and Jude Cassidy recruited twenty-six adults in the area of Pittsburgh, whose mothers had signed up to a longitudinal study up to forty years earlier. Back then, in the 60s and 70s, the mothers had been asked to rate their one-month-old babies on factors like crying, spitting, sleeping, feeding and predictability, and then do the same for the 'average baby'. Twelve of the babies were judged to be at risk because their mothers had rated them more negatively than an average baby. Back to the present, and the researchers interviewed the adults using the Adult Attachment Interview, which includes questions about memories of their childhood, their memories of separation and loss and whether they felt affected by their parents' behaviour. Based on these kinds of questions, the participants were classified as being securely or insecurely attached, the latter classification suggesting that they have ongoing problems forming healthy emotional attachments to other people. The key finding is that 9 of the 12 adults who, so many years earlier, had been perceived negatively by their mothers were today classified as insecurely attached adults, compared with just 2 of the 14 adults who'd been positively perceived by their mothers. '...These findings reflect transmission from one individual's representational world to that of another,' the researchers said. In other words, the researchers believe that a mother who views her baby negatively has attachment problems and these problems tend to be passed onto that baby, even affecting his or her attachment style thirty or forty years later. How could a negative attachment style be transmitted in this way? Apparently, earlier work in Broussard's lab showed that 'mothers with a negative perception of their infants had limited awareness of their infant's states, had difficulties recognising their infant's signals, and lacked a flexible and effective range of responses.' Moreover, the researchers surmised, babies with mothers who perceive them negatively may fail to come to see their mother as a secure base and may come to feel 'rejected and unloved, feelings that may contribute to an insecure state of mind [in adulthood] with respect to attachment.' Given their results, Broussard and Cassidy suggested more professional support be given to new mothers, especially during the critical early period between hospital discharge and the next contact with medical staff.As with so many studies that look for effects of parenting on children, this study contains a serious confound that's barely touched upon by the researchers. The effects that Broussard and Cassidy attribute to parenting and attachment style could well be genetic. We're not surprised when the children of tall parents grow up to be tall. Perhaps we shouldn't be surprised that the children of insecurely attached parents grow up to be insecurely attached themselves. _________________________________Broussard, E., & Cassidy, J. (2010). Maternal perception of newborns predicts attachment organization in middle adulthood. Attachment & Human Development, 12 (1), 159-172 DOI: 10.1080/14616730903282464
... Read more »
Broussard, E., & Cassidy, J. (2010) Maternal perception of newborns predicts attachment organization in middle adulthood. Attachment , 12(1), 159-172. DOI: 10.1080/14616730903282464
- March 15, 2010
- 03:33 AM
- 32 views
The Neuroscience of Anorexia Nervosa
by Dr Shock in Dr Shock MD PhD
One of the most striking features of those suffering from anorexia nervosa is their perception of their bodies. You can put them in front of a mirror and they will still tell you they’re to fat when in fact they’re skinny. A recent publication in Nature Proceedings has an explanation.
This explanation is based on the [...]
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Riva, Guiseppe. (2010) Neuroscience and Eating Disorders: The role of the medial-temporal lobe. Nature Proceedings. info:/
- March 14, 2010
- 11:50 PM
- 41 views
Science blogs and public engagement with science: practices, challenges, and talking out of your ass
by Isis the Scientist in On Becoming a Domestic and Laboratory Goddess...
This week a couple of my Sciblings have been abuzz about an article published in some journal I'd never heard of... a minor impact journal...the Journal of Who Gives a Fuck Science Communication. Bora has a great break down of some of the major criticisms. Drugmonkey, one of the subjects of the "analysis" in this article, is also displeased and critical of the author's conclusions.I've
since read the offending article and can only tell you this - I have no
idea what the balls the author is talking about. Seriously, this
article is about as informative as this: Video 1: A current favorite at the Isis house. When emailed this video, PhysioProf
replied, " Couldn't they afford to animate some fucking legs on those
fuckers?" I have always wondered why Mr. Lunt has no eyes.But, for those of you who are still interested, here's the run down...Inna Kouper,
a graduate student in Library and Information Science at Indiana
University, somehow magically chose 11 blogs to study, one of which was
Pharyngula. Now, I'm not hating on Pharyngula. PZ plays an important role in the blogosphere and, while I think that sometimes his commenters get out of control,
he's got a unique voice and an uncanny ability to rally the troops. No
one can deny that the climate at Pharyngula is not necessarily
reflective of the entire blogosphere. Still, the fact is that Inna
Krouper sampled 11 blogs. There are 80 blogs currently at
ScienceBlogs, 8 more at Discover Blogs, and a bazillion independent and
network blogs indexed by the Nature Network. Yet, somehow Inna chose
these 11 blogs as representative of the genre and one of them was
motherfucking Pharyngula. Then, she did this:A
combination of quantitative and qualitative techniques of content
analysis has been used in this study. The qualitative analysis
involved iterative close reading of posts and comments with the purpose
of identifying common types of statements and activities
conceptualized as modes of participation. This conceptualization was
informed by the speech act theory and the pragmatics perspective yet it
was purposefully left rather loose and open to allow for the categories
to emerge from the data. Each time a mode of participation was
identified, it was entered into a catalog, and then a post or a comment
was assigned a corresponding code. Along with the modes of
participation, the posts were coded for topics and sources of the post;
the comments were coded for the reader's identification elements (e.g.,
a nickname, first name, full name, link to blog, or blog author).
Subsequently all codes were counted and the analysis proceeded with the
examination of the most frequent and rare patterns and their groupings.Translation?Figure 1: Inna sat down one night, read some blogs, and then wrote some shit. She must really be itching to finish the ole thesis.I
mean, I truly am baffled by these methods, especially when the author
brags that "it is necessary to analyze current practices of science
blogging. To date no attempts have been made to do that. The present
study is the first step in this direction." This article is a step
alright...Figure 2: Problem is, none of realize where that step is taking us until it is too late to unlearn the stupid.I'm
just plain ole disappointed by the "methodology." This author could
have taken the opportunity to perform a carefully controlled study with
randomly-selected non-scientists. She could have shown them blinded
content and administered questionnaires. Instead she wrote 10 pages of
opinion and passed it off as science.After pages upon pages of presenting cherry-picked content, Inna concludes this:Science
blogs examined in this study are very heterogeneous. They provide
information and explain complicated matters, but their evaluations are
often trivial and they rarely provide extensive critique or articulate
positions on controversial issues... It appears that science blogging
can also be characterized as relying on reductive analysis and
dependent reporting and drawing caustic and petty commentary. These
characteristics may as well be applied to the newspaper and magazine
science communication, but with the newer science communication outlet
such as blogging they indicate that the potential of blogging to do
something differently, e.g., to provide informed expert and citizen
commentary, is not realized. In their current multiplicity of forms and
contents science blogs present a challenge rather than an opportunity
for public engagement with science. Lack of genre conventions, which
for the audience translates into broken expectations and uncertainty,
impedes the development of stable readership and participation from the
larger public, which may also be very heterogeneous. The "neighborhood
bar" or "water cooler" commentary creates a sense of community with
shared context and culture, but at the same time it creates a barrier
that prevents strangers and outsiders from joining the conversation. As
a community of scientists or individuals close to science, the
existing readers may enjoy the entertaining nature of science blogs and
not need science blogs to serve as a place for discussion and rational
debate. Relying on such community of readers, bloggers may reduce their
interpretive activities and resort to copying, re-distributing, and
re-packaging of the existing information, which is still quite
rewarding given the background of the majority of current readers and
yet requires much less time and effort. This study provides further
evidence that blogging as a web tool has no magic properties on its
own. Without a concerted effort of different social actors involved it
will not solve any problems...Reading this, I
realize that I did my PhD in the wrong damned field. I would be a much
more prolific publisher if I had entered a field where I could have
written whatever bullshit moved me on any given day and called it
"research." I also wonder how many of you feel like you
simply add "caustic and petty commentary"? I question how Inna can
conclude that blogs pose a barrier to the conversation. That's a
difficult statement to take seriously, knowing that Inna had no access
to traffic data for any of the blogs she read. For me, I know that a
single blog will be read by 1000s more non-scientists than any original
scientific article I publish in a peer-reviewed journal. And, she
certainly wouldn't have found the analysis trivial if she had read some
of Ed Yong or Carl Zimmer's work, not that I find any of the blogs she included trivial. Then again, I think it is the diversity of voice is what makes the blogosphere so beautiful. My
sample size = 1 is probably no better than Inna's sample size = 11, but
I can at least offer my experience to the data set. I get many letters
a week from young people interested in science careers and soliciting
advice on graduate school, fields of study, and professional
development. The number of people who have come to my office in person
to have these conversations is trivial in comparison. Thus, these data
would lead me to conclude that my blog presence has lowered the barrier
to engagement with this audience.I'll also never forget one of the occasions,
quite a while ago, that I wrote about some novel research. It was a
topic semi-related to my expertise.&nb... Read more »
Inna Kouper. (2010) Science blogs and public engagement with science: practices, challenges, and opportunities. Journal of Science Communication, 9(1). info:/
- March 14, 2010
- 05:24 PM
- 16 views
If graves could talk, Patrick Wall’s would be screaming (oh, and genes affect pain)
by Lorimer Moseley in BodyInMind
In 1986, Pat Wall and Steve McMahon commented on the folly of talking about nociception as though it is pain -
‘the labelling of nociceptors as pain fibres was not an admirable simplification but an unfortunate trivialization’ and
‘…pain is an integrated package of analysed results related to meaning, significance and imperative action’ [1]
Almost 25 years have [...]... Read more »
[1] Wall, P., & McMahon, S. (1986) The relationship of perceived pain to afferent nerve impulses. Trends in Neurosciences, 254-255. DOI: 10.1016/0166-2236(86)90070-6
[2] Reimann, F., Cox, J., Belfer, I., Diatchenko, L., Zaykin, D., McHale, D., Drenth, J., Dai, F., Wheeler, J., Sanders, F.... (2010) Pain perception is altered by a nucleotide polymorphism in SCN9A. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.0913181107
- March 14, 2010
- 02:59 PM
- 27 views
The Cocaine Conundrum
by Dirk Hanson in Addiction Inbox
Effective treatment remains elusive.
For addiction to cocaine, amphetamine, and other stimulants, the treatment picture has been complicated by the lack of any truly significant anti-craving medications. (See post, “No Pill for Stimulant Addiction"). The National Institute on Drug Abuse (NIDA) has yet to approve any medications for the treatment of either cocaine or amphetamine addiction.
Take the case of cocaine. Partly the problem stems from the direct effect cocaine has on dopamine transmission. The hunt for a pharmaceutical approach to blunt that effect is complicated by the problematic nature of dopamine receptors. Dopamine antagonist drugs like the antipsychotic drug haloperidol do not always block the stimulant rush. And their side effects, such as lethargy, emotional blunting, and tardive dyskinesia, make them unsuitable for ongoing addiction therapy. Conversely, some drugs that act as dopamine agonists turn out to be addictive in their own right. Many designer drugs are like that.
Because of all this, different approaches may be needed. The direct ride to the pleasure pathway provided by stimulants makes it difficult to tamper selectively with their effects. An antibody that would reduce cocaine consumption and sop up cocaine molecules in the brain, a kind of vaccine against cocaine, is one approach being pursued (See post, “Cocaine Vaccine Hits Snag”).
But other avenues of attack are being exploited. Scientists in NIDA’s Intramural Research Program are testing compounds that target certain proteins known as dopamine transporters. Transporters move dopamine molecules in and out of the synaptic gap between neurons in the brain. Interfering with that transportation system is another way of altering dopamine uptake, and it represents one active avenue of approach to the treatment of cocaine addiction.
The researchers tested Benztropine Mesylate (BZT), brand name Cogentin, one of a class of drugs known as anticholinergic suppressants commonly used in the management of Parkinson’s disease. What exactly does benztropine do? It possesses both anticholinergic (acetylcholine-blocking) and antihistaminic effects. It has chemical similarities to atropine, which is used for Parkinson’s and for heart disease.
To begin with, the researchers wanted to establish that benztropine itself is non-addictive. By substituting different BZT analogs for cocaine during self-administration testing, “two of the three BZT analogs that were tested significantly reduced drug self-administration… which indicates that those BZT analogs themselves have low potential for abuse.”
Next, the cocaine-addicted rats were given different BZT analogs before they got their cocaine. “When given before rats had access to cocaine in the self-administration chambers,” the researchers reported in the Journal of Pharmacology and Experimental Therapeutics, “two BZT analogs also significantly reduced the number of times the rats would press a lever to receive cocaine.” Monoamine uptake inhibitors were used as a control. The authors conclude that “these compounds are promising candidates for the development of medications for cocaine addiction.”
Hiranita, T., Soto, P., Newman, A., & Katz, J. (2009). Assessment of Reinforcing Effects of Benztropine Analogs and Their Effects on Cocaine Self-Administration in Rats: Comparisons with Monoamine Uptake Inhibitors Journal of Pharmacology and Experimental Therapeutics, 329 (2), 677-686 DOI: 10.1124/jpet.108.145813
Photo credit: http://www.drugabuse.gov... Read more »
Hiranita, T., Soto, P., Newman, A., & Katz, J. (2009) Assessment of Reinforcing Effects of Benztropine Analogs and Their Effects on Cocaine Self-Administration in Rats: Comparisons with Monoamine Uptake Inhibitors. Journal of Pharmacology and Experimental Therapeutics, 329(2), 677-686. DOI: 10.1124/jpet.108.145813
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