The retina is a beautiful and wondrous structure, and it has some really weird cells. Retina by Cajal (source)Retinal Ganglion Cells (RGC) have all sorts of differentiating characteristics. Some are directly sensitive to brightness (like rods and cones), while some are sensitive to the specific direction that a bar is traveling. I am discussing really amazing new techniques to see inside cells this month, and have already posted about the magic that is Array Tomography. Today we'll look at another amazing new technique that (like array tomography) combines nano-scale detail with a scale large enough to see many neurons at once. This technique is called Serial Block-face Electron Microscopy (SBEM), and was recently used to investigate how starburst amacrine cells control the direction-sensitivity of retinal ganglion cells.Serial Block-face EM (source)SBEM images are acquired by embedding a piece of tissue (like a retina) in some firm substance and slicing it superthin (like 10s of nanometers thick) with a diamond blade. The whole slicing apparatus is set up directly under a scanning electron microscope, so as soon as the blade cuts, an image is taken of the surface remaining. Then another thin slice is shaved off and the next image is taken, and so on.Using this technique, Briggman et al. (2011) are able to trace individual neurons and their connections for a (relatively) large section of retina. What is so great about this paper is that before they sliced up the retina, they moved bars around in front of it and measured the directional selectivity of a bunch of neurons. Then, using blood vessels and landmarks to orient themselves, they were able to find the exact same cells in the SBEM data and trace them.Briggman et al. (2011) Fig1C: Landmark blood vesselsThe colored circles above represent the cell bodies and the black 'tree' shape are the blood vessel landmarks. Once they found the cell bodies, the could trace the cells through the stacks of SBEM data. What is really neat is that you can try your hand at this yourself. This exact data set has been turned into a game called EYEWIRE by the Seung lab at MIT. Reconstructing the cells, they could not only tell which cells connected to which other cells, but they could also see exactly where on the dendrites the cells connected. This is the really amazing part. They found that specific dendritic areas made synapses with specific cells.Briggman et al. (2011) Fig4: dendrites as the computational unitThis starburst amacrine cell overlaps with many retinal ganglion cells (dotted lines represent the dendritic spread of individual RGCs)...BUT its specific dendrites (left, right, up down etc) synapse selectively onto RGCs sensitive to a particular direction. Each color represents synapses onto a specific direction-sensitivity. e.g. yellow dots are synapses from the amacrine cell onto RGCs which are sensitive to downward motion.This suggests that each individual dendritic area of these starburst amacrine cells inhibits (probably) a specific type of RGC, and that these dendrites act relatively independently of one another. "The specificity of each SAC dendritic branch for selecting a postsynaptic target goes well beyond the notion that neuron A selectively wires to neuron B, which is all that electrophysiological measurements can test. Instead the dendrite angle has an additional, perhaps dominant, role, which is consistent with SAC dendrites acting as independent computational units." -Briggman et al (2011)(discussion)These cells are weird for so many reasons, but the ability of the dendrites to act so independently of one another is a new and exciting development that I hope to see more research on soon. © TheCellularScaleBriggman KL, Helmstaedter M, & Denk W (2011). Wiring specificity in the direction-selectivity circuit of the retina. Nature, 471 (7337), 183-8 PMID: 21390125... Read more »
Briggman KL, Helmstaedter M, & Denk W. (2011) Wiring specificity in the direction-selectivity circuit of the retina. Nature, 471(7337), 183-8. PMID: 21390125
For those of you lucky enough to not have encountered it, there is a concept known as privilege that floats around in predominately feminist-leaning groups. The basic idea of the concept of privilege is that some groups of people have … Continue reading →... Read more »
Uhlmann, E., Zhu, L., Pizarro, D., & Bloom, P. (2012) Blood is thicker: Moral spillover effects based on kinship. Cognition, 124(2), 239-243. DOI: 10.1016/j.cognition.2012.04.010
When it comes to eating disorder treatment, few (if any) approaches are as divisive as Family-Based Treatment, also known as the Maudsley Method (I’ll use the terms interchangeably) . When I first heard about Maudsley, sometime during my mid-teens, most likely through an ED recovery community on Livejournal, I thought it was scaaary. But as I’ve learned more about it, my opinion changed (although, it does still seem kind-of scary).
As a side-note: I know many people reading this post know more about Maudsley than I ever will, so your feedback will be very much appreciated, especially if I got something wrong. I should also mention that I never did FBT or any kind-of family treatment/therapy as part of my ED recovery. (I have done family therapy, but it was unrelated to my ED; it was a component of a family member’s treatment for an unrelated mental health issue.)
In this post, I want to briefly explain what the Maudsley Method entails and put it into context. I also want to discuss some of the key research studies testing the efficacy of FBT and …
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Smith, A., & Cook-Cottone, C. (2011) A Review of Family Therapy as an Effective Intervention for Anorexia Nervosa in Adolescents. Journal of Clinical Psychology in Medical Settings, 18(4), 323-334. DOI: 10.1007/s10880-011-9262-3
by Persuasion Strategies in Persuasive Litigator
By Dr. Ken Broda-Bahm: Last week in the U.S. Senate, a measure to require universal background checks on gun purchases failed to get the 60 votes needed to survive. The arguments supporting the common good of keeping firearms out of the wrong hands were, to 45 Senators, was not as strong as the individual rights based aversion to new restrictions in any form. Though this decision was out of step with prevailing public opinion (with 86 percent of the public supporting such checks), it was quite consistent with a very common and very American tendency for common good arguments to...... Read more »
Hamedani MG, Markus HR, & Fu AS. (2013) In the land of the free, interdependent action undermines motivation. Psychological science, 24(2), 189-96. PMID: 23302297
by ebender in Daily Observations
APS James McKeen Cattell Fellow Michael E. Lamb, University of Cambridge, has won the 2014 G. Stanley Hall Award for Distinguished Contribution to Developmental Psychology and the 2013 Award for The post Lamb Wins G. Stanley Hall Award appeared first on Association for Psychological Science.... Read more »
Calling in the car, listening to the tv while cooking, checking your messages in a meeting: we modern people are all so used to multi-tasking that we actually started thinking we’re good at it. But we’re not, American researchers say.
Why do people multi-task? The first answer at hand would be because people are busy and know from experience that multi-tasking isn’t a problem for them. But this idea doesn’t pass the test of science. It appears that frequent multi-taskers have other reasons to do so.... Read more »
Sanbonmatsu, D., Strayer, D., Medeiros-Ward, N., & Watson, J. (2013) Who Multi-Tasks and Why? Multi-Tasking Ability, Perceived Multi-Tasking Ability, Impulsivity, and Sensation Seeking. PLoS ONE, 8(1). DOI: 10.1371/journal.pone.0054402
Even though I consider that I am across the literature at the boundary of economics and evolutionary biology, now and then an article pops up that I somehow missed. The latest article of this type is a 2009 article by Douglas Kenrick and colleagues, titled (as is this post) Deep Rationality: The Evolutionary Economics of Decision Making. [...]The post Deep Rationality: The Evolutionary Economics of Decision Making appeared first on Evolving Economics.... Read more »
Kenrick, D., Griskevicius, V., Sundie, J., Li, N., Li, Y., & Neuberg, S. (2009) Deep Rationality: The Evolutionary Economics of Decision Making. Social Cognition, 27(5), 764-785. DOI: 10.1521/soco.2009.27.5.764
Bankers, investors, stock market traders and their ilk have been vilified in recent years, in large part because the global financial crisis has been blamed on their allegedly unchecked selfishness and greed.
In fact, there's a widespread implicit belief that a love of money goes hand in hand with selfishness. A study published in 2008 backed this up - people with a greater love of money tended to report being more selfish at work.
A new study with business students at Loyola University challenges this narrative. In contrast to the 2008 paper, Michael Babula's study measured actual behaviour. The fifty students completed questionnaires about their religiosity and desire for wealth, then they headed, one at a time, across the building to give a short presentation, either about careers for economics students or about the relevance of the Good Samaritan parable to their future career.
Before they headed over to give their speech, half were told to hurry, time was short; the others were told there was no rush. Then, just before they reached the lecture room, a distressed, anxious stranger approached them. This person had just heard news that a relative had had an accident, but now their mobile phone had run out of battery and they had no change for a public pay-phone. The key test was whether and how much each student would offer to help the stranger in distress.
Seventy-eight per cent of the business students offered some kind of help to the stranger. Sixty-six per cent went so far as refusing to leave the stranger or giving him/her their mobile phone. The degree to which the students reported being wealth-driven was not associated with their levels of helping. Neither was their self-reported willingness to accept an illegal stock trading tip off. Being in a hurry also made no difference, neither did the content of the speech they were about to give. A factor that was linked with helping behaviour was "intrinsic religiosity" - that is, pursuing religion as an end in itself, not for the sake of status or other gain.
Babula cautioned that this was an exploratory study and he acknowledged the small size of his sample. However, he said it showed the importance of measuring actual behaviour, rather than relying on questionnaires as past research has tended to do. "Wealth-driven individuals often do engage in intrinsically motivated helping behaviour when directly facing an emergency situation," he said.
Though today's executives are widely reviled - an attitude reflected by Hollywood's release of a new version of Wall Street: Money Never Sleeps, and Vatican official Tarcisio Bertone's statement: "Greed market has substituted free market" - Babula urged social scientists to "reserve judgment" and to "take a cautious approach to studying the helping behaviour of wealth-driven individuals.
"The world has certainly encountered modern-day Samaritans coming from the business community." he added. "Witness the life of Oskar Schindler."
Babula, M. (2013). The unlikely Samaritans. Journal of Applied Social Psychology, 43 (4), 899-908 DOI: 10.1111/jasp.12055
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.
... Read more »
Workplace psychopathy was an obscure, unknown issue prior to the mid-1990s, but hundreds of popular accounts have been published since then. A measured review by Sarah Francis Smith and Scott Lilienfield gets to the heart of what we really know about the phenomenon. There is a lot to cover so we're publishing about it in two posts.Psychopathy? It's complicatedFrom the off, the authors raise how complicated the issue is. Many studies rely on psychopathy and outcome data from single sources, leaving open the possibility of both rater bias - the manager whose performance and 'psychopathic tendencies' are rated by the same hypercritical individual - and halo effects, where a rater sees their organisation as ethical because their boss is so personally pleasant. Where possible I've flagged this as a monomethod issue.Moreover, psychopathy is measured and defined in many ways, using approaches that are variously clinical or occupational. One durable distinction is between primary psychopathy - the emotional and personality traits of an individual - and secondary psychopathy, concerned with behaviours. The primary are arguably key, as a restrained psychopath can choose to refrain from unproductive behaviours.How common in business and in leaders?A commonly cited figure of 3% prevalence in managers versus 1% in the general population is based on a single study, so is there other evidence out there to corroborate higher psychopathy in business? Yes, but it's still tentative.One study compared a small executive sample to larger psychiatric and forensic populations, and did indeed find the executives scored higher on specific scales that were argued to relate to psychopathy. However, the scales were designed to measure other traits like narcissism, not psychopathy per se, using a measure that was not well-validated. Another study reported that commerce majors showed higher psychopathic traits, but not behaviours, than other undergraduates.Perhaps the clearest support comes from Babiak et al's (2010) finding that psychopathic traits are higher within a corporate sample relative to community controls, and that high scorers tended to have higher executive positions. So psychopathy may be more common in business and even leadership, although we don't yet have comprehensive indications of how much. But does it matter?We'll find out tomorrow.Smith, S., & Lilienfeld, S. (2013). Psychopathy in the workplace: The knowns and unknowns Aggression and Violent Behavior, 18 (2), 204-218 DOI: 10.1016/j.avb.2012.11.007... Read more »
Smith, S., & Lilienfeld, S. (2013) Psychopathy in the workplace: The knowns and unknowns. Aggression and Violent Behavior, 18(2), 204-218. DOI: 10.1016/j.avb.2012.11.007
Last week Science published a study (a follow-up of Salimpoor et al., 2011) in which Canadian researchers showed that music can arouse feelings of euphoria and craving, similar to tangible rewards that involve the striatal dopaminergic system. ... Read more »
Salimpoor, V., van den Bosch, I., Kovacevic, N., McIntosh, A., Dagher, A., & Zatorre, R. (2013) Interactions Between the Nucleus Accumbens and Auditory Cortices Predict Music Reward Value. Science, 340(6129), 216-219. DOI: 10.1126/science.1231059
Salimpoor, V., Benovoy, M., Larcher, K., Dagher, A., & Zatorre, R. (2011) Anatomically distinct dopamine release during anticipation and experience of peak emotion to music. Nature Neuroscience. DOI: 10.1038/nn.2726
One of the oft-cited takeaways from the past week is that people are basically awesome. In the midst of unpredictable danger and tragedy, residents (and guests) of the Boston area didn’t hesitate to help their fellow citizens. But what’s troubling about these realizations of human goodness is that they suggest an a priori doubt about [...]... Read more »
Fischer, P., Krueger, J., Greitemeyer, T., Vogrincic, C., Kastenmüller, A., Frey, D., Heene, M., Wicher, M., & Kainbacher, M. (2011) The bystander-effect: A meta-analytic review on bystander intervention in dangerous and non-dangerous emergencies. Psychological Bulletin, 137(4), 517-537. DOI: 10.1037/a0023304
Every Sunday, I'd like to post a review of an interesting peer-reviewed science article. To kick things off I'm picking an old favorite, originally posted in 1964! It is certainly well cited, Google Scholar lists the citation count at 452! Indeed this paper was a "Citation Classic" in Current Contents in 1981. At the time the lead author Robert Bolles, was still living and stated:"I have always believed in the idea that experimenters should look at their animals...the human eyeball is the instrument of choice if you want to observe a new phenomenon, and particularly if you want to gain a new understanding of it."Sprague-Dawley RatIn fact this article describes qualitatively the behaviors of infant rats from birth to about 24 days (rats are weened at day 21). In the first experiment, Bolles and Woods observed 13 litters with an average of 9 pups (117 pups) in their "natural" laboratory environment (cages). The animals were of the Sprague-Dawley line, which is still used today. They did use several different methods of observation and schedules of observation to arrive at a comprehensive guide to the ontogeny of lab rats.They begin with postural observations, describing three postures that develop over time: lying, sitting and standing. Lying being the default resting position of the rat, often using other bodies for support. Sitting began on day 4 when subjects first began to lift their heads, and was fully developed by day 17 when subjects could sit and perform activities such as grooming. Also beginning on day 4 are the first attempts to support weight on the legs, and by day 10 the animals can support themselves. By day 13 they can run, by day 15 they can stand on three legs and scratch with the fourth. They can rear up on two legs with support for the front legs on day 16 and can rear independent of support (for the purpose of play-fighting with siblings) by day 18.In similiar fashion reflexes are described. Without relating the specific timeline the reflexes are: twitiching, head waving, stretching and yawning, body flexion, righting reaction, freezing, sniffing, auditory orientation, and visual orientation. When describing startle response int he auditory orientation section there is a great footnote on the word "click:"*The sound used was relatively well-controlled and constant, but, unfortunately rather poorly defined; it was the sound of a Parker T-Ball Jotter pen being retracted at a distance of approximately 1 foot.Psychologists are hilarious. Also found it interesting that the animals did not freeze in fear until day 26 and they froze for approximately 15 seconds. I've never seen any rats hold still for that long unless they were sleeping. Following this functional activities are described. Here is the list: sleeping, consumatory behavior, locomotor activity, climbing, grooming, exploration manipulation, digging, and defecation Here the theme of development was similar as above, with rudimentary non-functional behaviors appearing first (such as scratching motion without making contact with the skin), that later developed into full-fledged adult-like behavior.Ultimately we get a description of the social behaviors in the observed rats. Social behavior in young rats is evidenced by chasing and fighting. Bolles, and Woods observed rats begin this social play-fighting on day 14 when their eyes began to open.The activity peaks between day 20 and 30 when the whole litter engages in a high level of activity.Table 1In a second experiment Bolles and Woods attempt to quantify the behaviors they observed in the first experiment. Using experimental methods the authors observed 12 rats (2 each from 6 litters) and summarized their behaviors as percentages. To the right is table 1 from the paper. There are many more graphs showing the time course of the development of behaviors and it really is a fascinating reference, but I won't reproduce all of that here.The first point of discussion and perhaps the most salient is that from these findings we can view rats as a far more social animal than might otherwise be considered. Early social interactions are to wrangle for nursing or comfort, and later become play fighting and chasing. As the authors noted this social behavior likely leads to long lasting changes in the adult organism and "offers interesting possibilities for research in this area." (See the next 50 years of rat studies for more on these possibilities)Bolles, R., & Woods, P. (1964). The ontogeny of behaviour in the albino rat Animal Behaviour, 12 (4), 427-441 DOI: 10.1016/0003-3472(64)90062-4... Read more »
Physicists are notorious for infecting other disciplines. Sometimes this can be extremely rewarding, but most of the time it is silly. I’ve already featured an example where one of the founders of algorithmic information theory completely missed the point of Darwinism; researchers working in statistical mechanics and information theory seem particularly susceptible to interdisciplinitis. The [...]... Read more »
Wissner-Gross, A.D., & Freer, C.E. (2013) Causal Entropic Forces. Phys. Rev. Lett., 110(16), 168702. info:/10.1103/PhysRevLett.110.168702
It’s not quite clear why human males continue to have facial hair. There are other ways to keep warm, and we’ve lost our hair over most of the rest of our bodies (or they’re at best residual). But facial hair serves another important purpose—determining male attractiveness to females... Read more »
Dixson, B., & Brooks, R. (2013) The role of facial hair in women's perceptions of men's attractiveness, health, masculinity and parenting abilities. Evolution and Human Behavior, 34(3), 236-241. DOI: 10.1016/j.evolhumbehav.2013.02.003
Minocycline, the tetracycline antibiotic, is probably not something that most people would traditionally link with autism or conditions presenting with autism-like behaviours. Indeed, the suggestion that antibiotics or antimicrobials if you prefer, may be able to modify either the behaviour or linked biochemistry of the autism spectrum disorders (ASDs) or even influence the onset and expression of ASD is quite frankly a little bit unusual.Minocycline (for chemists) @ Wikipedia But unusual is what often crops up on this blog. And how if one assumes that autism, sorry the autisms, are not just conditions solely pertaining to the grey-pinkish matter floating inside our skull, one starts to see how behaviour and physiology might provide some interesting perspectives. Say for example, when one starts to look at the gut microbiome...On today's post I'm considering a few reports which recently cropped up on the research radar including the results of placebo-controlled trial of minocycline for Fragile X syndrome (FXS) published by Mary Jacena Leigh and colleagues* (open-access), a small open-trial of minocycline reported by Carlos Pardo and colleagues** (open-access) and although not autism-related, the results of a study by Parvin Ataie-Kachoie and colleagues*** (open-access) on what happened to an ovarian cancer cell line when minocycline was added, specifically with the cytokine IL-6 in mind. A bit of a mixed bag of studies by all accounts but with some potential common threads.The Leigh study has already been covered by some media (see here) so no grand description needed from me. Suffice to say that there is a suggestion from this MIND Institute study, that minocycline might have some modest positive impact on various aspects of behaviour in paediatric cases of FXS with the requirement for further research. As per some previous chatter on this blog, this is not necessarily new news for FXS as per studies like the one by Paribello and colleagues**** (open-access). Interestingly, the Paribello results also mention something called matrix metalloproteinase-9 (MMP-9) as a particular target of minocycline which has also been discussed on this blog (see here). So, potentially (potentially!) there may be some merit in looking at minocycline for cases of FXS; although as per my blog caveat, I'm not recommending anything.Moving on. The Pardo study (see here for the trial record), whilst small in participant numbers, looked more directly at the use of minocycline - and vitamin B6 - with ten children diagnosed with an ASD. The focus was on autism with a regressive aetiology linked to presentation, and alongside various behavioural measures, there was also analyses of various biological fluids for "markers of neuroinflammation". The study was open and unblinded so not exactly the same calibre as the Leigh trial.The main result of the trial, er... no clinical improvements following minocycline use, even after six months of use. Indeed not only were no significant changes to behaviour reported but a variety of respiratory and gastrointestinal (GI) side-effects correlated with minocycline use. The efficacy and safety profile was not particularly great based on these study results allowing for the lack of any control group and the dosage used.There were however, a few reported changes to some of the biochemistry under investigation, specifically with brain derived neurotrophic factor (BDNF) and hepatocyte growth factor (HGF) in mind but not in the more classically related parameters such as that MMP-9 connection. This lack of effect of minocycline on MMP-9 is slightly unusual but potentially revealing. Certainly the review by Siller & Broadie***** (open-access) hints that MMP inhibition might be a key part of the effects of minocycline in FXS. It's possible a few scenarios might pertain with regards to the biological/genetic differences between autism and FXS. One might even speculate that there is some involvement for the TIMPs (tissue inhibitors of metalloproteinases) in that non MMP inhibitory effect noted from minocycline in autism, but much more work is perhaps needed.Indeed the authors very overtly noted that "minocycline exerted biological effects that were not translated into behavioral or neurological changes" which certainly questions the link between some of the biochemistry that was seemingly affected and presented symptoms assuming there wasn't more subtle behavioural changes.Finally, there is the Ataie-Kachoie study on minocycline application to ovarian cancer cell lines. I'll freely admit that I know even less about cancer cell lines than I do about autism so please excuse any widely inaccurate statements that I might make. The long-and-short of it was that in the lab, minocycline seems to have an interesting effect on "the IL-6 signaling pathway" at least in ovarian cancer cells such that minocycline might reduce IL-6 or at least prevent increases after certain events. As part of my learning jounrney through this paper I did not know that IL-6 was for example being linked to cancer metastasis as discussed by Tawara and colleagues****** for example. Seemingly this metastasis might correlate with those MMPs (particularly MMP-2 and MMP-9).I know I'm moving further and further away from my autism and FXS purpose with the Ataie-Kachoie data, but there may be some lessons to be learned. That for example minocycline might affect cases of FXS by means of impacting on MMP-9 is already under discussion. The added suggestion that minocycline might also be working on cytokines like IL-6 in an anti-inflammatory fashion is certainly another source of discussion. Indeed, I note from the Pardo autism study, that in Table 3 showing the pre- and post-treatment effects on biochemistry, the value reduction for serum IL-6 just managed to escape that magical significance point coming in at p=0.08. The change in another interesting cytokine, TNF-alpha, was even closer (p=0.074).This has been a post comparing apples and pears to a large extent and reiterating my earlier caveat, I am by no means advocating minocycline for anything other than it's intended use with appropriate medical physician support and supervision. Outside of the discussions already included, what this post does serve to show is that (a) the actions of medicines are not necessarily restricted to what's printed on the patient information leaflet, an... Read more »
Leigh, M., Nguyen, D., Mu, Y., Winarni, T., Schneider, A., Chechi, T., Polussa, J., Doucet, P., Tassone, F., Rivera, S.... (2013) A Randomized Double-Blind, Placebo-Controlled Trial of Minocycline in Children and Adolescents with Fragile X Syndrome. Journal of Developmental , 34(3), 147-155. DOI: 10.1097/DBP.0b013e318287cd17
When we recognise someone, we integrate information from across their face into a perceptual whole, and do so using a specialised brain region. Recognising other kinds of objects does not engage such specific brain areas, and is achieved in a much more parts-based way.... Read more »
You never used to hear anyone say the word cognition. More and more, it seems to crop up in all kinds of places. I see cognition crop up in newspapers, magazines, and letters from my kid’s school. As someone who makes his living off of cognition, that’s comforting. But what is cognition really about? Is [...]... Read more »
Mayer, R. (2001) What Good is Educational Psychology? The Case of Cognition and Instruction. Educational Psychologist, 36(2), 83-88. DOI: 10.1207/S15326985EP3602_3
Miller, G. (2003) The cognitive revolution: a historical perspective. Trends in Cognitive Sciences, 7(3), 141-144. DOI: 10.1016/S1364-6613(03)00029-9
Tom Brady is no stranger to pain (source)
Every Wednesday afternoon, I gather with a bunch of faculty and graduate students at the University of Illinois to discuss a journal article about social psychology, and to eat a snack. This blog post reflects the discussion we had during this week's seminar affectionately called Social Wednesdays and Grub (SWAG).
This week in SWAG we read an article about racial biases
in perceptions of others’ pain. The American medical field has a long history
of racial bias (Note: I think if you switched the words “medical field” with
almost any other field, the sentence would be factually accurate. For example,
“mathematics field” or “psychology field” but not “magnetic field”). American
blacks tend to be diagnosed less accurately by medical staff than whites, to
receive less optimal health care, and to be cared for less intimately. The
authors, led by Sophie Trawalter of the University of Virginia, wondered about
the source of this racial bias. They reasoned that it might arise in part from
a belief that low status groups experience less pain than other groups in
society. Blacks and other traditionally low status groups in America are
perceived as having overcome greater hardships throughout their lives. As a
result of contending with, and overcoming these hardships, low status groups
are perceived to experience less pain than their more advantaged counterparts—their
tough circumstances have made them tougher. This racial bias in pain perception
is theorized to underlie the black-white treatment gap in medicine.
Read More->... Read more »
What do we (not) know about how paracetamol (acetaminophen) works? (Toussaint et al., 2010). . .From the beginning, the focus of the search for paracetamol’s analgesic mechanism has concentrated on the central nervous system. When administered intraventricularly [i.e., directly into the ventricular system of the brain], acetaminophen produces no significant analgesia (115, 132). This finding lead to attempts to inject acetaminophen into the spinal cord (i.t.), which produced marked dose-related antinociception (132).Yesterday’s post about Tylenol as a cure for mortality salience and existential dread got me a little worked up. The first author’s public endorsement of acetaminophen as a possible treatment for chronic anxiety disorders was too much to handle (along with the less than stellar experimental rigor). Is watching a 4 min clip of a David Lynch film really the same thing as a clinically diagnosed psychiatric disorder (Randles et al., 2013)? Why Tylenol and not other pain relievers? What is the hypothesized mechanism of action? Wouldn’t we already know by now, from epidemiological studies at the very least, if Tylenol was an effective anti-anxiety medication?So I started wondering about acetaminophen's actual mechanism of action. I was quite surprised that it's somewhat mysterious. Randles et al. cited one paper on this:Second, acetaminophen affects a number of brain regions, some of which are not directly related to physical or social distress (Toussaint et al., 2010).This led me to believe there was evidence from human neuroimaging studies. Turns out there isn't, beyond the Dewall et al. (2010) paper, which states:Although the precise mechanisms by which acetaminophen exerts an analgesic effect are still unclear, it is widely accepted that acetaminophen reduces pain through central, rather than peripheral, nervous system mechanisms (Anderson, 2008; H.S. Smith, 2009).I would like to point out that the spinal cord is part of the central nervous system. So if it's really true that acetaminophen exerts its pain-relieving effects through synapses in the spinal cord, then what does this say about providing relief from the angst of social exclusion, mortality salience, and existential dread? That it's based on nociceptive spinal cord neurons in laminae I, II, and V? For a visual illustration of this pathway, I highly recommend viewing the animation, Dissection of DLF blocks analgesia, at Neuroscience Online. One hypothesis is that Tylenol (acetaminophen) may act on descending serotonergic pathways (purple projection) at the level of the spinal cord (red synapses). Figure modified from Neuroscience Online.However, it's not that simple. The review paper by Toussaint et al. (2010) concluded, "No one mechanism has been definitively shown to account for its analgesic activity." For its proposed mechanisms of action, they presented evidence both for and against Cyclooxygenase (EC 126.96.36.199, COX) inhibition, COX-1, COX-2, 'COX-3', peroxidase, nitric oxide synthase, cannabinoid receptors, and of course serotonin:There is substantial evidence that paracetamol’s mechanism of analgesia in some manner involves the descending serotonergical pathway. 5-HT neurons, largely originating in raphe nuclei located in the brain stem (117, 118) send projections down to the spinal cord that synapse on afferent neurons entering the spinal cord. These descending projections exert an inhibitory (analgesic) effect on the incoming pain signal before it is transmited to higher CNS centres.Note that these are not the same serotonergic pathways often implicated in depression. The terminal synapses for the latter are indeed located in the brain and not the spinal cord.Last night, in real life, I followed the Watertown news live via @sethmnookin and @taylordobbs (like many others).This morning I dreamt that my workplace had transformed into an institutional fortress taken over by a gang of murderous criminals. The actual law enforcement authorities were too busy watching television talk shows to do anything about it. The thugs were threatening and torturing and killing people in the building. I managed to escape down a balcony exit and hid out for a while, avoiding detection but fearful that the thugs would find me and kill me. They were unstoppable, and there seemed to be no way out. I informed an old West-style sheriff, who managed to detain a carload of the evildoers. While continuing to hide, I wondered whether I would be able to shoot them all dead with a fully automatic weapon before they shot and killed me.Then an early morning doorbell rang and woke me up. It was an unexpected FedEx delivery. In my barely awake state, I thought it might be a bomb.Why am I telling you all this?? Because I find it very hard to believe that Tylenol, a drug that's relatively ineffective for my own headache pain, could possibly alleviate the anxiety caused by this nightmare. Or by the real life nightmare that's affected so many people in Boston.ReferencesDewall CN, Macdonald G, Webster GD, Masten CL, Baumeister RF, Powell C, Combs D, Schurtz DR, Stillman TF, Tice DM, Eisenberger NI. (2010). Acetaminophen reduces social pain: behavioral and neural evidence. Psychol Sci. 21:931-7. Randles, D., Heine, S., & Santos, N. (2013). The Common Pain of Surrealism and Death: Acetaminophen Reduces Compensatory Affirmation Following Meaning Threats. Psychological Science DOI: 10.1177/0956797612464786... Read more »
Toussaint, K., Yang, X., Zielinski, M., Reigle, K., Sacavage, S., Nagar, S., & Raffa, R. (2010) What do we (not) know about how paracetamol (acetaminophen) works?. Journal of Clinical Pharmacy and Therapeutics, 35(6), 617-638. DOI: 10.1111/j.1365-2710.2009.01143.x
Shakespeare wasn't kidding about the "winter of our discontent." In the colder and darker months, people do more internet searches for mental health terms, from anxiety and ADHD all the way to suicide. Search patterns also promise that like a refreshed browser window, better times are due to arrive soon.
John Ayers, of the Center for Behavioral Epidemiology and Community Health in San Diego, and other researchers dove into Google Trends to explore whether certain searches vary by season. "Seasonal affective disorder is one of the most studied phenomena in mental health," Ayers says, "with many individuals suffering mood changes from summer to winter due to changes in solar intensity." He wanted to find out whether any other mental health complaints changed with the seasons, as some studies had hinted.
Since Google Trends breaks down searches by category, the researchers started in the "mental health" section. Looking at all mental health searches in the United States between 2006 and 2011, they saw a consistent cycle with peaks in the winter and troughs in the summer. (If you do this search yourself, you'll see that there's also a dip around the December holidays—but the curve reliably bottoms out in July of each year.)
The team did some statistical smoothing and found that mental health searches overall were about 14% higher in the winter than in the summer. To confirm that the difference was due to the season, they ran the same analysis on data from Australia. Searches cycled in the same way—about 11% higher in winter than summer—but the peaks in the southern-hemisphere country were almost exactly 6 months out of sync with the United States.
When the scientists broke down searches by specific symptoms or illnesses, the seasonal cycle remained—and in some cases got much stronger. "We were very surprised" to see this, Ayers says. Searches including the terms ADHD, anxiety, bipolar, depression, anorexia or bulimia, OCD, schizophrenia, and suicide all rose in the winter and fell in the summer.
One of the most dramatically cycling search terms was schizophrenia, at 37% higher in the winter. Eating disorder terms varied just as strongly. (The smallest seasonal difference was for anxiety, which was just 7% higher in the winter in the United States, and 15% in Australia.)
Some of this seasonality might be due to the schedule of the school year, Ayers points out. Referrals for kids with ADHD and eating disorders may come from their schools.
Other explanations involve winter itself. The effect of shorter days on our circadian rhythms and hormone levels might be a factor, the authors write, as in seasonal affective disorder. They speculate that a lack of vitamin D (which we make using sunlight) in the winter might contribute. Even omega 3 fatty acids might matter: we consume less of them in winter, and omega 3 deficiency has been linked to some mental illnesses.
There's also the question of what we're doing all season. People hunkered indoors during the colder months may have fewer chances for socializing, which is "a well-known health emollient," the authors write. The same goes for physical activity.
"There is a lot more we need to learn about mental health and seasonality," Ayers says. "For instance, is there a universal mechanism that impacts our mental health?"
Of course, sometimes our malaise isn't about the season.
Whatever portion of mental health is predictable, though, doctors would love to know about it and use that information to help.
This study doesn't give reveal much about low-income or elderly populations who aren't online. And knowing what people are searching for isn't exactly the same as knowing what symptoms they're experiencing. "We are actively working to address these limitations," Ayers says. Working with Google.org, the charitable branch of Google, he hopes to develop systems similar to Google Flu Trends that can track a population's mental health.
"Intuition suggests that these results are reflective of an important link between the seasons and mental health," Ayers says. For now, we have the reassurance of computer algorithms that skies will be clearer soon.
Ayers, J., Althouse, B., Allem, J., Rosenquist, J., & Ford, D. (2013). Seasonality in Seeking Mental Health Information on Google American Journal of Preventive Medicine, 44 (5), 520-525 DOI: 10.1016/j.amepre.2013.01.012
Image: Skaneateles, NY, by me.
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Ayers, J., Althouse, B., Allem, J., Rosenquist, J., & Ford, D. (2013) Seasonality in Seeking Mental Health Information on Google. American Journal of Preventive Medicine, 44(5), 520-525. DOI: 10.1016/j.amepre.2013.01.012
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