Our experience of current warmth can override our scientific knowledge in driving beliefs about climate change, which is part of the reason we struggle to take the resulting risks seriously, underlines Columbia University’s Elke Weber. ... Read more »
Weber, E. (2006) Experience-Based and Description-Based Perceptions of Long-Term Risk: Why Global Warming does not Scare us (Yet). Climatic Change, 77(1-2), 103-120. DOI: 10.1007/s10584-006-9060-3
Li, Y., Johnson, E., & Zaval, L. (2011) Local Warming: Daily Temperature Change Influences Belief in Global Warming. Psychological Science, 22(4), 454-459. DOI: 10.1177/0956797611400913
Lately I've been gearing up for some nano-particle research, and so I've been doing a lot of reading about very small things. While perusing the literature, I came across a paper published online in Environmental Science and Technology that takes a look at microplastics.Let’s start with the Great Pacific Garbage Patch, a very good example of this type of marine pollution. This huge collection of marine debris in the North Pacific Ocean is created by an ocean gyre, a stable circular ocean current that draws in debris where it is trapped and builds up. The collected debris is our litter – plastics and other material that are not biodegradable. They can’t escape the gyre, they just collect. And as they sit out there swirling around, they break down into smaller and smaller pieces called microplastics.Microplastics are defined as those plastic particles less than 5 mm in length, and these small particles are a huge marine pollution problem. They are classified into two groups: (1) primary microplastics that are created at the microscale for use in products like cosmetics and drugs and (2) secondary microplastics that are products of the breakdown of larger items. As a whole, they are persistent and widespread – we’re talking worldwide, the Great Pacific Garbage Patch is just the most well-known aggregation. These microplastics are very abundant, we’re talking 1,000-100,000 particles per cubic meter of seawater! And there is growing evidence of the danger these tiny materials are having on marine life, everything from turtles to sea birds to fish and even zooplankton.A new study by Watts et al. takes look at the uptake of these microplastics in the shore crab (Carcinus maenas). Previous studies have shown that an important prey species of the shore crab, the common mussel (Mytilus edulis), accumulates microplastics as it filters the water for food (“ventilation”). In laboratory conditions, the direct transfer of microplastics from mussels to crabs has been shown, but then again, it has also been shown that crabs uptake microplastics as they pull water through their gills. So what exactly is going on here? How are these crabs exposed and are they able to clear the microplastics from their bodies?This is one of those studies where I just love to describe the methods. The first thing the researchers had to do was to assess the ability of the crabs to uptake microplastics (in the form of 8-10 um polystyrene microspheres) through their gills. To do this, they fitted the crabs with masks designed to allow measurements of ventilation. Yep, they put little masks on crabs. Picture that. I love science. Next they assessed the ability of the crab to take up microspheres in their food by exposing mussels and then turning them into “jellified mussel homogenate” to then feed to the crabs. I wonder which undergrad had the lovely job of making gelatin mussel popsicles? To see if the microplastcs were cleared, they let the crabs sit in their tanks and tested the abundance of microspheres in the water during water changes every 2 days for 22 days, sampling periodically. During each stage of the experiment, they measured the abundance of microspheres in the gut and gill tissues, fecal material, and hemolymph (like blood). Using fluorescent microscopy and Coherent Raman scattering microscopy (CRS; a multiphoton microscopy that produces label-free contrast of both the target sample and the surrounding biological matrix), they were able to look at the location of the microplastics within the tissues.The researchers found that the masked crabs took up 31,000-62,000 microspheres (0.39-7.7% of the initial exposure concentration) into their gills after only 16 hours. But this uptake was not even across the gills, with greater uptake in the posterior gills. The crabs where able to expel some of the spheres, but slowly, still expiring microspheres 21 days after being exposed. Imaging the gills showed the microspheres to be associated with the gill epidermis. The feeding experiment showed all crabs to have microspheres in their foregut and later in their fecal material. The residence time of these microspheres was short, but still took longer to excrete than regular food waste, up to 14 days. Microscopy showed microspheres associated with the internal setae of the foregut lining. But, neither the ventilation experiment nor the feeding experiment showed any microspheres in the hemolymph.Back to the question of what’s going on here? The shore crabs did take up microplastics in both types of exposure, but residence time is the key. They were able to clear the microplastics they got through dietary means, but they were still trying to clear microplastics they took up during ventilation almost a month later. The authors constructed a model to explain the mechanism of the movement of the microplastics. They found that the crabs tended to exhibit an asymmetry in microplastic uptake in the gills, which they attributed to the pumping mechanism of the scaphognathite being more dominant on one side of the gill chamber. Also, the posterior gills have a larger surface area than the anterior gills so they are more likely to take up microplastics into their lamellae. The crabs were unable to dislodge the tiny particles by normal gill cleaning actions. It is interesting that no microspheres were found in the hemolymph at any of the sampling points in either experiment. That suggests that there is no movement of the particles. It is likely that the particle size they used (10 um) was a little bit too large as it has been shown that sizes of 0.5 um are able to translocate in these crabs. This idea of particle size is something I’ve been seeing with increasing frequency within the nano-particle literature, along with polymer type, shape, and coatings. To that I would add that species is probably also in the mix as gills in crabs and fish are structured differently, and nano-particles have been shown to move in to organs like the liver in fish.Studies like this are interesting because they show how very small things can become a very large problem affecting multiple tissues of the same organism up to multiple levels of a trophic cascade. I mean, think about it, even we humans could be affected. After all, we consume a lot of crab. How many microplastics are you ingesting when you stop at the crab shack for a quick lunch?Watts AJ, Lewis C, Goodhead RM, Beckett SJ, Moger J, Tyler CR, & Galloway TS (2014). Uptake and Retention of Microplastics by the Shore Crab Carcinus maenas. Environmental science & technology PMID: 24972075I know I used some technical terms, if you need some help with crustacean anatomy check out Invertebrate Anatomy OnLine.(image via UGA Evolution 3000H)... Read more »
Watts AJ, Lewis C, Goodhead RM, Beckett SJ, Moger J, Tyler CR, & Galloway TS. (2014) Uptake and Retention of Microplastics by the Shore Crab Carcinus maenas. Environmental science . PMID: 24972075
Despite all the efforts, people are losing the war on obesity. There is probably a number of factors involved, genetics, underlying medical problems, most of all diet, but in any […]... Read more »
Williams KW, Liu T, Kong X, Fukuda M, Deng Y, Berglund ED, Deng Z, Gao Y, Liu T, Sohn JW.... (2014) Xbp1s in Pomc Neurons Connects ER Stress with Energy Balance and Glucose Homeostasis. Cell metabolism. PMID: 25017942
Five of the coolest news stories from the past week... Read more »
Koubeissi, M., Bartolomei, F., Beltagy, A., & Picard, F. (2014) Electrical stimulation of a small brain area reversibly disrupts consciousness. Epilepsy , 32-35. DOI: 10.1016/j.yebeh.2014.05.027
Sleep disturbance following traumatic brain injury (TBI) is a common clinical challenge.Hypersomnia and insomnia can both been seen in the TBI population.The risk factors related to TBI-related sleep disturbance are not well known. Identification of risk factors can provide insight into clinical assessment and management.Lijun Hou and colleagues recently examined risk factors related to subjective sleep complaints in a series of 98 TBI subjects.The study sample include adults admitted to a one of two Chinese hospitals following a initial episode of TBI. For enrollment, subjects were required to have evidence of a brain imaging abnormality on CT after their TBI.Subjects were interviewed by phone one to four years following TBI and administered three questionnaires including:Pittsburgh Sleep Quality IndexEpworth Sleepiness ScaleHospital Anxiety and Depression Scale The key findings from this study included:Severity of TBI ratings for the sample were mild (70%), moderate (15%) and severe (15%)Prevalence of sleep disturbance was 38% in the sample overallSleep disturbance rates increased with increasing TBI severity with rates of 30% in the mild TBI group, 53% in the moderate TBI group and 57% in the severe TBI groupThe predominant risk factor for hypersomnia was severity of TBI. Those with severe TBI were most likely to have hypersomniaRisk factors for insomnia included post-TBI headache and dizziness complaints and post-TBI anxiety and depression symptomsThis study was unable to identify specific brain CT findings as risk factors for later sleep disturbance. Sleep disturbance rates were similar for subjects with frontal lobe injury and those with injury to other brain regions. The authors conclude sleep disturbance is a common complication of TBI and often is not diagnosed and not treated.A weakness of this study is the relatively small sample size and the use of self-report measures rather than sleep laboratory confirmed sleep disturbance.Insomnia after TBI may be part of a broader presentation of an anxiety disorder or mood disorder. Clinicians should screen TBI patients for presence of psychiatric disorders when a insomnia is present.Hypersomnia following severe TBI may contribute to significant morbidity. Pharmacological interventions for hypersomnia such as modafanil are available and may be part of a multidisciplinary treatment program.Readers with more interest in this research can access the free full-text manuscript by clicking on the PMID link in the reference below.Photo of a tricolor heron is from the author's files.Follow the author on Twitter at WRY999.Hou L, Han X, Sheng P, Tong W, Li Z, Xu D, Yu M, Huang L, Zhao Z, Lu Y, & Dong Y (2013). Risk factors associated with sleep disturbance following traumatic brain injury: clinical findings and questionnaire based study. PloS one, 8 (10) PMID: 24098425... Read more »
Hou L, Han X, Sheng P, Tong W, Li Z, Xu D, Yu M, Huang L, Zhao Z, Lu Y.... (2013) Risk factors associated with sleep disturbance following traumatic brain injury: clinical findings and questionnaire based study. PloS one, 8(10). PMID: 24098425
We expect of our jurors and judges calm, reasoned evaluation of the evidence. Of course we know the reality is rather different - prejudice and emotional reactions will always play their part. Now two new studies add insight into the ways people's legal judgements depart from cool objectivity.Beatrice Capestany and Lasana Harris focused on two main factors - the disgust level of a crime, and whether or not the perpetrators' personality was described in biological terms. Seventeen participants were presented with pairs of crime vignettes, with each crime in a pair matched for severity in terms of US Federal sentencing guidelines, but one crime high in disgust value, the other low. For example, one vignette described a man pulling a gun on a love rival, taking aim and missing. The matching vignette described a man who stabbed his boss with scissors, once in the neck and once in the back, causing serious blood loss.Each vignette concluded with a personality description that was either trait-based (e.g. Gerald has an impulsive personality) or biological (e.g. Terry has a gene mutation that makes him impulsive). These contrasting personality descriptions were always irrelevant to the crime - so, in the aforementioned impulsivity examples, the crime in question was pre-meditated.Capestany and Harris found that participants recommended more serious punishments for crimes that were more disgusting. This sounds like emotion clouding judgment. But in a sense, greater disgust made participants more reliable decision makers because when disgust levels were high, the participants' recommendations more closely matched Federal sentencing guidelines. Perhaps, the researchers surmised, this is because the US legal system is rooted in historical moral judgments that were guided by disgust reactions.Capestany and Harris also scanned the brains of their participants. This revealed greater engagement of brain regions involved in logical reasoning when participants were presented with crimes higher in disgust. In other words, a stronger emotional reaction to the crime actually led to greater activation of neural areas involved in logic.When it came to the influence of the personality descriptions, participants judged criminals to be less culpable when they'd been described in biological terms, presumably because biological factors are perceived as deterministic and reduce the sense that the criminal has control over their behaviour. The brain scans showed greater recruitment of logical reasoning centres when vignettes included trait (non-biological) descriptions of the criminal's personality, so perhaps participants jumped to conclusions when given biological information."Biological personality descriptions dehumanise the person, reducing them to a mechanistic, biological organism and not a human being whose mental states are highly unique and salient during responsibility judgments," the researchers said.Another way that a suspect can be dehumanised is by describing their actions in animalistic terms. This is what happened in the the UK with the real life case of Raoul Moat in 2010, after he shot three people in England. He was described in the media as a "brute" and like "an animal in the wild" when he went on the run.A team led by Eduardo Vasquez has investigated people's sentencing decisions when criminal acts are described in animalistic terms (e.g. "... the perpetrator slunk onto the victim's premises ... He roared at the victim before pounding him with his fists") versus in non-animalistic terms, but with wording matched for seriousness (e.g. "the perpetrator stole onto the victim's premises ... He shouted at the victim before punching him with his fists").Seventy-six participants recommended more serious sentences (one to two years extra duration) for criminals whose behaviour was described in animalistic terms. A follow-up study suggested this was because criminals described in animalistic terms were predicted to be more likely to re-offend.Vasquez and his colleagues said their results "add to a growing body of literature examining the consequences of dehumanisation". They admitted that the implications for actual trials are unclear - after all, the descriptions they used are rarely heard in court. Nonetheless, they said there could be real-life relevance: "Media reports influence legal proceedings and most people rely on the media for information about criminal justice... People exposed to these [animalistic] descriptions may vote for harsher policies to address crime."_________________________________ Capestany, B., & Harris, L. (2014). Disgust and biological descriptions bias logical reasoning during legal decision-making Social Neuroscience, 9 (3), 265-277 DOI: 10.1080/17470919.2014.892531Vasquez, E., Loughnan, S., Gootjes-Dreesbach, E., & Weger, U. (2014). The animal in you: Animalistic descriptions of a violent crim... Read more »
Capestany, B., & Harris, L. (2014) Disgust and biological descriptions bias logical reasoning during legal decision-making. Social Neuroscience, 9(3), 265-277. DOI: 10.1080/17470919.2014.892531
Vasquez, E., Loughnan, S., Gootjes-Dreesbach, E., & Weger, U. (2014) The animal in you: Animalistic descriptions of a violent crime increase punishment of perpetrator. Aggressive Behavior, 40(4), 337-344. DOI: 10.1002/ab.21525
Birt-Hogg-Dubé Syndrome is caused by inactivating mutations in the FLCN gene, characterised by skin lesions on the face and upper body; lung cysts and predisposition to pneumothorax; and kidney cancer. Although symptoms typically appear in the third and fourth decade … Continue reading →... Read more »
Johannesma PC, van den Borne BE, Gille JJ, Nagelkerke AF, van Waesberghe JT, Paul MA, van Moorselaar RJ, Menko FH, & Postmus PE. (2014) Spontaneous pneumothorax as indicator for Birt-Hogg-Dubé syndrome in paediatric patients. BMC pediatrics, 171. PMID: 24994497
It may be time to leave “busy as a bee” with other dubious animal similes like “happy as a clam” and “drunk as a skunk.” That’s because some bees, it turns out, aren’t all that busy. A small group of hive members do the bulk of the foraging, while their sisters relax at home. But […]The post Some Bees Are Busier Than Others appeared first on Inkfish.... Read more »
Tenczar, P., Lutz, C., Rao, V., Goldenfeld, N., & Robinson, G. (2014) Automated monitoring reveals extreme interindividual variation and plasticity in honeybee foraging activity levels. Animal Behaviour, 41-48. DOI: 10.1016/j.anbehav.2014.06.006
It’s hard to find the best person for the job through an interview. New research uncovers part of the problem: judging a candidate’s calibre becomes trickier when we’re also trying to sell them the benefits of joining the organisation.In an initial study, participants were asked to interview a person (another participant) who was acting as an applicant for a fictional position. Half the interviewers were told their priority was to get a good sense of the applicant, while the rest had to prioritise attracting the candidate to the vacant position. Following the interview, the interviewer participants then had to judge the applicant’s character by rating their Core Self Evaluation (CSE), a measure of their self-esteem and belief in their own competence, which is reliably predictive of job performance. Which set of interviewers ought to do a better job?Researchers Jennifer Marr and Dan Cable tackled this topic because two fields of psychology make competing claims. Research on automatic processing suggests that when we apply explicit, rational processes to judgments that rely on quick intuition, we only muddy the water, or worse, become so self-conscious that we choke under pressure. We already know that some elements of applicant evaluation are fast - see this piece, so maybe we make our best judgments when we’re less concerned about making them? On the other hand, the theory of motivated cognition argues that when insufficiently focused we become vulnerable to biases or even blind to the obvious, as shown in the now-classic inattentional blindness experiments where focus on one task (counting basketball passes) makes it hard to spot salient events like the appearance of someone in an ape suit.The new findings back the motivated cognition account - participants asked to entice the applicant were poorer judges of character than those explicitly asked to evaluate them. A follow-up field study found similar effects in genuine interviews within two samples: applicants to an MBA program and teachers applying for school assignments. In both samples, interviewees rated as having high CSE were more likely to go onto success - job offers for MBAs or "above and beyond" citizenship behaviours by the teachers - but only when the ratings came from interviewers who reported having a strong focus on evaluation. Those who reported giving more attention to selling the role produced CSE estimates that didn’t predict future success. The authors note in their conclusion that “interviewers who focused only on evaluating applicants actually believed they were less able to select the best applicants than those who adopted a selling focus.” In fact the reverse was true, and the risk goes the other way: when we focus too much on soliciting applicants, we can miss the gorilla in the room: that they simply aren’t up to snuff._________________________________ Marr, J., & Cable, D. (2013). Do Interviewers Sell Themselves Short? The Effects of Selling Orientation on Interviewers' Judgments Academy of Management Journal, 57 (3), 624-651 DOI: 10.5465/amj.2011.0504 --further reading--Experienced job interviewers are no better than novices at spotting lying candidatesMind where you sit - how being in the middle is associated with superior performancePost written by Alex Fradera (@alexfradera) for the BPS Research Digest.
... Read more »
Marr, J., & Cable, D. (2013) Do Interviewers Sell Themselves Short? The Effects of Selling Orientation on Interviewers' Judgments. Academy of Management Journal, 57(3), 624-651. DOI: 10.5465/amj.2011.0504
Scientists at the University of Tokyo have developed an approach with industrial potential to produce nano-sized composite silicon-based powders as negative electrodes for the next generation lithium ion batteries.... Read more »
Homma, K., Kambara, M., & Yoshida, T. (2014) High throughput production of nanocomposite SiO powders by plasma spray physical vapor deposition for negative electrode of lithium ion batteries . Science and Technology of Advanced Materials, 15(2), 25006. DOI: 10.1088/1468-6996/15/2/025006
"These results confirm the elevation of urinary p-cresol in a sizable set of small autistic children and spur interest into biomarker roles for p-cresol and p-cresylsulfate in autism".The peasant dance @ Wikipedia That was the primary conclusion from the paper by Gabriele and colleagues  looking at "three components of urinary p-cresol, namely p-cresylsulfate, p-cresylglucuronate and free p-cresol" in samples from 33 participants diagnosed with an autism spectrum disorder (ASD) compared with matched asymptomatic controls. The confirmation bit of that quote refers to the fact that members of this authorship group have previously reported on elevated urinary p-cresol in cases of autism  which was talked about in the very first proper research-based post on this blog (see here).Before proceeding, perhaps it might be worth my while going through a few descriptive details. p-cresol (para-cresol) otherwise known as 4-methylphenol is a compound of some note in terms of the various ways and means one arrives at this organic aromatic compound. The solvent toluene is eventually metabolised into p-cresol, as is the amino acid tyrosine in the presence of strains of the anaerobic bacterium Clostridium difficile  for example. That being said, there are quite a few other ways in which one might come into contact with this compound.According to the paper by Vanholder and colleagues  there is quite a bit of evidence to suggest that whilst p-cresol and its metabolites are compounds found in some quantity in just about everyone, under certain circumstances, elevations in amount may not be particularly desirable  particularly when it comes to renal functions. Indeed, quite a bit of the focus has been on the conjugated derivative p-cresylsulfate (formed through O-sulfonation) when it comes to toxicity . I'll come back to this issue shortly.A few points on the Gabriele paper might be useful:Based on a small participant group comprising 33 participants of various ages on the autism spectrum and 33 sex- and age-matched asymptomatic controls, levels of free p-cresol and it's two metabolites were measured via HPLC with fluorescence detection.All metabolites were "significantly elevated" in ASD cases compared to controls."This increase was limited to ASD children ≤8 [less than or equal to 8] years". Also: "Urinary levels of p-cresol and p-cresylsulfate were associated with stereotypic, compulsive/repetitive behaviors (p < 0.05), although not with overall autism severity".I probably don't need to say it, but when it comes to talk about biomarkers and autism, I do tend to be a little restrained about the promise of any results. Think back to my recent post on organic acids as biomarkers for autism (see here) and just about all the caveats talked about then in terms of heterogeneity and comorbidity come into play here too. That also this and other results from this group are based on HPLC with either UV (ultraviolet) or fluorescence detection could also be considered problematic as a function of the many and varied components found in urine and how without mass spectrometry or NMR, assigning labels to compounds is slightly problematic. Think casomorphins as another example...Elevated levels of urinary p-cresol are also not a feature of every metabolomic study looking at autism. In their review of all-things p-cresol and autism, Persico & Napolioni  talked about how the results from Yap and colleagues  reported "blunted and not increased levels of p-cresylsulfate in autistic patients". The Yap study did utilise (1)H NMR spectroscopy and so did not suffer the same analytical shortcomings as the more recent trials. That all being said, I don't want to come down too hard on the latest results from Gabriele and colleagues. They got what they got and now put their results out for further inspection and hopefully, independent verification.I am also wondering whether the paper by Clayton and colleagues  might also be relevant in this case. Dr Clayton, who some might remember from other work talked about on this blog (see here), discussed how "in individuals with high bacterially mediated p-cresol generation, competitive O-sulfonation of p-cresol reduces the effective systemic capacity to sulfonate acetaminophen [paracetamol]". Sulphation capacity when it comes to autism is already something of a research interest (see here) which when added to a growing body of work looking at paracetamol use during pregnancy and possible links to offspring development (see here) might indicate some other interesting investigations to be done. I wonder if perhaps even the sulphation depleting metabolism of something like p-cresol might actually be the more important part of such investigations to autism research?Music to close, and are you a troublemaker?---------- Gabriele S. et al. Urinary p-cresol is elevated in young French children with autism spectrum disorder: a replication study. Biomarkers. 2014 Jul 10:1-8. Altieri L. et al. Urinary p-cresol is elevated in small children with severe autism spectrum disorder. Biomarkers. 2011 May;16(3):252-60. Dawson LF. et al. The analysis of para-cresol production and tolerance in Clostridium difficile 027 and 012 strains. BMC Microbiology 2011, 11:86  Vanholder R. et al. p-cresol: a toxin revealing many neglected but relevant aspects of uraemic toxicity. Nephrol Dial Transplant. 1999 Dec;14(12):2813-5. Liabeuf S. et al. Free p-cresylsulphate is a predictor of mortality in patients at different stages of chronic kidney disease. Nephrol Dial Transplant. 2010 Apr;25(4):1183-91. Vanholder R. et al. The Uremic Toxicity of Indoxyl Sulfate and p-Cresyl Sulfate: A Systematic Review. J Am Soc Nephrol. 2014 May 8. [Epub ahead of print] Persico AM. & Napolioni V. Urinary p-cresol in autism spectrum disorder. Neurotoxicol Teratol. 2013 Mar-Apr;36:82-90. Yap IK. et al. Urinary metabolic phenotyping differentiates children with autism from their unaffected siblings and age-matched controls. J Proteome Res. 2010 Jun 4;9(6):2996-3004. Clayton TA. et al. Pharmacometabonomic identification of a significant host-microbiome metabolic interaction affecting human drug metabolism. Proc Natl Acad Sci U S A. 2009 Aug 25;106(34):14728-33.----------... Read more »
Gabriele S, Sacco R, Cerullo S, Neri C, Urbani A, Tripi G, Malvy J, Barthelemy C, Bonnet-Brihault F, & Persico AM. (2014) Urinary p-cresol is elevated in young French children with autism spectrum disorder: a replication study. Biomarkers : biochemical indicators of exposure, response, and susceptibility to chemicals, 1-8. PMID: 25010144
Where are they?
Close-up view of the meninges surrounding the brain.
The term meninges comes from the Greek for "membrane" and refers to the three membranes that surround the brain and spinal cord. The membrane layers (discussed in detail below) from the outside in are the: dura mater, arachnoid mater, and pia mater. Their positioning around the brain can be seen in the image to the right.What are they and what do they do?The brain is soft and mushy, and without structural support it would not be able to maintain its normal shape. In fact, a brain taken out of the head and not properly suspended (e.g. in saline solution) can tear simply due to the effects of gravity. While the bone of the skull and spine provide most of the safeguarding and structural support for the central nervous system (CNS), alone it isn't quite enough to fully protect the CNS. The meninges help to anchor the CNS in place to keep, for example, the brain from moving around within the skull. They also contain cerebrospinal fluid (CSF), which acts as a cushion for the brain and provides a solution in which the brain is suspended, allowing it to preserve its shape.The outermost layer of the meninges is the dura mater, which literally means "hard mother." The dura is thick and tough; one side of it attaches to the skull and the other adheres to the next meningeal layer, the arachnoid mater. The dura provides the brain and spinal cord with an extra protective layer, helps to keep the CNS from being jostled around by fastening it to the skull or vertebral column, and supplies a complex system of veinous drainage through which blood can leave the brain.The arachnoid gets its name because it has the consistency and appearance of a spider web. It is much less substantial than the dura, and stretches like a cobweb between the dura and pia mater. By connecting the pia to the dura, the arachnoid helps to keep the brain in place in the skull. Between the arachnoid and the pia there is also an area known as the subarachnoid space, which is filled with CSF. The arachnoid serves as an additional barrier to isolate the CNS from the rest of the body, acting in a manner similar to the blood-brain barrier by keeping fluids, toxins, etc. out of the brain.The pia mater is another thin layer, but unlike the arachnoid it closely follows all of the contours (i.g. gyri and sulci) of the brain. Thus, instead of a cobweb, it forms a tight membrane around the brain and spinal cord. The pia acts as a barrier and also aids in the production of CSF.These three layers are similar in structure and function around both the spinal cord and brain, but there are a few differences. While there is not normally a space between the dura and skull, there is one between the dura of the spinal cord and the bone of the vertebral column. It is known as epidural space, and analgesics and anasthesia are sometimes injected here. Also, the dura of the spinal cord and its accompanying arachnoid layer extend several vertebrae below the end of the cord. This creates a CSF-filled area called the lumbar cistern where there is no spinal cord present. The lack of the presence of the cord makes the lumbar cistern a good place to sample CSF when necessary because one doesn't have to worry about damaging the spinal cord with a needle puncture. Thus, the lumbar cistern is the site where CSF is aspirated in a lumbar puncture, also known as a spinal tap.There are a number of things that can go wrong with the meninges. Due to the large numbers of blood vessels that travel through these membranes, many problems are vascular in nature. For example, blood (e.g. due to damage caused by trauma) can collect in spaces between the layers of the meninges, creating a hematoma that can put pressure on the brain as it expands. Also, the meninges are susceptible to infection, most commonly due to viruses or bacteria. Such an infection can cause meningitis, which is characterized by an inflammation of the meninges. Because of the importance of the meninges in protecting the brain and maintaining normal brain function, meningitis can pose a serious threat to the brain and potentially be life-threatening.Patel, N., & Kirmi, O. (2009). Anatomy and Imaging of the Normal Meninges Seminars in Ultrasound, CT and MRI, 30 (6), 559-564 DOI: 10.1053/j.sult.2009.08.006... Read more »
Fish might not be the first thing you think about when we talk spinal cord injury but that is exactly what scientists are doing. Don’t ask where they got the […]... Read more »
Lewandowski, G., & Steward, O. (2014) AAVshRNA-Mediated Suppression of PTEN in Adult Rats in Combination with Salmon Fibrin Administration Enables Regenerative Growth of Corticospinal Axons and Enhances Recovery of Voluntary Motor Function after Cervical Spinal Cord Injury. Journal of Neuroscience, 34(30), 9951-9962. DOI: 10.1523/JNEUROSCI.1996-14.2014
The plane crash in Ukraine brings up many questions related to loss and grief. How will those left behind cope with the devastating event? How can we support them? With regard to how young people cope with bereavement, Dr. Mariken Spuij’s recent articles provide new insights.... Read more »
Spuij M, Prinzie P, Dekovic M, van den Bout J, & Boelen PA. (2013) The effectiveness of Grief-Help, a cognitive behavioural treatment for prolonged grief in children: study protocol for a randomised controlled trial. Trials, 395. PMID: 24252587
I am a neuroscientist, and as a neuroscientist I have a strange belief that most of who we are comes from our brains. My entire career is based around understanding behavior from this neural level which I feel to be fairly justifiable. So when I see paper looking at the genetics of behavior, I expect to see at […]... Read more »
Ripke, S., Neale, B., Corvin, A., Walters, J., Farh, K., Holmans, P., Lee, P., Bulik-Sullivan, B., Collier, D., Huang, H.... (2014) Biological insights from 108 schizophrenia-associated genetic loci. Nature, 511(7510), 421-427. DOI: 10.1038/nature13595
Coming from a, to put it gently, very broken home, my babysitter was the television. Yep, so now that you are feeling nice and awkward let’s talk television. New research, […]... Read more »
Linebarger DL, Barr R, Lapierre MA, & Piotrowski JT. (2014) Associations Between Parenting, Media Use, Cumulative Risk, and Children's Executive Functioning. Journal of developmental and behavioral pediatrics : JDBP, 35(6), 367-77. PMID: 25007059
How many times can you say the word “gonad” in a sentence without giggling? If the answer is one, then I congratulate you on turning thirteen. If the answer is many, then you must be a biologist. Biologists appreciate the value of a good gonad, and so should you. The gonad of the worm C. elegans serves as an important model in which to study tissue organization and development, as you’ll see in the paper that accompanies today’s image. At the end of cell division, cytokinesis typically results in two separate daughter cells. Some cytokinesis, though, is incomplete and leads to two daughter cells sharing cytoplasm. This shared cytoplasm, or syncytium, can be found in the germ cells of many species from worms to humans. The germline of the worm C. elegans is a polarized tube in which germ cells are arranged around the shared cytoplasmic core and move along a conveyer belt of oocyte production. Amini and colleagues recently reported on the formation of the syncytial C. elegans germline throughout development, and the role of the short Anillin family scaffold protein ANI-2. ANI-2 is localized to the intercellular bridges that connect the germ cells to the shared cytoplasm, and loss of ANI-2 results in destabilization of intercellular bridges and sterility. The defects seen in worms lacking ANI-2 are likely due to a loss of the stability and elasticity of the intercellular bridges that is required to compensate for the stress of cytoplasmic streaming during oogenesis. Images above show the germlines of wild-type and ani-2(-) worms at different larval stages (membranes in green; nuclei in red). Worms lacking ANI-2 have abnormal multinucleated germ cells (arrowheads). Amini, R., Goupil, E., Labella, S., Zetka, M., Maddox, A., Labbe, J., & Chartier, N. (2014). C. elegans Anillin proteins regulate intercellular bridge stability and germline syncytial organization originally published in the Journal of Cell Biology, 206 (1), 129-143 DOI: 10.1083/jcb.201310117... Read more »
Amini, R., Goupil, E., Labella, S., Zetka, M., Maddox, A., Labbe, J., & Chartier, N. (2014) C. elegans Anillin proteins regulate intercellular bridge stability and germline syncytial organization. originally published in the Journal of Cell Biology, 206(1), 129-143. DOI: 10.1083/jcb.201310117
The paper by Amanda Wood and colleagues  (open-access) makes a potentially very important contribution to the growing literature looking at how prenatal exposure to sodium valproate (VPA) may affect some children. Authors reported on: "regional structural cortical brain changes in humans exposed to VPA in utero" and specifically, increased cortical thickness in the left inferior frontal gyrus.Lightning and lava @ Oliver Spalt @ Wikipedia In case you need any background on the story behind pregnancy exposure to VPA, I would direct you to a few previous posts where the topic has been covered on this blog (see here and see here) with an autism slant. You might also read my small contribution to a more formal article on this topic here.Outside of any reported elevated risk of offspring autism or autistic traits associated with prenatal VPA exposure, I'm also minded to bring in some interesting work on intestinal inflammation being reported in a VPA mouse model (see here) to further highlight that important gut-brain axis which I seem to be a little obsessed with.The Wood paper is open-access and has some accompanying media coverage but a few pointers might be useful...Following other work by the authors on this topic  the idea behind this latest research was to apply the science of neuroimaging to a participant group comprising 16 children exposed to VPA in-utero compared with age- and sex-matched children not exposed to such pharmaceutics prenatally.MRI scans were taken and analysed and "whole brain group differences" assessed. Results: well, as discussed, there were some findings in terms of cortical thickness but also specifically with language skills in mind. To quote again: "Asymmetry of cortical thickness in the inferior frontal lobes was seen in controls but not cases". I understand that this finding might have some relevance to language processing  although set my non-expert stall out on such matters. As per that previous link  and other evidence , language functions in VPA exposed children tend to poorer compared to controls and to those exposed to other anti-convulsant medication during the nine months that made us. This last point on different medications potentially carrying different risk profiles  is something equally interesting.Allowing for the relatively small participant groups studied and the lack of any other research parameter such as looking at accompanying brain chemistry which may be important , the Wood paper offers some intriguing insights into how pregnancy VPA use might affect infant brain development. The very important detail of analysis being based on real human children and not rat offspring also invites some further examination of previous results based on rodents . Rats are rats, children are children.I'm going to leave you with a quote from the authors about their study: "VPA remains an important medication for people with epilepsy. What this study really tells us is that further research is required so that all women with epilepsy can make informed decisions about their medication use during pregnancy". I couldn't agree more, and as per the Treating for Two initiative, I'm not the only one.Music then... HRH Gaga and Just Dance.---------- Wood AG. et al. Altered cortical thickness following prenatal sodium valproate exposure. Annals of Clinical and Translational Neurology. 2014. July 3. doi: 10.1002/acn3.74 Nadebaum C. et al. Language skills of school-aged children prenatally exposed to antiepileptic drugs. Neurology. 2011 Feb 22;76(8):719-26. Powell HWR. et al. Hemispheric asymmetries in language-related pathways: A combined functional MRI and tractography study. NeuroImage. 2006; 32: 388-399. Shallcross R. et al. In utero exposure to levetiracetam vs valproate: development and language at 3 years of age. Neurology. 2014 Jan 21;82(3):213-21. Vajda FJE. et al. The teratogenicity of the newer antiepileptic drugs – an update. Acta Neurol Scand. 2014. July 18 Almeida LE. et al. Increased BDNF expression in fetal brain in the valproic acid model of autism. Mol Cell Neurosci. 2014 Mar;59:57-62. Mychasiuk R. et al. Effects of rat prenatal exposure to valproic acid on behaviour and neuro-anatomy. Dev Neurosci. 2012;34(2-3):268-76.----------Wood, A., Chen, J., Barton, S., Nadebaum, C., Anderson, V., Catroppa, C., Reutens, D., O'Brien, T., & Vajda, F. (2014). Altered cortical thickness following prenatal sodium valproate exposure Annals of Clinical and Translational Neurology DOI: 10.1002/acn3.74... Read more »
Wood, A., Chen, J., Barton, S., Nadebaum, C., Anderson, V., Catroppa, C., Reutens, D., O'Brien, T., & Vajda, F. (2014) Altered cortical thickness following prenatal sodium valproate exposure. Annals of Clinical and Translational Neurology. DOI: 10.1002/acn3.74
There has been a rash of great white shark sightings and attacks in the news recently. But, have attacks and sightings remained constant, or are they really on the increase? Several news studies provide evidence that the Marine Mammal Protection Act of 1972, the ban on commercial whaling in 1982, and the ban on great white hunting in 1997 have increased the number of sharks on the coasts of the North America and Australia. In addition, great white sharks live much longer than previously assumed, according to the result of a new vertebral column radiocarbon study. More sharks and long lives suggest that more attacks and sightings will be made.... Read more »
Burgess GH, Bruce BD, Cailliet GM, Goldman KJ, Grubbs RD, Lowe CG, MacNeil MA, Mollet HF, Weng KC, & O'Sullivan JB. (2014) A Re-Evaluation of the Size of the White Shark (Carcharodon carcharias) Population off California, USA. PloS one, 9(6). PMID: 24932483
Curtis TH, McCandless CT, Carlson JK, Skomal GB, Kohler NE, Natanson LJ, Burgess GH, Hoey JJ, & Pratt HL Jr. (2014) Seasonal Distribution and Historic Trends in Abundance of White Sharks, Carcharodon carcharias, in the Western North Atlantic Ocean. PloS one, 9(6). PMID: 24918579
Sprivulis P. (2014) Western Australia coastal shark bites: A risk assessment. The Australasian medical journal, 7(2), 137-42. PMID: 24611078
Hamady LL, Natanson LJ, Skomal GB, & Thorrold SR. (2014) Vertebral bomb radiocarbon suggests extreme longevity in white sharks. PloS one, 9(1). PMID: 24416189
Scientists at the University of the Basque Country (UPV/EHU) have studied the effects of using lanthanum-based perovskite ceramic contact materials in solid oxide fuel cells (SOFCs).... Read more »
Morán-Ruiz, A., Vidal, K., Laguna-Bercero, M., Larrañaga, A., & Arriortua, M. (2014) Effects of using (La0.8Sr0.2)0.95Fe0.6Mn0.3Co0.1O3 (LSFMC), LaNi0.6Fe0.4O3−δ (LNF) and LaNi0.6Co0.4O3−δ (LNC) as contact materials on solid oxide fuel cells. Journal of Power Sources, 1067-1076. DOI: 10.1016/j.jpowsour.2013.10.031
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