Post List

  • April 18, 2015
  • 07:24 PM
  • 9 views

Introducing Lassa-VSV, a hybrid virus that kills brain tumours

by Betty Zou in Eat, Read, Science

In a paper published this past week in the Journal of Virology, researchers at Yale University and Harvard University tried to overcome the neurotoxicity of VSV by engineering a hybrid virus. The researchers wanted to know if swapping out the G protein of VSV with the G protein from another virus would lessen the harmful effects of VSV on the brain while maintaining its tumour-killing abilities.... Read more »

Wollmann G, Drokhlyansky E, Cepko C, & van den Pol AN. (2015) Lassa-VSV chimeric virus safely destroys brain tumors. Journal of virology. PMID: 25878115  

  • April 18, 2015
  • 02:14 PM
  • 10 views

Kids with ADHD must squirm to learn

by Dr. Jekyll in Lunatic Laboratories

For decades, frustrated parents and teachers have barked at fidgety children with ADHD to “Sit still and concentrate!” But new research shows that if you want ADHD kids to learn, you have to let them squirm. The foot-tapping, leg-swinging and chair-scooting movements of children with attention-deficit/hyperactivity disorder are actually vital to how they remember information and work out complex cognitive tasks.... Read more »

  • April 18, 2015
  • 08:00 AM
  • 19 views

Is There Signal in the fMRI Noise?

by Neuroskeptic in Neuroskeptic_Discover

A new paper in Neuroimage suggests that methods for removing head motion and physiological noise from fMRI data might be inadvertently excluding real signal as well.

The authors, Molly G. Bright and Kevin Murphy of Cardiff, studied the technique called nuisance regression. It's a popular approach for removing fMRI noise. Noise reduction is important because factors such as head movement, the heart beat, and breathing, can contaminate the fMRI signal and lead to biased results. Nuisance regres... Read more »

  • April 18, 2015
  • 05:22 AM
  • 18 views

Autistic traits in adult-onset psychiatric disorders?

by Paul Whiteley in Questioning Answers

"To conclude, the presentation of ALTs [autistic-like traits/symptoms] at the sub-threshold or threshold level may be closely associated with BPD [bipolar disorder] and SZ [schizophrenia]."That was the conclusion reached in the paper by Junko Matsuo and colleagues [1] (open-access here) based on their analysis of nearly 300 adults aged between 25-59 years including those diagnosed with "MDD [major depressive disorder], n=125; bipolar disorder, n=56; schizophrenia, [and] n=44; healthy controls, n=65." The 'healthy controls' definition is that of the authors not mine."Autistic-like traits/symptoms were measured using the Social Responsiveness Scale for Adults [SRS-A]" we are told. Bearing in mind quite a bit of variation in the SRS-A scores across various diagnoses (including remitted and unremitted subgroupings too) there was a tendency towards "significantly higher total and social communication and autistic mannerisms subscale scores on the SRS-A compared to the HC [healthy controls] group."Further: "Almost half of the clinical subjects, except those with remitted MDD, fell into the mild-to-severe range for ALTs, which is typical for sub-threshold or threshold ASD [autism spectrum disorder]." This effect seemed to be independent of symptom severity in those with BPD or SZ. However: "ALTs in subjects with MDD were associated with the depressive symptom severity in our study; in other words, although subjects with severe depressive symptoms tended to exhibit high ALTs, subjects with less severe depressive symptoms did not differ from healthy controls with regard to the proportion or degree of high ALTs."Acknowledging the requirement for further investigation and the fact that authors "did not conduct a thorough and comprehensive evaluation of ASD" in their participant cohort, these are interesting findings. Regular readers might already have noted that I'm coming around to the idea that there may be some important links between the presentation of [some] autism and a variety of psychiatric diagnoses. I know this might take some people into some uncomfortable territory and muddy the waters when it comes to what exactly is being examined when it comes to autism research (see here for example) but to me this is really quite important science. Not least when it comes to the idea that a diagnosis of autism might elevate the risk of certain other labels being diagnosed (see here) and what that means for diagnostic vigilance and screening save any further health inequalities becoming apparent.The detail about autistic-like traits/symptoms being 'associated' with depressive symptoms is something particularly interesting. As per some recent discussions on this blog on depression and autism potentially being interlinked (see here) and some flesh being put on the scientific bones when it comes to what facets of depression might be linked to autism (see here), I think there is quite a lot more to see in this area. We're not yet in a position to talk about what [definite] mechanisms might be influencing any correlation between autistic traits and depressive symptoms although I'm minded to suggest that there may be some possible research avenues based on the peer-reviewed literature as it stands. Take for example the idea that vitamin D might be implicated in both cases of autism and depression (see here and see here respectively). Even more 'out there', I'd like to pose another question: could studies of gluten also provide some research leads (see here and see here)? Either way, the application of the spectrum of autistic traits is growing and getting ever more complicated [2].Music: The Strokes - Reptilia.----------[1] Matsuo J. et al. Autistic-Like Traits in Adult Patients with Mood Disorders and Schizophrenia. PLoS One. 2015 Apr 2;10(4):e0122711.[2] Koolschijn PC. et al. Are Autistic Traits in the General Population Related to Global and Regional Brain Differences? J Autism Dev Disorders. 2015. April 7.----------Matsuo J, Kamio Y, Takahashi H, Ota M, Teraishi T, Hori H, Nagashima A, Takei R, Higuchi T, Motohashi N, & Kunugi H (2015). Autistic-Like Traits in Adult Patients with Mood Disorders and Schizophrenia. PloS one, 10 (4) PMID: 25838109... Read more »

Matsuo J, Kamio Y, Takahashi H, Ota M, Teraishi T, Hori H, Nagashima A, Takei R, Higuchi T, Motohashi N.... (2015) Autistic-Like Traits in Adult Patients with Mood Disorders and Schizophrenia. PloS one, 10(4). PMID: 25838109  

  • April 18, 2015
  • 04:45 AM
  • 22 views

Major Advance in Artificial Photosynthesis

by Perikis Livas in Chilon

A potentially game-changing breakthrough in artificial photosynthesis has been achieved with the development of a system that can capture carbon dioxide emissions before they are vented into the atmosphere and then, powered by solar energy, convert that carbon dioxide into valuable chemical products, including biodegradable plastics, pharmaceutical drugs and even liquid fuels.... Read more »

  • April 17, 2015
  • 07:47 PM
  • 31 views

Study links brain anatomy, academic achievement, and family income

by Dr. Jekyll in Lunatic Laboratories

Many years of research have shown that for students from lower-income families, standardized test scores and other measures of academic success tend to lag behind those of wealthier students. Well now a new study offers another dimension to this so-called “achievement gap”After imaging the brains of high- and low-income students, they found that the higher-income students had thicker brain cortex in areas associated with visual perception and knowledge accumulation.... Read more »

Allyson Mackey et al. (2015) Students’ Family Income Linked With Brain Anatomy, Academic Achievement. Psychological Science. info:/

  • April 17, 2015
  • 03:56 PM
  • 21 views

Artificial blood vessel lets researchers assess clot removal devices

by Dr. Jekyll in Lunatic Laboratories

For the first time, researchers have created an in vitro, live-cell artificial vessel that can be used to study both the application and effects of devices used to extract life-threatening blood clots in the brain. The artificial vessel could have significant implications for future development of endovascular technologies, including reducing the need for animal models to test new devices or approaches.... Read more »

  • April 17, 2015
  • 03:09 PM
  • 32 views

Peer review: bad with it, worse without it

by SciELO in SciELO in Perspective

Peer review is seen as one of the pillars - if not the most important - of scientific communication. Despite the difficulties in going through the review process, the authors believe that the process improves the quality of the manuscript, and they want to be published on refereed journals that have a sound evaluation mechanism. Recent cases of attempted manipulation of the peer review process by fake reviews concern the international scientific community, however, it does not undermine its credibility and trust. The peer review crisis can be an opportunity to strengthen and improve the process. … Read More →... Read more »

Nicholas David, Hamid R. Jamali, Eti Herman, Carol Tenopir, Rachel Volentine, Suzie Allard, & Kenneth Levine. (2015) Peer review: still king in the digital age. Learned Publishing, 28(1), 15-21. DOI: http://dx.doi.org/10.1087/20150104  

  • April 17, 2015
  • 12:27 PM
  • 35 views

Electricity generation from pollution? Yes, it is possible !

by Ruth Garcia de la Calle in ADVOCATE Marie Curie Network

how bacteria batteries work and the role they play in contaminated groundwater remediation. ... Read more »

  • April 17, 2015
  • 12:25 PM
  • 25 views

On the trail of nitrogen to quantify N removal from contaminated aquifers

by Ruth Garcia de la Calle in ADVOCATE Marie Curie Network

Naomi Wells is working on developing better ways of measuring where water pollution comes from, and how long it’s going to stick around for. She uses light stable isotopes to improve the understanding of the fate and transport of key nutrients across biomes, landscapes, and scales.... Read more »

  • April 17, 2015
  • 11:15 AM
  • 25 views

The downfall of coal: job trends in a changing energy landscape

by Jonathan Trinastic in Goodnight Earth

Coal jobs have decreased dramatically in the past seven years, but are renewable energy and natural gas jobs compensating? New policy work reveals the geographical patterns in job changes that do not bode well for coal-producing states.... Read more »

  • April 17, 2015
  • 10:44 AM
  • 23 views

Sick Coyotes Are More Likely to Come into Cities

by Elizabeth Preston in Inkfish



Run-ins are on the rise between coyotes and city-dwelling humans, and scientists aren't sure why. Now researchers in Alberta think they've found a piece of the puzzle. Coyotes are more likely to creep into human spaces if they're unhealthy.

Conflict between humans and coyotes has increased during the last 20 years, write University of Alberta graduate student Maureen Murray and her coauthors. Yet coyotes were expanding their range for decades before that. They've spread to inhabit nearly ... Read more »

Murray, M., Edwards, M., Abercrombie, B., & St. Clair, C. (2015) Poor health is associated with use of anthropogenic resources in an urban carnivore. Proceedings of the Royal Society B: Biological Sciences, 282(1806), 20150009-20150009. DOI: 10.1098/rspb.2015.0009  

  • April 17, 2015
  • 10:03 AM
  • 41 views

Mapping the language system: Part 2

by Dan Mirman in Minding the Brain

This is the second of a multi-part post about a pair of papers that just came out (Mirman et al., 2015, in press). Part 1 was about the behavioral data: we started with 17 behavioral measures from 99 participants with aphasia following left hemisphere stroke. Using factor analysis, we reduced those 17 measures to 4 underlying factors: Semantic Recognition, Speech Production, Speech Recognition, and Semantic Errors. For each of these factors, we then used voxel-based lesion-symptom mapping (VLSM) to identify the left hemisphere regions where stroke damage was associated with poorer performance. The speech factors mapped out parallel ventral and dorsal systems around the Sylvian fissure for speech recognition and speech production, respectively.Credit: Mirman et al., Nature CommunicationsSpeech production deficits were associated with lesions in the "dorsal speech pathway" superior to the Sylvian fissure, primarily in the supramarginal gyrus and extending anteriorly into inferior postcentral, precentral, and premotor cortex (blue-green in the above figure). Speech recognition deficits were associated with lesions in the "ventral speech pathway" inferior to the Sylvian fissure, primarily in the superior temporal gyrus, including Wernicke’s area and extending deep into planum temporale (red-yellow on the above figure). This is somewhat different from the classic Broca-Wernicke-Lichtheim model of language: the speech production system is not localized just to inferior frontal regions ("Broca's area") but extends posteriorly through somatosensory and inferior parietal regions thought to be important for skilled action. In other words, speech production is a skilled action that involves an integrated neural system for motor planning, sensing positions of the articulators, and executing the movements. This is consistent with the frameworks developed by Greg Hickok (e.g., Hickok, 2012; Hickok & Poeppel, 2007) and (independently) Josef Rauschecker (e.g., Rauschecker & Scott, 2009). Our ventral speech recognition stream was largely restricted to the superior temporal gyrus and planum temporale (as in Rauschecker's model; Hickok's model includes middle and inferior temporal regions in speech recognition). Also, we did not find involvement of the auditory system in speech production -- such involvement is a key aspect of Hickok's model, though our orthogonal factors may have contributed to this lack of overlap.The semantic errors factor was associated with damage to the anterior temporal lobe, which should not be surprising because several previous studies (including previous VLSM with a subset of these participants) have found that left ATL damage is associated with production of semantic errors in picture naming. There is a lot of evidence that the ATLs are neural hubs for a distributed neural system supporting semantic memory. From that perspective, damage to ATL should impair semantic memory and semantic errors are symptom of that impairment. Following that logic, the semantic recognition deficits should also be associated with ATL damage but that's not what we found. Instead, we found that semantic recognition deficits were associated with damage to white matter medial to the insula and lateral to the basal ganglia, where three major tracts converge: the inferior fronto-occipital fasciculus (green in the figure below), the uncinate fasciculus (light blue in the figure below), and the anterior thalamic radiations (dark blue in the figure below).Credit: Mirman et al., Nature CommunicationsIn the second paper of the pair (in press at Neuropsychologia) we used a multivariate lesion-symptom mapping approach based on support-vector regression (Zhang et al., 2014) to re-analyze these data and ruled out some methodological VLSM issues as possible causes of this result. That paper discusses the implications of these results in more detail, but the upshot is that each of these tracts is important for semantic memory because they connect the frontal lobe with the distributed neural system involved in semantic memory. Our finding suggests that the convergence of these tracts creates a vulnerable "white matter bottleneck" where a small amount of damage can have a big effect on the connections between the frontal lobe and the rest of the brain.Hickok G (2012). Computational neuroanatomy of speech production. Nature Reviews Neuroscience, 13 (2), 135-145. PMID: 22218206Hickok, G. S., & Poeppel, D. (2007). The cortical organization of speech processing Nature Reviews Neuroscience, 8 (May), 393-402.... Read more »

Hickok G. (2012) Computational neuroanatomy of speech production. Nature Reviews Neuroscience, 13(2), 135-145. PMID: 22218206  

Hickok, Gregory S, & Poeppel, David. (2007) The cortical organization of speech processing. Nature Reviews Neuroscience, 8(May), 393-402. info:/

Zhang Y., Kimberg D.Y., Coslett H.B., Schwartz M.F., & Wang Z. (2014) Multivariate lesion-symptom mapping using support vector regression. Human Brain Mapping, 35(12), 5861-5876. PMID: 25044213  

  • April 17, 2015
  • 06:08 AM
  • 53 views

Marathon runners forget how painful it was

by BPS Research Digest in BPS Research Digest

Image: Flickr/GregThe sense of accomplishment from running a marathon is hugely uplifting. But let's not romanticise it, there's also a lot of pain involved. Despite this, many people pull on their running shoes time and again. A new study helps make sense of their behaviour – it turns out most marathon runners forget just how painful it was the last time. Przemyslaw Bąbel recruited 62 runners (39 men) who took part in the 11th Cracovia Marathon in Cracow, Poland in 2012. Moments after they crossed the finishing line he asked them to complete a series of questionnaires about the intensity of the pain they were in, its unpleasantness, and the positive and negative emotions they were feeling. The key finding is that when he contacted them again, three or six months later, and asked them to recall how much pain they'd been in at the end of the marathon, most of them underestimated the pain they'd experienced, both in terms of its intensity and unpleasantness. For example, of those contacted six months later, they remembered the pain intensity as being around 3.2 on a 7-point scale, on average, whereas their actual average pain intensity rating after the marathon was 5.5.Although the runners tended to underestimate their marathon pain, there was still a link between pain experienced and pain remembered – those who'd suffered more tended to remember the run as being more painful. Another key factor was negative emotion: those who reported feeling more emotions like distress and fear at the end of the marathon, tended to remember higher levels of pain and greater pain unpleasantness. This is consistent with what we know about pain experience having a powerful psychological component, influenced in part by context and a person's emotions. Other recent research has shown that, looking back, women tend to overestimate the pain they experienced after gynaecological surgery far more than after giving birth by caesarian section, presumably because the birth by caesarian, like completing a marathon, is an emotionally positive experience, whereas the gynaecological surgery is not.How we remember pain is a relatively understudied area, yet it has important real-life applications, such as people's ability to report the effectiveness of pain relief treatments, which of course depends on recalling accurately their past pain. Bąbel said this is the first time anyone has studied the memory of pain in the context of exercise. Much remains to be investigated, such as the influence on pain memory of people's goals, expectations and emotions prior to painful exercise._________________________________ Bąbel, P. (2015). Memory of pain induced by physical exercise Memory, 1-12 DOI: 10.1080/09658211.2015.1023809 --further reading--Why you're particularly likely to run your first marathon when your age ends in a "9"Acceptance, not distraction, is the way to deal with painPost written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

... Read more »

  • April 17, 2015
  • 04:38 AM
  • 44 views

Rhabdomyomas: an additional BHD hamartoma phenotype?

by Danielle Stevenson in BHD Research Blog

Hamartomas are benign, focal malformations formed by an excess of normal tissue growing in a disorganised fashion. Several hamartoma syndromes have been linked to aberrant mTOR signalling including BHD and Tuberous Sclerosis Complex (TSC). In addition to the predisposition of BHD patients to develop hair follicle hamartomas or fibrofolliculomas (Birt et al., 1977), Fuyura et al., (2012) propose that the pulmonary cysts in BHD patients are hamartoma-like cystic alveolar formations. The benign nature of these BHD growth phenotypes, in comparison to the potentially malignant growth of BHD renal cell carcinomas, shows that folliculin (FLCN) haploinsufficiency gives a less severe pathology than FLCN loss-of-function.

A recently published study from Bondavalli et al., (2015) was the first report of a cardiac rhabdomyoma (hamartoma) in an infant carrying a FLCN mutation. Cardiac rhabdoyomas are the most common cardiac tumour in children and can be sporadic or syndromic. Syndromic cardiac rhabdomyomas are associated with TSC and mutations in the TSC1 and TSC2 genes, however no such mutations were found in the infant.... Read more »

Bondavalli D, White SM, Steer A, Pflaumer A, & Winship I. (2015) Is cardiac rhabdomyoma a feature of Birt Hogg Dubé syndrome?. American journal of medical genetics. Part A, 167(4), 802-4. PMID: 25655561  

  • April 17, 2015
  • 03:52 AM
  • 37 views

Higher cancer mortality rates associated with mental illness

by Paul Whiteley in Questioning Answers

The findings reported by Steve Kisely and colleagues [1] were of some interest recently and their assertion that despite cancer incidence being "the same as the general population for most psychiatric disorders" or even slightly reduced when a diagnosis of schizophrenia was for example received, mortality due to cancer was "increased in psychiatric patients."Such findings were based on their examination of: "Mental health records [that] were linked with cancer registrations and death records from 2002 to 2007." It follows other work from these authors in this area including that looking at the gap in life expectancy 'from preventable physical illness in psychiatric patients' [2].Head-scratching (no, not for that reason) aside as to why cancer should be more deadly for those diagnosed with a psychiatric condition, the authors suggest that lifestyle factors such as alcohol or tobacco use probably wouldn't account for the quandary presented. One suggestion however - "inequity in access to specialist procedures" - does invite further investigation on the back of what has been previously reported in the area of psychiatric diagnosis and health inequality (see here for example).Indeed, 'disparities in cancer-related healthcare provision' was also one of the explanations put forward by one researcher who replied to my tweet about the Kisely paper (and he should know) complete with reference to research backing up this claim [3]. The Mitchell paper found that: "Rates of mammography screening are lower in women with mental illness, particularly women with SMI [severe mental illness]." Whilst this only covers one type of cancer and one type of screening method, the idea that cancer screening and treatment resources may be 'failing' those with a psychiatric diagnosis is an important one also covered by other researchers [4]. Indeed, Martens et al suggested that "good continuity of care by primary care physicians" may mitigate the issues like screening uptake and the idea of a more 'joined-up' service delivery between psychiatry and other branches of clinical care.Of the various messages to come from the Kisely findings, I'd like to think that a primary one is that of psychiatric diagnoses not appearing in some sort of clinical vacuum with regards to other symptoms and conditions being present and what effect they can have on quality of life. As per my ramblings about autism and the wide spectrum of comorbidities that can and do impact on health and quality of life, we need to be mindful of how presentation of behavioural / psychiatric symptoms can impact on the presentation and treatment of other conditions, many of which are perfectly treatable / manageable in modern medicine.But the question is not completely answered [5]... and one wonders whether the findings from Minna Torniainen and colleagues [6] on a potential 'protective effect' from antipsychotics on early mortality in cases of schizophrenia might also bring some potential explanation(s) to the table?To close: The Force Awakens trailer number 2.----------[1] Kisely S. et al. Why do psychiatric patients have higher cancer mortality rates when cancer incidence is the same or lower? Aust N Z J Psychiatry. 2015 Mar 31. pii: 0004867415577979.[2] Lawrence D. et al. The gap in life expectancy from preventable physical illness in psychiatric patients in Western Australia: retrospective analysis of population based registers. BMJ. 2013 May 21;346:f2539.[3] Mitchell AJ. et al. Breast cancer screening in women with mental illness: comparative meta-analysis of mammography uptake. Br J Psychiatry. 2014 Dec;205(6):428-35.[4] Martens PJ. et al. Are cervical cancer screening rates different for women with schizophrenia? A Manitoba population-based study. Schizophr Res. 2009 Aug;113(1):101-6.[5] Chang CK. et al. A cohort study on mental disorders, stage of cancer at diagnosis and subsequent survival. BMJ Open. 2014 Jan 29;4(1):e004295.[6] Torniainen M. et al. Antipsychotic Treatment and Mortality in Schizophrenia. Schizophr Bull. 2015; 41: 656-663.----------Kisely S, Forsyth S, & Lawrence D (2015). Why do psychiatric patients have higher cancer mortality rates when cancer incidence is the same or lower? The Australian and New Zealand journal of psychiatry PMID: 25829481... Read more »

  • April 16, 2015
  • 02:39 PM
  • 43 views

Could maple syrup help cut use of antibiotics?

by Dr. Jekyll in Lunatic Laboratories

Another reason to have those waffles… well maybe. Researchers have found that a concentrated extract of maple syrup makes disease-causing bacteria more susceptible to antibiotics. In an ever increasing antibiotic resistant world, this news is almost as sweet as the syrup (okay no more bad puns). The findings suggest that combining maple syrup extract with common antibiotics could increase the microbes’ susceptibility, leading to lower antibiotic usage.... Read more »

  • April 16, 2015
  • 01:10 PM
  • 39 views

Counting Chicks

by sedeer in Inspiring Science

It’s probably not a surprise that humans aren’t the only animals with a sense of numbers. While they’re probably not …Continue reading →... Read more »

  • April 16, 2015
  • 10:32 AM
  • 45 views

What is Neurofeedback Training for ADHD?

by William Yates, M.D. in Brain Posts

There are a variety of behavioral strategies for treating the attention and activity components of attention deficit hyperactivity disorder (ADHD).One of these strategies is known as neurofeedback. A recent study in the journal Pediatrics found evidence for effectiveness of in-school neurofeedback for ADHD in a randomized controlled trial.In this trial, 104 children between the ages of 7 and 11 years of age were randomized to one of three research arms: in-school neurofeedback, cognitive therapy and control condition.Subject children in the study received a supervised 45 minute intervention three times per week over a 5 month period.The in-school neurofeedback system utilized in this study was the Play Attention system by Unique Logic and Technology. This system is a computer-based program that is installed by CD on a Mac or PC computer. Users wear a bicycle helmet with sensors and manipulate screen figures. The goal is to decrease brain EEG theta activity and increase EEG beta activity. The feedback provided by the system allows users to get real time information on EEG activity.In the clinical trial students randomized to the in-school neurofeedback arm outperformed on key outcome variables including:Conners 3-P Inattention scaleConners 3-P Executive function scaleConners 3-P Hyperactivity/Impulsivity scaleBRIEF Global Executive Composite scaleChildren were allowed to be on stimulant medication in this study. Stimulant dosages were independently monitored over the course of the study. Subjects in the neurofeedback arm received a equal dose of stimulant during the study while the other two groups had a naturalistic increase in dose. This suggests the neurofeedback intervention reduced need for escalating doses of stimulant.The authors note that the use of a helmet in the neurofeedback group alone prevented complete blinding in the study and could confound their findings.Readers with more information about this study can access the free full-text manuscript by clicking on the PMID link below. Additionally, the Play Attention neurofeedback website can be accessed here. I am not paid for this post and receive no money from the neurofeedback company.Figure of frontal lobe known to be involved in attention and executive function is a screen shot from the iPad app Brain Tutor.Follow the author on Twitter WRY999.Steiner NJ, Frenette EC, Rene KM, Brennan RT, & Perrin EC (2014). In-school neurofeedback training for ADHD: sustained improvements from a randomized control trial. Pediatrics, 133 (3), 483-92 PMID: 24534402... Read more »

  • April 16, 2015
  • 09:48 AM
  • 43 views

Mapping the language system: Part 1

by Dan Mirman in Minding the Brain

My colleagues and I have a pair of papers coming out in Nature Communications and Neuropsychologia that I'm particularly excited about. The data came from Myrna Schwartz's long-running anatomical case series project in which behavioral and structural neuroimaging data were collected from a large sample of individuals with aphasia following left hemisphere stroke. We pulled together data from 17 measures of language-related performance for 99 participants, each of those participants was also able to provide high-quality structural neuroimaging data to localize their stroke lesion. The behavioral measures ranged from phonological processing (phoneme discrimination, production of phonological errors during picture naming, etc.) to verbal and nonverbal semantic processing (synonym judgments, Camel and Cactus Test, production of semantic errors during picture naming, etc.). I have a lot to say about our project, so there will be a few posts about it. This first post will focus on the behavioral data.We used factor analysis to reduce the 17 measures to 4 underlying functional systems (also called principal components, or latent variables, or factors), which captured 76% of the variance in the original data:Semantic Recognition: difficulty recognizing the meaning or relationship of concepts, such as synonym judgments, semantic category discrimination, Camel and Cactus Test, and Peabody Picture Vocabulary Test.Speech Recognition: difficulty with fine-grained speech perception, such as phoneme discrimination and rhyme judgment.Speech Production: difficulty planning and executing speech actions, such as word and nonword repetition and the tendency to make phonological errors during picture naming (e.g., giraffe --> “girappe”).Semantic Errors: making semantic errors during picture naming (e.g., giraffe --> “zebra”), regardless of performance on other tasks that involved processing meaning.These four factors may seem very intuitive and perhaps inevitable, but there are several alternative outcomes that would have been equally intuitive, so I want to highlight two ways in which these results might be surprising. First, the behavioral tests included measures of verbal short-term memory (immediate serial recall, semantic and phonological span tasks, nonword repetition), so we could have observed a STM factor. Instead, semantic STM was part of the semantic recognition factor and ISR and phonological STM was part of the speech recognition and production factors. This is not to say that STM is not important, but the domain-specific contribution (i.e., phonological or semantic processing) seems to be more important than a domain-general STM contribution. Second, we might have found dissociations between performance on verbal (words) and nonverbal (pictures) semantic tasks. Consider the three semantic measures mentioned above: synonym judgments, Camel and Cactus Test, and making semantic errors during picture naming. A core semantic deficit (such as semantic dementia) should affect performance on all three, which would produce a single semantic factor. A verbal semantic deficit should primarily affect just synonym judgments (and other semantic tasks that are entirely in the verbal domain) and possibly production of semantic errors (since it includes a verbal component). Instead, we found very high correlations among tasks involving extracting semantic information from either words or pictures (or both, such as word-to-picture matching), and performance on these tasks were not very correlated with production of semantic errors. We take this to mean that there is an important distinction between the functional systems involved in extracting semantic information (Semantic Recognition) and using that information to drive (verbal) behavior.The next post (Part 2) will focus on the lesion-symptom mapping results, which identify the left hemisphere regions critical for each of the four functional systems identified in the factor analysis.Mirman, D., Chen, Q., Zhang, Y., Wang, Z., Faseyitan, O.K., Coslett, H.B., & Schwartz, M.F. (2015). Neural Organization of Spoken Language Revealed by Lesion-Symptom Mapping. Nature Communications, 6 (6762), 1-9. DOI: 10.1038/ncomms7762.Mirman, D., Zhang, Y., Wang, Z., Coslett, H.B., & Schwartz, M.F. (in press). The ins and outs of meaning: Behavioral and neuroanatomical dissociation of semantically-driven word retrieval and multimodal semantic recognition in aphasia Neuropsychologia. ... Read more »

Mirman, D., Chen, Q., Zhang, Y., Wang, Z., Faseyitan, O.K., Coslett, H.B., & Schwartz, M.F. (2015) Neural Organization of Spoken Language Revealed by Lesion-Symptom Mapping. Nature Communications, 6(6762), 1-9. info:/

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