Posts tagged brain

ScienceDaily (June 15, 2012) — Researchers at The University of Nottingham have identified three sets of genetic markers that could potentially pave the way for new diagnostic tools for a deadly type of brain tumour that mainly targets children.

The study, published in the latest edition of the journal Lancet Oncology, was led by Professor Richard Grundy at the University’s Children’s Brain Tumour Research Centre and Dr Suzanne Miller, a post doctoral research fellow in the Centre.

It focuses on a rare and aggressive cancer called Central Nervous System primitive neuro-ectodermal brain tumours. Patients with CNS PNET have a very poor prognosis and current treatments, including high dose chemotherapy and cranio-spinal radiotherapy are relatively unsuccessful and have severe lifelong side-effects. This is particularly the case in very young children.

Despite the need for new and more effective treatments, little research has been done to examine the underlying causes of CNS PNET, partly due to their rarity. The Nottingham study aimed to identify molecular markers as a first step to improving the treatments and therapies available to fight the cancer.

The Nottingham team collaborated with researchers at the Hospital for Sick Kids in Toronto, Canada, to perform an International study collecting 142 CNS PNET samples from 20 institutions in nine countries.

Professor Richard Grundy said: “Following our earlier research we realised that an international effort was needed to bring sufficient numbers of cases together to make the breakthrough we needed to better understand this disease or indeed diseases identified in our study. The next step is to translate this knowledge into improving treatments.”

By studying the genetics of the tumours, they discovered that instead of one cancer, the tumours have three sub-types featuring distinct genetic abnormalities and leading to different outcomes for patients.

They found that each group had its own genetic signature through subtle differences in the way they expressed two genetic markers, LIN28 and OLIG2.

When compared with clinical factors including age, survival and metastases (the spread of the tumours through the body), they discovered that group 1 tumours (primitive neural) were found most often in the youngest patients and had the poorest survival rates. Patients with group 3 tumours had the highest incidence of metastases at diagnosis.

Ultimately, the research has identified the two genetic markers LIN28 and OLIG2 as a promising basis for more effective tools for diagnosing and predicting outcomes for young patients with these types of brain tumours.

The research was funded by the Canadian Institute of Health Research, the Brainchild/Sick Kids Foundation and the Samantha Dickson Brain Tumour Trust.

Chief Executive of Samantha Dickson Brain Tumour Trust, Sarah Lindsell, said: “As the UK’s leading brain tumour charity, and the largest dedicated funder of brain tumour research, we are delighted that our investment has led to such significant success. It is great to see that understanding of these tumours is improving — this is desperately needed given the poor outcomes for children with this tumour. Samantha Dickson Brain Tumour Trust is proud to have been instrumental in this work.”

Source: Science Daily

June 15, 2012

The research led by Newcastle University’s Dr Mark Cunningham and Professor Miles Whittington and supported by the Dr Hadwen Trust for Humane Research, indicates a novel electrical bio-marker in humans.

The brain produces electrical rhythms and using EEG - electrodes on the scalp - researchers were able to monitor the brain patterns in patients with epilepsy. Both in patients and in brain tissue samples the team were able to witness an abnormal brain wave noticeable due to its rapidly increasing frequency over time.

Comparing these to a musical ‘glissando’, an upwards glide from one pitch to another, the team found that this brain rhythm is unique to humans and they believe it could be related to epilepsy.

Dr Cunningham, senior lecturer in Neuronal Dynamics at Newcastle University said: “We were able to examine EEG collected from patients with drug resistant epilepsy who were continually monitored over a two week period. During that time we noticed patterns of electrical activity with rapidly increasing frequency, just like glissandi, emerging in the lead-up to an epileptic seizure.”

"We are in the early days of the work and we want to investigate this in a larger group of patients but it may offer a promising insight into when a seizure is going to start."

Professor Whittington added: “Classical composers such as Gustav Mahler are famous for using notes of rapidly increasing pitch – called glissando - to convey intense expressions of anticipation. Similarly we identified glissando-like patterns of brain electrical activity generated in anticipation of seizures in patients with epilepsy.”

The team recorded electrical activity taken from patients in Newcastle and Glasgow with the help of collaborators Dr Roderick Duncan and Dr Aline Russell and worked in collaboration with the Epilepsy Surgery Group at Newcastle General Hospital part of the Newcastle Hospitals NHS Foundation Trust.

Having received permission from patients to use brain tissue removed during an operation to cure their seizures, the team were able to observe and study in great detail glissando discharges in slices of this human epileptic tissue maintained in the lab.

Publishing in Epilepsia online, the team discovered that glissandi are highly indicative of pathology associated with human epilepsy and, unlike other forms of epileptic activity studied previously, are extremely difficult to reproduce in normal, non-epileptic brain tissue. The team worked with Professor Roger Traub at the IBM Watson Research Centre in New York to provide predictions using highly detailed computational models. By manipulating the chemical conditions surrounding human epileptic brain tissue according to these predictions, they discovered that glissandi did not require any of the conventional chemical connections between nerve cells thought to underlie most brain functions. Instead, glissandi were generated by a combination of large changes in the pH of the tissue, specific electrical properties of certain types of nerve cell and, most importantly, direct electrical connections between these nerve cells.

"This work also suggests that given the lengths one has to go to reproduce this experimentally in rodents that the glissandi may be a unique feature of the human epileptic brain," explains Dr Cunningham.

Dr Kailah Eglington, Chief Executive of the Dr Hadwen Trust, said: “Of all human brain disorders, epilepsy research ranks as one that currently employs substantial numbers of laboratory animals worldwide.

"Dr Cunningham’s work at Newcastle University aims to address the shortcomings of existing animal-based research by removing animals from the equation and addressing the issue directly in humans."

Provided by Newcastle University

Source: medicalxpress.com

June 15, 2012

The first large non-commercial study to investigate whether the main active constituent of cannabis (tetrahydrocannabinol or THC) is effective in slowing the course of progressive multiple sclerosis (MS) shows that there is no evidence to suggest this; although benefits were noted for those at the lower end of the disability scale.

The CUPID (Cannabinoid Use in Progressive Inflammatory brain Disease) study was carried out by researchers from the Peninsula College of Medicine and Dentistry (PCMD), Plymouth University. The study was funded by the Medical Research Council (MRC) and managed by the National Institute for Health Research (NIHR) on behalf of the MRC-NIHR partnership, the Multiple Sclerosis Society and the Multiple Sclerosis Trust.

The preliminary results of CUPID are to be presented by lead researcher Professor John Zajicek at the Association of British Neurologists’ Annual Meeting in Brighton on Tuesday 29th May.

CUPID enrolled nearly 500 people with MS from 27 centres around the UK, and has taken eight years to complete. People with progressive MS were randomised to receive either THC capsules or identical placebo capsules for three years, and were carefully followed to see how their MS changed over this period. The two main outcomes of the trial were a disability scale administered by neurologists (the Expanded Disability Status Scale), and a patient report scale of the impact of MS on people with the condition (the Multiple Sclerosis Impact Scale 29).

Overall the study found no evidence to support an effect of THC on MS progression in either of the main outcomes. However, there was some evidence to suggest a beneficial effect in participants who were at the lower end of the disability scale at the time of enrolment but, as the benefit was only found in a small group of people rather than the whole population, further studies will be needed to assess the robustness of this finding. One of the other findings of the trial was that MS in the study population as a whole progressed slowly, more slowly than expected. This makes it more challenging to find a treatment effect when the aim of the treatment is that of slow progression.

As well as evaluating the potential neuroprotective effects and safety of THC over the long-term, one of the aims of the CUPID study was to improve the way that clinical trial research is done by exploring newer methods of measuring MS and using the latest statistical methods to make the most of every piece of information collected. This analysis will continue for several months. The CUPID study will therefore provide important information about conducting further large scale clinical trials in MS.

Professor John Zajicek, Professor of Clinical Neuroscience at PCMD, Plymouth University, said: “To put this study into context: current treatments for MS are limited, either being targeted at the immune system in the early stages of the disease or aimed at easing specific symptoms such as muscle spasms, fatigue or bladder problems. At present there is no treatment available to slow MS when it becomes progressive. Progression of MS is thought to be due to death of nerve cells, and researchers around the world are desperately searching for treatments that may be ‘neuroprotective’. Laboratory experiments have suggested that certain cannabis derivatives may be neuroprotective.”

He added: “Overall our research has not supported laboratory based findings and shown that, although there is a suggestion of benefit to those at the lower end of the disability scale when they joined CUPID, there is little evidence to suggest that THC has a long term impact on the slowing of progressive MS.”

Dr Doug Brown, Head of Biomedical Research at the MS Society, said: “There are currently no treatments for people with progressive MS to slow or stop the worsening of disability. The MS Society is committed to supporting research in this area and this was an important study for us to fund. While this study sadly suggests THC is ineffective at slowing the course of progressive MS, we will not stop our search for effective treatments. We are encouraged by the possibility shown by this study that THC may have potential benefits for some people with MS and we welcome further investigation in this area.”

Provided by The Peninsula College of Medicine and Dentistry

Source: medicalxpress.com

June 15, 2012 By Angela Herring

Object manip­u­la­tion or tool use is almost a uniquely human trait, said Dagmar Sternad, director of Northeastern’s Action Lab, a research group inter­ested in move­ment coor­di­na­tion. “Not only does it require cer­tain cog­ni­tive abil­i­ties but also dis­tinct motor abilities.”

Professor Dagmar Sternad and postdoctoral researcher C.J. Hasson show that we subconsciously adjust our “safety margin” when we move a dynamic object like a cup of coffee based on the amount of variability in the situation. Credit: John Guillemin

Simply moving one’s own body, for instance by directing a hand toward a coffee cup, requires the orga­ni­za­tion of var­ious phys­i­o­log­ical sys­tems including the cen­tral and periph­eral ner­vous sys­tems and the mus­cu­loskeletal system.

Once the hand grasps and picks up the cup, the ques­tions become even more com­pli­cated. What if the cup is filled with liquid? At this point, the com­plexity of the con­trol problem bal­loons — the pres­ence of the liquid intro­duces non­linear fluid dynamics with the risk of a spill because of the inherent vari­ability in one’s movement.

Sternad, a pro­fessor of , biology, elec­trical and com­puter engi­neering and physics and post­doc­toral researcher C.J. Hasson are inter­ested in how we adapt our move­ment strate­gies when inter­acting with dynamic objects in the environment.

In a recent paper pub­lished in the Journal of Neu­ro­phys­i­ology, Hasson and Sternad explored the ques­tion by looking at the everyday task of manip­u­lating a cup of coffee. They show that how we adapt our move­ment strate­gies is directly related to the amount of vari­ability and reli­a­bility in our sur­round­ings and ourselves.

“Because we’re humans and not machines, we’re noisy and vari­able,” said Hasson. “We can’t expect that a move­ment will unfold exactly as we planned it.”

For the study, 18 healthy par­tic­i­pants vis­ited the Action Lab to play a video game, wherein they attempted to move a vir­tual cup filled with vir­tual liquid across a large video screen. Instead of a normal video-game con­troller, sub­jects moved the vir­tual cup by grasping a manip­u­landum — a large robotic arm. Sim­ilar to the real-life sce­nario, the robot sim­u­lated the forces one would feel from the weight of the object and the sloshing of the liquid in the cup.

They asked par­tic­i­pants to move the cup across the screen within a com­fort­able time of two sec­onds, a task for which there is an infi­nite number of pos­si­bil­i­ties. You could move fast for one second and slow for one second, slow for a half second and then fast for one and a half sec­onds. The team hypoth­e­sized that par­tic­i­pants would nat­u­rally adapt a safe move­ment strategy with prac­tice — and they did.

But the most intriguing result, said Hasson, was that the size of each participant’s safety margin —or how close they let the liquid get to the edge of the cup — could be pre­dicted by how vari­able they were in their move­ments. Those with more vari­ability tended to adapt a “safer” strategy with a larger safety margin.

“If you have a large safety margin and I move with a small margin, the ques­tion is, ‘Why am I more risky than you?’” Hasson said. “Well, you may find that I am much more con­sis­tent in my move­ments, so I don’t need a big safety margin. If you’re more vari­able, you need a larger safety margin.”

The results have impli­ca­tions in assessing elderly patients and patients of motor dis­or­ders such as cere­bral palsy. “If vari­ability deter­mines the move­ments that you do, maybe that’s an inter­ven­tion point,” said Sternad.

Provided by Northeastern University

Source: medicalxpress.com

June 15, 2012

Whether or not a neuron transmits an electrical impulse is a function of many factors. European research is using a heady mixture of techniques – molecular, microscopy and electrophysiological – to identify the necessary input for nerve transmission in the cortex.

Credit: Thinkstock

In the central nervous system (CNS), a nerve cell or neuron has a ‘forest’ of elaborate dendritic trees arising from the cell body. These literally receive many thousands of synapses (junctions that allow transmission of a signal) at positions around the tree. These inputs then are able to generate an impulse, or ‘spike’, known as an action potential at the initial part of the axon.

Previous research has confirmed that an activated synapse will generate an electric signal as a result of neurotransmitters released from pre-synaptic axons. Electrical recordings from the neocortex have confirmed that, in line with the cable theory prediction, that modulation of potential at the dendrite is highly distance-dependent from the cell body or soma.

The ‘Information processing in distal dendrites of neocortical layer 5 pyramidal neurons’ (Channelrhodopsin) project aimed to shed more light on how more distal sites in the ‘tree’ influence the action potential of the post-synaptic neuron. Furthermore, they investigated exactly how dendritic spikes can be generated, another issue about which there is little information so far.

Recent research has highlighted the importance of activation of N-methyl-D-aspartate (NMDA) receptors to bring about the production of a signal that will proceed to the soma and then result in a spike. There is also indirect evidence that interneurons targeting dendrites can control level of dendrite excitability.

Channelrhodopsin scientists simultaneously recorded the pre- and post-synaptic electrical recordings of identified interneurons and a special type of neuron, pyramidal cells that are primary excitation units in the mammalian cortex.

The project team first characterised the different types of inhibitory neuron deep in the cortex in layer 5 at apical tuft dendrites. The researchers then showed that a special type of inhibitory interneuron in the outer layer of the neocortex can suppress dendritic spiking in layer 5.

Project results show that a superficial inhibitory neuron can impact information processing in a specific pyramidal neuron. The research will have massive implications for neuroscience and help to unravel the integrative operations of CNS neurons.

Provided by CORDIS

Source: medicalxpress.com

ScienceDaily (June 14, 2012) — Rockville, Md. — Scientists have found new evidence that people spot a face in the crowd more quickly when teeth are visible — whether smiling or grimacing — than a face with a particular facial expression. The new findings, published in the Journal of Vision, counters the long held “face-in -the-crowd” effect that suggests only angry looking faces are detected more readily in a crowd.

Examples of stimuli — closed mouth and open mouth with visible teeth — presented in the experiment. (Credit: ARVO)

"The research concerned with the face-in-the-crowd effect essentially deals with the question of how we detect social signals of friendly or unfriendly intent in the human face," said author Gernot Horstmann, PhD, of the Center for Interdisciplinary Research and Department of Psychology at Bielefeld University, Germany. "Our results indicate that, contrary to previous assertions, detection of smiles or frowns is relatively slow in crowds of neutral faces, whereas toothy grins and snarls are quite easily detected."

In two studies, the researchers asked subjects to search for a happy or an angry face within a crowd of neutral faces, and measured the search speed. While the search was relatively slow when emotion was signaled with a closed mouth face, the speed search doubled when emotion was signaled with an open mouth and visible teeth. This was the case for both happy and angry faces, and happy faces were found even somewhat faster than angry faces.

Horstmann and his colleagues conducted these experiments as a result of discrepancies in previous studies that investigated visual search for emotional faces. According to the research team, the inconsistent results with respect to which of the two expressions are found faster — the happy face or the angry face — suggested that the emotional expression category could not be the only important factor determining the face-in- the-crowd effect.

The scientists believe this new study may explain the discrepancies. “This will probably inspire researchers to clarify whether emotion and, in particular, threat plays an additional, unique role in face detection,” said Horstmann.

Source: Science Daily

ScienceDaily (June 14, 2012) — No effective treatments are currently available for the prevention or cure of Alzheimer’s disease (AD), the most frequent form of dementia in the elderly. The most recognized risk factors, advancing age and having the apolipoprotein E Ɛ4 gene, cannot be modified or treated. Increasingly, scientists are looking toward other risk factors to identify preventive and therapeutic strategies. Much attention recently has focused on the metabolic syndrome (MetS), with a strong and growing body of research suggesting that metabolic disorders and obesity may play a role in the development of dementia.

A new supplement to the Journal of Alzheimer’s Disease provides a state-of-the-art assessment of research into the link between metabolic syndrome and cognitive disorders. The supplement is guest edited by Vincenza Frisardi, of the Department of Neurological and Psychiatric Sciences, University of Bari, and the Geriatric Unit and Gerontology-Geriatrics Research Laboratory, IRCCS, Foggia, Italy, and Bruno P. Imbimbo, Research and Development Department, Chiesi Farmaceutici, Parma, Italy.

The prevalence of MetS and obesity has increased over the past several decades. MetS is a cluster of vascular and metabolic risk factors including obesity, hypertension, an abnormal cholesterol profile, and impaired blood glucose regulation. “Although molecular mechanisms underlying the relationship between MetS and neurological disorders are not fully understood, it is becoming increasingly clear that cellular and biochemical alterations observed in MetS may represent a pathological bridge between MetS and various neurological disorders,” explains Dr. Frisardi.

Type 2 diabetes (T2D) has been linked with cognitive impairment in a number of studies. The risk for developing both T2D and AD increases proportionately with age, and evidence shows that individuals with T2D have a nearly twofold higher risk of AD than nondiabetic individuals.

Paula I. Moreira, Faculty of Medicine and Center for Neuroscience and Cell Biology, University of Coimbra, Portugal, outlines some of the likely mechanisms. Both AD and T2D present similar abnormalities in the mitochondria, which play a pivotal role in cellular processes that impair their ability to regulate oxidation in the cell. Human amylin, a peptide that forms deposits in the pancreatic cells of T2D patients, shares several properties with amyloid-ß plaques in the Alzheimer’s brain. Insulin resistance is another feature shared by both disorders. Impairment of insulin signalling is directly involved in the development of tau tangles and amyloid ß (Aß) plaques. “Understanding the key mechanisms underlying this deleterious interaction may provide opportunities for the design of effective therapeutic strategies,” Dr. Moreira notes.

In another article, author, José A. Luchsinger of the Division of General Medicine, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, notes that while there seems to be little dispute that T2D can cause cerebrovascular disease and vascular cognitive impairment, whether T2D can cause late onset AD remains to be determined. “Although the idea is highly speculative, the association between T2D and cognitive impairment may not be causal. Several lines of evidence provide some support to the idea that late onset Alzheimer’s disease could cause T2D, or that both could share causal pathways,” he notes. He reviews epidemiological, imaging, and pathological studies and clinical trials to provide insight. “Given the epidemic of T2D in the world, it’s important to determine whether the association between T2D and cognitive impairment, particularly late onset AD, is causal and if so, what are the mechanisms underlying it.”

Dr. Frisardi notes that most efforts by the pharmaceutical industry have been directed against the production and accumulation of amyloid-ß. “Unfortunately, these efforts have not produced effective therapies yet, since the exact mechanisms of AD are largely unknown. Given that the onset of AD most likely results from the interaction of genetic and environmental factors, the research agenda should consider new platforms of study, going beyond the monolithic outlook of AD, by synthesizing epidemiological, experimental, and biological data under a unique pathophysiological model as a point of reference for further advances in the field.”

Source: Science Daily

June 14, 2012

Visual and auditory stimuli that elicit high levels of engagement and emotional response can be linked to reliable patterns of brain activity, a team of researchers from The City College of New York and Columbia University reports. Their findings could lead to new ways for producers of films, television programs and commercials to predict what kinds of scenes their audiences will respond to.

"Peak correlations of neural activity across viewings can occur in remarkable correspondence with arousing moments of the film,” the researchers said in an article published in the journal Frontiers in Human Neuroscience. “Moreover, a significant reduction in neural correlation occurs upon a second viewing of the film or when the narrative is disrupted by presenting its scenes scrambled in time.”

The researchers used EEG (electroencephalography), which measures electrical activity across the scalp, to collect data on brainwaves of 20 human subjects, who were shown scenes from three films with repeat viewings. Two films, Alfred Hitchcock’s “Bang! You’re Dead” and Sergio Leone’s “The Good, the Bad and the Ugly,” contained moments of high drama expected to trigger responses. The third, an amateur film of people walking on a college campus, was used as a control.

"We found moments of high correlation (between brainwave activity during separate viewings) and moments when this did not occur," said Dr. Lucas C. Parra, Herbert G. Kayser Professor of Biomedical Engineering in CCNY’s Grove School of Engineering, and a corresponding author. "By looking at patterns of oscillation we could tell at which moments a person was particularly engaged. Additionally, we could see whether the correlation occurred across subjects and repeated viewings."

[Video: Reading the Brain during Film Viewing]
Video of EEG readings during scenes from “Bang, You’re Dead”

Measurements along the EEG alpha activity scale show the degree of attentiveness in a person, he explained. When the oscillations are strong, a person is relaxed, i.e. not engaged. When a person is very attentive, alpha activity is low.

Peaks in engagement were correlated to three kinds of scenes, said Dr. Jasek Dmochowski, a post-doctoral fellow in the Grove School and a corresponding author. They included moments with powerful visual cues, such as a close-up on the gun in “Bang! You’re Dead,” scenes with ominous music in which the visual component was not significant, and meaningful scene changes.

The researchers found significantly less neural correlation on participants’ second viewings and when scenes were scrambled and shown out of sequence. “Following a narrative is complex and involves a lot of distributed processing. When a person doesn’t have a sense of the narrative there is much less correlation (across views of the same or another subject),” Dr. Dmochowski said.

Having demonstrated the correlations between intense stimuli and brainwave reliability, the research team now wants to locate where in the brain the response occurs, Professor Parra said. He wants to deploy a combination of EEG and magnetic resonance imaging to “get the best of both worlds:” the fine temporal resolution of EEG and the detailed imagery of MRI.

The team sees several potential applications for the ability to quantify levels of engagement, including neuro-marketing, quantitative assessment of entertainment, measuring the impact of narrative discourse and the study of attention deficit disorders. “Advertisers would love to know where and when an ad is engaging,” he noted.

"The potential to measure engagement is huge since this provides an objective way to collect data," added Dr. Dmochowski, who currently is investigating whether there is a correlation between social media usage and brain activity in young people while watching “The Walking Dead,” a drama series on the American Movie Classics cable network.

"We are mining Twitter to measure the depth of watching," he continued. "We think there will be many correlations between scenes that elicit social media responses and neural signatures, and we can look at both positive and negative responses."

Provided by City College of New York

Source: medicalxpress.com

ScienceDaily (June 13, 2012) — Ever wonder why Jimi Hendrix’s rendition of “The Star-Spangled Banner” moved so many people in 1969 or why the music in the shower scene of “Psycho” still sends chills down your spine?

Jimi Hendrix (Credit: Public domain image, courtesy of UCLA)

A UCLA-based team of researchers has isolated some of the ways in which distorted and jarring music is so evocative, and they believe that the mechanisms are closely related to distress calls in animals.

They report their findings in the latest issue of the peer-reviewed scientific journal Biology Letters, which publishes online June 12.

"Music that shares aural characteristics with the vocalizations of distressed animals captures human attention and is uniquely arousing," said Daniel Blumstein, one of the study’s authors and chair of the UCLA Department of Ecology and Evolutionary Biology.

Read more …

ScienceDaily (June 13, 2012) — Children who are skilled in understanding how shapes fit together to make recognizable objects also have an advantage when it comes to learning the number line and solving math problems, research at the University of Chicago shows.

The work is further evidence of the value of providing young children with early opportunities in spatial learning, which contributes to their ability to mentally manipulate objects and understand spatial relationships, which are important in a wide range of tasks, including reading maps and graphs and understanding diagrams showing how to put things together. Those skills also have been shown to be important in Science Technology, Engineering and Math (STEM) fields.

Scholars at UChicago have shown, for instance, that working with puzzles and learning to identify shapes are connected to improved spatial understanding and better achievement, particularly in geometry. A new paper, however, is the first to connect robust spatial learning with better comprehension of other aspects of mathematics, such as arithmetic.

"We found that children’s spatial skills at the beginning of first and second grades predicted improvements in linear number line knowledge over the course of the school year," said Elizabeth Gunderson, a UChicago postdoctoral scholar who is lead author of the paper, "The Relation Between Spatial Skill and Early Number Knowledge: The Role of the Linear Number Line," published in the current issue of the journal Development Psychology.

In addition to finding the importance of spatial learning to improving understanding of the number line, the team also showed that better understanding of the number line boosted mathematics performance on a calculation task.

Read more …