Posts tagged psychology

ScienceDaily (July 20, 2012) — Conditions such as Parkinson’s disease are a result of pathogenic changes to proteins. In the neurodegenerative condition of Parkinson’s disease, which is currently incurable, the alpha-synuclein protein changes and becomes pathological. Until now, there have not been any antibodies that could help to demonstrate the change in alpha-synuclein associated with the disease. An international team of experts led by Gabor G. Kovacs from the Clinical Institute of Neurology at the MedUni Vienna has now discovered a new antibody that actually possesses this ability.

"It opens up new possibilities for the development of a diagnostic test for Parkinsonism," says Kovacs, highlighting the importance of this discovery. "This new antibody will enable us to find the pathological conformation in bodily fluids such as blood or CSF." A clinical study involving around 200 patients is already underway, and the first definitive results are expected at the end of 2012. The tests being carried out in collaboration with the University Department of Neurology, led by Walter Pirker, are designed to determine the extent to which the new antibody can be used as an early diagnostic tool in order to understand the condition better and be able to treat it more effectively.

A step towards a blood test for Parkinson’s With Parkinsonism, the diseased form of alpha-synuclein, which has the same primary structure as the healthy form, undergoes an “abnormal fold.” Says Kovacs: “Until now, however, it was not possible to distinguish between the two.” The previous immunodiagnostic techniques only allowed the general presence of alpha-synuclein to be confirmed. The new, monoclonal antibody, however, which the researchers at the MedUni Vienna have developed in collaboration with the German biotech firm Roboscreen, is now able to detect a strategic part of the protein responsible for the structural changes. The results of the study have now been published in the journal Acta Neuropathologica.

Says Kovacs: “It is still not possible to say whether or not we will be able to diagnose Parkinson’s from a blood test, but this discovery certainly represents a major step in that direction.” Theoretically, it should be possible to diagnose Parkinson’s disease five to eight years before it develops.

In Austria, there are between 15,000 and 16,000 people living with Parkinson’s syndrome. Its frequency increases with age. As society becomes older, Parkinson’s disease, a degenerative condition of the brain, will become an increasingly widespread problem.

Source: Science Daily

ScienceDaily (July 20, 2012) — Scientists at the University of Manchester have uncovered how the internal mechanisms in nerve cells wire the brain. The findings open up new avenues in the investigation of neurodegenerative diseases by analysing the cellular processes underlying these conditions.

Illustration of spectraplakins in axonal growth organising microtubules. (Credit: Image courtesy of University of Manchester)

Dr Andreas Prokop and his team at the Faculty of Life Sciences have been studying the growth of axons, the thin cable-like extensions of nerve cells that wire the brain. If axons don’t develop properly this can lead to birth disorders, mental and physical impairments and the gradual decay of brain capacity during aging.

Axon growth is directed by the hand shaped growth cone which sits in the tip of the axon. It is well documented how growth cones perceive signals from the outside to follow pathways to specific targets, but very little is known about the internal machinery that dictates their behaviour.

Dr Prokop has been studying the key driver of growth cone movements, the cytoskeleton. The cytoskeleton helps to maintain a cell’s shape and is made up of the protein filaments, actin and microtubules. Microtubules are the key driving force of axon growth whilst actin helps to regulate the direction the axon grows.

Dr Prokop and his team used fruit flies to analyse how actin and microtubule proteins combine in the cytoskeleton to coordinate axon growth. They focussed on the multifunctional proteins called spectraplakins which are essential for axonal growth and have known roles in neurodegeneration and wound healing of the skin.

What the team demonstrate in this recent paper is that spectraplakins link microtubules to actin to help them extend in the direction the axon is growing. If this link is missing then microtubule networks show disorganised criss-crossed arrangements instead of parallel bundles and axon growth is hampered.

By understanding the molecular detail of these interactions the team made a second important finding. Spectraplakins collect not only at the tip of microtubules but also along the shaft, which helps to stabilise them and ensure they act as a stable structure within the axon.

This additional function of spectraplakins relates them to a class of microtubule-binding proteins including Tau. Tau is an important player in neurodegenerative diseases, such as Alzheimer’s, which is still little understood. In support of the author’s findings, another publication has just shown that the human spectraplakin, Dystonin, causes neurodegeneration when affected in its linkage to microtubules.

Talking about his research Dr Prokop said: “Understanding cytoskeletal machinery at the cell level is a holy grail of current cell research that will have powerful clinical applications. Thus, cytoskeleton is crucially involved in virtually all aspects of a cell’s life, including cell shape changes, cell division, cell movement, contacts and signalling between cells, and dynamic transport events within cells. Accordingly, the cytoskeleton lies at the root of many brain disorders. Therefore, deciphering the principles of cytoskeletal machinery during the fundamental process of axon growth will essentially help research into the causes of a broad spectrum of diseases. Spectraplakins like at the heart of this machinery and our research opens up new avenues for its investigation”

What Dr Prokop’s paper in the Journal of Neuroscience also demonstrates is the successful research technique using the fruit fly Drosophila. The team was able to replicate its findings regarding axon growth in mice which in turn means the findings can be translated to humans.

Dr Prokop points out fruit flies provide ideal means to make sense of these findings and essentially help to unravel the many mysteries of neurodegeneration.

Dr Prokop continues: “Understanding how spectraplakins perform their cellular functions has important implications for basic as well as biomedical research. Thus, besides their roles during axon growth, spectraplakins of mice and humans are clinically important for a number of conditions and processes including skin blistering, neuro-degeneration, wound healing, synapse formation and neuron migration during brain development. Understanding spectraplakins in one biological process will instruct research on the other clinically relevant roles of these proteins.”

Source: Science Daily

ScienceDaily (July 19, 2012) — While clinical trial results are being released regarding drugs intended to decrease amyloid production — thought to contribute to decline in Alzheimer’s disease — clinical trials of drugs targeting other disease proteins, such as tau, are in their initial phases.

Penn Medicine research presented July 19 at the 2012 Alzheimer’s Association International Conference (AAIC) shows that an anti-tau treatment called epithilone D (EpoD) was effective in preventing and intervening the progress of Alzheimer’s disease in animal models, improving neuron function and cognition, as well as decreasing tau pathology.

By targeting tau, the drug aims to stabilize microtubules, which help support and transport of essential nutrients and information between cells. When tau malfunctions, microtubules break and tau accumulates into tangles.

"This drug effectively hits a tau target by correcting tau loss of function, thereby stabilizing microtubules and offsetting the loss of tau due to its formation into neurofibrillary tangles in animal models, which suggests that this could be an important option to mediate tau function in Alzheimer’s and other tau-based neurodegenerative diseases," said John Trojanowski, MD, PhD, professor of Pathology and Laboratory Medicine in the Perelman School of Medicine at the University of Pennsylvania. "In addition to drugs targeting amyloid, which may not work in advanced Alzheimer’s disease, our hope is that this and other anti-tau drugs can be tested in people with Alzheimer’s disease to determine whether stabilizing microtubules damaged by malfunctioning tau protein may improve clinical and pathological outcomes."

The drug, identified through Penn’s Center for Neurodegenerative Disease Research (CNDR) Drug Discovery Program, was previously shown to prevent further neurological damage and improve cognitive performance in animal models*. The Penn research team includes senior investigator Bin Zhang, MD, and Kurt Brunden, PhD, director of Drug Discovery at CNDR.

Bristol-Myers Squibb, who developed and owns the rights to the drug, has started enrolling patients into a phase I clinical trial in people with mild Alzheimer’s disease.

Source: Science Daily

July 19, 2012

Korean scientists have used tiny stars, squares and triangles as a toolkit to create live neural circuits in a dish.

They hope the shapes can be used to create a reproducible neural circuit model that could be used for learning and memory studies as well as drug screening applications; the shapes could also be integrated into the latest neural tissue scaffolds to aid the regeneration of neurons at injured sites in the body, such as the spinal cord.

Published today in the Journal of Neural Engineering, the study, by researchers at the Korea Advanced Institute of Science and Technology (KAIST), found that triangles were the most effective shape for helping to facilitate the growth of axons and guide them onto specific paths to form a complete circuit.

Co-author of the study, Professor Yoonkey Nam, said: “Eventually, we want to know if we can design a neural tissue model that biologically mimics some neural circuits in our brain.”

A neuron is an electrically excitable cell that processes and transmits information around the body. The neuron is composed of three main parts: a cell body, or soma, dendrites and an axon, which extends from the soma and links to other cells, creating a network.

When axons grow they are usually guided by proteins. Many researchers have been trying to re-create this key process in a dish by manipulating nerve cells from rat brains.

As nerve cells are usually just a few tens of micrometres in size, the challenge associated with creating a live neural network is firstly positioning cells in desired locations and, secondly, making connections between these cells by guiding the axons in designated directions.

The researchers investigated whether two star shapes, five regular shapes (square, circle, triangle, pentagon and hexagon) and three different sizes of isosceles triangles could guide axons in designated directions. Each shape was the size of a single cell and was replicated to form an array which was printed onto a glass surface.

Each of the arrays had an overall size of 1cm-by-1cm with a gap of 10 micrometres between each shape. Hippocampal neurons were taken from rats and plated onto the patterned surfaces. The neurons were fluorescently labelled with dyes so that images could be taken of their growth.

The researchers found that triangles were the most efficient shape to encourage the growth and guidance of an axon. The key to this was the angles at the points where two of the triangle’s lines meet, also known as the vertices. It was shown that the smaller the vertices, the higher chance the triangle had of inducing growth.

"Based on our results, we are suggesting a new design principle for guiding axons in a dish. We can control the axonal growth in a certain direction by putting a sharp triangle pointing to a certain direction. Then, a neuron that adhered to the triangle will have an axon in the sharp vertex direction.

"Overall, we integrated microtechnology with neurobiology to find a new engineering solution" continued Professor Nam.

Provided by Institute of Physics

Source: medicalxpress.com

ScienceDaily (July 19, 2012) — A joint study carried out by The University of Nottingham and the multinational food company Unilever has found for the first time that fat in food can reduce activity in several areas of the brain which are responsible for processing taste, aroma and reward.

The research, now available in the Springer journal Chemosensory Perception, provides the food industry with better understanding of how in the future it might be able to make healthier, less fatty food products without negatively affecting their overall taste and enjoyment. Unveiled in 2010, Unilever’s Sustainable Living Plan sets out its ambition to help hundreds of millions of people improve their diet around the world within a decade.

This fascinating three-year study investigated how the brains of a group of participants in their 20s would respond to changes in the fat content of four different fruit emulsions they tasted while under an MRI scanner. All four samples were of the same thickness and sweetness, but one contained flavour with no fat, while the other three contained fat with different flavour release properties.

The research found that the areas of the participants’ brains which are responsible for the perception of flavour — such as the somatosensory cortices and the anterior, mid & posterior insula — were significantly more activated when the non-fatty sample was tested compared to the fatty emulsions despite having the same flavour perception. It is important to note that increased activation in these brain areas does not necessarily result in increased perception of flavour or reward.

Dr Joanne Hort, Associate Professor in Sensory Science at The University of Nottingham said: “This is the first brain study to assess the effect of fat on the processing of flavour perception and it raises questions as to why fat emulsions suppress the cortical response in brain areas linked to the processing of flavour and reward. It also remains to be determined what the implications of this suppressive effect are on feelings of hunger, satiety and reward.”

Unilever food scientist Johanneke Busch, based at the company’s Research & Development laboratories in Vlaardingen, Netherlands added: “There is more to people’s enjoyment of food than the product’s flavour — like its mouthfeel, its texture and whether it satisfies hunger, so this is a very important building block for us to better understand how to innovate and manufacture healthier food products which people want to buy.”

Source: Science Daily

July 19, 2012 By Emily Martinez

(Medical Xpress) — UT Dallas researchers recently demonstrated how nerve stimulation paired with specific experiences, such as movements or sounds, can reorganize the brain. This technology could lead to new treatments for stroke, tinnitus, autism and other disorders.

Dr. Michael Kilgard helped lead a team that paired vagus nerve stimulation with physical movement to improve brain function.

In a related paper, UT Dallas neuroscientists showed that they could alter the speed at which the brain works in laboratory animals by pairing stimulation of the vagus nerve with fast or slow sounds.

A team led by Dr. Robert Rennaker and Dr. Michael Kilgard looked at whether repeatedly pairing vagus nerve stimulation with a specific movement would change neural activity within the laboratory rats’ primary motor cortex. To test the hypothesis, they paired the vagus nerve stimulation with movements of the forelimb in two groups of rats. The results were published in a recent issue of Cerebral Cortex.

After five days of stimulation and movement pairing, the researchers examined the brain activity in response to the stimulation. The rats who received the training along with the stimulation displayed large changes in the organization of the brain’s movement control system. The animals receiving identical motor training without stimulation pairing did not exhibit any brain changes, or plasticity.

People who suffer strokes or brain trauma often undergo rehabilitation that includes repeated movement of the affected limb in an effort to regain motor skills. It is believed that repeated use of the affected limb causes reorganization of the brain essential to recovery. The recent study suggests that pairing vagus nerve stimulation with standard therapy may result in more rapid and extensive reorganization of the brain, offering the potential for speeding and improving recovery following stroke, said Rennaker, associate professor in The University of Texas at Dallas’ School of Behavioral and Brain Sciences.

“Our goal is to use the brain’s natural neuromodulatory systems to enhance the effectiveness of standard therapies,” Rennaker said. “Our studies in sensory and motor cortex suggest that the technique has the potential to enhance treatments for neurological conditions ranging from chronic pain to motor disorders. Future studies will investigate its effectiveness in treating cognitive impairments.”

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July 19, 2012

(Medical Xpress) — When learning to master complex movements such as those required in surgery, is being physically guided by an expert more effective than learning through trial and error?

Dr. George Van Doorn and a participant in the fMRI

New research by Monash University’s Departments of Psychological Studies and Physiology challenges earlier claims that externally guided (or passive) movement is a superior learning method to self-generated (or active) movement.

In the first study of its kind, researchers discovered that different brain regions become active depending on the type of movement used. Lead researcher Dr. George Van Doorn, head of Psychological Studies, said the findings did not support the view that passive movement was a more effective way to learn.

“There has been much debate over the last 30 years about which form of movement is better,” Dr. Van Doorn said. “We found that active movements result in greater activation in brain areas implicated in higher-order processes such as monitoring and controlling goal-directed behaviour, attention, execution of movements, and error detection.

“Passive movements, in contrast, produced greater activity in areas associated with touch perception, length discrimination, tactile object recognition, and the attenuation of sensory inputs.”

People were tested while making movements themselves, and while being guided.

“Whilst inside a functional Magnetic Resonance Imaging (fMRI) machine, we had people either freely move their index finger around a two-dimensional, raised-line pattern to measure self-generated touch. Or we had an experimenter guide the person’s finger around the pattern, to measure externally generated touch. Using the fMRI, we found that different brain regions become active depending on the type of movement used,” Dr. Van Doorn said.

Dr. Van Doorn said touch was becoming a popular area of investigation, with more scientists contributing to understanding about this important, though under-acknowledged, sensory system.

All researchers involved in this study are located at Monash University’s Gippsland campus. The study findings were presented at EuroHaptics 2012, a major international conference and the primary European meeting for researchers in the field of human haptic sensing and touch-enabled computer applications.

Provided by Monash University

Source: medicalxpress.com

ScienceDaily (July 19, 2012) — By decoding brain activity, scientists were able to “see” that two monkeys were planning to approach the same reaching task differently — even before they moved a muscle.

The obstacle-avoidance task is a variation on the center-out reaching task in which an obstacle sometimes prevents the monkey from moving directly to the target. The monkey must first place a cursor (yellow) on the central target (purple). This was the starting position. After the first hold, a second target appeared (green). After the second hold an obstacle appeared (red box). After the third hold, the center target disappeared, indicating a “go” for the monkey, which then moved the cursor out and around the obstacle to the target. (Credit: Moran/Pearce)

Anyone who has looked at the jagged recording of the electrical activity of a single neuron in the brain must have wondered how any useful information could be extracted from such a frazzled signal.

But over the past 30 years, researchers have discovered that clear information can be obtained by decoding the activity of large populations of neurons.

Now, scientists at Washington University in St. Louis, who were decoding brain activity while monkeys reached around an obstacle to touch a target, have come up with two remarkable results.

Their first result was one they had designed their experiment to achieve: they demonstrated that multiple parameters can be embedded in the firing rate of a single neuron and that certain types of parameters are encoded only if they are needed to solve the task at hand.

Their second result, however, was a complete surprise. They discovered that the population vectors could reveal different planning strategies, allowing the scientists, in effect, to read the monkeys’ minds.

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