Posts tagged movement
Articles and news from the latest research reports.
Simple test can help detect Alzheimer’s before dementia signs show
York University researchers say a simple test that combines thinking and movement can help to detect heightened risk for developing Alzheimer’s disease in a person, even before there are any telltale behavioural signs of dementia.
Faculty of Health Professor Lauren Sergio and PhD candidate Kara Hawkins who led the study asked the participants to complete four increasingly demanding visual-spatial and cognitive-motor tasks, on dual screen laptop computers. The test aimed at detecting the tendency for Alzheimer’s in those who were having cognitive difficulty even though they were not showing outward signs of the disease.
“We included a task which involved moving a computer mouse in the opposite direction of a visual target on the screen, requiring the person’s brain to think before and during their hand movements,” says Sergio in the School of Kinesiology & Health Science. “This is where we found the most pronounced difference between those with mild cognitive impairment (MCI) and family history group and the two control groups.”
Hawkins adds, “We know that really well-learned, stereotyped motor behaviours are preserved until very late in Alzheimer’s disease.” These include routine movements, such as walking. The disruption in communication will be evident when movements require the person to think about what it is they are trying to do.
For the test, the participants were divided into three groups – those diagnosed with MCI or had a family history of Alzheimer’s disease, and two control groups, young adults and older adults, without a family history of the disease.
The study, Visuomotor Impairments in Older Adults at Increased Alzheimer’s Disease Risk, published in the Journal of Alzheimer’s Disease, found that 81.8 per cent of the participants that had a family history of Alzheimer’s disease and those with MCI displayed difficulties on the most cognitively demanding visual motor task.
“The brain’s ability to take in visual and sensory information and transform that into physical movements requires communication between the parietal area at the back of the brain and the frontal regions,” explains Sergio. “The impairments observed in the participants at increased risk of Alzheimer’s disease may reflect inherent brain alteration or early neuropathology, which is disrupting reciprocal brain communication between hippocampal, parietal and frontal brain regions.”
“In terms of being able to categorize the low Alzheimer’s disease risk and the high Alzheimer’s disease risk, we were able to do that quite well using these kinematic measures,” says Hawkins. “This group had slower reaction time and movement time, as well as less accuracy and precision in their movements.”
Hawkins says the findings don’t predict who will develop Alzheimer’s disease, but they do show there is something different in the brains of most of the participants diagnosed with MCI or who had a family history of the disease.
(Image caption: Newly discovered neuron type (yellow) helps zebrafish to coordinate its eye and swimming movements. The image shows the blue-stained brain of a fish larva with the suggested position of the eyes. Credit: © Max Planck Institute of Neurobiology/Kubo)
How vision makes sure that little fish do not get carried away
Our eyes not only enable us to recognise objects; they also provide us with a continuous stream of information about our own movements. Whether we run, turn around, fall or sit still in a car – the world glides by us and leaves a characteristic motion trace on our retinas. Seemingly without effort, our brain calculates self-motion from this “optic flow”. This way, we can maintain a stable position and a steady gaze during our own movements. Together with biologists from the University of Freiburg, scientists from the Max Planck Institute of Neurobiology in Martinsried near Munich have now discovered an array of new types of neurons, which help the brain of zebrafish to perceive, and compensate for, self-motion.
Most land animals walk forward by default, but can switch to backward walking when they sense an obstacle or danger in the path ahead. The impulse to change walking direction is likely to be transmitted by descending neurons of the brain that control local motor circuits within the central nervous system. This neuronal input can change walking direction by adjusting the order or timing of individual leg movements.
Screening for flies with altered walking patterns
In the current study, Dickson and his team aimed to understand the fly’s change in walking direction at the cellular level. Using a novel technology known as thermogenetics, they were able to identify the neurons in the brain that cause a change in locomotion. Their studies involved screening large numbers of flies with it which specific neurons were activated by heat, producing certain behaviors only when warmed to 30°C, but not at 24°C . Analysing several thousand flies, the researchers looked for strains that exhibited altered walking patterns compared to control animals.
Moonwalker-neurons control backward walking
Using the thermogenetic screen, the IMP-researchers isolated four lines of flies that walked backward on heat activation. They were able to track down these changes to specific nerve cells in the fly brain which they dubbed “moonwalker neurons”. They could also show that silencing the activity of these neurons using tetanus toxin rendered the flies unable to walk backward.
Among the moonwalker neurons, the activity of descending MDN-neurons is required for flies to walk backward when they encounter an obstacle. Input from MDN brain cells is sufficient to induce backward walking in flies that would otherwise walk forward. Ascending moonwalker neurons (MAN) promote persistent backward walking, possibly by inhibiting forward walking.
“This is the first identification of specific neurons that carry the command for the switch in walking direction of an insect”, says Salil Bidaye, lead author of the study. “Our findings provide a great entry point into the entire walking circuit of the fly. “
Although there are obvious differences in how insects and humans walk, it is likely that there are functional analogies at a neural circuit level. Insights into the neural basis of insect walking could also generate applications in the field of robotics. To date, none of the engineered robots that are used for rescue or exploration missions can walk as robustly as animals. Understanding how insects change their walking direction at a neuronal level would reveal the mechanistic basis of achieving such robust walking behavior.
Scientists redefine how the brain plans movement
University of Queensland researchers have made a surprise discovery about how the brain plans movement that may lead to more targeted treatments for patients with Parkinson’s disease.
The discovery was made by UQ’s Queensland Brain Institute (QBI) researcher Professor Pankaj Sah in collaboration with neurologist Professor Peter Silburn and neurosurgeon Associate Professor Terry Coyne from the UQ Centre for Clinical Research.
Professor Sah said the team examined the brains of 10 patients with Parkinson’s disease while the patients were awake during deep brain stimulation surgery, and found more than one part of the brain is responsible for planning movement.
“This study aimed to improve understanding of how different parts of the brain are involved in planning movement and controlling gait,” Professor Sah said.
The team was particularly interested in a part of the brain stem known as the pedunculopontine nucleus (PPN), which lies in the deepest part of the brain.
The PPN has previously been targeted as a treatment point for people with advanced Parkinson’s disease who are unable to walk.
“To date, we have known that walking is generally controlled by the outer part of the brain known as the cortex,” Professor Sah said.
“When you decide to walk, the cortex sends signals to your brain stem which in turn signals the spinal cord to initiate movement.
“We have also known that neurons in the PPN are activated during limb movement, but our study has shown they were also activated when patients were simply thinking about walking.
“This is a complete surprise, because general thinking has been that movement planning takes place in the cortex, but this study indicates it might be happening in the brain stem as well.”
Parkinson’s disease is the second most common neurodegenerative disorder after Alzheimer’s disease, affecting more than six million people globally, and about 1 in 350 Australians.
Professor Sah said improved understanding of how the brain plans movement could lead to more targeted treatments for people with Parkinson’s.
“The cells involved in these networks seem to be one type of cell, so when thinking about drug treatments for Parkinson’s, maybe we should be targeting these cells,” Professor Sah said.
All the patients treated with deep brain stimulation also recorded positive outcomes with improvements with gait, highlighting the importance of neuroscientists working with clinicians.
Findings of the research are published in the Nature Neuroscience journal.
(Source: uq.edu.au)
Universal emotions like anger, sadness and happiness are expressed nearly the same in both music and movement across cultures, according to new research.
The researchers found that when Dartmouth undergraduates and members of a remote Cambodian hill tribe were asked to use sliding bars to adjust traits such as the speed, pitch, or regularity of music, they used the same types of characteristics to express primal emotions. What’s more, the same types of patterns were used to express the same emotions in animations of movement in both cultures.
"The kinds of dynamics you find in movement, you find also in music and they’re used in the same way to provide the same kind of meaning," said study co-author Thalia Wheatley, a neuroscientist at Dartmouth University.
The findings suggest music’s intense power may lie in the fact it is processed by ancient brain circuitry used to read emotion in our movement.
"The study suggests why music is so fundamental and engaging for us," said Jonathan Schooler, a professor of brain and psychological sciences at the University of California at Santa Barbara, who was not involved in the study. "It takes advantage of some very, very basic and, in some sense, primitive systems that understand how motion relates to emotion."
Universal emotions
Why people love music has been an enduring mystery. Scientists have found that animals like different music than humans and that brain regions stimulated by food, sex and love also light up when we listen to music. Musicians even read emotions better than nonmusicians.
Past studies showed that the same brain areas were activated when people read emotion in both music and movement. That made Wheatley wonder how the two were connected.
To find out, Wheatley and her colleagues asked 50 Dartmouth undergraduates to manipulate five slider bars to change characteristics of an animated bouncy ball to make it look happy, sad, angry, peaceful or scared.
"We just say ‘Make Mr. Ball look angry or make Mr. Ball look happy,’" she told LiveScience.
To create different emotions in “Mr. Ball,” the students could use the slider bars to affect how often the ball bounced, how often it made big bounces, whether it went up or down more often and how smoothly it moved.
Another 50 students could use similar slider bars to adjust the pitch trajectory, tempo, consonance (repetition), musical jumps and jitteriness of music to capture those same emotions.
The students tended to put the slider bars in roughly the same positions whether they were creating angry music or angry moving balls.
To see if these trends held across cultures, Wheatley’s team traveled to the remote highlands of Cambodia and asked about 85 members of the Kreung tribe to perform the same task. Kreung music sounds radically different from Western music, with gongs and an instrument called a mem that sounds a bit like an insect buzzing, Wheatley said. None of the tribes’ people had any exposure to Western music or media, she added.
Interestingly, the Kreung tended to put the slider bars in roughly the same positions as Americans did to capture different emotions, and the position of the sliders was very similar for both music and emotions.
The findings suggest that music taps into the brain networks and regions that we use to understand emotion in people’s movements. That may explain why music has such power to move us — it’s activating deep-seated brain regions that are used to process emotion, Wheatley said.
"Emotion is the same thing no matter whether it’s coming in through our eyes or ears," she said.
Sophisticated worms
One cell does it all: Sensory input to motor output in extraordinary neuronIt’s one of the basic tenets of biological research — by studying simple “model” systems, researchers hope to gain insight into the workings of more complex organisms.
Caenorhabditis elegans — a tiny, translucent worm with just 302 neurons — has long been studied to understand how a nervous system is capable of translating sensory input into motion and behavior.
New research by the laboratory of Professor Aravi Samuel in the Harvard Physics Department and the Center for Brain Sciences, however, is uncovering surprising sophistication in the individual neurons of the worm’s “simple” nervous system.
Quan Wen, a postdoctoral fellow in the Samuel lab who spearheaded the research, has shown that a single type of neuron in the C. elegans nerve cord (the worm equivalent of the spinal cord) packs both sensory and motor capabilities. The locomotory systems of most creatures, including humans, use different neurons to gather sensory information about animal movement or to send signals to muscle cells. C. elegans encodes an entire sensorimotor loop into one particularly sophisticated type of motor neuron. The work is described in the journal Neuron.
“This type of circuit is completely new — this is not the way people think about any motor circuit,” Samuel said.
The discovery arose from researchers asking a simple question: How does C. elegans organize its movements?
“What sent us down this road was a phenomenon that we’ve observed in the lab,” Samuel explained. “If we place the worms in a wet environment, they will swim. On surfaces, however, they crawl. The question was how the animal ‘knew’ to do each. The answer had to be feedback: Something is telling the worm that it’s in a low-viscous environment here, and a high-viscous environment there.
“The general name for this is ‘proprioceptive feedback,’ ” Samuel continued. “It’s that process that allows your brain to understand what each of your legs is doing and coordinate your ability to walk, it gives you an awareness of your body posture. The real puzzle in this case, however, was that C. elegans has so few neurons … we didn’t understand how proprioceptive feedback could come back into the system.”
(Image credit: snickclunk)
Neuroscience gets behind the mask of Greek theatre
Over 2000 years may have elapsed since masked Greek tragedies had their heyday on stage in Athens, but some of the most modern neuroscience may be able to give classicists a better understanding of how the ancients watched and thought about those plays that today exist only on paper.
Fly tweet
This device sends twitter messages based on the activities of a collection of houseflies. The flies live inside an acrylic sphere along with a computer keyboard. As the flies move and interact inside their home, they fly over the keys on the keyboard. These movements are collected in real-time via video. When a particular key is triggered by the flies, the key’s corresponding character is entered into a twitter text box. When 140 characters are reached or the flies trigger the “enter” key, the message containing the accumulated characters is tweeted. Thus live twitter messages are perpetually sent in real-time based on the simple movements of the community of houseflies. These constantly accumulating messages appear as records of random activity within the larger sphere of social media and networking.
(Source: dwbowen.com)
Coffee May Help Some Parkinson’s Disease Movement Symptoms, Research Suggests
"Studies have shown that people who use caffeine are less likely to develop Parkinson’s disease, but this is one of the first studies in humans to show that caffeine can help with movement symptoms for people who already have the disease," said study author Ronald Postuma, MD, MSc, with McGill University in Montreal and the Research Institute of the McGill University Health Center. Postuma is also a member of the American Academy of Neurology.
Computers may help patients restore movement after stroke
New research suggests that patients whose mobility has been limited by stroke may one day use their imagination and a computer link to move their hands.
Leuthardt
In patients, scientists at Washington University School of Medicine in St. Louis have shown they can detect the brain simply thinking about moving a partially or completely paralyzed hand. The half of the brain that normally thinks such thoughts and moves the hand can no longer do so because of stroke damage. Instead, the signal comes from the undamaged half of the brain.
The new study suggests it may be possible to harness these signals to restore a fuller range of movement in the patient’s limbs.
“We’ve known for some time that the brain can reroute or otherwise adapt its circuits to cope with an injury,” says senior author Eric Leuthardt, MD, associate professor of neurosurgery, of biomedical engineering and of neurobiology. “Now we have proof-of-principle that we can use technology to aid that process.”
To demonstrate the potential to help restore movement, scientists connected brain signals detected by an electrode-studded cap to the movements of a cursor on a computer screen. In 30 minutes or less, patients learned to control the movement of the cursor with thoughts of moving their impaired hand. Researchers are now working on a motorized glove that will make the imagined movements a reality.
The results are available online in The Journal of Neural Engineering.
Leuthardt, who is director of Washington University’s Center for Innovation in Neuroscience and Technology, is a pioneer in the field of brain-computer interfaces, or devices that allow the brain to communicate directly with computers to restore abilities lost to injury or disease.
Much of Leuthardt’s research has focused on patients with epilepsy who are undergoing surgery to remove the part of the brain where their seizures originate. He uses the electrode grids temporarily implanted on the surface of the brain to pinpoint areas where the seizures begin. With the patients’ permissions, Leuthardt also uses the implants to gather and analyze detailed information on brain activity for future use in brain-computer interfaces. This approach laid the foundations for the technique now being applied to the stroke population.
In the new research, first author David Bundy, a graduate student, worked with four patients who had suffered strokes that caused extensive damage on one side of the brain. All were experiencing paralysis or significant difficulty moving the hand on the opposite side of the body.
The brain signals that control movement are low-frequency signals, which makes them relatively easy to detect with electrodes on the outside of the skull. Researchers fitted patients with an electrode-studded cap connected to a computer, and asked them to perform a finger-tapping activity. Depending on a cue flashed on a screen in front of them, the patients either tapped the fingers of their unimpaired hand or imagined tapping the fingers of the impaired hand. Scientists used the cap to identify signals in healthy part of the brain that accompanied the imaginary movements.
The researchers are now developing motorized braces that can be controlled by similar signals, with the goal of restoring full movement in weak or paralyzed limbs.
“This is an exciting development that opens up new opportunities to help even more patients overcome limitations imposed by brain damage or degeneration,” Leuthardt says.