The man whose brain ignores one half of his world
A stroke left a man named Alan Burgess with hemispatial neglect - an inability to pay attention to sensory stimuli on his left side. The stroke damaged the parietal lob on the right side of his brain, thus causing him to ignore people, sounds and objects on his left.
Hemispatial neglect is not blindness, or a loss of sight. It is a loss of attention. This causes patients to simply ignore the left side of space. People with hemispatial neglect are often unaware of their condition. Patients often only eat whatever food is on the right side of their plate, may only apply make up on one side of their face, and will frequently bump into objects on their neglected side.
The clock picture above is an example of a classic clock-drawing test neglect patients are asked to complete. They are presented with the full drawing of the clock, and asked to recreate it. Neglect patients will ignore the left hand side of the clock, and even though they can perceive a full circle somehow, they can’t attend to all the numbers and so only fill in half.
Rehabilitation is particularly hard for neglect patients, as they often cannot understand that they have a problem, as to them nothing appears to be missing. This paper describes an interesting case where a patient actually recovered from hemispatial neglect. The patient originally had a stroke in the right hemisphere, which caused the left field neglect. While in hospital, they then had a stroke in their other hemisphere, which caused the neglect to go away. Scientists are now trying to figure out why this happened and people have been trying to recreate this recovery in other patients. They can create “virtual lesions” where they use TMS (transcranial magnetic stimulation) to disrupt a part of the brain, just like the lesion in the patient who recovered, and see whether the same recovery happens for other neglect patients. Currently these brain stimulating techniques are of interest as potential therapies.
Blind patient reads words stimulated directly onto retina: neuroprosthetic device uses implant to project visual braille
Before I started studying psychology I didn’t realise how much it actually covers as a topic. I thought that it was merely about studying when behaviour and thoughts are disrupted by brain disorders (i.e. clinical psychology). Once I went to University however, my mind was totally changed. Suddenly I was learning about how people read, how people communicate and how people perceive the world around them. So this post, while some might think it is a bit of a deviation away from psychology, is really about a psychological topic that I find really fascinating: perception.
For the first time, researchers have streamed braille patterns directly into a blind patient’s retina, allowing him to read four letter words accurately and quickly. This device (the Argus II) has been implanted in over 50 patients, many of who can no see colour, movement and objects.
The device uses a small camera mounted on a pair of glasses, a portable processor to translate the signal from the camera into electrical stimulation, and a microchip with electrodes implanted directly onto the retina.
“In this clinical test with a single blind patient, we bypassed the camera that is the usual input for the implant and directly stimulated the retina. Instead of feeling the braille on the tips of his fingers, the patient could see the patterns we projected and then read individual letters in less than a second with up to 89% accuracy,” explains researcher Thomas Lauritzen, lead author of the paper.
Ping-pong-playing robot learns to play like a person
A ROBOT that learns to play ping-pong from humans and improves as it competes against them could be the best robotic table-tennis challenger the world has seen.
Katharina Muelling and colleagues at the Technical University of Darmstadt in Germany suspended a robotic arm from the ceiling and equipped it with a camera that watches the playing area. Then Muelling physically guided the arm through different shots to return incoming balls.
The arm was then left to draw on its training to return balls hit by a human opponent. When the ball was in a position it had not seen before, the arm used its library of shots to improvise new ones. After an hour of unassisted practise, the system successfully returned 88 per cent of shots.
Other robots have played table tennis in the past, but none have used human demonstration to learn the game. Ales Ude of the Jožef Stefan Institute in Slovenia says that doing so allows robots to play more like people.
The work, which will be presented at an AAAI symposium in Arlington, Virginia, next month, is part of a broader goal to develop robots that can do a range of tasks after being guided by their owners, Muelling says.
Using a high-tech imaging process to measure the thickness of the eye’s retina may one day predict the progression of multiple sclerosis, a new study suggests.
The finding might lead to better ways to judge the effectiveness of treatments because different parts of the retina seem to indicate different aspects of the disease and the toll it takes on different parts of the brain, the researchers said.
The report was published online Oct. 1 in the Archives of Neurology.
Scientists on the Florida campus of The Scripps Research Institute have designed a compound that shows promise as a potential therapy for one of the diseases closely linked to fragile X syndrome, a genetic condition that causes mental retardation, infertility, and memory impairment, and is the only known single-gene cause of autism.
The study, published online ahead of print in the journal ACS Chemical Biology September 4, 2012, focuses on tremor ataxia syndrome, which usually affects men over the age of 50 and results in Parkinson’s like-symptoms—trembling, balance problems, muscle rigidity, as well as some neurological difficulties, including short-term memory loss and severe mood swings.
Devices could reveal inner workings of neurons and how they communicate with each other.
Automated assistance may soon be available to neuroscientists tackling the brain’s complex circuitry, according to research presented last week at the Aspen Brain Forum in Colorado. Robots that can find and simultaneously record the activity of dozens of neurons in live animals could help researchers to reveal how connected cells interpret signals from one another and transmit information across brain areas — a task that would be impossible using single-neuron studies.
A robot that can access the internal workings of neurons could be scaled up to allow 100 cells to be studied at a time. MIT McGovern Institute/E. Boyden/Sputnik Animation
The robots are designed to perform whole-cell patch-clamping, a difficult but powerful method that allows neuroscientists to access neurons’ internal electrical workings, says Edward Boyden of the Massachusetts Institute of Technology in Cambridge, who is leading the work.
Talk about brainwashing—a newfound plumbing system, identified in mice, likely helps the brain empty its waste, a new study says. Because mouse biology is similar to ours, the same findings should apply to people too, experts say.
Thanks to a blood-brain barrier—a natural wall that protects the brain tissue—the organ never touches blood, thus protecting it from microbes, viruses, and other pathogens.
To get nutrients to brain tissue and remove its waste, the brain makes a liquid called cerebrospinal fluid. But exactly how the fluid removes gunk generated by brain cells wasn’t certain until now.
Experiments in the 1950s and ’60s hinted that diffusion—the passive method by which, say, food coloring spreads out in a glass of water—moved cerebrospinal fluid around the brain.
Yet this process is too slow to explain the brain’s lightning-fast activity and immaculate cleanliness.
It turns out that, while studying brain tissue, the researchers in the 1950s and ’60s unwittingly turned off the plumbing that washes the tissue.
“The idea of a cleaning system based on pressure has been around for a long time, but if you open the skull anywhere, like a hydraulic pump, it stops. They thought [the cleaning system] didn’t exist,” said study leader Maiken Nedergaard, a neuroscientist at the University of Rochester Medical Center.
The pump system is “on the order of a thousand times faster than diffusion,” she said. “I’m surprised that no one had discovered this until now.”
Brazilian construction worker has a lucky escape after a 1.8m-long iron bar fell from a building through his head.
A builder is recovering after an operation to remove a 1.8m-long iron bar from his head. The bar fell from the fifth floor of a building under construction, went through Eduardo Leite’s hard hat, pierced the back of his skull and exited between his eyes. Amazingly the 24-year-old survived and when he arrived at hospital he was conscious and able to tell doctors what had happened.
A new study from The University of Queensland shows monitoring the brain of stroke patients using Quantitative EEG (QEEG) studies could inform treatments and therefore, minimising brain damage of stroke victims.
“The main goals of this research were to evaluate key findings, identify common trends and determine what the future priorities should be, both for research and for translating this to best inform clinical management of stroke patients,” Dr Finnigan from UQ’s Centre for Clinical Research said.
The review of outcomes from hundreds of patients has highlighted that QEEG indicators are particularly informative in two ways.
“Firstly they can help predict long-term deficits caused by stroke, … In addition, they could provide immediate information on how patients are responding to treatments and guide decisions about follow-on treatments, even before stroke symptoms change,” Dr Finnigan said.
Disconnect, for a moment, from the argument of whether prayer is real. That’s for another time and another place. The fact remains that it is an ancient, powerful, and widely practiced behavior. What is it about the human brain that encourages so many to appeal to a higher power? And what is happening inside the brain when people pray?
When we look at prayer through the lens of neuroscience, we can make an interesting observation: Talking to God is not really different from talking to one’s friends and neighbors.
The brain’s evolution was a highly social process and involved complex problem solving. Yet, invisible entities are not a force of natural selection. Check out this fMRI study of religious folks, and you’ll see that religious people’s brains view prayer as communication with an actual physical entity.
Believer or not, it’s good conversation fodder for your next cocktail party. For sure, it appears that religion is far more than illusion for the religious.
The Human Connectome Project
In the 1970s, a Cambridge University study completed a wiring diagram of the nervous system of a tiny worm, Caenorhabditis elegans, mapping the connections between its 302 neurons. Such wiring diagrams, called “connectomes”, represent the web of nerve-fibres that criss-cross the brain. The connectome of the worm took over a dozen years of tedious manual labour to complete, but now the Human Connectome Project is tackling a much more ambitious project: constructing maps of the millions of kilometres of neural connections in the human brain. This would be a painstaking manual process, requiring up to 10 researchers to analyse endless electron microscopic images of brain slices and trace the connections. It could literally take thousands of years to complete—and so the project is wisely accelerating the process by teaching vastly powerful computers to analyse the brain slices using a technique called “automated machine learning”, which lets them modify their behaviour in response to new data. Humans will still need to proofread the computers’ work, but it’ll speed up the process exponentially. “No one thinks this is going to produce a wiring diagram like you might have for the electricity in your house,” says Thomas Insel, director of the National Institute of Mental Health—but even a crude map could vastly advance our understanding of the brain, and help us to understand how neural connections give rise to intelligence, personality and memory.
Science has prevailed over injustice in the state of New Jersey, where all jurors will soon learn about memory’s unreliability and the limits of eyewitness testimony. According to instructions issued July 19 by New Jersey’s Supreme Court, judges must tell jurors that “human memory is not foolproof,” and enumerate the many ways in which eyewitness recall can be distorted or mistaken. Cognitive scientists who study memory have celebrated the new requirements. “Eyewitness identification evidence is seen by jurors as being trustworthy and reliable,” said psychologist Charles Brainerd of Cornell University, who specializes in memory. “The science shows exactly the opposite.” The guidelines were prompted by State v. Henderson, in which the New Jersey Supreme Court overturned the conviction of Larry Henderson, an accused murder accomplice whose identification from a lineup was unduly influenced by police. Though egregiously unjust, Henderson’s case was hardly unusual: Eyewitness misidentification is the most common cause of wrongful conviction in the United States. Of prisoners exonerated by DNA testing, some 75 percent were mistakenly identified. (via Science of Eyewitness Memory Enters Courtroom | Wired Science | Wired.com)
To give you a personal example of this, one time I overheard my mother talking about the time we were at a gas station, and there was this tiger in cage on display in a show there. I then began to remember the incident, and it felt old. I remembered the tiger vividly, and walking up to the bars to see it, and how there were a few cars parked by the gas station. Then my mother stated that I was 18 months old during it. Obviously, there was no way that my recall of the events remotely resembled what actually happened. The trickery of memory can fool anyone. I don’t think it’s too much of a stretch to say that most of our memories are flawed and really just reconstructions, reinterpreted each time we recall them through different lenses of ego, bias, and emotion.
In the 90s, there were numerous cases of people that successfully sued psychiatrists and psychologies on the charge that they helped confabulate false memories (they said that the false memories were really just “deeply depressed” memories) of childhood sexual abuse, incest and satanic rituals. It usually starts out in the following way: someone suffering from depression or anxiety goes to see a professional. The professional starts out with the assumption that said afflictions are cased by repressed childhood trauma, and then encourages the patient to “try to remember a moment where you were abused, or when so and so happened”. Hypnosis could be used to try to “recover” these memories, which were assumed to be there. As a result, many families were torn and there were people wrongly accused of demonic rituals, or child abuse. This is why doctors and other professionals are nowadays encouraged to ask “open ended” questions, so as not to induce suggestibility and influence false memory syndrome.
Retinal ganglion cells transmit signals from the rods and cones in the eye to the brain. The retinal ganglion cells shown here have the extraordinary property that their dendrites all point in a single direction. Remarkably, these neurons respond best to objects moving in the direction that the cells “point.”
In this particular image, a mouse retina is seen with “J” retinal ganglion cells marked by the expression of a fluorescent protein. Of course, in real eyes it’s not that simple - the millions of other neurons that these are entangled with are not marked, and thus appear invisible. The image was obtained with a confocal scanning microscope, and pseudocoloured.
Part of the Cell Picture Show’s amazing Brainbow series.