NEUROLOGISTS DECODE BRAIN MAPS TO DISCOVER HOW WE TAKE AIM

Serena Williams won her third consecutive US Open title a few days ago, thanks to reasons including obvious ones like physical strength and endurance. But how much did her brain and its egocentric and allocentric functions help the American tennis star retain the cup?

Quite significantly, according to York University neuroscience researchers whose recent study shows that different regions of the brain help to visually locate objects relative to one's own body (self-centred or egocentric) and those relative to external visual landmarks (world-centred or allocentric).

"The current study shows how the brain encodes allocentric and egocentric space in different ways during activities that involve manual aiming," explains Distinguished Research Professor Doug Crawford, in the Department of Psychology. "Take tennis for example. Allocentric brain areas could help aim the ball toward the opponent's weak side of play, whereas the egocentric areas would make sure your muscles return the serve in the right direction."

The study finding will help healthcare providers to develop therapeutic treatment for patients with brain damage in these two areas, according to the neuroscientists at York Centre for Vision Research. "As a neurologist, I am excited by the finding because it provides clues for doctors and therapists how they might design different therapeutic approaches," says Ying Chen, lead researcher and PhD candidate in the School of Kinesiology and Health Science.

The study, "Allocentric versus Egocentric Representation of Remembered Reach Targets in Human Cortex," published in the Journal of Neuroscience, was conducted using the state-of-the-art fMRI scanner at York U's Sherman Health Science Research Centre. A dozen participants were tested using the scanner, which Chen modified to distinguish brain areas relating to these two functions.

The participants were given three different tasks to complete when viewing remembered visual targets: egocentric reach (remembering absolute target location), allocentric reach (remembering target location relative to a visual landmark) and a nonspatial control, colour report (reporting color of target).

When participants remembered egocentric targets' locations, areas in the upper occipital lobe (at the back of the brain) encoded visual direction. In contrast, lower areas of the occipital and temporal lobes encoded object direction relative to other visual landmarks. In both cases, the parietal and frontal cortex (near the top of the brain) coded reach direction during the movement.

A GLIMPOSE IN TO THE 3 D BRAIN HOW MEMORIES FORM

People who wish to know how memory works are forced to take a glimpse into the brain. They can now do so without bloodshed: RUB researchers have developed a new method for creating 3D models of memory-relevant brain structures. They published their results in the journalFrontiers in Neuroanatomy.

The way neurons are interconnected in the brain is very complicated. This holds especially true for the cells of the hippocampus. It is one of the oldest brain regions and its form resembles a see horse (hippocampus in Latin). The hippocampus enables us to navigate space securely and to form personal memories. So far, the anatomic knowledge of the networks inside the hippocampus and its connection to the rest of the brain has left scientists guessing which information arrived where and when.

Signals spread through the brain

Accordingly, Dr Martin Pyka and his colleagues from the Mercator Research Group have developed a method which facilitates the reconstruction of the brain's anatomic data as a 3D model on the computer. This approach is quite unique, because it enables automatic calculation of the neural interconnection on the basis of their position inside the space and their projection directions. Biologically feasible network structures can thus be generated more easily than it used to be the case with the method available to date.

Deploying 3D models, the researchers use this technique to monitor the way neural signals spread throughout the network time-wise. They have, for example, found evidence that the hippocampus' form and size could explain why neurons in those networks fire in certain frequencies.

Information become memories

In future, this method may help us understand how animals, for example, combine various information to form memories within the hippocampus, in order to memorise food sources or dangers and to remember them in certain situations.

STRATEGIC OR RANDOM HOW THE BRAIN CHOOSES

Many of the choices we make are informed by experiences we've had in the past. But occasionally we're better off abandoning those lessons and exploring a new situation unfettered by past experiences. Scientists at the Howard Hughes Medical Institute's Janelia Research Campus have shown that the brain can temporarily disconnect information about past experience from decision-making circuits, thereby triggering random behavior

In the study, rats playing a game for a food reward usually acted strategically, but switched to random behavior when they confronted a particularly unpredictable and hard-to-beat competitor. The animals sometimes got stuck in a random-behavior mode, but the researchers, led by Janelia lab head Alla Karpova and postdoctoral fellow Gowan Tervo, found that they could restore normal behavior by manipulating activity in a specific region of the brain. Because the behavior of animals stuck in this random mode bears some resemblance to that of patients affected by a psychological condition called learned helplessness, the findingsmay help explain that condition and suggest strategies for treating it. Karpova, Tervo and their colleagues published their findings in the September 25, 2014, issue of the journal Cell.

The brain excels at integrating information from past experiences to guide decision-making in new situations. But in certain circumstances, random behavior may be preferable. An animal might have the best chance of avoiding a predator if it moves unpredictably, for example. And in a new environment, unrestricted exploration might make more sense than relying on an internal model developed elsewhere. So scientists have long speculated that the brain may have a way to switch off the influence of past experiences so that behavior can proceed randomly, Karpova says. But others disagreed. "They argue that it's inefficient, and that it would be at odds with what some people call one of the most central operating principles of the brain -- to use our past experience and knowledge to optimize behavioral choices," she notes.

Karpova and her colleagues wanted to see if they could create a situation that would force animals to switch into this random mode of behavior. "We tried to create a setting that would push the need to create behavioral variability and unpredictability to its extreme," she says. They did this by placing rats in a competitive setting in which a computer-simulated competitor determined which of two holes in a wall would provide a sugary reward. The virtual competitor, whose sophistication was varied by the experimenters, analyzed the rats' behavior to predict their future choices.

"We thought if we came up with very sophisticated competitors, then the animals would eventually be unable to figure out how to outcompete them, and be forced to either give up or switch into this [random] mode, if such a mode exists," Karpova says. And that's exactly what happened: When faced with a weak competitor, the animals made strategic choices based on the outcomes of previous trials. But when a sophisticated competitor made strong predictions, the rats ignored past experience and made random selections in search of a reward.

Now that they had evidence that the brain could generate both strategic and random behavior, Karpova and her colleagues wanted to know how it switched between modes. Since that switch determines whether or not an animal's internal model of the world influences its behavior, the scientists suspected it might involve a brain region called the anterior cingulate cortex, where that internal model is likely encoded.

They found that they could cause animals to switch between random and strategic behavior by manipulating the level of a stress hormone called norepinephrine in the anterior cingulate cortex. Increasing norepinephrine in the region activated random behavior and suppressed the strategic mode. Inhibiting release of the hormone had the opposite effect.

Karpova's team observed that animals in their experiments sometimes continued to behave randomly, even when such behavior was no longer advantageous. "If all they've experienced is this really sophisticated competitor for several sessions that thwarts their attempts at strategic, model-based counter-prediction, they go into this [random mode], and they can get stuck in it for quite some time after that competitor is gone," she says. This, she says, resembles the condition of learned helplessness, in which strategic decision-making is impaired following an experience in which a person finds they are unable to control their environment.

The scientists could release the animals from this "stuck" state by suppressing the release of norepinephrine in the anterior cingulate cortex. "Just by manipulating a single neuromodulatory input into one brain area, you can dramatically enhance the strategic mode. The effect is strong enough to rescue animals out of the random mode and successfully transform them into strategic decision makers," Karpova says. "We think this might shed light on what has gone wrong in conditions such as learned helplessness, and possibly how we can help alleviate them."

Karpova says that now that her team has uncovered a mechanism that switches the brain between random and strategic behavior, she would like to understand how those behaviors are controlled in more natural settings. "We normally try to use all of our knowledge to think strategically, but sometimes we still need to explore," she says. In most cases, that probably means brief bouts of random behavior during times when we are uncertain that past experience is relevant, followed by a return to more strategic behavior -- a more subtle balance that Karpova intends to investigate at the level of changes in activity in individual neural circuits.

NEW INFORMATION ABOUT HOW NEURONS ACT COULD LEAD TO BRAIN DISORDER ADVANCEMENTS

Neurons are electrically charged cells, located in the nervous system, that interpret and transmit information using electrical and chemical signals. Now, researchers at the University of Missouri have determined that individual neurons can react differently to electrical signals at the molecular level and in different ways -- even among neurons of the same type. This variability may be important in discovering underlying problems associated with brain disorders and neural diseases such as epilepsy.

"Genetic mutations found in neurological disorders create imbalances in the inward and outward flow of electrical current through cells," said David Schulz, associate professor in the Division of Biological Sciences in the College of Arts and Science and a researcher in the Interdisciplinary Neuroscience Program at MU. "Often, neurons react to electrical signals, or voltage, and compensate by altering their own electrical outputs. The variability in these imbalances, even among multiple cells of the same kind within the brain, is one of the major problems scientists face when trying to design therapeutics for disorders like epilepsy. Seizures in individuals can be caused by different imbalances -- therefore getting to the root of how neurons act individually makes our studies important."

Schulz and his team previously proved that two identical neurons can reach the same electrical activity in different ways. In his new study, Schulz hypothesized that neurons might use the cell's genetic code, or its messenger RNA (mRNA), to "fine tune" the production of proteins, helping individual cells react accordingly.

Using clusters of neurons obtained from Jonah crabs, Schulz and his team experimentally altered electrical input and output in the neurons and measured the messenger RNA (mRNA) levels found within the cells. Invertebrates like crabs are useful in neuroscience research because their neurons are simple enough to observe and study, but advanced enough that they can be "scaled up" to apply to higher organisms, Schulz said.

They found that when normal patterns of stimulation were maintained, cells engaged the correct ratios of mRNA to produce the proteins needed to help keep electrical impulses in order; however, when normal patterns of activity were not maintained, this fundamentally changed the cells at the molecular level.

"We were the first to show that the correct ratios of mRNAs are actively maintained by the actual activity or voltage of the cell, and not chemical feedback," Schulz said. "These results represent a novel aspect of regulation that might be useful for developing therapeutics for neuronal disorders later."

Schulz' study, "Activity-dependent feedback regulates correlated ion channel mRNA levels in single identified motor neurons," was published in the August 18^th edition ofCurrent Biology.

NEW EEG ELECTRODE SET FOR FAST EASY MEASUREMENT OF BRAIN FUNCTION ABNORMALITIES

A new, easy-to-use EEG electrode set for the measurement of the electrical activity of the brain was developed in a recent study completed at the University of Eastern Finland. The solutions developed in the PhD study of Pasi Lepola, MSc, make it possible to attach the electrode set on the patient quickly, resulting in reliable results without any special treatment of the skin. As EEG measurements in emergency care are often performed in challenging conditions, the design of the electrode set pays particular attention to the reduction of electromagnetic interference from external sources

EEG measurements can be used to detect such abnormalities in the electrical activity of the brain that require immediate treatment. These abnormalities are often indications of severe brain damage, cerebral infarction, cerebral haemorrhage, poisoning, or unspecified disturbed levels of consciousness. One of the most serious brain function abnormalities is a prolonged epileptic seizure, status epilepticus, which is impossible to diagnose without an EEG measurement. In many cases, a rapidly performed EEG measurement and the start of a proper treatment significantly reduces the need for aftercare and rehabilitation. This, in turn, drastically improves the cost-effectiveness of the treatment chain.

Although the benefits of EEG measurements are indisputable, they remain underused in acute and emergency care. A significant reason for this is the fact that the electrode sets available on the markets are difficult to attach on the patient, and their use requires special skills and constant training. This new type of an electrode set is expected to provide solutions for making EEG measurements feasible at as an early stage as possible.

The EEG electrode set was produced using screen printing technology, in which silver ink was used to print the conductors and measurement electrodes on a flexible polyester film. The EEG electrode set consists of 16 hydrogel-coated electrodes which, unlike in the traditional method, are placed on the hair-free areas of the patient's head, making it easy to attach. The new EEG electrode set significantly speeds up the measurement process because there is no need to scrape the patient's skin or to use any separate gels. As the electrode set is flexible and solid, the electrodes get automatically placed in their correct places. Furthermore, there is no need to move the patient's head when putting on the EEG electrode set, which is especially important in patients possibly suffering from a neck or skull injury. Due to the fact that the disposable electrode set is easy and fast to use, it is particularly well-suited to be used in emergency care, in ambulances and even in field conditions. Thanks to the materials used, the electrode set does not interfere with any magnetic resonance or computed tomography imaging the patient may undergo.

The performance of the electrode set was tested by using various electrical tests, on several volunteers, and in real patient cases. The results were compared to those obtained by traditional EEG methods.

The PhD study also focused on the use of screen printing technology solutions to protect electrodes against electromagnetic interference. The silver or graphite shielding layer printed to the outer edge of the electrode set was discovered to significantly reduce external interference on the EEG signal. This shielding layer can be easily and cost-efficiently introduced to all measurement electrodes produced with similar methods. Protecting the electrode with a shielding layer is beneficial when measuring weak signals in conditions that contain external interference.