Neuroscience
Month
The human brain likes to make predictions about how the world works. Imagine, for example, that you move to a new town. At first, you don’t know where to go for dinner. But after weeks of trying different restaurants, you pick a favorite, a little Thai place that makes the best green curry. Several months later, however, you notice the curry isn’t as spicy and the vegetables seem undercooked. At first you give your favorite place the benefit of the doubt. But after a few more so-so dinners, you suddenly realize that something must have changed—perhaps the owner hired a new chef—and your notion that this is the best place around is no longer valid. So you begin searching for a new favorite restaurant.
Neuroscientists have long been interested in this adaptability, particularly in the moment when an individual discards an old belief and begins to formulate a new one. “You go from being confident in your model of the world to being uncertain and then abandoning the model altogether,” says Alla Karpova, a group leader at the Howard Hughes Medical Institute’s Janelia Farm Research Campus. She and her colleagues wondered what goes on in the brain when this happens. In rats, they found that the rejection of an old belief correlates with abrupt changes in activity in the medial prefrontal cortex, a brain region involved in cognitive functions such as reward anticipation and decision-making. The team’s research is published in the October 5, 2012, issue of Science.
Groundbreaking research taking place at the University of York could lead to Alzheimer’s disease being diagnosed in minutes using a simple brain scan.
Scientists are working on new technology that could revolutionise the way in which Magnetic Resonance Imaging (MRI) scans are used to view the molecular events behind diseases like Alzheimer’s, without invasive procedure, by increasing the sensitivity of an average hospital scanner by 200,000 times.
The technology underpinning this project, SABRE (Signal Amplification by Reversible Exchange), has received a £3.6m Strategic Award from the Wellcome Trust to fund a team of seven post-doctoral researchers from this month.
The new grant brings the total support for SABRE from the Wellcome Trust, the Wolfson Foundation, Bruker Biospin, the University of York and the Engineering and Physical Sciences Research Council (EPSRC) to over £12.5m in the last three years.
A new Centre for Hyperpolarisation in Magnetic Resonance (CHyM) is being purpose-built at York to house the project. The building, which is nearing completion at York Science Park, includes a chemical laboratory, four high field nuclear magnetic resonance systems and space for 30 research scientists.
The SABRE project is led by Professor Simon Duckett, from the Department of Chemistry at York, Professor Gary Green, from the York Neuroimaging Centre (YNiC) and Professor Hugh Perry, from the Centre for Biological Sciences, University of Southampton.
Professor Duckett said: “While MRI has completely changed modern healthcare, its value is greatly limited by its low sensitivity. As well as tailoring treatments more accurately to the needs of individual patients, our hope is that in the future doctors will be able to accurately make diagnoses that currently take days, weeks and sometimes months, in just minutes.”
Professor Green added: “SABRE has the potential to revolutionise clinical MRI and related MR methods by providing a huge improvement in the sensitivity of scanners. This will ultimately produce a step change in the use and type of information available to scientists and clinicians through MRI, allowing the diagnosis, treatment and clinical monitoring of diverse neurodegenerative diseases.”
Research identifies the mechanism that protects our brains from turning stress and trauma into post-traumatic stress disorder
Researchers from the University of Exeter Medical School have for the first time identified the mechanism that protects us from developing uncontrollable fear.
Our brains have the extraordinary capacity to adapt to changing environments – experts call this ‘plasticity’. Plasticity protects us from developing mental disorders as the result of stress and trauma.
Researchers found that stressful events re-programme certain receptors in the emotional centre of the brain (the amygdala), which the receptors then determine how the brain reacts to the next traumatic event.
These receptors (called protease-activated receptor 1 or PAR1) act in the same way as a command centre, telling neurons whether they should stop or accelerate their activity.
Before a traumatic event, PAR1s usually tell amygdala neurons to remain active and produce vivid emotions. However, after trauma they command these neurons to stop activating and stop producing emotions – so protecting us from developing uncontrollable fear.
This helps us to keep our fear under control, and not to develop exaggerated responses to mild or irrelevant fear triggers – for example, someone who may have witnessed a road traffic accident who develops a fear of cars or someone who may have had a dog jump up on them as a child and who now panics when they see another dog.
The research team used mice in which the PAR1 receptors were genetically de-activated and found that the animals developed a pathological fear in response to even mild, aversive stimuli.
The study was led by Professor Robert Pawlak of University of Exeter Medical School. He said: “The discovery that the same receptor can either awaken neurons or ‘switch them off’ depending on previous trauma and stress experience, adds an entirely new dimension to our knowledge of how the brain operates and emotions are formed.”
Professor Pawlak added: “We are now planning to extend our study to investigate if the above mechanisms, or genetic defects of the PAR1 receptor, are responsible for the development of anxiety disorders and depression in human patients. There is more work to be done, but the potential for the development of future therapies based on our findings is both exciting and intriguing.”
The article describing the above findings has recently been published in one of the most prestigious psychiatry journals, Molecular Psychiatry.