Posts tagged brain
Articles and news from the latest research reports.
New study suggests memory impairment tied to object perception
A new study from Georgia Tech and the University of Toronto suggests that memory impairments for people diagnosed with early stage Alzheimer’s disease may be due, in part, to problems in determining the differences between similar objects. The findings also support growing research indicating that a part of the brain once believed to support memory exclusively – the medial temporal lobe - also plays a role in object perception. The results are published in the October edition of Hippocampus.
Mild cognitive impairment (MCI) is a disorder commonly thought to be a precursor to Alzheimer’s disease. The study’s investigators, partnering with the Emory Alzheimer’s Disease Research Center, tested MCI patients on their ability to determine whether two rotated, side-by-side pictures were different or identical.
Memory load leaves us ‘blind’ to new information
Trying to keep an image we’ve just seen in memory can leave us blind to things we are ‘looking’ at, according to the results of a study by researchers at the Institute of Cognitive Neuroscience.
It’s been known for some time that when our brains are focused on a task, we can fail to see other things that are in plain sight. This phenomenon, known as ‘inattentional blindness’, is exemplified by the famous ‘invisible gorilla’ experiment where people concentrate on a video of players throwing around a basketball and try to count the number of times the ball is thrown, but fail to observe a man in a gorilla suit walk across the centre of the screen.
The new results reveal that our visual field does not need to be cluttered with other objects to cause this ‘blindness’ and that focusing on remembering something we have just seen is enough to make us unaware of things that happen around us.
“An example of where this is relevant in the real world is when people are following directions on a Sat Nav whilst driving,” explains Professor Nilli Lavie from UCL Institute of Cognitive Neuroscience, who led the study. “Our research would suggest that focusing on remembering the directions we’ve just seen on the screen means that we’re more likely to fail to observe other hazards around us on the road, for example an approaching motorbike or a pedestrian on a crossing, even though we may be ‘looking’ at where we’re going.”
Specific regions of the hippocampus connected to discrete steps of task mastery, study finds
In a study published in Nature Neuroscience, neurobiologists from the Friedrich Miescher Institute for Biomedical Research have been linking synapse formation in the hippocampus to distinct learning steps. They show how different regions of the hippocampus have specific and sequential functions in the mastery of a complex task.
The setup is natural. The mouse finds herself in the water and is looking for a dry place. But how does she solve this task? And what happens if she finds herself in the same situation again? Here is what the scientists observed: At the beginning, the mouse swims all around the little pool, randomly searching for the platform. After two days, there is a change in search approach: The mouse has learned where about the platform is and will start to search right away in the area of the platform. Finally, after another five days, the mouse knows exactly where the platform is and swims directly for it. What is astonishing is that every mouse behaves same way and all the mice learn to find the platform in about the same time, through the same trial and error search strategy stages.
Pico Caroni, senior group leader at the Friedrich Miescher Institute for Biomedical Research, and his team not only described for the first time how mice learn to master such a complex task step by step, but they have also been able to show how one region of the brain, the hippocampus, is engaged in these learning processes. The hippocampus is the region of the brain that is the relay station for a lot of sensory information. In this function, the hippocampus is extremely important for learning and the consolidation of memory. The hippocampus can be divided into three areas termed ventral (vH), intermediate (iH) and dorsal hippocampus (dH). Even though the composition of the neuronal networks in each area is comparable, they differ in gene expression, connectivity, tuning and function.
Caroni and his team could now show that this difference has functional implications in learning. It has been known that during learning new synapses are formed in the hippocampus by so called mossy fibers. In their study published in Nature Neuroscience the scientists show that each search strategy, each level of learning, is associated with a different region of the hippocampus. First, mossy fiber synapses are formed in vH. With the first change in search strategy, mossy fiber formation moves to iH. The mice now have a clear understanding of the relative position of the platform, e.g. distance from the pool wall. Finally, synapse formation moves to dH. By now the mouse has a clear map of the pool, the platform and her position in these surroundings. From now on the mouse will always know where the platform is and will directly head for it.
"We believe that many complex learning tasks are achieved through sub-tasks and that the three areas of the hippocampus are involved in similar ways," comments Caroni. "Our experiments indicate further that this approach is innate, which indicates that similar processes may play as we learn to bike or become proficient in playing tennis."
(Source: medicalxpress.com)
By stitching together 40 high-resolution shots of the hippocampal region of a mouse model of Down syndrome, neurobiologist Ahmad Salehi created this single hyper-informative image which presents a global view of the hippocampus with enough resolution to examine the connections of individual dendrites.
(Source: the-scientist.com)
Potential new class of drugs blocks nerve cell death
Diseases that progressively destroy nerve cells in the brain or spinal cord, such as Parkinson’s disease (PD) and amyotrophic lateral sclerosis (ALS), are devastating conditions with no cures.
Now, a team that includes a University of Iowa researcher has identified a new class of small molecules, called the P7C3 series, which block cell death in animal models of these forms of neurodegenerative disease. The P7C3 series could be a starting point for developing drugs that might help treat patients with these diseases. These findings are reported in two new studies published the week of Oct. 1 in the online early edition of the Proceedings of the National Academy of Sciences (PNAS).
“We believe that our strategy for identifying and testing these molecules in animal models of disease gives us a rational way to develop a new class of neuroprotective drugs, for which there is a great, unmet need,” says Andrew Pieper, M.D., Ph.D., associate professor of psychiatry at the UI Carver College of Medicine, and senior author of the two studies.
About six years ago, Pieper, then at the University of Texas Southwestern Medical Center, and his colleagues screened thousands of compounds in living mice in search of small, drug-like molecules that could boost production of neurons in a region of the brain called the hippocampus. They found one compound that appeared to be particularly successful and called it P7C3.
“We were interested in the hippocampus because new neurons are born there every day. But, this neurogenesis is dampened by certain diseases and also by normal aging,” Pieper explains. “We were looking for small drug-like molecules that might enhance production of new neurons and help maintain proper functioning in the hippocampus.”
However, when the researchers looked more closely at P7C3, they found that it worked by protecting the newborn neurons from cell death. That finding prompted them to ask whether P7C3 might also protect existing, mature neurons in other regions of the nervous system from dying as well, as occurs in neurodegenerative disease.
Using mouse and worm models of PD and a mouse model of ALS, the research team has now shown that P7C3 and a related, more active compound, P7C3A20, do in fact potently protect the neurons that normally are destroyed by these diseases. Their studies also showed that protection of the neurons correlates with improvement of some disease symptoms, including maintaining normal movement in PD worms, and coordination and strength in ALS mice.
(Source: now.uiowa.edu)
A new font tailored for people afflicted with dyslexia is now available for use on mobile devices, thanks to a design by Abelardo Gonzalez, a mobile app designer from New Hampshire. Gonzalez, in collaboration with educators, has selected a font that many people with dyslexia find easier to read. Even better, the new font is free and has already been made available for some word processors and ebook readers. The font, called OpenDyslexic, has also been added to the font choices used by Instapaper—a program that allows users to copy a web page and save it to their hard drive.
Cognitive signals for brain–machine interfaces in posterior parietal cortex include continuous 3D trajectory commands
Cortical neural prosthetics extract command signals from the brain with the goal to restore function in paralyzed or amputated patients. Continuous control signals can be extracted from the motor cortical areas, whereas neural activity from posterior parietal cortex (PPC) can be used to decode cognitive variables related to the goals of movement. Because typical activities of daily living comprise both continuous control tasks such as reaching, and tasks benefiting from discrete control such as typing on a keyboard, availability of both signals simultaneously would promise significant increases in performance and versatility. Here, we show that PPC can provide 3D hand trajectory information under natural conditions that would be encountered for prosthetic applications, thus allowing simultaneous extraction of continuous and discrete signals without requiring multisite surgical implants. We found that limb movements can be decoded robustly and with high accuracy from a small population of neural units under free gaze in a complex 3D point-to-point reaching task. Both animals’ brain-control performance improved rapidly with practice, resulting in faster target acquisition and increasing accuracy. These findings disprove the notion that the motor cortical areas are the only candidate areas for continuous prosthetic command signals and, rather, suggests that PPC can provide equally useful trajectory signals in addition to discrete, cognitive variables. Hybrid use of continuous and discrete signals from PPC may enable a new generation of neural prostheses providing superior performance and additional flexibility in addressing individual patient needs.
Auto experts recognize cars like most people recognize faces
When people – and monkeys – look at faces, a special part of their brain that is about the size of a blueberry “lights up.” Now, the most detailed brain-mapping study of the area yet conducted has confirmed that it isn’t limited to processing faces, as some experts have maintained, but instead serves as a general center of expertise for visual recognition.
Neuroscientists previously established that this region, which is called the fusiform face area (FFA) and is located in the temporal lobe, is responsible for a particularly effective form of visual recognition. But there has been an ongoing debate about whether this area is hard-wired to recognize faces because of their importance to us or if it is a more general mechanism that allows us to rapidly recognize objects that we work with extensively.
In the new study published this week in the online early edition of the Proceedings of the National Academy of Sciences, a team of Vanderbilt researchers report that they have recorded the activity in the FFAs of a group of automobile aficionados at extremely high resolution using one the most powerful MRI scanners available for human use and found no evidence that there is a special area devoted exclusively to facial recognition. Instead, they found that the FFA of the auto experts was filled with small, interspersed patches that respond strongly to photos of faces and autos both.
The New Medicine: Hacking Our Biology is part of the series “Engineers of the New Millennium” from IEEE Spectrum magazine and the Directorate for Engineering of the National Science Foundation. These stories explore technological advances in medical inventions to enhance and extend life.
Scientists at the Universities of Sheffield and Sussex are embarking on an ambitious project to produce the first accurate computer models of a honey bee brain in a bid to advance our understanding of Artificial Intelligence (AI), and how animals think.
The team will build models of the systems in the brain that govern a honey bee’s vision and sense of smell. Using this information, the researchers aim to create the first flying robot able to sense and act as autonomously as a bee, rather than just carry out a pre-programmed set of instructions.
If successful, this project will meet one of the major challenges of modern science: building a robot brain that can perform complex tasks as well as the brain of an animal. Tasks the robot will be expected to perform, for example, will include finding the source of particular odours or gases in the same way that a bee can identify particular flowers.
It is anticipated that the artificial brain could eventually be used in applications such as search and rescue missions, or even mechanical pollination of crops.