Posts Tagged ‘scientific explanations’

neuro-monitoring and scientific explanations

October 30, 2011 Comments off

By-pass of damaged brain region with a biomimetic device that mimics signal processing function of hippocampal neurons and circuits as envisioned by Dr. Theodore W. Berger and the Biomedical Engineering Laboratories at the University of Southern California.

neural engineering – “…Using an electronic system that duplicates the neural signals associated with memory, they managed to replicate the brain function in rats associated with long-term learned behavior, even when the rats had been drugged to forget. “Flip the switch on, and the rats remember. Flip it off, and the rats forget,” said Theodore Berger of the USC Viterbi School of Engineering’s Department of Biomedical Engineering. Berger is the lead author of an article that will be published in the Journal of Neural Engineering. His team worked with scientists from Wake Forest University in the study, building on recent advances in our understanding of the brain area known as the hippocampus and its role in learning. In the experiment, the researchers had rats learn a task, pressing one lever rather than another to receive a reward. Using embedded electrical probes, the experimental research team, led by Sam A. Deadwyler of the Wake Forest Department of Physiology and Pharmacology, recorded changes in the rat’s brain activity between the two major internal divisions of the hippocampus, known as subregions CA3 and CA1. During the learning process, the hippocampus converts short-term memory into long-term memory, the researchers prior work has shown. “No hippocampus,” says Berger, “no long-term memory, but still short-term memory.” CA3 and CA1 interact to create long-term memory, prior research has shown…” (USC: Restoring Memory, Repairing Damaged Brains)

critical roles in processing, storing and recalling information – “…Memories are formed in the part of the brain known as the hippocampus, a seahorse-shaped structure that plays critical roles in processing, storing and recalling information. The hippocampus is very susceptible to damage through stroke or lack of oxygen and is critically involved in Alzheimer’s disease, said study co-author Michael Fanselow, a UCLA professor of psychology and a member of the UCLA Brain Research Institute. When a memory is first formed, a small protein involved in synaptic transmission — the NMDA receptor — is indispensable to the process, said study co-author Bryce Vissel, a group leader of the neuroscience research program at Sydney’s Garvan Institute of Medical Research. Activation of the NMDA receptor allows calcium to enter a neuron, and calcium permeability enables a chain of molecular reactions that help encode experience and consolidate memory, Fanselow and Vissel said. Learning theorists have assumed that learning cannot occur without NMDA receptors. But the new findings show that NMDA receptors are not essential in “second-learning,” when the rules of “first-learning” are applied to new yet similar scenarios. Instead, another class of receptors known as AMPA receptors, also calcium permeable, appears to take up the task…” (Neuroscience research may help patients recover from brain injury)

brain signals – “…Using the experimental microelectrodes, the scientists recorded brain signals as the patient repeatedly read each of 10 words that might be useful to a paralyzed person: yes, no, hot, cold, hungry, thirsty, hello, goodbye, more and less. Later, they tried figuring out which brain signals represented each of the 10 words. When they compared any two brain signals – such as those generated when the man said the words “yes” and “no” – they were able to distinguish brain signals for each word 76 percent to 90 percent of the time. When they examined all 10 brain signal patterns at once, they were able to pick out the correct word any one signal represented only 28 percent to 48 percent of the time – better than chance (which would have been 10 percent) but not good enough for a device to translate a paralyzed person’s thoughts into words spoken by a computer. “This is proof of concept,” Greger says, “We’ve proven these signals can tell you what the person is saying well above chance. But we need to be able to do more words with more accuracy before it is something a patient really might find useful…” (The Brain Speaks)

brain-imaging methods – “…psychiatrist Andreas Meyer-Lindenberg and collaborators at the Central Institute of Mental Health and the University of Heidelberg Medical Faculty in Mannheim, Germany, have previously used brain-imaging methods to search for abnormalities in the brains of people with genetic risk factors for mental illness. In the new study, Meyer-Lindenberg says, the group wanted to apply the same approach to environmental risk factors, which can be even more powerful than genetic factors. “Urbanicity … has a much higher associated risk than any gene,” he says. “The idea was to take people with that risk factor and see if there’s anything different in their brains.” In an initial study, the researchers placed ads in local newspapers to recruit 32 healthy German adults from cities (with more than 100,000 inhabitants), towns (with more than 10,000 inhabitants), or rural areas. Inside a functional magnetic resonance imaging (fMRI) scanner, which monitors brain activity, a subject worked on difficult arithmetic problems while a fake “performance monitor” indicated a dismal success rate compared with other subjects. Then the researchers ramped up the stress. Meyer-Lindenberg explains: “We would call them in between runs and say, ‘We notice this seems to be very hard for you, but please understand these experiments are very expensive, so if you could just try to at least be above the bottom quarter, we’d really appreciate it.’ ” Measurements of the subjects’ heart rates, blood pressure, and stress hormone levels indicated that the stress was indeed getting to them…” (The Mental Hazards of City Living)

synthetic or computer-mediated telepathy – “A brain–computer interface (BCI), sometimes called a direct neural interface or a brain–machine interface (BMI), is a direct communication pathway between the brain and an external device. BCIs are often aimed at assisting, augmenting or repairing human cognitive or sensory-motor functions. Research on BCIs began in the 1970s at the University of California Los Angeles (UCLA) under a grant from the National Science Foundation, followed by a contract from DARPA. The papers published after this research also mark the first appearance of the expression brain–computer interface in scientific literature. The field of BCI research and development has since focused primarily on neuroprosthetics applications that aim at restoring damaged hearing, sight and movement. Thanks to the remarkable cortical plasticity of the brain, signals from implanted prostheses can, after adaptation, be handled by the brain like natural sensor or effector channels. Following years of animal experimentation, the first neuroprosthetic devices implanted in humans appeared in the mid-nineties…Research is ongoing into synthetic or computer-mediated telepathy which would allow user-to-user communication through analysis of neural signals. The research aims to detect and analyze the word-specific neural signals, using EEG, which occur before speech is vocalized, and to see if the patterns are generalizable. As of 2009, the research is focused on military uses…” (Brain–computer interface)

audio spotlight transmission to your cranium “…Indeed it isn’t. It’s an ad for “Paranormal State,” a ghost-themed series premiering on A&E this week. The billboard uses technology manufactured by Holosonic that transmits an “audio spotlight” from a rooftop speaker so that the sound is contained within your cranium. The technology, ideal for museums and libraries or environments that require a quiet atmosphere for isolated audio slideshows, has rarely been used on such a scale before. For random passersby and residents who have to walk unwittingly through the area where the voice will penetrate their inner peace, it’s another story. Ms. Wilson, a New York-based stylist, said she expected the voice inside her head to be some type of creative project but could see how others might perceive it differently, particularly on a late-night stroll home. “I might be a little freaked out, and I wouldn’t necessarily think it’s coming from that billboard,” she said. Joe Pompei, president and founder of Holosonics, said the creepy approach is key to drawing attention to A&E’s show. But, he noted, the technology was designed to avoid adding to noise pollution. “If you really want to annoy a lot of people, a loudspeaker is the best way to do it,” he said. “If you set up a loudspeaker on the top of a building, everybody’s going to hear that noise. But if you’re only directing that sound to a specific viewer, you’re never going to hear a neighbor complaint from street vendors or pedestrians. The whole idea is to spare other people…” (Voice to Skull Technology in New York)

subvocal speech recognition – “…What is analyzed is silent, or subauditory, speech, such as when a person silently reads or talks to himself,” said Chuck Jorgensen, a scientist whose team is developing silent, subvocal speech recognition at NASA’s Ames Research Center, Moffett Field, Calif. “Biological signals arise when reading or speaking to oneself with or without actual lip or facial movement,” Jorgensen explained. “A person using the subvocal system thinks of phrases and talks to himself so quietly, it cannot be heard, but the tongue and vocal chords do receive speech signals from the brain,” Jorgensen said. In their first experiment, scientists “trained” special software to recognize six words and 10 digits that the researchers repeated subvocally. Initial word recognition results were an average of 92 percent accurate. The first sub-vocal words the system “learned” were “stop,” “go,” “left,” “right,” “alpha” and “omega,” and the digits “zero” through “nine.” Silently speaking these words, scientists conducted simple searches on the Internet by using a number chart representing the alphabet to control a Web browser program…” (NASA Develops System To Computerize Silent, “Subvocal Speech”)

olfactory system – “…No one could trace signals across neural connections to a specific type of neuron at a specific location before,” said biology Professor Liqun Luo. This is Luo’s first study of the mouse olfactory system, but his lab has spent 10 years studying olfactory pathways in the fruit fly. Because mouse brains are so much larger and more complex that those of flies, Luo and postdoctoral researcher Kazunari Miyamichi had to develop an entirely new experimental technique…They found that most of the nerve pathways heading to the higher processing centers that direct the mice’s innate like or dislike of certain odors, and trigger a response to them, originated from one region – the top part of the olfactory bulb. This could explain how the mouse brain directs the animal’s innate fear response to cat or fox urine. This is in contrast to the neurons heading to the brain areas which process learned responses to odor. The neurons associated with learned responses are scattered all over the olfactory bulb, and their relative lack of organization could reflect their flexibility in allowing the mice to learn to avoid or be attracted to new smells. The group also found that each neuron in the brain’s higher centers receives signals from at least four neurons in the olfactory bulb, each of which receives input from a large number of like odor receptors. This progressive funneling and processing helps explain how the brain integrates the information from many different odors, Luo said…” (The brain knows what the nose smells, but how? Stanford researchers trace the answer)

scientific evidence of audible sounds/voice from water – “…Efficient conversion of light into sound can be achieved by concentrating the light sufficiently to ionize a small amount of water, which then absorbs laser energy and superheats. The result is a small explosion of steam, which can generate a 220 decibel pulse of sound. Optical properties of water can be manipulated with very intense laser light to act like a focusing lens, allowing nonlinear self-focusing (NSF) to take place. In addition, the slightly different colors of the laser, which travel at different speeds in water due to group velocity dispersion (GVD), can be arranged so that the pulse also compresses in time as it travels through water, further concentrating the light. By using a combination of GVD and NSF, controlled underwater compression of optical pulses can be attained…” (Lasers Generate Underwater Sound)

biological markers – “…The most convincing scientific progress in psychiatry in the past decade has had little to do with genomics. It is the rigorous, scientific verification that certain forms of psychotherapy are effective. This is perhaps not surprising. One of the major insights in the modern biology of learning and memory is that education, experience, and social interactions affect the brain. When you learn something and then remember it for a long time, it’s because genes are being turned on and off in certain brain cells, leading to the growth of new synaptic contacts between the nerve cells of the brain. Insofar as psychotherapy works and produces stable, learned changes in behavior, it can cause stable anatomical changes in the brain. We are now beginning to measure such changes with brain imaging. If a person with obsessive-compulsive neurosis or depression undergoes psychotherapy—and if the treatment is successful in changing behavior—the treatment will cause a reversal in the biological markers of these disorders. Taken together, these advances could open up new approaches to the treatment of depression, bipolar disorders, and schizophrenia, areas that have been at a pharmacological standstill for decades…” (A Biology of Mental Disorder)

lack of rigorous scientific data – “…We don’t need brain imaging to understand that psychotherapy works. I guess all those decades of psychology research showing the effectiveness of psychotherapy were for naught until we had the sheer magic of brain imaging. While I believe understanding human genetics and the neurological basis of mental disorders is important, invaluable work, I think articles like Kandel’s sort of miss the point. This work is slow and arduous, and for every one step forward, we take two steps back. Indeed, we are making progress, but it is not progress one can easily track or summarize in a mainstream news article of this nature. In the treatment of mental disorders, we have plenty of approaches that work just as well as (and, in fact, work better than) any medical treatment for a medical disease. (Honestly, Kandel should look at the research behind the vast majority of surgical procedures to see the lack of rigorous scientific data that he’s demanding for mental illnesses.) Genetics may one day hold some sort of key to our understanding of mental disorders. But that’s a line that’s been repeated hundreds of times over the past two decades, and one that seems no truer today than it did in 1989…” (Chasing the Genetic Ghosts of Mental Illness)

designer drugs and genetic engineering – – not the answers – “…Armed with the entire sequence of genes, scientists have also developed ways to compare genomes of groups carrying different diseases in the search for stretches of DNA that might be correlated with the conditions. This is referred to as genome-wide association, or GWA. According to Jonathan Latham and Allison Wilson of the Bioscience Resource Project, more than 700 studies examining over 80 different diseases have all come up with similar results. Comparisons involving heart disease, cancer, stroke, autoimmune diseases, obesity, autism, Parkinson’s disease, depression, schizophrenia, and other common illnesses reveal that many genes may have a tiny influence but none can be considered the major factor underlying the condition. This is a stunning revelation that some geneticists find difficult to accept because it means designer drugs and genetic engineering to target or replace a genetic defect are not the answers. Billions of dollars have been and are being spent on GWAs and the search for major genetic determinants of disease. It’s time to accept the reality that they won’t be found and that we must instead turn to the challenge of addressing the more important contributors to human disease: malnutrition, lack of exercise, and polluted air, water, and soil…” (Genome studies lead to unexpected results)