Biological Psychology Links

by Sujata Gupta FINDING it difficult to revise for an exam? Help could be on its way in the form of the first non-invasive way of stimulating the brain that can boost visual memory. The technique uses transcranial direct current stimulation (tDCS), in which weak electrical currents are applied to the scalp using electrodes. The method can temporarily increase or decrease activity in a specific brain region and has already been shown to boost verbal and motor skills in volunteers. Richard Chi, a PhD student at the Centre for the Mind, University of Sydney, and colleagues wanted to follow up on previous research showing that lesions in the left anterior temporal lobe (ATL), an area near the temple, can lead to improvements in visual memory and perceptual skills similar to the abilities exhibited by some people with autism. Chi's team wondered if inhibiting that area using tDCS might likewise improve memory. To investigate, his team showed 36 volunteers a dozen "study" slides covered with shapes that varied in their number, arrangement, colour and size (see "Brain games"). The volunteers were then shown five "test" slides - two with patterns that appeared in the study slides, two with completely new patterns and one whose pattern looked similar to that on a study slide. Participants were asked to identify which of the test slides they had already seen, first performing the task without any brain stimulation. © Copyright Reed Business Information Ltd.

By ALIYAH BARUCHIN On July 9, 2009, Steve Wulchin went to wake his 19-year-old son, Eric, in their home in Boulder, Colo. Eric had been given a diagnosis of epilepsy three years earlier, but other than that, his father said, “there was nothing out of the ordinary.” His seizures had been well controlled; he had not had one in six months. Yet that morning, Mr. Wulchin found Eric lying on the floor. CPR and paramedics were too late; Eric had died at about 2:30 a.m. The cause of Eric’s death was ultimately listed as Sudep, for sudden unexplained death in epilepsy. The syndrome accounts for up to 18 percent of all deaths in people with epilepsy, by most estimates; those with poorly controlled seizures have an almost 1 in 10 chance of dying over the course of a decade. Yet many patients and their families never hear about Sudep until someone dies. Mr. Wulchin said none of Eric’s four neurologists ever mentioned it to the family. “The message we got back was, ‘There’s no reason why he can’t live a long and normal life,’ ” he said. “It never occurred to me that this was a possibility.” Now, physicians, researchers, advocates and relatives like Mr. Wulchin, a technology executive, are trying to raise awareness about Sudep. One of their goals is to establish registries of deaths and autopsy results, building databases to support future research. Copyright 2010 The New York Times Company

Miriam Frankel A type of brain cell thought to be responsible for supporting other cells may have a previously unsuspected role in controlling breathing. Star-shaped cells called astrocytes, found in the brain and spinal cord, can 'sense' changes in the concentration of carbon dioxide in the blood and stimulate neurons to regulate respiration, according to a study published online in Science today1. The research may shed some light on the role of astrocytes in certain respiratory illnesses, such as cot death, which are not well understood. Astrocytes are a type of glial cell — the most common type of brain cell, and far more abundant than neurons. "Historically, glial cells were only thought to 'glue' the brain together, providing neuronal structure and nutritional support but not more," explains physiologist Alexander Gourine of University College London, one of the authors of the study. "This old dogma is now changing dramatically; a few recent studies have shown that astrocytes can actually help neurons to process information." "The most important aspect of this study is that it will significantly change ideas about how breathing is controlled," says David Attwell, a neuroscientist at University College London, who was not involved in the study. During exercise, the amount of CO2 in the blood increases, making the blood more acidic. Until now, it was thought that this pH change was 'sensed' by specialized neurons that signal to the lungs to expel more CO2. But the study found that astrocytes can sense such a decrease in pH too — a change that causes an increase in the concentration of calcium ions (Ca2+) in the cells and the release of the chemical messenger adenosine-5'-triphosphate (ATP). © 2010 Nature Publishing Group,

by Helen Thomson I'VE just had a brainwave. Oh, and there's another. And another! In fact, you will have had thousands of them since you started reading this sentence. These waves of electricity flow around our brains every second of the day, allowing neurons to communicate while we walk, talk, think and feel. Exactly where brainwaves are generated in the brain, and how they communicate information, is something of a mystery. As we begin to answer these questions, surprising functions of these ripples of neural activity are emerging. It turns out they underpin almost everything going on in our minds, including memory, attention and even our intelligence. Perhaps most importantly, haphazard brainwaves may underlie the delusions experienced by people with schizophrenia, and researchers are investigating this possibility in the hope that it will lead to treatments for this devastating condition. So what exactly is a brainwave? Despite the way it is bandied about in everyday chit-chat, the term "brainwave" has a specific meaning in neuroscience, referring to rhythmic changes in the electrical activity of a group of neurons. Each neuron has a voltage, which can change when ions flow in or out of the cell. This is normally triggered by stimulation from another cell, and once a neuron's voltage has reached a certain point, it too will fire an electrical signal to other cells, repeating the process. When many neurons fire at the same time, we see these changes in the form of a wave, as groups of neurons are all excited, silent, then excited again, at the same time. © Copyright Reed Business Information Ltd.

By SINDYA N. BHANOO It takes an elephant much longer to notice a fly and flick it away than it takes a shrew, and the reason is not that the elephant’s great brain is too busy with philosophy, or that it simply does not concern itself with flies. It’s a matter of round-trip travel time — in the nervous system. The trip from the elephant’s skin to the brain and back again to the muscles to flick the tail is 100 times as long as the same trip in a shrew, according to a new study published in the Proceedings of the Royal Society B. The nervous system acts like an information superhighway, sending messages back and forth from the brain throughout the body. The bigger the animal, the greater the distance traveled. Nerves have a maximum speed limit of about 180 feet per second, said Maxwell Donelan, the study’s lead author. “It makes sense that in a large animal, like an elephant, messages have a longer way to travel,” he said. Dr. Donelan believes that large animals may have to compensate for this handicap by thinking ahead, and avoiding risky situations. “That’s what we want to study next,” he said. “It could be that the nervous systems of large animals have evolved to become excellent predictive machines.” Copyright 2010 The New York Times Company

By DENISE GRADY For her first appointment with Dr. Daniel Simon, Neelima Raval showed up with a rolling file cabinet full of documents. She had downloaded every word written by or about Dr. Paolo Zamboni, a vascular surgeon from Italy with a most unorthodox theory about multiple sclerosis. Dr. Zamboni believes that the disease, which damages the nervous system, may be caused by narrowed veins in the neck and chest that block the drainage of blood from the brain. He has reported in medical journals that opening those veins with the kind of balloons used to treat blocked heart arteries—an experimental treatment he calls the “liberation procedure”— can relieve symptoms. The idea is a radical departure from the conventional belief that multiple sclerosis is caused by a malfunctioning immune system and inflammation. The new theory has taken off on the Internet, inspiring hope among patients, interest from some researchers and scorn from others. Supporters consider it an outside-the-box idea that could transform the treatment of the disease. Critics call it an outlandish notion that will probably waste time and money, and may harm patients. These critics warn that multiple sclerosis has unpredictable attacks and remissions that make it devilishly hard to know whether treatments are working — leaving patients vulnerable to purported “cures” that do not work. Copyright 2010 The New York Times Company

DALLAS – – Researchers at UT Southwestern Medical Center at Dallas are using magnetic fields to treat diseases in the world’s second laboratory dedicated to magnetic seizure therapy (MST) research. The director of the new Neuro Stimulation Laboratory, Dr. Mustafa M. Husain, and co-investigator Dr. Larry Thornton, associate professors of psychiatry, hope this therapeutic tool at UT Southwestern will offer a better option for patients suffering from neuropsychiatric diseases, including major depression. MST stimulates the brain by directing a diffused electrical current to targeted areas but without the direct electrical stimulation used in electroconvulsive therapy (ECT), or “shock therapy” said Dr. Eric Nestler, chairman of psychiatry. MST also doesn’t seem to have the same side effects as ECT. © 2002 The University of Texas Southwestern Medical Center at Dallas

Reduction of agitation leads to less stress for caregiver; better care for patient San Antonio, Texas and Long Branch, N.J. – Results from a Phase II, multi-center study found dronabinol, a synthetic version of the active ingredient in marijuana, reduces agitation in patients with Alzheimer's disease. In addition, the research concluded that reduced agitation may contribute to the relief of caregiver burden associated with the condition. The findings were presented at the American Society of Consultant Pharmacists' 34th annual meeting. "Our results show dronabinol is an effective treatment for behavioral agitation in patients with Alzheimer's and may ultimately help reduce the stress often experienced by caregivers," said geriatrician Joel S. Ross, M.D. a member of the teaching faculty at Monmouth Medical Center and the lead investigator in the study. "While difficult for the patient, the effects of agitation can greatly impact the emotional and physical health of family members and caregivers. By reducing patients' agitation, caregivers are able to focus more time and energy on their patients' overall wellbeing." Dronabinol, marketed as Marinol, is synthetic delta-9-tetrahydrocannabinol (delta-9-THC). Delta-9-THC also is a naturally occurring component of Cannabis sativa L (marijuana). Dronabinol has been approved by the U.S. Food and Drug Administration (FDA) for the treatment of anorexia in patients with HIV/AIDS and for the treatment of nausea and vomiting associated with cancer chemotherapy. Recent clinical tests also have examined dronabinol's potential to relieve symptoms of multiple sclerosis.1

Communication in the brain travels from one nerve cell to another through critical connections called synapses. These neuron-to-neuron junctions form early in brain development, and their construction was thought to be guided by the nerve cells themselves. Now, investigators supported by the National Institute on Drug Abuse (NIDA), National Institutes of Health, have discovered that cells called glia, known to provide support for neurons in the mature brain, also play a crucial role in formation of synapses during the surge of development following birth. This key insight into the process of normal synapse development may lead to improved treatment of conditions such as drug addiction and epilepsy, which are characterized in part by too many synapses. The research, led by Dr. Ben Barres of Stanford University School of Medicine in Stanford, California, is reported in the February 11, 2005 issue of the journal Cell. “Synapses are the key connections between cells in the brain. We know that drugs alter these connections, and that the developing brain is vulnerable to addictive drugs’ disruption of normal communication,” says NIDA Director Dr. Nora D. Volkow. “Compounds that direct synapse formation may offer a therapeutic option for people fighting drug addiction or other neurologic conditions.” Glia account for 90 percent of the cells in a mammalian brain, but until recently scientists focused mainly on the supportive role that glial cells play in helping mature neurons survive. Dr. Barres, along with Stanford postdoctoral fellows Dr. Karen Christopherson and Dr. Erik Ullian, developed a method for growing neurons in a laboratory without glial cells.

By BENEDICT CAREY For an organ that has been scanned millions of times by experts using high-end imaging technology, the brain remains in large part a shrouded landscape, as lost in darkness as the ocean floor. One reason has less to with the brain’s complexity than its uniformity: it contains billions of identical-looking cells, most sprouting multiple identical-looking branches to other cells, near and far. A needle in a haystack at least looks different from the strands around it; finding and mapping large numbers of neurons is more like working out the root system beneath a tropical rain forest. But last week, researchers at Harvard published pictures in which all those anonymous gray cells glowed in distinctive colors, like a bougainvillea bush gone haywire. The scientists bred mice so their brain cells had genetic inserts containing genes for three colors of fluorescent protein, red, green and blue. They prompted each insert to randomly express one color, using a genetic trigger. Because there were multiple copies of the three-gene insert in each cell, the cell itself expressed a random mixture of the three colors, some 90 shades in all. What emerged was a kind of beaded rainbow belt of neurons, with the fluorescent glow radiating out through each cell’s neural branches. The researchers called the technique “Brainbow.” Copyright 2007 The New York Times Company

By Charles Q. Choi The blast waves from explosions could jolt the skull into generating electricity, potentially damaging the brain, scientists now suggest. Although the burns and shrapnel wounds that explosions can inflict are their most obvious hazards, perhaps the greatest danger comes from a blast's shock wave. These rapidly generate ripples in a person's innards, potentially causing traumatic brain injuries with deleterious effects ranging from a simple concussion to long-term impaired mental function. Now scientists have uncovered a surprising possible way by which a blast might affect the brain — electric fields created when bone is hit by a shock wave. Story continues below ↓advertisement | your ad here "It's always exciting to look at a phenomenon that may have been missed in the past," said researcher Steven Johnson, a theoretical physicist at MIT. "Moreover, this is potentially an issue that can directly affect the lives of our soldiers , which gives it a special interest for all of us who are involved." A variety of materials generate electricity when mechanically stressed. This effect, known as piezoelectricity, is commonly seen in guitar pickups and loudspeakers. Johnson and his colleagues developed a new computer model of the electric fields generated in the skull by an improvised explosive device (IED) — the kind often rigged up nowadays in combat zones. The model results suggest the generated electric fields could exceed electrical safety guidelines by a factor of 10. In fact, they might be comparable in magnitude to medical procedures employing electromagnetic fields that can disrupt brain function. © 2010 LiveScience.com.

ATLANTA - Tests of the first two oral drugs developed for treating multiple sclerosis show that both cut the frequency of relapses and may slow progression of the disease, but with side effects that could pose a tough decision for patients. Two experts not involved in the studies said the drugs appear effective but with potentially dangerous side effects. It’s too soon to know if the pills will be approved by the government or widely adopted by physicians, they said. About 2.5 million people around the world have multiple sclerosis, a neurological disease that can cause muscle tremors, paralysis and problems with speech, memory and concentration. The studies involve the most common form of the disease, in which people are well for a while and then suffer periodic relapses. Current treatments can reduce the duration and severity of symptoms but require daily or regular shots or infusions. The new studies tested two types of pills. Cladribine, made by Merck Serono, is already sold to treat a rare blood cancer. For MS, it would be taken eight to 10 days a year. Fingolimod is a daily MS pill being developed by Novartis. The research found that patients on the pills were about half as likely to suffer relapses of symptoms as those who took dummy pills or a commonly prescribed shot for MS. © 2010 The Associated Press.

By Jennifer Viegas, Discovery News — Genetically engineered fruit flies have been made to jump, beat their wings and fly on human command, according to a new study published in the journal Cell. The flies are the first creatures that humans have remotely controlled. Someday, a related nerve stimulation process may restore nerve circuits in people with neurological diseases or injuries, such as the spinal cord trauma of the late actor and activist Christopher Reeve. Manipulation of behavior in insects and animals, even humans, has been possible for the past 50 years or so. Most of the studies, however, involved invasive electrical stimulation of specific parts of the brain. Surgeon Wilder Penfield, for example, electrically stimulated the cortexes of neurosurgery patients, who later said that the electricity affected their thinking and memory. Monkeys undergoing brain stimulation also have been tricked into thinking that something was vibrating their hands. "Attempts to manipulate behavior in an active and predictive way have been a focus of the laboratory for several years," explained Gero Miesenböck, who co-authored the Cell paper with Susana Lima, and is an associate professor of cell biology at the Yale University School of Medicine. Copyright © 2005 Discovery Communications Inc.

Depression, coordination and speech problems, muscle weakness and disability are just a few of the symptoms of Multiple Sclerosis (MS). Researchers from the Mouse Biology Unit of the European Molecular Biology Laboratory (EMBL) in Italy and the Department of Neuropathology at the Faculty of Medicine, University of Göttingen, Germany, have now discovered that these symptoms are aggravated by a specific signal in cells in the nervous system. The study, which will appear in this week's online issue of Nature Immunology, suggests that blocking the proteins that regulate the signal might be an efficient strategy for new therapies against MS. Nerve cells in our brain and spinal cord communicate with each other using electrical signals. This communication is fast and efficient because - just like wires in an electrical circuit - the axons of our nerves are surrounded by an insulating layer. In MS this protective sheath, made up of a mixture of lipids and proteins called myelin, gets destroyed by cells of our own immune system, and the communication between nerve cells gets disrupted. A central player in the molecular mechanisms behind MS is a signaling molecule called NF-kB. "We have known for a long time that NF-kB is crucially involved in MS," says Manolis Pasparakis, a former Group Leader at EMBL's Mouse Biology Unit who now works as a Professor at the Institute for Genetics at the University of Cologne, "but until now it was not clear if it was friend or foe. We were not sure whether it protects the brain cells against the consequences of the disease or actually aggravates the damage."

By Gero Miesenböck In 1937 the great neuroscientist Sir Charles Scott Sherrington of the University of Oxford laid out what would become a classic description of the brain at work. He imagined points of light signaling the activity of nerve cells and their connections. During deep sleep, he proposed, only a few remote parts of the brain would twinkle, giving the organ the appearance of a starry night sky. But at awakening, “it is as if the Milky Way entered upon some cosmic dance,” Sherrington reflected. “Swiftly the head-mass becomes an enchanted loom where millions of flashing shuttles weave a dissolving pattern, always a meaningful pattern though never an abiding one; a shifting harmony of subpatterns.” Although Sherrington probably did not realize it at the time, his poetic metaphor contained an important scientific idea: that of the brain revealing its inner workings optically. Understanding how neurons work together to generate thoughts and behavior remains one of the most difficult open problems in all of biology, largely because scientists generally cannot see whole neural circuits in action. The standard approach of probing one or two neurons with electrodes reveals only tiny fragments of a much bigger puzzle, with too many pieces missing to guess the full picture. But if one could watch neurons communicate, one might be able to deduce how brain circuits are laid out and how they function. This alluring notion has inspired neuroscientists to attempt to realize Sherrington’s vision. © 1996-2008 Scientific American Inc

Key breakthroughs into epilepsy will rely on the consistent support of charities, says a lead researcher specialising in the condition. Internationally renowned Professor John Duncan says: ‘Those with epilepsy can take some comfort from the fact we are narrowing down the likely causes and consequences of this potentially-devastating disease of the brain. ‘But we still have much to learn, and unfortunately this is unlikely to happen without generous donations from charities.’ Paddington Bear ©P & Company 2001

Columbus, Ohio – A tiny difference in a gene may signal that a person is twice as susceptible to multiple sclerosis (MS) as normal. It could also foretell of a more rapidly progressing form of the disease, according to new research at The Ohio State University College of Medicine and Public Health. The study focused on a gene known as CD24, which directs the making of a protein found on immune cells and that plays an important role in immune responses. Specifically, the study looked at two different versions of the CD24 gene. The two versions differ because of a minute difference known as a single nucleotide polymorphism, or SNP (pronounced ‘snip’). A SNP is a difference of one so-called base, or nucleotide, in the gene’s DNA compared to the same gene in another person. SNPs are common and occur naturally. They may help give a unique pattern to each person’s DNA.

A mutated gene has been discovered as the key behind epilepsy and mental retardation specific to women, thanks to new research at Adelaide’s Women’s & Children’s Hospital and the University of Adelaide, Australia. The world-first discovery, published today in Nature Genetics, shows that although men carry the ‘bad’ gene, only women are affected. The research has been led by Dr Leanne Dibbens and Associate Professor Jozef Gecz from the Department of Genetic Medicine, Women’s & Children’s Hospital, and the Discipline of Paediatrics at the University of Adelaide. The discovery is a result of a major international collaboration involving the Sanger Institute in Cambridge (UK), Wellcome Trust (UK) and many other collaborators in Australia, the United States, Ireland and Israel. Their work has linked, for the first time, a large family of genes known as protocadherins with a condition known as “epilepsy and mental retardation limited to females” (EFMR). Although a relatively uncommon disorder, the condition is hereditary, with successive generations of women affected. In just one of seven families studied across the world, 23 women were affected by the disorder across five generations. This discovery will now enable such families to benefit from genetic counselling, including screening for the genetic mutation at pregnancy. © 2008 Eureka! Science News

HELEN PEARSON
Hey man, dig those spaced-out fish. Researchers have found a real space cadet - a mutant zebrafish that swims towards danger, rather than away from it1. Misplaced connections in its brain reveal that a single type of cell controls the urge to get away. Poke a baby zebrafish (Danio rerio) in the head and it normally flips and swims for its life. However, Michael Granato and colleagues at the University of Pennsylvania School of Medicine in Philadelphia searched for mutants whose escape response is up the spout. 1.Lorent, K., Liu, K. S., Fetcho, J. R. & Granato, M. The zebrafish space cadet gene controls axonal pathfinding of neurons that modulate fast turning movements. Development 128, 2131–2142 (2001). © Macmillan Magazines Ltd 2001 - NATURE NEWS SERVICE Nature © Macmillan Publishers Ltd 2001 Reg. No. 785998 England.

HELEN PEARSON
A cell door that automatically snaps shut in milliseconds - this isn't the latest jailbreak deterrent but a fundamental part of our cells. Nearly 50 years after this microscopic marvel was discovered, researchers in New York have dissected the inner workings of the molecule responsible for generating the body's electrical impulses1. All excitable cells - such as those responsible for nerve signals, muscle contraction or the heart beat - depend on ion channels in the cell membrane. Triggered to open by a small voltage, such channels let through a flood of electrically charged ions, then promptly slam shut. The 'ball-and-chain' model was put forward in the 1970s to explain how this 'inactivation' occurs. The model suggested that a plug - or ball - swinging on a molecular 'chain' on the inside of the channel stops up the opening. Now Roderick MacKinnon and his colleagues at Rockefeller University in New York have found that the ball is more like a snake that sneaks inside the channel to block it. 1.Zhou, M., Morais-Cabral, J. H., Mann, S. & MacKinnon, R. Potassium channel receptor site for the inactivation gate and quaternary amine inhibitors. Nature 411, 657–661 (2001). © Macmillan Magazines Ltd 2001 - NATURE NEWS SERVICE Nature © Macmillan Publishers Ltd 2001 Reg. No. 785998 England.

Chapter 3. Neurophysiology: Conduction, Transmission, and the Integration of Neural Signals