Posts tagged neuroscience
Articles and news from the latest research reports.
With an incredible diversity of cell types, the central nervous system (CNS), comprising the brain, spinal cord and retina, can be considered to be the most complex organ in the body.
Professor Bill Harris, an experimental biologist and Head of the Department of Physiology, Development and Neuroscience, is fascinated by how this complex and sophisticated system is built out of a collection of undifferentiated cells.
By putting an advanced technology to novel use, he has been able to observe for the first time the entire process of retinal development at the cellular level in zebrafish embryos. This has achieved a long-sought goal in developmental neurobiology: a complete analysis of the building of a vertebrate CNS structure in vivo.
White matter, old dogs, and new tricks at Dartmouth
Most people equate “gray matter” with the brain and its higher functions, such as sensation and perception, but this is only one part of the anatomical puzzle inside our heads. Another cerebral component is the white matter, which makes up about half the brain by volume and serves as the communications network.
The gray matter, with its densely packed nerve cell bodies, does the thinking, the computing, the decision-making. But projecting from these cell bodies are the axons—the network cables. They constitute the white matter. Its color derives from myelin—a fat that wraps around the axons, acting like insulation.
Alex Schelgel, first author on a paper in the August 2012 Journal of Cognitive Neuroscience, has been using the white matter as a landscape on which to study brain function. An important result of the research is showing that you can indeed “teach old dogs new tricks.” The brain you have as an adult is not necessarily the brain you are always going to have. It can still change, even for the better.
"This work is contributing to a new understanding that the brain stays this plastic organ throughout your life, capable of change," Schlegel says. "Knowing what actually happens in the organization of the brain when you are learning has implications for the development of new models of learning as well as potential interventions in cases of stroke and brain damage."
Schlegel is a graduate student working under Peter Tse, an associate professor of psychological and brain sciences and a coauthor on the paper. “This study was Peter’s idea,” Schlegel says. “He wanted to know if we could see white matter change as a result of a long-term learning process. Chinese seemed to him like the most intensive learning experience he could think of.”
Twenty-seven Dartmouth students were enrolled in a nine-month Chinese language course between 2007 and 2009, enabling Schlegel to study their white matter in action. While many neuroscientists use magnetic resonance imaging (MRI) in brain studies, Schlegel turned to a new MRI technology, called diffusion tensor imaging (DTI). He used DTI to measure the diffusion of water in axons, tracking the communication pathways in the brain. Restrictions in this diffusion can indicate that more myelin has wrapped around an axon.
"An increase in myelination tells us that axons are being used more, transmitting messages between processing areas," Schlegel says. "It means there is an active process under way."
Their data suggest that white matter myelination is precisely what was seen among the language students. There is a structural change that goes along with this learning process. While some studies have shown that changes in white matter occurred with learning, these observations were made in simple skill learning and strictly on a “before and after” basis.
"This was the first study looking at a really complex, long-term learning process over time, actually looking at changes in individuals as they learn a task," says Schlegel. "You have a much stronger causal argument when you can do that."
The work demonstrates that significant changes are occurring in adults who are learning. The structure of their brains undergoes change.
"This flies in the face of all these traditional views that all structural development happens in infancy, early in childhood," Schlegel says. "Now that we actually do have tools to watch a brain change, we are discovering that in many cases the brain can be just as malleable as an adult as it is when you are a child or an adolescent."
(Source: eurekalert.org)
Using precisely-targeted lasers, researchers manipulate neurons in worms’ brains and take control of their behavior
In the quest to understand how the brain turns sensory input into behavior, Harvard scientists have crossed a major threshold. Using precisely-targeted lasers, researchers have been able to take over an animal’s brain, instruct it to turn in any direction they choose, and even to implant false sensory information, fooling the animal into thinking food was nearby.
As described in a September 23 paper published in Nature, a team made up of Sharad Ramanathan, an Assistant Professor of Molecular and Cellular Biology, and of Applied Physics, Askin Kocabas, a Post-Doctoral Fellow in Molecular and Cellular Biology, Ching-Han Shen, a Research Assistant in Molecular and Cellular Biology, and Zengcai V. Guo, from the Howard Hughes Medical Institute were able to take control of Caenorhabditis elegans – tiny, transparent worms – by manipulating neurons in the worms’ “brain.”
(Image credit: Ian D. Chin-Sang)
Kansas State University researchers have discovered a molecule that may be capable of delivering drugs inside the body to treat diseases.
For the first time, researchers have designed and created a membrane-bounded vesicle formed entirely of peptides — molecules made up of amino acids, the building blocks of protein. The membrane could serve as a new drug delivery system to safely treat cancer and neurodegenerative diseases.
A study led by John Tomich, professor of biochemistry at Kansas State University, has been published in the journal PLOS ONE in September, and a patent for the discovery is pending.
(Source: k-state.edu)
Tomoko Sakai and colleagues from Kyoto University in Japan subjected a pregnant chimp to a 3D ultrasound to gather images of the fetus between 14 and 34 weeks of development. The volume of its growing brain was then compared to that of an unborn human.
The team found that brain size increases in both chimps and humans until about 22 weeks, but after then only the growth of human brains continues to accelerate. This suggests that as the brain of modern humans rapidly evolved, differences between the two species emerged before birth as well as afterwards.
The researchers now plan to examine how different parts of the brain develop in the womb, particularly the forebrain, which is responsible for decision-making, self-awareness and creativity.
(Source: newscientist.com)
The BCMI-MIdAS (Brain-Computer Music Interface for Monitoring and Inducing Affective States) project
The central purpose of the project is to develop technology for building innovative intelligent systems that can monitor our affective state, and induce specific affective states through music, automatically and adaptively. This is a highly interdisciplinary project, which will address several technical challenges at the interface between science, technology and performing arts/music (incorporating computer-generated music and machine learning).
Research questions
- How can music change affective states and what are the specific musical traits (i.e., the parameters of a piece of music) that elicit such states?
- How can we control such traits in a piece of music in order to induce specific affective states in a participant?
- How can we effectively detect information about affective states induced by music in the EEG signal, going beyond EEG asymmetry and characterising information contained in synchronisation patterns?
- How can we use the EEG to monitor the affective state induced by music on-line (i.e., in “real-time”)?
- How can we produce a generative music system capable of generating music embodying musical traits aimed at inducing specific affective states, observable in the EEG of the participant?
- How can we build an intelligent adaptive system for monitoring and inducing affective states through music on-line?
(Source: cmr.soc.plymouth.ac.uk)
The zebrafish is a major player in the study of vertebrate biology and human disease. Its transparent, externally fertilized eggs, short reproductive cycle and fast growth mean that its embryonic development can be studied closely while the animal is alive, and the fish is a useful model for studying gene behaviour and function.
Now, researchers led by Stephen Ekker, a molecular biologist at the Mayo Clinic in Rochester, Minnesota, have for the first time made custom changes to parts of the zebrafish (Danio rerio) genome, using artificial enzymes to cut portions of DNA out of targeted positions in a gene sequence, and replace them with synthetic DNA.
Sleep Oscillations in the Thalamocortical System Induce Long-Term Neuronal Plasticity
Long-term plasticity contributes to memory formation and sleep plays a critical role in memory consolidation. However, it is unclear whether sleep slow oscillation by itself induces long-term plasticity that contributes to memory retention. Using in vivo prethalamic electrical stimulation at 1 Hz, which itself does not induce immediate potentiation of evoked responses, we investigated how the cortical evoked response was modulated by different states of vigilance. We found that somatosensory evoked potentials during wake were enhanced after a slow-wave sleep episode (with or without stimulation during sleep) as compared to a previous wake episode. In vitro, we determined that this enhancement has a postsynaptic mechanism that is calcium dependent, requires hyperpolarization periods (slow waves), and requires a coactivation of both AMPA and NMDA receptors. Our results suggest that long-term potentiation occurs during slow-wave sleep, supporting its contribution to memory.
Naked mole-rats evolved to thrive in an acidic environment that other mammals, including humans, would find intolerable. Researchers at the University of Illinois at Chicago report new findings as to how these rodents adapted, which may offer clues to relieving pain in other animals and humans.
Dark matter DNA active in brain during day — night cycle
NIH study of rats shows DNA regions thought inactive highly involved in body’s clock
Long stretches of DNA once considered inert dark matter appear to be uniquely active in a part of the brain known to control the body’s 24-hour cycle, according to researchers at the National Institutes of Health.
Working with material from rat brains, the researchers found some expanses of DNA contained the information that generate biologically active molecules. The levels of these molecules rose and fell, in synchrony with 24-hour cycles of light and darkness. Activity of some of the molecules peaked at night and diminished during the day, while the remainder peaked during the day and diminished during the night.