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Tero Toivanen

Does Vitamin D Improve Brain Function?: Scientific American - 0 views

www.scientificamerican.com/article.cfm

vitamin D improve brain function

shared by Tero Toivanen on 03 Nov 09 - Cached
  • And although vitamin D is well known for promoting bone health and regulating vital calcium levels—hence its addition to milk—it does more than that. Scientists have now linked this fat-soluble nutrient’s hormonelike activity to a number of functions throughout the body, including the workings of the brain.
  • We know there are receptors for vitamin D throughout the central nervous system and in the hippocampus
  • We also know vitamin D activates and deactivates enzymes in the brain and the cerebrospinal fluid that are involved in neurotransmitter synthesis and nerve growth.
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  • In addition, animal and laboratory studies suggest vitamin D protects neurons and reduces inflammation.
  • The scientists found that the lower the subjects’ vitamin D levels, the more negatively impacted was their perform­ance on a battery of mental tests. Compared with people with optimum vitamin D levels, those in the lowest quartile were more than twice as likely to be cognitively impaired.
  • The data show that those people with lower vitamin D levels exhibited slower information-processing speed. This correlation was particularly strong among men older than 60 years.
  • Although we now know that low levels of vitamin D are associated with cognitive impairment, we do not know if high or optimum levels will lessen cognitive losses. It is also unclear if giving vitamin D to those who lack it will help them regain some of these high-level functions.
  • So how much is enough vitamin D? Experts say 1,000 to 2,000 IU daily—about the amount your body will synthesize from 15 to 30 minutes of sun exposure two to three times a week—is the ideal range for almost all healthy adults. Keep in mind, however, that skin color, where you live and how much skin you have exposed all affect how much vitamin D you can produce.
  • Tero Toivanen on 03 Nov 09
     
    And although vitamin D is well known for promoting bone health and regulating vital calcium levels-hence its addition to milk-it does more than that. Scientists have now linked this fat-soluble nutrient's hormonelike activity to a number of functions throughout the body, including the workings of the brain.
Tero Toivanen

NIMH · Our brains are made of the same stuff, despite DNA differences - 0 views

www.nimh.nih.gov/...-despite-dna-differences.shtml

nimh brains dna differences gene prefrontal cortex schizophrenia autism research study genetic variation neuroscience neurons

shared by Tero Toivanen on 30 Oct 11 - No Cached
  • “Having at our fingertips detailed information about when and where specific gene products are expressed in the brain brings new hope for understanding how this process can go awry in schizophrenia, autism and other brain disorders,” said NIMH Director Thomas R. Insel, M.D.
  • Among key findings in the prefrontal cortex:Individual genetic variations are profoundly linked to expression patterns. The most similarity across individuals is detected early in development and again as we approach the end of life.Different types of related genes are expressed during prenatal development, infancy, and childhood, so that each of these stages shows a relatively distinct transcriptional identity. Three-fourths of genes reverse their direction of expression after birth, with most switching from on to off.Expression of genes involved in cell division declines prenatally and in infancy, while expression of genes important for making synapses, or connections between brain cells, increases. In contrast, genes required for neuronal projections decline after birth – likely as unused connections are pruned.By the time we reach our 50s, overall gene expression begins to increase, mirroring the sharp reversal of fetal expression changes that occur in infancy.Genetic variation in the genome as a whole showed no effect on variation in the transcriptome as a whole, despite how genetically distant individuals might be. Hence, human cortexes have a consistent molecular architecture, despite our diversity.
  • Among key findings:Over 90 percent of the genes expressed in the brain are differentially regulated across brain regions and/or over developmental time periods. There are also widespread differences across region and time periods in the combination of a gene’s exons that are expressed.Timing and location are far more influential in regulating gene expression than gender, ethnicity or individual variation.Among 29 modules of co-expressed genes identified, each had distinct expression patterns and represented different biological processes. Genetic variation in some of the most well-connected genes in these modules, called hub genes, has previously been linked to mental disorders, including schizophrenia and depression.Telltale similarities in expression profiles with genes previously implicated in schizophrenia and autism are providing leads to discovery of other genes potentially involved in those disorders.Sex differences in the risk for certain mental disorders may be traceable to transcriptional mechanisms. More than three-fourths of 159 genes expressed differentially between the sexes were male-biased, most prenatally. Some genes found to have such sex-biased expression had previously been associated with disorders that affect males more than females, such as schizophrenia, Williams syndrome, and autism.
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  • Our brains are all made of the same stuff. Despite individual and ethnic genetic diversity, our prefrontal cortex shows a consistent molecular architecture.
  • Males show more sex-biased gene expression. More genes differentially expressed (DEX) between the sexes were found in males than females, especially prenatally. Some genes found to have such sex-biased expression had previously been associated with disorders that affect males more than females, such as schizophrenia, Williams syndrome, and autism.
  • Tero Toivanen on 30 Oct 11
     
    Our brains are all made of the same stuff. Despite individual and ethnic genetic diversity, our prefrontal cortex shows a consistent molecular architecture. 
David McGavock

About Neuroscience News - Neuroscience News - 0 views

neurosciencenews.com/about-neuroscience-news

neuroscience news Brain research learning science

shared by David McGavock on 26 Jun 18 - No Cached
  • In 2001, there was a need for a science website that was dedicated strictly to neuroscience research news, so NeuroscienceNews.com was started. To this day, the site is an independent science news website focusing mainly on neuroscience and other cognitive sciences.No funds have been taken from governments, grants, pharmaceutical companies, big businesses, banks, schools, or others with possibly conflicting interests, to help with this site at any time.We scour news sources from universities, labs, news agencies, scientists, science publishers, and other science departments. We post full articles, releases, abstracts, and sometimes full research journal papers on our site. We also take submissions from nearly anyone.We attempt to link to the original news releases in our posts. We try to include a link to the research papers discussed in the press release, or article, as well as other information that may be important to our readers. We try to include the full list of authors, journal names, research title and identifiers (doi) under the content of each post.
  • David McGavock on 26 Jun 18
     
    We scour news sources from universities, labs, news agencies, scientists, science publishers, and other science departments. We post full articles, releases, abstracts, and sometimes full research journal papers on our site. We also take submissions from nearly anyone.
Tero Toivanen

Phasic Firing Of Dopamine Neurons Is Key To Brain's Prediction Of Rewards - 0 views

www.sciencedaily.com/...090403144032.htm

dopamine neurons brain learning rewards behavior

shared by Tero Toivanen on 23 May 09 - Cached
  • Our research findings provide a direct functional link between the bursting activity of midbrain dopamine neurons and behavior. The research has significant applications for the improvement of health, because the dopamine neurons we are studying are the same neurons that become inactivated during Parkinson's Disease and with the consumption of psychostimulants such as cocaine and amphetamine
  • Midbrain dopamine neurons fire in two characteristic modes, tonic and phasic, which are thought to modulate distinct aspects of behavior. When an unexpected reward is presented to an individual, midbrain dopamine neurons fire high frequency bursts of electrical activity. Those bursts of activity allow us to learn to associate the reward with cues in our environment, which may predict similar rewards in the future.
  • When researchers placed the mice in reward-based situations, they found that the mice without the NMDA receptor in their dopaminergic neurons could not learn tasks that required them to associate sensory cues with reward. Those same mice, however, were able to learn tasks that did not involve an association with rewards.
Tero Toivanen

AK's Rambling Thoughts: Nerve Cells and Glial Cells: Redefining the Foundation of Intel... - 0 views

artksthoughts.blogspot.com/...nd-glial-cells-redefining.html

brain Glial Cells neuron action potential axon synapse network microglia macroglia astrocytes oligodendrocytes ependymal cells radial glia

shared by Tero Toivanen on 25 Jun 09 - Cached
  • Glia are generally divided into two broad classes, microglia and macroglia. Microglia are part of the immune system, specialized macrophages, and probably don't participate in information handling. Macroglia are present in both the peripheral and central nervous systems, in different types.
  • Traditionally, there were four types of glia in the CNS: astrocytes, oligodendrocytes, ependymal cells, and radial glia. Of these, the one type that's most important to the developing revolution in our ideas are those cells called astrocytes.2 It turns out that there are at least two types of cell (at least) subsumed under this name.24, 25, 31, 32 One, which retains the name of astrocyte, takes up neurotransmitters released by neurons (and glial cells), aids in osmoregulation,10 controls circulation in the brain,1, 31 and generally appears to provide support for the neurons and other types of glia.
  • Although both NG2-glia and astrocytes extend processes to nodes of Ranvier in white matter ([refs]) and synapses in grey matter, their geometric relationship to these neuronal elements is different. Thus, although astrocytes and NG2-glia bear a superficial resemblance, they are distinguished by their different process arborizations. This will reflect fundamental differences in the way these two glial cell populations interact with other elements in the neural network.
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  • Both types of glia are closely integrated with the nervous system, receiving information from action potentials via synapses22 (which, only a few years ago were thought to be limited to neurons), and returning control of neuron activity through release of neurotransmitters and other modulators. Both, then, demonstrate the potential for considerable intelligent activity, contributing to the overall intelligence of the brain.
  • Astrocytes probably (IMO) are limited, or mostly so, to maintaining the supplies of energy and necessary metabolites. They receive action potentials,3, 6 which allows them to closely and quickly monitor general activity and increase circulation in response, even before the neurons and NG2-glia have reduced their supply of ATP.21 They appear to be linked in a network among themselves,2, 5 allowing them to communicate their needs without interfering with the higher-level calculations of the brain.
  • NG2-glia appear to have several functions, but one of the most exciting things about them is that they seem to be able to fire action potentials.33 Their cell membranes, like those of the dendrites of neurons, have all the necessary channels and receptors to perform real-time electrical calculations in the same way as neural dendrites. They have also demonstrated the ability to learn through long term potentiation.
  • Dividing NG2-glia also retain the ability to fire action potentials, as well as receiving synaptic inputs from neurons.23 Presumably, they continue to perform their full function, including retaining any elements of long term potentiation or depression contained in their synapses.
  • Oligodendrocytes are responsible for the insulation of the axons, wrapping around approximately 1 mm of each of up to 50 axons within their reach, and forming the myelin sheath.
  • Although the precise type of neuron formed by maturing cells hasn't been determined, the very fact that cells of this type can change into neurons is very important. We actually don't know whether the cells that do this maturation are the same as those that perform neuron-like activities, there appear to be two separate types of NG2-glia, spiking and non-spiking.26 It may very well be that the "spiking" type have actually differentiated, while the "non-spiking" type may be doing the maturing. Of course, very few differentiated cell types remain capable of division, as even the "spiking" type do.
  • What's important about both dendrites and NG2-glia isn't so much their ability to propagate action potentials, as that their entire cell membranes are capable of "intelligent" manipulation of the voltage across it.
  • While there are many ion channels involved in controlling the voltage across the cell membrane, the only type we really need to worry about for action potentials is voltage-gated sodium channels. These are channels that sometimes allow sodium ions to pass through the cell membrane, which they will do because the concentration of sodium ions outside the cell is very much higher than inside. When and how much they open depends, among other things, on the voltage across the membrane.
  • A normal neuron will have a voltage of around -60 to -80mV (millivolts), in a direction that tends to push the sodium ions (which are positive) into the cell (the same direction as the concentration is pushing). When the voltage falls to around -55mV, the primary type of gate will open for a millisecond or so, after which it will close and rest for several milliseconds. It won't be able to open again until the voltage is somewhere between -55 and around -10mV. Meanwhile, the sodium current has caused the voltage to swing past zero to around +20mV.
  • When one part of the cell membrane is "depolarized" in this fashion, the voltage near it is also depressed. Thus, if the voltage is at zero at one point, it might be at -20mV 10 microns (μm) away, and -40mV 20μm away, and -60mV 30μm, and so on. Notice that somewhere between 20μm and 30μm, it has passed the threshold for the ion channels, which means that they are open, allowing a current that drives the voltage further down. This will produce a wave of voltage drop along the membrane, which is what the action potential is.
  • After the action potential has passed, and the gates have closed (see above), the voltage is recovered by diffusion of ions towards and away from the membrane, the opening of other gates (primarily potassium), and a set of pumps that push the ions back to their resting state. These pumps are mostly powered by the sodium gradient, except for the sodium/potassium pump that maintains it, which is powered by ATP.
  • the vast majority of calculation that goes into human intelligence takes place at the level of the network of dendrites and NG2-glia, with the whole system of axons, dendrites, and action potentials only carrying a tiny subset of the total information over long distances. This is especially important considering that the human brain has a much higher proportion of glial matter than our relatives.
  • This, in turn, suggests that our overall approach to understanding the brain has been far too axon centric, there needs to be a shift to a more membrane-centric approach to understanding how the brain creates intelligence.
  • Tero Toivanen on 25 Jun 09
     
    Our traditional idea of how the brain works is based on the neuron: it fires action potentials, which travel along the axon and, when the reach the synapses, the receiving neuron performs a calculation that results in the decision when (or whether) to fire its own action potential. Thus, the brain, from a thinking point of view, is viewed as a network of neurons each performing its own calculation. This view, which I'm going to call the axon-centric view, is simplistic in many ways, and two recent papers add to it, pointing up the ways in which the glial cells of the brain participate in ongoing calculation as well as performing their more traditional support functions.
Tero Toivanen

The five ages of the brain: Adolescence - life - 04 April 2009 - New Scientist - 0 views

www.newscientist.com/...-of-the-brain-adolescence.html

Adolescence brain scanning grey-matter neural connections prefrontal cortex white matter

shared by Tero Toivanen on 21 Jun 09 - Cached
  • Jay Giedd at the National Institute of Mental Health in Bethesda, Maryland, and his colleagues have followed the progress of nearly 400 children, scanning many of them every two years as they grew up. They found that adolescence brings waves of grey-matter pruning, with teens losing about 1 per cent of their grey matter every year until their early 20s (Nature Neuroscience, vol 2, p 861).
  • This cerebral pruning trims unused neural connections that were overproduced in the childhood growth spurt, starting with the more basic sensory and motor areas.
  • Among the last to mature is the dorsolateral prefrontal cortex at the very front of the frontal lobe. This area is involved in control of impulses, judgement and decision-making, which might explain some of the less-than-stellar decisions made by your average teen. This area also acts to control and process emotional information sent from the amygdala - the fight or flight centre of gut reactions - which may account for the mercurial tempers of adolescents.
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  • These changes have both benefits and pitfalls. At this stage of life the brain is still childishly flexible, so we are still sponges for learning. On the other hand, the lack of impulse control may lead to risky behaviours such as drug and alcohol abuse, smoking and unprotected sex.
  • As grey matter is lost, though, the brain gains white matter
  • Substance abuse is particularly concerning, as brain imaging studies suggest that the motivation and reward circuitry in teen brains makes them almost hard-wired for addiction.
  • since drug abuse and stressful events - even a broken heart - have been linked to mood disorders later in life, this is the time when both are best avoided.
  • Making the most of this time is a matter of throwing all that teen energy into learning and new experiences - whether that means hitting the books, learning to express themselves through music or art, or exploring life by travelling the world.
  • Tero Toivanen on 21 Jun 09
     
    Jay Giedd at the National Institute of Mental Health in Bethesda, Maryland, and his colleagues have followed the progress of nearly 400 children, scanning many of them every two years as they grew up. They found that adolescence brings waves of grey-matter pruning, with teens losing about 1 per cent of their grey matter every year until their early 20s (Nature Neuroscience, vol 2, p 861).
Tero Toivanen

Lab Notes : The Brains of Early Birds and Night Owls - 0 views

blog.newsweek.com/...arly-birds-and-night-owls.aspx

brain sleep Early Birds Night Owls Science University of Liege Belgium

shared by Tero Toivanen on 21 Jun 09 - Cached
  • There was no real difference between the early birds and the night owls in their performance on the morning test. But the evening test was a different story: night owls were less sleepy and had faster reaction times than early birds.
  • So even though both groups were sleeping and waking according to their preferred schedule, night owls generally outlasted early birds in how long they could stay awake and mentally alert before becoming mentally fatigued. The fMRI supported the behavioral results: 10.5 hours after waking up, the early birds had lower activity in brain regions linked to attention and the circadian master clock, compared to night owls.
  • Tero Toivanen on 21 Jun 09
     
    A new study, in the journal Science, reports some intriguing differences between the brain-activity patterns of the two types that underlie the behavioral differences.
Ruth Howard

Artificial Synesthesia for Synthetic Vision via Sensory Substitution - 0 views

www.seeingwithsound.com/asynesth.htm

synesthesia

shared by Ruth Howard on 18 Aug 10 - Cached
  • The additional perception is regarded by the trained synesthete as real, often outside the body, instead of imagined in the mind's eye. Its reality and vividness are what makes artificial synesthesia so interesting in its violation of conventional perception. Synesthesia in general is also fascinating because logically it should have been a product of the human brain, where the evolutionary trend has been for increasing coordination, mutual consistency and perceptual robustness in the processing of different sensory inputs.
  • synesthesia
  • options it may provide for people with sensory disabilities like deafness and blindness, where a neural joining of senses can help in replacing one sense by the other:
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  • hear colors, taste shapes, or experience other curious sensory modality crossings, allegedly related to abnormal functioning of the hippocampus, one of the limbic structures in the brain. It has also been suggested that synesthesia constitutes a form of "supernormal integration" involving the posterior parietal cortex. The Russian composer Alexander Scriabin and Russian-born painter Wassily Kandinsky both pioneered artistic links between sight and sound, while they may have been synesthetes themselves. Russian mnemonist Solomon Shereshevskii, studied for decades by neuropsychologist Alexander Luria, appears to have used his natural synesthesia to memorize amazing amounts of data.
  • in seeing with your ears when using a device that maps images into sounds, or in hearing with your eyes when using a device that maps sounds into images.
  • In case of "explicit" synesthesia, the sounds would induce conscious sensations (qualia) of light and visual patterns.
Tero Toivanen

YouTube - Man without a memory - Clive Wearing [BBC - Time: Daytime] - 3 views

www.youtube.com/watch

youtube neuropsychology memory present moment

shared by Tero Toivanen on 03 Jan 10 - Cached
Ruth Howard liked it
  • Tero Toivanen on 03 Jan 10
     
    Man who don't have memory and is constantly living in the present moment.
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  • Ruth Howard on 04 Jan 10
     
    I love that ' bump up against' people and ideas counter to those which we' ve previously aligned-that' s kind of how I see aging gracefully-being able to see many more and others viewpoints-otherwise aging can seem like becoming caricatures of ourselves-we so believe our own thoughts (beliefs are after all only our much/most repeated thoughts!) and there' s no room for anyone or anything else! Mmmmmm yeah but now to live it!
  • Tero Toivanen on 04 Jan 10
     
    My mother had a stroke and now she has big problems to communicate. She understands allmost everything, but have great problems to express herself speaking. Aging is not easy thing if you have problems with your health.
  • Ruth Howard on 05 Jan 10
     
    Truly! It' s alot slower to align with our preferences for sure when sick. I sincerely recommend www.bruno-groening.org as a resource The Bruno Groning Circle of Friends-all volunteers!. It' s a type of Faith healing that I recognise as quite remarkable. It has strong old world Germanic Christian vibe and/but dont let that put you off the ' healing stream' which is very easy to teach to yourself/your mother and available to all regardless of religious affliations.
  • Tero Toivanen on 05 Jan 10
     
    Thak you for the link : )
Tero Toivanen

Map of Synapse May Help Understand Basis of Many Diseases - NYTimes.com - 3 views

www.nytimes.com/...21brain.html

synapse map brain research neuroscience neurons science

shared by Tero Toivanen on 22 Dec 10 - No Cached
  • The research team, led by Seth Grant of the Sanger Institute near Cambridge, England, compiled the first exact inventory of all the protein components of the synaptic information-processing machinery. No fewer than 1,461 proteins are involved in this biological machinery, they report in the current issue of Nature Neuroscience.
  • Each neuron in the human brain makes an average 1,000 or so connections with other neurons. There are 100 billion neurons, so the brain probably contains 100 trillion synapses, its most critical working part.
  • The 1,461 genes that specify these synaptic proteins constitute more than 7 percent of the human genome’s 20,000 protein-coding genes, an indication of the synapse’s complexity and importance.
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  • Dr. Grant believes that the proteins are probably linked together to form several biological machines that process the information and change the physical properties of the neuron as a way of laying down a memory.
  • The new catalog of synaptic proteins “should open a major new window in mental disease,” said Jeffrey Noebels, an expert on the genetics of epilepsy at the Baylor College of Medicine. “We can go in there and systematically look for disease pathways and therefore druggable targets.”
  • Tero Toivanen on 22 Dec 10
     
    The research team, led by Seth Grant of the Sanger Institute near Cambridge, England, compiled the first exact inventory of all the protein components of the synaptic information-processing machinery. No fewer than 1,461 proteins are involved in this biological machinery
  • Ruth Howard on 26 Dec 10
     
    Seeing mental health as a druggable target is psychotic...
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