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Tero Toivanen

Selective aphasia in a brain damaged bilingual patient : Neurophilosophy - 0 views

  • A unique case study published in the open access journal Behavioral and Brain Functions sheds some light on this matter. The study, by Raphiq Ibrahim, a neurologist at the University of Haifa, describes a bilingual Arabic-Hebrew speaker who incurred brain damage following a viral infection. Consequently, the patient experienced severe deficits in Hebrew but not in Arabic. The findings support the view that specific components of a first and second language are represented by different substrates in the brain.
  • A native Arabic speaker, he learned Hebrew at an early age (4th grade) and later used it competently both professionally and academically.
  • A CT scan showed that he had suffered a massive hemorrhage in the left temporal lobe, which was compressing the tissue on both sides of the central sulcus, the prominent gfissure which separates the frontal and parietal lobes.
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  • A craniotomy was performed to relieve the pressure, and afterwards another scan showed moderate hemorrhage and herpes encephalitis in the left temporal lobe, and another hemorrhage beneath the outer membrane (the dura) lying over the right frontal lobe.
  • During his 2 month stay there, he developed epileptic seizures which originated in the left temporal lobe, and amnestic aphasia (an inability to name objects or to recognize their written or spoken names). 
  • After the rehabilitation period, a series of linguistic tests was administered to determine the extent of his speech deficits. M.H. exhibited deficits in both languages, but the most severe deficits were seen only in Hebrew. In this language he had a severe difficulty in recalling words and names, so that his speech was non-fluent and interrupted by frequent pauses. He had difficulty understanding others' spoken Hebrew, and also had great difficulty reading and writing Hebrew. In Arabic, his native language, all of these abilities were affected only mildy.
  • The results support a neurolinguistic model in which the brain of bilinguals contains a semantic system (which represents word meanings) which is common to both languages and which is connected to independent lexical systems (which encode the vocabulary of each language). The findings further suggest that the second language (in this case, Hebrew) is represented by an independent subsystem which does not represent the first language (Arabic) and is more succeptible to brain damage.
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    A unique case study published in the open access journal Behavioral and Brain Functions sheds some light on this matter. The study, by Raphiq Ibrahim, a neurologist at the University of Haifa, describes a bilingual Arabic-Hebrew speaker who incurred brain damage following a viral infection. Consequently, the patient experienced severe deficits in Hebrew but not in Arabic. The findings support the view that specific components of a first and second language are represented by different substrates in the brain.
Tero Toivanen

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

  • 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.
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    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

How To Keep Mentally Fit As You Age | Boost Your IQ - 0 views

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    When you are young and mentally fit, you will perhaps never be able to comprehend that your memory, intelligence and overall mental fitness can actually decline as you age. However, as we grow older, our mental sharpness will gradually decline (and at an increasing rate) if we fail to keep on top of things.
Tero Toivanen

Eide Neurolearning Blog: Recess Essential for Improving Attention - 0 views

  • New research suggests that play and down time may be as important to a child’s academic experience as reading, science and math, and that regular recess, fitness or nature time can influence behavior, concentration and even grades.
  • Young children with sensory processing disorders are especially susceptible to behavioral and attention problems if they are not allowed to move and exercise throughout their day.
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    New research suggests that play and down time may be as important to a child's academic experience as reading, science and math, and that regular recess, fitness or nature time can influence behavior, concentration and even grades.
Tero Toivanen

Low Pessimism Protects Against Stroke: The Health and Social Support (HeSSup) Prospecti... - 2 views

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    It's good for your life and health to be optimist.
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    It' s a slightly different perspective that I' m enjoying at this time but I appreciate it may only be true for some-I' ve just begun to understand what "faith" means tho I' m not religious-still! (I feel some empathy now as to why people are) I feel much more inclined to just sit still and connect inside with the Source of me-any meditation or spiritual practice can lead me there or creativity,music too,nature! But to deliberately connect to the part of us all that is connected and knows/is All. From that place I' ve understood that theres noone to be, nowhere to go, nothing to do as we are all there already as we are all IT! So of course daily I forget this but this insight has gifted me much more optimism as I can assume that whatever I really ask for/intend/desire is already in the big melting pot that we can Life/God. That is ' faith' Ive realised now- to ask and know intimately that it' s already a given and to STOP Worrying and completely ignore the naysayers etc. It' s really trusting that I' m connected to it all and I am not separate. I' m beginning to observe quite distinctly the thoughts that separate me from what I want/intend. Particularly in relation to my fellow beings! But then I turn to the place that is connected and I feel so good! and just thinking of the situation from that place and holding that good feeling in relation and giving it over (the problem) really helps! I know several spiritual teachers have said "give it over to me". I' m starting to understand it really is that simple. Trying hard and worrying just create such muck and mire! This may be part of the surrender letting go and letting God that others speak of also? I reckon it would be interesting to see where how people get there faith/trust in life that creates the underlying optimism. What gives that to them? I remember as a child I had it naturally I often got what I asked for and intended and there was an abundance of flow and optimism. No resistance. Fear and doubt come later
Tero Toivanen

The Neural Advantage of Speaking 2 Languages: Scientific American - 0 views

  • The ability to speak a second language isn’t the only thing that distinguishes bilingual people from their monolingual counterparts—their brains work differently, too. Research has shown, for instance, that children who know two languages more easily solve problems that involve misleading cues.
  • The findings suggest that after learning a second language, people never look at words the same way again.
  • “The most important implication of the study is that even when a per­son is reading in his or her native language, there is an influence of knowledge of the nondominant second language,” Van Assche notes. “Becoming a bilingual changes one of people’s most automatic skills.”
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    "The most important implication of the study is that even when a per son is reading in his or her native language, there is an influence of knowledge of the nondominant second language," Van Assche notes. "Becoming a bilingual changes one of people's most automatic skills."
Ruth Howard

BBC News - Brain scans 'can distinguish memories', say scientists - 0 views

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    Scientists say they have been able to tell which past event a person is recalling using a brain scan. The University College London researchers showed people film clips and were able to predict which ones they were subsequently thinking about.
Tero Toivanen

Sign language study shows multiple brain regions wired for language - 1 views

  • A new study from the University of Rochester finds that there is no single advanced area of the human brain that gives it language capabilities above and beyond those of any other animal species.
  • Instead, humans rely on several regions of the brain, each designed to accomplish different primitive tasks, in order to make sense of a sentence.
  • "We're using and adapting the machinery we already have in our brains," said study coauthor Aaron Newman. "Obviously we're doing something different [from other animals], because we're able to learn language unlike any other species. But it's not because some little black box evolved specially in our brain that does only language, and nothing else."
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  • The team of brain and cognitive scientists
  • published their findings in the latest edition of the journal Proceedings of the National Academies of Sciences.
  • The study found that there are, in fact, distinct regions of the brain that are used to process the two types of sentences: those in which word order determined the relationships between the sentence elements, and those in which inflection was providing the information.
  • In fact, Newman said, in trying to understand different types of grammar, humans draw on regions of the brain that are designed to accomplish primitive tasks that relate to the type of sentence they are trying to interpret. For instance, a word order sentence draws on parts of the frontal cortex that give humans the ability to put information into sequences, while an inflectional sentence draws on parts of the temporal lobe that specialize in dividing information into its constituent parts, the study demonstrated.
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    A new study from the University of Rochester finds that there is no single advanced area of the human brain that gives it language capabilities above and beyond those of any other animal species.
Tero Toivanen

YouTube - Posit Science: The Science with Dr. Merzenich - 0 views

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    Dr Michael Merzenich talks about brain plasticity in YouTube video.
David McGavock

About Neuroscience News - Neuroscience News - 0 views

  • 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.
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    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.
neurola

Neuro Leadership Conference | Neuro Leadership Academy - 2 views

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    Visit neuro-la.com to learn how neuroscience can be used to improve leadership. Improve your abilities and revolutionise your group.
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