Thursday, April 19, 2012
Can You Make Yourself Smarter?
Monday, March 12, 2012
Depth and Breadth for an Efficient Brain: No Short Cuts
A recent development in our understanding of neural structure might be mapped onto this set of physical properties. Based on graph theory, we now know that the way in which the human brain is wired resembles a small-world network. That is, neurons are connected to each other in the brain such that there is an optimal balance between short-distance, local, connections with close neighboring neurons, as well as long-distance connections via hub neurons. This balance of having both types of connections results in the most efficient structure with which information can be transmitted from one neuron to another, on average. Too many local connections, and information must shuttle through an adverse number of short-range synapses before reaching a distant neuron, increasing time of transfer. Too many long-distance connections, and also information must ridiculously pass through distant neurons before arriving at the neuron which is just beside. Other properties emerge that also are used to characterize the degree to which a network is a small-world network - level of clustering and randomness of connections. Using such indices, we now know that the evident connectivity of the brain seems to represent a high-level of efficiency with regards to the processing of information pertaining to stimuli, memory, thought, and action. Because of such neural organization, we are able to read or hear, comprehend, remember, reason, and respond, all literally within the blink of an eye.
With this background, we come back to the opening questions. If our brains are generally already efficient, how does this efficiency change with age, and if it goes down (as we are apt to assume), how do we keep it at optimum efficiency for as long as possible apart from the use of chemical and physical interventions? How do we optimize our small-world networks via mental interventions?
Tuesday, January 24, 2012
Lifelong brain-stimulating habits linked to lower Alzheimer's protein levels
Rodrigo y Gabriela Return to Mexico City in Triumph
Solar Eruption Triggers Strongest Radiation Storm in 7 Years - Mashable
National Geographic | Solar Eruption Triggers Strongest Radiation Storm in 7 Years Mashable A huge eruption on the Sun has caused the strongest radiation storm since 2005, which is due to hit Earth on Tuesday, Jan 24, possibly causing widespread communications interference. The eruption occurred late on January 22, 2012 sending a burst of ... Huge solar eruption to reach Earth todayTG Daily Largest Solar Radiation Storm in Six Years Headed Toward EarthBusinessWeek Astronauts in Space Safe from Huge Solar Radiation StormSpace.com Fox News -Los Angeles Times -USA TODAY all 690 news articles » |
Thursday, January 19, 2012
Genetic contributions to stability and change in intelligence from childhood to old age
Genetic contributions to stability and change in intelligence from childhood to old age
Nature advance online publication 18 January 2012. doi:10.1038/nature10781
Authors: Ian J. Deary, Jian Yang, Gail Davies, Sarah E. Harris, Albert Tenesa, David Liewald, Michelle Luciano, Lorna M. Lopez, Alan J. Gow, Janie Corley, Paul Redmond, Helen C. Fox, Suzanne J. Rowe, Paul Haggarty, Geraldine McNeill, Michael E. Goddard, David J. Porteous, Lawrence J. Whalley, John M. Starr & Peter M. Visscher
Understanding the determinants of healthy mental ageing is a priority for society today. So far, we know that intelligence differences show high stability from childhood to old age and there are estimates of the genetic contribution to intelligence at different ages. However, attempts to discover whether genetic causes contribute to differences in cognitive ageing have been relatively uninformative. Here we provide an estimate of the genetic and environmental contributions to stability and change in intelligence across most of the human lifetime. We used genome-wide single nucleotide polymorphism (SNP) data from 1,940 unrelated individuals whose intelligence was measured in childhood (age 11 years) and again in old age (age 65, 70 or 79 years). We use a statistical method that allows genetic (co)variance to be estimated from SNP data on unrelated individuals. We estimate that causal genetic variants in linkage disequilibrium with common SNPs account for 0.24 of the variation in cognitive ability change from childhood to old age. Using bivariate analysis, we estimate a genetic correlation between intelligence at age 11 years and in old age of 0.62. These estimates, derived from rarely available data on lifetime cognitive measures, warrant the search for genetic causes of cognitive stability and change.
Learning the Exception to the Rule: Model-Based fMRI Reveals Specialized Representations for Surprising Category Members
Category knowledge can be explicit, yet not conform to a perfect rule. For example, a child may acquire the rule "If it has wings, then it is a bird," but then must account for exceptions to this rule, such as bats. The current study explored the neurobiological basis of rule-plus-exception learning by using quantitative predictions from a category learning model, SUSTAIN, to analyze behavioral and functional magnetic resonance imaging (fMRI) data. SUSTAIN predicts that exceptions require formation of specialized representations to distinguish exceptions from rule-following items in memory. By incorporating quantitative trial-by-trial predictions from SUSTAIN directly into fMRI analyses, we observed medial temporal lobe (MTL) activation consistent with 2 predicted psychological processes that enable exception learning: item recognition and error correction. SUSTAIN explains how these processes vary in the MTL across learning trials as category knowledge is acquired. Importantly, MTL engagement during exception learning was not captured by an alternate exemplar-based model of category learning or by standard contrasts comparing exception and rule-following items. The current findings thus provide a well-specified theory for the role of the MTL in category learning, where the MTL plays an important role in forming specialized category representations appropriate for the learning context.
Tuesday, October 11, 2011
HPB launches mental health kit for the elderly
Robot brain implanted in a rodent: Researcher implants robotic cerebellum to repair motor function
How the brain makes memories: Rhythmically
Thursday, September 22, 2011
Ageing: Longevity hits a roadblock
Ageing: Longevity hits a roadblock
Nature 477, 7365 (2011). doi:10.1038/477410a
Authors: David B. Lombard, Scott D. Pletcher, Carles Cantó & Johan Auwerx
Increased expression of sirtuin proteins has been shown to enhance lifespan in several organisms. New data indicate that some of the reported effects may have been due to confounding factors in experimental design. Here, experts discuss the significance of these data for research into ageing. See Letter p.482
Thursday, September 08, 2011
Equilibrium in the brain: Excitation and inhibition remain balanced, even when the brain undergoes reorganization
Neuroscience: When lights take the circuits out
Neuroscience: When lights take the circuits out
Nature 477, 7363 (2011). doi:10.1038/477165a
Authors: João Peça & Guoping Feng
Circuit-level perturbations in the brain's electrical activity may underlie social-interaction deficits seen in people with schizophrenia and autism. A new optogenetic tool was instrumental in making this discovery. See Article p.171
Friday, September 02, 2011
The ageing systemic milieu negatively regulates neurogenesis and cognitive function
The ageing systemic milieu negatively regulates neurogenesis and cognitive function
Nature 477, 7362 (2011). doi:10.1038/nature10357
Authors: Saul A. Villeda, Jian Luo, Kira I. Mosher, Bende Zou, Markus Britschgi, Gregor Bieri, Trisha M. Stan, Nina Fainberg, Zhaoqing Ding, Alexander Eggel, Kurt M. Lucin, Eva Czirr, Jeong-Soo Park, Sebastien Couillard-Després, Ludwig Aigner, Ge Li, Elaine R. Peskind, Jeffrey A. Kaye, Joseph F. Quinn, Douglas R. Galasko, Xinmin S. Xie, Thomas A. Rando & Tony Wyss-Coray
In the central nervous system, ageing results in a precipitous decline in adult neural stem/progenitor cells and neurogenesis, with concomitant impairments in cognitive functions. Interestingly, such impairments can be ameliorated through systemic perturbations such as exercise. Here, using heterochronic parabiosis we show that blood-borne factors present in the systemic milieu can inhibit or promote adult neurogenesis in an age-dependent fashion in mice. Accordingly, exposing a young mouse to an old systemic environment or to plasma from old mice decreased synaptic plasticity, and impaired contextual fear conditioning and spatial learning and memory. We identify chemokines—including CCL11 (also known as eotaxin)—the plasma levels of which correlate with reduced neurogenesis in heterochronic parabionts and aged mice, and the levels of which are increased in the plasma and cerebrospinal fluid of healthy ageing humans. Lastly, increasing peripheral CCL11 chemokine levels in vivo in young mice decreased adult neurogenesis and impaired learning and memory. Together our data indicate that the decline in neurogenesis and cognitive impairments observed during ageing can be in part attributed to changes in blood-borne factors.
Tuesday, August 16, 2011
Theory of Psychoneuroenergetics
Monday, August 15, 2011
Error and Perfection
Our minds then try to reduce this error through adaptation. One method of adaptation is to change the goal so that it is closer to what we can achieve. This can be realized by having a modified goal, or a completely new goal. Interestingly, having a "no goal" state is in itself an idealized goal which can result in error when we seek to achieve it. Another adaptative method is to change the way we achieve the goal. We can re-analyze our previous behavior to reason which actions led to more or less error, and modify those behaviors accordingly.
Formal representations of this heuristics can easily be implemented. However, the question remains as to how the goals come to be about. Contribution from environmental and genetic forces can then be considered this level.
Final resolutions will either be that no error, or goal-relative perfection, is achieved, or else the ability to adapt is halted.
Sunday, August 14, 2011
"What" Precedes "Which": Developmental Neural Tuning in Face- and Place-Related Cortex
Although category-specific activation for faces in the ventral visual pathway appears adult-like in adolescence, recognition abilities for individual faces are still immature. We investigated how the ability to represent 'individual' faces and houses develops at the neural level. Category-selective regions of interest (ROIs) for faces in the fusiform gyrus (FG) and for places in the parahippocampal place area (PPA) were identified individually in children, adolescents, and adults. Then, using an functional magnetic resonance imaging adaptation paradigm, we measured category selectivity and individual-level adaptation for faces and houses in each ROI. Only adults exhibited both category selectivity and individual-level adaptation bilaterally for faces in the FG and for houses in the PPA. Adolescents showed category selectivity bilaterally for faces in the FG and houses in the PPA. Despite this profile of category selectivity, adolescents only exhibited individual-level adaptation for houses bilaterally in the PPA and for faces in the 'left' FG. Children only showed category-selective responses for houses in the PPA, and they failed to exhibit category-selective responses for faces in the FG and individual-level adaptation effects anywhere in the brain. These results indicate that category-level neural tuning develops prior to individual-level neural tuning and that face-related cortex is disproportionately slower in this developmental transition than is place-related cortex.
"How Merkel Decided to End Nuclear Power
Wednesday, August 03, 2011
Data are traveling by light
Thursday, July 28, 2011
How Eating Frog Legs Is Causing Frog Extinctions
Frog legs are still an amazingly popular food item around the world, including here in the U.S. According to a new report, an average of 2,280 metric tons of frog legs are imported into this country each year--that's the equivalent of somewhere between 450 million and 1.1 billion frogs. Another 2,216 metric tons of live frogs are imported every year for sale in Asian-American markets. [More]
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