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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. 
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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  • As grey matter is lost, though, the brain gains white matter
  • 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.
  • 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

Wired 14.02: Buddha on the Brain - 0 views

www.wired.com/...dalai.html

brain meditation Dalai Lama Buddha buddhism Tibet neuroscience

shared by Tero Toivanen on 28 Jun 09 - Cached
  • Davidson's research created a stir among brain scientists when his results suggested that, in the course of meditating for tens of thousands of hours, the monks had actually altered the structure and function of their brains.
  • Lutz asked Ricard to meditate on "unconditional loving-kindness and compassion." He immediately noticed powerful gamma activity - brain waves oscillating at roughly 40 cycles per second -�indicating intensely focused thought. Gamma waves are usually weak and difficult to see. Those emanating from Ricard were easily visible, even in the raw EEG output. Moreover, oscillations from various parts of the cortex were synchronized - a phenomenon that sometimes occurs in patients under anesthesia.
  • The researchers had never seen anything like it. Worried that something might be wrong with their equipment or methods, they brought in more monks, as well as a control group of college students inexperienced in meditation. The monks produced gamma waves that were 30 times as strong as the students'. In addition, larger areas of the meditators' brains were active, particularly in the left prefrontal cortex, the part of the brain responsible for positive emotions.
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  • In the traditional view, the brain becomes frozen with the onset of adulthood, after which few new connections form. In the past 20 years, though, scientists have discovered that intensive training can make a difference. For instance, the portion of the brain that corresponds to a string musician's fingering hand grows larger than the part that governs the bow hand - even in musicians who start playing as adults. Davidson's work suggested this potential might extend to emotional centers
  • But Davidson saw something more. The monks had responded to the request to meditate on compassion by generating remarkable brain waves. Perhaps these signals indicated that the meditators had attained an intensely compassionate state of mind. If so, then maybe compassion could be exercised like a muscle; with the right training, people could bulk up their empathy. And if meditation could enhance the brain's ability to produce "attention and affective processes" - emotions, in the technical language of Davidson's study - it might also be used to modify maladaptive emotional responses like depression.
  • Davidson and his team published their findings in the Proceedings of the National Academy of Sciences in November 2004. The research made The Wall Street Journal, and Davidson instantly became a celebrity scientist.
  • Tero Toivanen on 28 Jun 09
     
    Davidson's research created a stir among brain scientists when his results suggested that, in the course of meditating for tens of thousands of hours, the monks had actually altered the structure and function of their brains
Tero Toivanen

Creativity and the Aging Brain | Psychology Today Blogs - 0 views

blogs.psychologytoday.com/...creativity-and-the-aging-brain

creativity aging brain

shared by Tero Toivanen on 23 May 09 - Cached
  • So instead of promoting retirement at age 65, perhaps we as a society should be promoting transition at age 65: transition into a creative field where our growing resource of individuals with aging brains can preserve their wisdom in culturally-valued works of art, music, or writing.
  • Numerous studies suggest that highly creative individuals also employ a broadened rather than focused state of attention. This state of widened attention allows the individual to have disparate bits of information in mind at the same time. Combining remote bits of information is the hallmark of the creative idea.
  • Other studies show that certain areas of the prefrontal cortex involved in self-conscious awareness and emotions are thinner in the aging brain. This may correlate with the diminished need to please and impress others, which is a notable characteristic of both aging individuals and creative luminaries.
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  • Finally, intelligence studies indicate that older individuals have access to an increasing store of knowledge gained over a lifetime of learning and experience. Combining bits of knowledge into novel and original ideas is what the creative brain is all about.
  • Tero Toivanen on 23 May 09
     
    The aging brain resembles the creative brain in several ways. For instance, the aging brain is more distractible and somewhat more disinhibited than the younger brain (so is the creative brain). Aging brains score better on tests of crystallized IQ (and creative brains use crystallized knowledge to make novel and original associations).
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