Skip to main content

Home/ Neuropsychology/ Group items tagged cerebral cortex

Rss Feed Group items tagged

Filter: All | Bookmarks | Topics Simple Middle
Tero Toivanen

New Light On Nature Of Broca's Area: Rare Procedure Documents How Human Brain Computes ... - 0 views

www.sciencedaily.com/...091015141500.htm

brain Broca's area Wernicke's area language cerebral cortex Sahin

shared by Tero Toivanen on 17 Oct 09 - Cached
  • The study – which provides a picture of language processing in the brain with unprecedented clarity – will be published in the October 16 issue of the journal Science.
  • "Two central mysteries of human brain function are addressed in this study: one, the way in which higher cognitive processes such as language are implemented in the brain and, two, the nature of what is perhaps the best-known region of the cerebral cortex, called Broca's area," said first author Ned T. Sahin, PhD, post-doctoral fellow in the UCSD Department of Radiology and Harvard University Department of Psychology.
  • The study demonstrates that a small piece of the brain can compute three different things at different times – within a quarter of a second – and shows that Broca's area doesn't just do one thing when processing language.
  • ...2 more annotations...
  • The procedure, called Intra-Cranial Electrophysiology (ICE), allowed the researchers to resolve brain activity related to language with spatial accuracy down to the millimeter and temporal accuracy down to the millisecond.
  • "We showed that distinct linguistic processes are computed within small regions of Broca's area, separated in time and partially overlapping in space," said Sahin. Specifically, the researchers found patterns of neuronal activity indicating lexical, grammatical and articulatory computations at roughly 200, 320 and 450 milliseconds after the target word was presented. These patterns were identical across nouns and verbs and consistent across patients.
  • Tero Toivanen on 17 Oct 09
     
    "Two central mysteries of human brain function are addressed in this study: one, the way in which higher cognitive processes such as language are implemented in the brain and, two, the nature of what is perhaps the best-known region of the cerebral cortex, called Broca's area," said first author Ned T. Sahin, PhD, post-doctoral fellow in the UCSD Department of Radiology and Harvard University Department of Psychology.
David McGavock

How Did Consciousness Evolve? - The Atlantic - 0 views

www.theatlantic.com/...485558

research Consciousness Evolution

shared by David McGavock on 12 Jun 16 - No Cached
  • consciousness, is rarely studied in the context of evolution.
  • What is the adaptive value of consciousness? When did it evolve and what animals have it?
  • Attention Schema Theory (AST),
  • ...20 more annotations...
  • suggests that consciousness arises as a solution to one of the most fundamental problems facing any nervous system: Too much information constantly flows in to be fully processed. The brain evolved increasingly sophisticated mechanisms for deeply processing a few select signals at the expense of others,
  • The next evolutionary advance was a centralized controller for attention that could coordinate among all senses. In many animals, that central controller is a brain area called the tectum
  • It coordinates something called overt attention
  • The tectum is a beautiful piece of engineering. To control the head and the eyes efficiently, it constructs something called an internal model, a feature well known to engineers. An internal model is a simulation that keeps track of whatever is being controlled and allows for predictions and planning.
  • With the evolution of reptiles around 350 to 300 million years ago, a new brain structure began to emerge – the wulst
  • our version is usually called the cerebral cortex and has expanded enormously
  • The cortex is like an upgraded tectum
  • The most important difference between the cortex and the tectum may be the kind of attention they control
  • tectum is the master of overt attention—pointing the sensory apparatus toward anything important
  • cortex ups the ante with something called covert attention
  • Your cortex can shift covert attention from the text in front of you to a nearby person, to the sounds in your backyard, to a thought or a memory. Covert attention is the virtual movement of deep processing from one item to another.
  • the cortex must model something much more abstract.
  • it does so by constructing an attention schema
  • a constantly updated set of information that describes what covert attention is doing moment-by-moment and what its consequences are
  • The attention schema is therefore strategically vague. It depicts covert attention in a physically incoherent way, as a non-physical essence. And this, according to the theory, is the origin of consciousness. We say we have consciousness because deep in the brain, something quite primitive is computing that semi-magical self-description.
  • In the AST, the attention schema first evolved as a model of one’s own covert attention. But once the basic mechanism was in place, according to the theory, it was further adapted to model the attentional states of others, to allow for social prediction
  • theory of mind, the ability to understand the possible contents of someone else’s mind.
  • Language is perhaps the most recent big leap in the evolution of consciousness. Nobody knows when human language first evolved. Certainly we had it by 70 thousand years ago when people began to disperse around the world, since all dispersed groups have a sophisticated language.
  • Maybe partly because of language and culture, humans have a hair-trigger tendency to attribute consciousness to everything around us.
  • Justin Barrett called it the Hyperactive Agency Detection Device, or HADD
  • David McGavock on 12 Jun 16
     
    The Attention Schema Theory (AST), developed over the past five years, may be able to answer those questions. The theory suggests that consciousness arises as a solution to one of the most fundamental problems facing any nervous system: Too much information constantly flows in to be fully processed. The brain evolved increasingly sophisticated mechanisms for deeply processing a few select signals at the expense of others, and in the AST, consciousness is the ultimate result of that evolutionary sequence. If the theory is right-and that has yet to be determined-then consciousness evolved gradually over the past half billion years and is present in a range of vertebrate species.
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.
  • ...5 more annotations...
  • 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).
1 - 3 of 3
Showing 20▼ items per page