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Tero Toivanen

'Noisiest' neurons persist in the adult brain - 0 views

www.physorg.com/news182609011.html

neurons neuroscience brain survival epilepsy hyperactive molecular signals neuronal activity

shared by Tero Toivanen on 18 Jan 10 - Cached
  • In addition, the observation that the "noisiest" neurons have a survival advantage helps explain the prevalence of epilepsy, in which some neurons become hyperactive and fire in an uncontrollable fashion.
  • during childhood, when many neurons are still being added to the brain, it is likely that neurons that become pathologically hyperactive will be preferentially selected for survival, and these abnormal neurons will be the trigger for epilepsy,
  • Investigating the molecular signals launched by neuronal activity will potentially lead to new drugs that bolster the survival of new neurons. These drugs could be used to increase the efficacy of treatments that depend on grafting stem cell-derived neurons into the adult brain to treat neurological diseases such as Parkinson's and Alzheimer's.
  • Tero Toivanen on 18 Jan 10
     
    'Noisiest' neurons persist in the adult brain
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.
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