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Our Brain's Sense Centers Are Continuously Active

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  • medit8ionsociety
    In a way like a Zen master being ever alert, our neurons are ever always active and awake. Somewhat long but interesting ... Our Brain s Sense Centers Are
    Message 1 of 1 , Feb 8, 2009
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      In a way like a Zen master being ever alert, our neurons
      are ever always active and awake. Somewhat long but interesting
      article from Medicalnewstoday.com:
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      Our Brain's Sense Centers Are Continuously Active
      But In The Absence Of A Stimulus Their Electrical
      Activity Remains In 'Screen Saver' Mode

      Even when our eyes are closed, the visual centers
      in our brain are humming with activity. Weizmann
      Institute scientists and others have shown in the
      last few years that the magnitude of sense-related
      activity in a brain that's disengaged from seeing,
      touching, etc., is quite similar to that of one
      exposed to a stimulus. New research at the Institute
      has now revealed details of that activity, explaining
      why, even though our sense centers are working, we
      don't experience sights or sounds when there's nothing
      coming in through our sensory organs.

      The previous studies of Prof. Rafael Malach and
      research student Yuval Nir of the Neurobiology
      Department used functional magnetic resonance
      imaging (fMRI) to measure brain activity in active
      and resting states. But fMRI is an indirect measurement
      of brain activity; it can't catch the nuances of
      the pulses of electricity that characterize neuron
      activity.

      Together with Prof. Itzhak Fried of the University
      of California at Los Angeles and a team at the EEG
      unit of the Tel Aviv Sourasky Medical Center, the
      researchers found a unique source of direct
      measurement of electrical activity in the brain:
      data collected from epilepsy patients who underwent
      extensive testing, including measurement of neuronal
      pulses in various parts of their brain, in the course
      of diagnosis and treatment.

      An analysis of this data showed conclusively that
      electrical activity does, indeed, take place even
      in the absence of stimuli. But the nature of the
      electrical activity differs if a person is experiencing
      a sensory event or undergoing its absence. In results
      that appeared recently in Nature Neuroscience, the
      scientists showed that during rest, brain activity
      consists of extremely slow fluctuations, as opposed
      to the short, quick bursts that typify a response
      associated with a sensory percept. This difference
      appears to be the reason we don't experience
      hallucinations or hear voices that aren't there
      during rest. The resting oscillations appear to be
      strongest when we sense nothing at all - during
      dream-free sleep.

      The slow fluctuation pattern can be compared to a
      computer screen-saver. Though its function is still
      unclear, the researchers have a number of hypotheses.
      One possibility is that neurons, like certain
      philosophers, must 'think' in order to be. Survival,
      therefore, is dependant on a constant state of
      activity. Another suggestion is that the minimal
      level of activity enables a quick start when a stimulus
      eventually presents itself, something like a getaway
      car with the engine running. Nir: 'In the old approach,
      the senses are 'turned on' by the switch of an outside
      stimulus. This is giving way to a new paradigm in which
      the brain is constantly active, and stimuli change and
      shape that activity.'

      Malach: 'The use of clinical data enabled us to solve
      a riddle of basic science in a way that would have
      been impossible with conventional methods. These findings
      could, in the future, become the basis of advanced
      diagnostic techniques.' Such techniques might not
      necessarily require the cooperation of the patient,
      allowing them to be used, for instance on people in
      a coma or on young children.

      ----------------------------
      Article adapted by Medical News Today from original press release.
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      Prof. Rafael Malach's research is supported by the Nella and Leon
      Benoziyo Center for Neurological Diseases; the Carl and Micaela
      Einhorn-Dominic Brain Research Institute; Ms. Vera Benedek, Israel;
      Benjamin and Seema Pulier Charitable Foundation, Inc.; and Ms. Mary
      Helen Rowen, New York, NY. Prof. Malach is the incumbent of the
      Barbara and Morris Levinson Professorial Chair in Brain Research.

      For the scientific paper, please see:
      http://www.nature.com/neuro/journal/v11/n9/full/nn.2177.html

      The Weizmann Institute of Science in Rehovot, Israel, is one of the
      world's top-ranking multidisciplinary research institutions. Noted
      for its wide-ranging exploration of the natural and exact sciences,
      the Institute is home to 2,600 scientists, students, technicians and
      supporting staff. Institute research efforts include the search for
      new ways of fighting disease and hunger, examining leading questions
      in mathematics and computer science, probing the physics of matter
      and the universe, creating novel materials and developing new
      strategies for protecting the environment.

      Source: Yivsam Azgad
      Weizmann Institute of Science
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      Article URL: http://www.medicalnewstoday.com/articles/138007.php
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