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Scientists Explore Consciousness

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  • medit8ionsociety
    Scientists Explore Consciousness New results published in the Proceedings of the National Academy of Sciences. An international team of scientists led by a
    Message 1 of 35 , Feb 19, 2008
      Scientists Explore Consciousness

      New results published in the Proceedings
      of the National Academy of Sciences.
      An international team of scientists
      led by a University of Leicester researcher
      has carried out a scientific study into the
      realm of consciousness.

      The scientists have made a significant
      step into the understanding of conscious
      perception, by showing how single neurons in the human
      brain reacted to perceived and nonperceived images.

      University of Leicester bioengineer Dr Rodrigo
      Quian Quiroga is spearheading this study
      which is opening new possibilities of exploring
      a hitherto relatively unchartered scientific area.

      The team have today (MONDAY FEB 18) published
      a paper in an international journal, the
      Proceedings of the National Academy of Sciences
      (PNAS) revealing new discoveries in the field
      of consciousness studies.

      Dr Quian Quiroga said: "There has been much
      interest in recent years in consciousness,
      which is considered by many as one of the major
      scientific challenges to be solved, or at least
      addressed in a scientific -rather than
      ust philosophical- way.

      "In fact, there are a few centres, journals
      and conferences dedicated to this topic. The problem
      with consciousness is that it is very hard to be
      defined and it implicates too many different things.
      For this reason, several researchers started
      to specify more clearly what they mean by
      consciousness (even if this is a limited view of
      the whole issue) and think about ways to study
      it in a scientific way. This approach was championed
      by the late Francis Crick and my former supervisor
      at Caltech, Christof Koch.

      "Following this line, the paper in PNAS asks
      how the activity of single neurons in the human
      brain can reflect conscious perception.

      "Recordings were done in epileptic patients
      candidates of curative surgery in which
      intracranial electrodes are implanted to
      establish the location of the epileptic
      focus and evaluate the potential outcome
      of the surgery. Patients usually stay for
      1 or 2 weeks in the guard and this gives us the
      extraordinary opportunity to perform experiments
      and study how neurons in the human brain
      respond to different perceptual and behavioural tasks.

      "In this particular study we showed pictures
      in a computer screen very briefly,
      at the threshold of conscious recognition.
      Subjects had to report whether they
      recognized or not the particular picture showed
      in each trial. The key point is
      that, since the pictures are shown very briefly,
      for exactly the same visual input sometimes the
      subjects reported recognizing the picture and sometimes
      not recognizing it. Then we could ask
      whether the neurons fire according to
      the subjects' conscious perception or the
      actual visual inputs.

      "We found that the neurons we recorded
      responded to the conscious perception in an
      "all-or-none" way by dramatically changing their firing
      rate only when the pictures were recognized.

      "For example, a neuron in the hippocampus
      of one patient fired very strongly to a picture
      of the patient's brother when recognized and remained
      completely silent when it was not, another
      neuron behaved in the same manner with pictures
      of the World Trade Centre, etc.

      "Interestingly, based on the firing of these
      neurons it was possible to
      predict far above chance whether a picture
      was recognized or not. Another
      interesting observation is that a picture
      flashed very briefly generated nearly
      the same response -if recognized- as when
      shown for much longer periods
      of time. This means that a single snapshot
      as brief as 33 ms was sufficient
      to trigger strong neuronal responses far
      outlasting the stimulus presentation,
      signaling the conscious perception of the
      picture shown."

      Dr Quian Quiroga said the study had important
      implications. Potential applications of
      this discovery include the development of Neural Prosthetic
      devices to be used by paralysed patients
      or amputees. A patient with a
      lesion in the spinal cord (as with the
      late Christopher Reeves), can still think
      about reaching a cup of tea with his arm,
      but this order is not transmitted to
      the muscles.

      The idea of Neural Prostheses is to read
      these commands directly from the
      brain and transmit them to bionic devices
      such as a robotic arm that the
      patient could control directly from
      the brain.

      Dr Quian Quiroga's work showing that it
      is possible to read signals from the
      brain is a good step forward in this
      direction. But there are still clinical and
      ethical issues that have to be resolved
      before Neural Prosthetic devices can
      be applied in humans.

      In particular, these would involve invasive
      surgery, which would have to be justified
      by a clear improvement for the patient
      before it could be undertaken.

      Dr Quian Quiroga's discovery has far-reaching
      implications not only for the development of
      neuronal prostheses, but for treatment of patients
      with pathologies involving the hippocampal
      formation, such as epilepsy, Alzheimers and
      schizophrenia and for further understanding of how
      perceptions and memories are represented in the brain.

      University Road
      LE1 7RH
    • jogeshwarmahanta
      Dear J,Since when I read this condition of yours somehow you occupied my mind. In your latest post when you asked for simulated dreams/translogical exercises,
      Message 35 of 35 , Mar 2, 2008
        Dear J,Since when I read this condition of yours somehow you
        occupied my mind. In your latest post when you asked for simulated
        dreams/translogical exercises, I thought that these are no good for
        you as I initiate these exercises just for freshers into the field.
        Then what do I give to you?

        Please go to "google alert".Fill in "human neuroplasticity". You
        will get every information on human neuroplasticity in your E-mail
        ID. Some are trash. Some are just commercial. But you will get great
        ideas befitting to you too. I will be happy to hear about the great
        ideas you get.
        Good luck.

        > "this is an interesting thread.
        > I have done yoga, of and on, mostly off, for over 30 years.
        > I suffered a severe back injury 10 years ago. I ruptured 3 discs
        > my back simultaneously. My spine was severely bent at about a 25
        > degree angle at the thoracic junction. I was in constant pain for
        > years. The doctors told me they could put a "broomstick" up my
        > or I could deal with the pain and "let nature take it's course".
        > also told me my spine would heal "fused" and I would "never" get
        > 25 degree scolosis "curve" out of my back that it would be forever
        > part of my "posture".
        > Now 10 years later, there is no abnormal lateral curve in my
        spine. I
        > can touch the floor in front of me with the bottom knuckles of the
        > backs of my hands and even flatten them for temporary stretching.
        I do
        > not do full yoga workouts, but I stretch my back and relieve the
        > deformed areas of my spine. I have a good doctor who encourages my
        > mental and physical disciplines I utilize to deal with disabilities
        > and former injuries. I also use an "inversion table" which
        allows me
        > to stretch "upside down" at various angles. The curve left my
        > thoracic nd lumbar spine without this equipment though. It was
        > through breathing and stretching, up to three hours a day, and
        > meditating twice a day up to two hours a day.
        > I believe all we need to heal chronic health conditions is in our
        > minds and our bodies, though strong nutrition and a healthy diet
        > locally grown organic produce, herbs, and greens, important as
        > I believe 90 percent of your health is in your mind, and strong
        > positive healing energy is sustainable by the thoughts you think
        > how you breathe every breath you take. I also believe the purer
        > water one drinks. the better one's health will be. I also believe
        > meditating in outdoor wooded settings is beneficial as well.
        > just some thoughts and practices, that have been helpful for
        > namaste"
        > J
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