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SCR: Peripheral drift illusion, Ramsøy

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  • Thomas Zoëga Ramsøy
    ================================== SCIENCE & CONSCIOUSNESS REVIEW SCI-CON.ORG NEWSLETTER ================================== April 6, 2004 ARTICLES IN THIS
    Message 1 of 1 , Apr 6 12:52 AM

      April 6, 2004

      1. SCR Original: Peripheral drift illusion
      2. Featured Research - TMS Study of ventral projections from V1 with
      implications for finding the NCC
      3. Featured Research - Auditory Processing in brain injured patients
      reveals differences between Minimally Conscious State and Persistent
      Vegetative State
      4. Featured Research - Avoidance of obstacles in the absence of visual
      5. Brain Activation May Explain PTSD Flashbacks
      6. News - Memories are harder to forget than currently thought
      7. Obituary for Donald Griffin; 3/Aug/1915 - 7/Nov/2003

      1. Peripheral drift illusion
      by Thomas Z. Ramsøy

      Illusions always seem to capture our attention, and they strike us as
      strange and interesting. However, we often do not think of these odd
      sensations as mere curiosities. In spite of this, a growing literature
      on illusions points to the fact that these sensations are not only
      interesting in themselves; they are potent sources for insight into
      normal vision.

      Read More: http://www.sci-con.org/articles/20040401.html

      2. TMS Study of ventral projections from V1 with implications for
      finding the NCC
      Overgaard M, Nielsen JF, Fuglsang-Frederiksen A
      University of Aarhus, Denmark
      The study of subliminal perception in normal and brain lesioned
      subjects has long been of interest to scholars studying the neural
      mechanisms behind conscious vision. Using brief durations and a
      developed methodology of introspective reporting, we present an
      experiment with visual stimuli that gives rise to little or no
      subliminal perception under normal viewing conditions. Coupled with
      transcranial magnetic stimulation, however, we find a dissociation
      between correctness and conscious awareness. Furthermore, we find
      support for the hypothesis that the ventral projection streams from V1
      are necessary for visual consciousness.

      Read More: http://tinyurl.com/2x34l [ScienceDirect.com]

      3. Auditory processing in severely brain injured patients: Differences
      between the minimally conscious state and persistent vegetative state.
      Mélanie Boly et al.
      Cyclotron Research Center, Belgium
      Background: The minimally conscious state (MCS) is a recently defined
      clinical condition; it differs from the persistent vegetative state
      (PVS) by the presence of inconsistent, but clearly discernible,
      behavioral evidence of consciousness.

      Results: In both patients in an MCS and the healthy controls, auditory
      stimulation activated bilateral superior temporal gyri (Brodmann areas
      41, 42, and 22). In patients in a PVS, the activation was restricted
      to Brodmann areas 41 and 42 bilaterally. We also showed that, compared
      with patients in a PVS, patients in an MCS demonstrated a stronger
      functional connectivity between the secondary auditory cortex and
      temporal and prefrontal association cortices.

      Conclusion: Although assumptions about the level of consciousness in
      severely brain injured patients are difficult to make, our findings
      suggest that the cerebral activity observed in patients in an MCS is
      more likely to lead to higher-order integrative processes, thought to
      be necessary for the gain of conscious auditory perception.

      Read More: http://tinyurl.com/2hlca [JAMA Journal Archives]

      4. Avoidance of obstacles in the absence of visual awareness
      R. McIntosh; K. McClements; I. Schindler
      University of Durham, UK
      The spatial character of our reaching movements is extremely sensitive
      to potential obstacles in the workspace. We recently found that this
      sensitivity was retained by most patients with left visual neglect
      when reaching between two objects, despite the fact that they tended
      to ignore the leftward object when asked to bisect the space between
      them. This raises the possibility that obstacle avoidance does not
      require a conscious awareness of the obstacle avoided. We have now
      tested this hypothesis in a patient with visual extinction following
      right temporoparietal damage. Extinction is an attentional disorder in
      which patients fail to report stimuli on the side of space opposite a
      brain lesion under conditions of bilateral stimulation. Our patient
      avoided obstacles during reaching, to exactly the same degree,
      regardless of whether he was able to report their presence. This
      implicit processing of object location, which may depend on spared
      superior parietal-lobe pathways, demonstrates that conscious
      awareness is not necessary for normal obstacle avoidance.

      Read More: http://tinyurl.com/24t3o [IngentaSelect.com]

      5. Brain Activation May Explain PTSD Flashbacks
      American Psychiatric Association News
      PTSD subjects appear to process traumatic memories differently from
      subjects without PTSD. This difference may help explain why people
      with PTSD tend to recall traumatic memories as visual flashbacks,
      while those without the disorder recall verbal narratives.

      When persons with posttraumatic stress disorder remember trauma, right
      areas of their brains tend to be activated, whereas when^ individuals
      without PTSD remember trauma, left areas of their^ brains are apt to
      be aroused, according to a study reported^ in the January /American
      Journal of Psychiatry.

      Read More: http://pn.psychiatryonline.org/cgi/content/full/39/6/61?etoc

      6. Memories are harder to forget than currently thought
      Previous studies in rodents had shown that the process of encoding a
      memory could be blocked by the use of a protein synthesis inhibitor
      called anisomycin. Experiments with anisomycin helped lead to the
      acceptance of a theory in which a learned behavior is consolidated
      into a stored form and that then enters a 'labile' - or adaptable -
      state when it is recalled. According to these previous studies, the
      act of putting a labile memory back into storage involves a
      reconsolidation process identical to the one used to store the memory
      initially. Indeed, experiments showed that anisomycin could make a
      mouse forget a memory if it were given anisomycin directly after
      remembering an event.

      In the PNAS study, however, the Penn researchers showed that
      disruption of a "re-remembered" memory was not permanent.

      "When we looked at mice 21 days after they were treated with
      anisomycin to block the reconsolidation of a memory, we showed that
      they could, in fact, remember the original learned behavior," Lattal
      said. "If you use the anisomycin, you can destroy a 'fresh' memory,
      but the 'forgetting' effect of anisomycin on an established memory is
      only temporary, at best."

      Read More:

      7. Obituary for Donald Griffin; 3/Aug/1915 - 7/Nov/2003
      We announce with great regret the passing of Donald R. Griffin, the
      foremost pioneer in modern times of scientific research on animal
      consciousness. Griffin broke a scientific taboo by suggesting that
      animals might have the capacity to think and reason, and that
      scientists should study these mental processes. This gave rise to the
      field known as cognitive ethology and, in general, animal sentience.

      Born in Southampton, N.Y., Dr. Griffin received his bachelor's,
      master's, and doctorate degrees from Harvard and worked there from
      1953 to 1965. He worked at Rockefeller University from 1965 to 1986.
      His wife, Jocelyn Crane, died in 1998. He leaves two daughters, Janet
      Abbott of Arlington, and Margaret Griffin of Montreal, and a son,
      John, of Boston.

      Read More: http://www.animalsentience.com/features/donald_griffin.htm
      http://tinyurl.com/ywa5e [Boston.com]
      Science and Consciousness Review <http://www.sci-con.org>
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