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Preservation of functional architecture in visual cortex of cats with experimentally induced hydrocephalus

Authors

  • Kazuyuki Imamura,

    1. Laboratory for Visual Neurocomputing, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
    2. Department of Neuroscience, Osaka Bioscience Institute, Suita-shi, Osaka, Japan
    3. Department of Physiology, Graduate School of Medicine, Osaka City University, Abeno-ku, Osaka-shi, Osaka, Japan
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  • Shigeru Tanaka,

    1. Laboratory for Visual Neurocomputing, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
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  • Jérôme Ribot,

    1. Laboratory for Visual Neurocomputing, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
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  • Masayuki Kobayashi,

    1. Department of Neuroscience, Osaka Bioscience Institute, Suita-shi, Osaka, Japan
    2. Department of Oral Physiology, Osaka University Graduate School of Dentistry, Suita-shi, Osaka, Japan
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  • Masao Yamamoto,

    1. Department of Neuroscience, Osaka Bioscience Institute, Suita-shi, Osaka, Japan
    2. Yamamoto Ophthalmic Clinic, Chuou-ku, Kobe-shi, Hyogo, Japan
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  • Kazuhiko Nakadate,

    1. Department of Neuroscience, Osaka Bioscience Institute, Suita-shi, Osaka, Japan
    2. Department of Histology and Neurobiology, Dokkyo University School of Medicine, Mibu-machi, Shimotsuga-gun, Tochigi, Japan
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  • Yasuyoshi Watanabe

    1. Department of Neuroscience, Osaka Bioscience Institute, Suita-shi, Osaka, Japan
    2. Department of Physiology, Graduate School of Medicine, Osaka City University, Abeno-ku, Osaka-shi, Osaka, Japan
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Dr Kazuyuki Imamura, 1Laboratory for Visual Neurocomputing, as above.
E-mail: imamurak@brain.riken.jp

Abstract

We investigated how neural function is preserved or matured in the visual cortex of cats, following the induction of hydrocephalus by kaolin injection. In vivo optical imaging of intrinsic signals in 11–17-week-old hydrocephalic cats revealed orientation maps showing the orderly arrangement of preferred orientations when stimulated by grating stimuli at a low spatial frequency, whereas stimulus-evoked intrinsic signals in response to gratings at a high spatial frequency were often too weak to construct orientation maps. Furthermore, in two of the three hydrocephalic cats, initially deteriorated orientation maps became almost regular maps in the second imaging experiments conducted 8 and 11 weeks, respectively, after the first imaging. This indicates that, despite large structural deformation of the hydrocephalic brain, orientation maps are elaborated sufficiently after the age of 5–6 months, by which time the orientation map formation is usually completed in normal cats. Single unit recording from the decompressed visual cortex revealed that many neurons showed normal orientation selectivity, whereas the binocularity of these neurons was found to be reduced. These results suggested that the deformed visual cortex of hydrocephalic cats exhibits a high plasticity, retaining its functional organization.

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