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Activation of suprachiasmatic nuclei and primary visual cortex depends upon time of day

Authors

  • Ram L. P. Vimal,

    1. Brain Imaging Center, McLean Hospital, Belmont, MA, USA
    2. Department of Psychiatry, Harvard Medical School, Belmont, MA, USA
    3. Vision Research Institute, 428 Great Road, Suite 11, Acton, MA 01720, USA
    4. Dristi Anusandhana Sansthana, A-60 Umed Park, Sola Road, Ahmedabad-61, Gujarat, India
    5. Dristi Anusandhana Sansthana, Sai Niwas, East of Hanuman Mandir, Betiahata, Gorakhpur U.P. 273001, India
    6. Dristi Anusandhana Sansthana, c/o NiceTech Computer Education Institute Pendra, Bilaspur C.G. 495119, India
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  • Manju-Uma C. Pandey-Vimal,

    1. Brain Imaging Center, McLean Hospital, Belmont, MA, USA
    2. Vision Research Institute, 428 Great Road, Suite 11, Acton, MA 01720, USA
    3. Dristi Anusandhana Sansthana, A-60 Umed Park, Sola Road, Ahmedabad-61, Gujarat, India
    4. Dristi Anusandhana Sansthana, Sai Niwas, East of Hanuman Mandir, Betiahata, Gorakhpur U.P. 273001, India
    5. Dristi Anusandhana Sansthana, c/o NiceTech Computer Education Institute Pendra, Bilaspur C.G. 495119, India
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  • Love-Shyam P. Vimal,

    1. Vision Research Institute, 428 Great Road, Suite 11, Acton, MA 01720, USA
    2. Dristi Anusandhana Sansthana, A-60 Umed Park, Sola Road, Ahmedabad-61, Gujarat, India
    3. Dristi Anusandhana Sansthana, c/o NiceTech Computer Education Institute Pendra, Bilaspur C.G. 495119, India
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  • Blaise B. Frederick,

    1. Brain Imaging Center, McLean Hospital, Belmont, MA, USA
    2. Department of Psychiatry, Harvard Medical School, Belmont, MA, USA
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  • Edward G. Stopa,

    1. Department of Pathology, Lifespan Academic Medical Center and Brown University School of Medicine, Providence, RI, USA
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  • Perry F. Renshaw,

    1. Brain Imaging Center, McLean Hospital, Belmont, MA, USA
    2. Department of Psychiatry, Harvard Medical School, Belmont, MA, USA
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  • Shalini P. Vimal,

    1. Vision Research Institute, 428 Great Road, Suite 11, Acton, MA 01720, USA
    2. Dristi Anusandhana Sansthana, A-60 Umed Park, Sola Road, Ahmedabad-61, Gujarat, India
    3. Dristi Anusandhana Sansthana, c/o NiceTech Computer Education Institute Pendra, Bilaspur C.G. 495119, India
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  • David G. Harper

    1. Department of Psychiatry, Harvard Medical School, Belmont, MA, USA
    2. Geriatric Psychiatric Program, McLean Hospital, Belmont, MA, USA
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Dr R. L. P. Vimal, 3Vision Research Institute, as above.
E-mail: rlpvimal@yahoo.co.in; rvimal@mclean.harvard.edu

Abstract

The human suprachiasmatic nucleus (SCN), the master biological clock, is a small (∼2 mm3) and deep structure located in the anterior hypothalamus. Previous methods do not allow in vivo study of the human SCN in a non-invasive manner. Therefore, we explored blood oxygen level-dependent (BOLD)-functional magnetic resonance imaging (fMRI) with OFF–ON–OFF block-designed visual stimuli to record the activities in the ‘SCN and peri SCN in the anterior hypothalamus’ (SCN+) and the primary visual area V1 using a 3T Siemens scanner and six normal subjects. We found that: (i) the BOLD-fMRI response to light and the mean of percentage activation in the SCN+ at midday was significantly less than that at night; and (ii) the number of activated voxels in most of the visual area V1 at midday was significantly higher than that at night. We conclude that BOLD-fMRI responses to light in the SCN+ and the V1 areas vary with time of day. This conclusion is consistent with: (i) the previously measured phase–response curve to light [J. Physiol., 549.3 (2003) 945] for the SCN activity at critical intensity threshold; and (ii) the interaction of the melanopsin-based signals with the rod-cone signals at the ‘giant’ retinal ganglion cells [Nature, 433 (2005) 749] for the V1 activity.

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