Whole-brain functional magnetic resonance imaging mapping of acute nociceptive responses induced by formalin in rats using atlas registration-based event-related analysis

Authors

  • Yen-Yu I. Shih,

    1. Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, Republic of China
    2. Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, Republic of China
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  • You-Yin Chen,

    1. Department of Electrical and Control Engineering, National Chiao-Tung University, Hsinchu, Taiwan, Republic of China
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  • Chiao-Chi V. Chen,

    1. Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, Republic of China
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  • Jyh-Cheng Chen,

    1. Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, Republic of China
    2. Department of Education and Research, Taipei City Hospital, Taipei, Taiwan, Republic of China
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  • Chen Chang,

    Corresponding author
    1. Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, Republic of China
    • Institute of Biomedical Sciences, Academia Sinica, No. 128, Sec. 2, Academia Road, Taipei, Taiwan, Republic of China
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  • Fu-Shan Jaw

    Corresponding author
    1. Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, Republic of China
    • Institute of Biomedical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, Taiwan, Republic of China
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Abstract

Nociceptive neuronal activation in subcortical regions has not been well investigated in functional magnetic resonance imaging (fMRI) studies. The present report aimed to use the blood oxygenation level-dependent (BOLD) fMRI technique to map nociceptive responses in both subcortical and cortical regions by employing a refined data processing method, the atlas registration-based event-related (ARBER) analysis technique. During fMRI acquisition, 5% formalin (50 μl) was injected into the left hindpaw to induce nociception. ARBER was then used to normalize the data among rats, and images were analyzed using automatic selection of the atlas-based region of interest. It was found that formalin-induced nociceptive processing increased BOLD signals in both cortical and subcortical regions. The cortical activation was distributed over the cingulate, motor, somatosensory, insular, and visual cortices, and the subcortical activation involved the caudate putamen, hippocampus, periaqueductal gray, superior colliculus, thalamus, and hypothalamus. With the aid of ARBER, the present study revealed a detailed activation pattern that possibly indicated the recruitment of various parts of the nociceptive system. The results also demonstrated the utilization of ARBER in establishing an fMRI-based whole-brain nociceptive map. The formalin induced nociceptive images may serve as a template of central nociceptive responses, which can facilitate the future use of fMRI in evaluation of new drugs and preclinical therapies for pain. © 2008 Wiley-Liss, Inc.

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