Three-dimensional optical tomographic brain imaging during kainic-acid-induced seizures in rats

A. Y. Bluestone, Kenichi Sakamoto, A. H. Hielscher, M. Stewart

    Research output: Contribution to journalConference articlepeer-review

    Abstract

    In this study, we explored the potential of diffuse optical tomography for brain oximetry and describe our efforts towards imaging hemodynamic changes in rat brains during kainic-acid (KA) induced seizures. Using electrophysiological techniques we first showed that KA induces a pronounced transient hypotension in urethane anesthetized rats that is coincident with seizure activity beginning in ventral and spreading to dorsal hippocampus. We observed sustained increases in vagus and sympathetic activity during generalized limbic seizure activity, which alters blood pressure regulation and heart rhythms. Subsequently, we used optical tomographic methods to study KA induced seizures in anesthetized animals to better define the hemodynamic cerebral vascular response. We observed a lateralized increase in deoxyhemoglobin after KA injection at the time when the blood pressure (BP) was decreased. By contrast, injection of phenylephrine produced a symmetric global increase in total hemoglobin. These findings indicate that our instrument is sensitive to the local hemodynamics, both in response to a global increase in blood pressure (phenylephrine injection) and a lateralized decrease in oxyhemoglobin produced by an asymmetric response to KA; a response that may be critically important for severe autonomic nervous system alterations during seizures. The results of this study provide the impetus for combining complimentary modalities, imaging and electrophysiological, to ultimately gain a better understanding of the underlying physiology of seizure activity in the rat.

    Original languageEnglish (US)
    Article number09
    Pages (from-to)58-66
    Number of pages9
    JournalProgress in Biomedical Optics and Imaging - Proceedings of SPIE
    Volume5746
    Issue numberI
    DOIs
    StatePublished - 2005
    EventMedical Imaging 2005 - Physiology, Function, and Structure from Medical Images - San Diego, CA, United States
    Duration: Feb 13 2005Feb 15 2005

    Keywords

    • Brain imaging
    • Kainic acid
    • Optical tomography
    • Seizure
    • Small animal imaging

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Biomaterials
    • Atomic and Molecular Physics, and Optics
    • Radiology Nuclear Medicine and imaging

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