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TRACKING AN ELECTRICALLY SILENT SOURCE IN THE HIPPOCAMPUS USING A CALCIUM-SENSITIVE FLUORESCENT DYE

Keshav, Arvind
http://rave.ohiolink.edu/etdc/view?acc_num=case1469380261

Abstract Details

2016, Master of Sciences (Engineering), Case Western Reserve University, Biomedical Engineering.
Analysis of the neural activity in the hippocampus in the presence of epileptogenic agents shows fast-moving spikes sensitive to N-Methyl-D-Aspartate (NMDA) coming from a putative electrically silent source moving at a slower speed and difficult to track with standard fluorescence methods. Advances in imaging technology have allowed for millisecond-resolution mapping of the changes in fluorescence with high spatial resolution. In this study, the presence of this electrically silent focus was revealed by mapping the increase in intracellular calcium using the calcium-sensitive fluorescent dye Oregon Green 488 BAPTA-1 (OGB-1). Results indicate that the focus and its propagation can indeed be tracked using OGB-1, with a mean propagation velocity, obtained by cross-correlation calculations, of 0.0036 ± 0.0009 m/s, well within the predicted range for the putative source from other indirect measurements. Additionally, we tested in vitro the hypothesis that the propagation of this focus was independent of the NMDA-sensitive spikes it generates. The NMDA blocker introduced prevented the generation of spikes, but the movement of the focus was unaffected. The mean propagation velocity was 0.0035 ± 0.001 m/s and t-test results showed no significant difference in propagation speeds with and without the NMDA blocker. Together, these results indicate that the electrically silent focus is indeed the source of the spikes and relies on a different unknown mechanism of propagation. A possible mechanism of propagation is through the diffusion of potassium. However, the speed of the potassium wave was found to be significantly lower than that observed for our source (P<0.0001). These results indicate the presence of a novel calcium wave in the hippocampus propagating through pyramidal cells and capable of generating NMDA-sensitive spikes.
Dominique Durand (Advisor)
Jeffrey Capadona (Committee Member)
Andrew Rollins (Committee Member)
69 p.
Biomedical Engineering; Biomedical Research
epilepsy; electrically silent source; calcium-sensitive fluorescent dyes; NMDA

Recommended Citations

Citations

  • Keshav, A. (2016). TRACKING AN ELECTRICALLY SILENT SOURCE IN THE HIPPOCAMPUS USING A CALCIUM-SENSITIVE FLUORESCENT DYE [Master's thesis, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1469380261

    APA Style (7th edition)

  • Keshav, Arvind. TRACKING AN ELECTRICALLY SILENT SOURCE IN THE HIPPOCAMPUS USING A CALCIUM-SENSITIVE FLUORESCENT DYE. 2016. Case Western Reserve University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1469380261.

    MLA Style (8th edition)

  • Keshav, Arvind. "TRACKING AN ELECTRICALLY SILENT SOURCE IN THE HIPPOCAMPUS USING A CALCIUM-SENSITIVE FLUORESCENT DYE." Master's thesis, Case Western Reserve University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1469380261

    Chicago Manual of Style (17th edition)

case1469380261
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© 2016, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.