10 March 2015 Detection of early seizures by diffuse optical tomography
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In epilepsy it has been challenging to detect early changes in brain activity that occurs prior to seizure onset and to map their origin and evolution for possible intervention. Besides, preclinical seizure experiments need to be conducted in awake animals with images reconstructed and displayed in real-time. We demonstrate using a rat model of generalized epilepsy that diffuse optical tomography (DOT) provides a unique functional neuroimaging modality for noninvasively and continuously tracking brain activities with high spatiotemporal resolution. We developed methods to conduct seizure experiments in fully awake rats using a subject-specific helmet and a restraining mechanism. For the first time, we detected early hemodynamic responses with heterogeneous patterns several minutes preceding the electroencephalographic seizure onset, supporting the presence of a “pre-seizure” state both in anesthetized and awake rats. Using a novel time-series analysis of scattering images, we show that the analysis of scattered diffuse light is a sensitive and reliable modality for detecting changes in neural activity associated with generalized seizure. We found widespread hemodynamic changes evolving from local regions of the bilateral cortex and thalamus to the entire brain, indicating that the onset of generalized seizures may originate locally rather than diffusely. Together, these findings suggest DOT represents a powerful tool for mapping early seizure onset and propagation pathways.
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Tao Zhang, Tao Zhang, M. Reza Hajihashemi, M. Reza Hajihashemi, Junli Zhou, Junli Zhou, Paul R. Carney, Paul R. Carney, Huabei Jiang, Huabei Jiang, "Detection of early seizures by diffuse optical tomography", Proc. SPIE 9333, Biomedical Applications of Light Scattering IX, 933304 (10 March 2015); doi: 10.1117/12.2075409; https://doi.org/10.1117/12.2075409

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