Journal of Neurogastroenterology and Motility
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Korean J Physiol Pharmacol 2017 Sep; 21(5): 555-563
Jungryul Ahn1,#, Myoung-Hwan Choi2,#, Kwangsoo Kim3, Solomon S. Senok4, Dong-il Dan Cho5, Kyo-in Koo2,*, and Yongsook Goo1,*
The advantage of topographic prominence-adopted filter for the detection of short-latency spikes of retinal ganglion cells
1Department of Physiology, Chungbuk National University School of Medicine, Cheongju 28644, 2Department of Biomedical Engineering, University of Ulsan, Ulsan 44610, 3Department of Electronics and Control Engineering, Hanbat National University, Daejeon 34158, Korea, 4Ajman University School of Medicine, PO Box 346, Ajman, United Arab Emirates, 5Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea
Electrical stimulation through retinal prosthesis elicits both short and long-latency retinal ganglion cell (RGC) spikes. Because the short-latency RGC spike is usually obscured by electrical stimulus artifact, it is very important to isolate spike from stimulus artifact. Previously, we showed that topographic prominence (TP) discriminator based algorithm is valid and useful for artifact subtraction. In this study, we compared the performance of forward backward (FB) filter only vs. TP-adopted FB filter for artifact subtraction. From the extracted retinae of rd1 mice, we recorded RGC spikes with 8×8 multielectrode array (MEA). The recorded signals were classified into four groups by distances between the stimulation and recording electrodes on MEA (200-400, 400-600, 600-800, 800-1000 μm). Fifty cathodic phase-1st biphasic current pulses (duration 500 μs, intensity 5, 10, 20, 30, 40, 50, 60 μA) were applied at every 1 sec. We compared false positive error and false negative error in FB filter and TP-adopted FB filter. By implementing TP-adopted FB filter, short-latency spike can be detected better regarding sensitivity and specificity for detecting spikes regardless of the strength of stimulus and the distance between stimulus and recording electrodes.
Keyword : Electrical stimulus artifact, Long-latency spike, Retinal ganglion cell, Retinal prosthesis, Short-latency spike