Introduction to Bioelectrodes

Ferris, Clifford D.

doi:10.1007/978-1-4684-2076-0

Cited by 45 publications

(11 citation statements)

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“…Beyond extending the verification of the equivalent circuit, it is also clear that electrode impedance increased substantially with decreasing frequency, and was 10-45 times higher at 10 Hz than at 1 KHz, consistent with previous reports (Lemon, 1984;Merrill and Ainsworth, 1972). Note that the rise in electrode impedance at low frequencies is not just a result of a constant capacitance across frequencies since R e and C e are generally considered to be frequency-dependent themselves (Ferris, 1974;Robinson, 1968), which is supported by our calculations of R e and C e ( Figure S1, see Supplementary results online) that rely on the recorded amplitudes and phase shifts with Fig. 4.…”

Section: Equivalent Circuit Verification and Signal Attenuationsupporting

confidence: 76%

Review of signal distortion through metal microelectrode recording circuits and filters

Nelson

Pouget

Nilsen

et al. 2008

Journal of Neuroscience Methods

149

132

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Interest in local field potentials (LFPs) and action potential shape has increased markedly. The present work describes distortions of these signals that occur for two reasons. First, the microelectrode recording circuit operates as a voltage divider producing frequency-dependent attenuation and phase shifts when electrode impedance is not negligible relative to amplifier input impedance. Because of the much higher electrode impedance at low frequencies, this occurred over frequency ranges of LFPs measured by neurophysiologists for one head-stage tested. Second, frequency-dependent phase shifts are induced by subsequent filters. Thus, we report these effects and the resulting amplitude envelope delays and distortion of waveforms recorded through a commercial data acquisition system and a range of tungsten microelectrodes. These distortions can be corrected, but must be accounted for when interpreting field potential and spike shape data.

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Section: Equivalent Circuit Verification and Signal Attenuationsupporting

confidence: 76%

Review of signal distortion through metal microelectrode recording circuits and filters

Nelson

Pouget

Nilsen

et al. 2008

Journal of Neuroscience Methods

149

132

View full text Add to dashboard Cite

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“…This is of good agreement with the phenomenon introduced in the literatures [9]. Because the influence of Electrode Polarization Impedance (EPI) only plays a major role below 1 kHz for both resistance and reactance, it is suggested that the influence of EPI can be deemed negligible while frequency exceeds 1 kHz.…”

Section: B Results From Electrical Impedance Measurementsupporting

confidence: 71%

Bioimpedance Study on Four Apple Varieties

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Abstract-Electrical Impedance Spectroscopy (EIS) has been used extensively to characterize electrical properties of plant tissue. This research explores the potential connections between electrical impedance and the major parameters can contribute to fruit taste. Experiments were performed on four apple varieties, Granny Smith, Fuji, Pink Lady and Red Delicious respectively. Electrical impedance was measured using a Solartron 1260A Impedance/Gain-Phase Analyzer at frequency range from 1Hz to 1MHz. Soluble solid content (SSC), titratable acidity (TA) and pH value of apple were measured as chemical parameters. It has been observed that the four apple varieties can be divided into three groups according to the ratio of SSC to TA (p<0.05), namely the low-acid variety, the high-acid variety, and the medium-acid variety. The three groups can also be exhibited from the correlations between impedance square root (ISR) and SSC and/or TA. SSC correlates linearly with impedance for low-acid variety, TA has linear relationship with ISR for high-acid variety, and both SSC and TA contribute to the linear relationship with ISR for medium variety. This investigation also reveals that apple acid percentage has significant influence on these relationships. In conclusion, electrical impedance approach provides a new method for apple quality assessment which can used to replace the traditional SSC and acidity measurements to quantify customers' requirements if the acceptable levels of SSC and TA from the observed varieties are given.

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“…Connections to a stimulus isolation unit are made through Ag/AgCl half-cells at both the pipette (Microelectrode Holder Half-Cells; WPI, Sarasota, FL) and perfusion chamber (Electrode Pellets, WPI). Connections through half-cells avoid the polarization of the electrolyte/metal interface that can cause erratic changes in delivered current over time (Ferris, 1974). Electrical stimulation (single pulses, 0.1-1 ms duration, 10-100 A) through this electrolyte filled micropipette produces a consistent elevation of cytoplasmic calcium in labeled varicosities (Fig.…”

Section: Electrical Stimulationmentioning

confidence: 97%