China
Africa
Explore chapters and articles related to this topic
Multi-Electrode Array Technologies for Neuroscience and Cardiology
Published in Lajos P. Balogh, Nano-Enabled Medical Applications, 2020
At present, the prime methodology for studying neuronal circuit-connectivity, physiology and pathology under in vitro or in vivo conditions is by using substrate-integrated microelectrode arrays. Although this methodology permits simultaneous, cell-non-invasive, long-term recordings of extracellular field potentials generated by action potentials, it is ‘blind’ to subthreshold synaptic potentials generated by single cells. On the other hand, intracellular recordings of the full electrophysiological repertoire (subthreshold synaptic potentials, membrane oscillations and action potentials) are, at present, obtained only by sharp or patch microelectrodes. These, however, are limited to single cells at a time and for short durations. Recently a number of laboratories began to merge the advantages of extracellular microelectrode arrays and intracellular microelectrodes. This Review describes the novel approaches, identifying their strengths and limitations from the point of view of the end users—with the intention to help steer the bioengineering efforts towards the needs of brain-circuit research.
Rapid Kindling: Behavioral and Electrographic
Published in Steven L. Peterson, Timothy E. Albertson, Neuropharmacology Methods in Epilepsy Research, 2019
The onset and termination of reverberatory seizure activity is best determined with the recording electrode in the dentate gyrus and recording maximal dentate activation. To record from the dentate gyrus, the recording electrode is placed 2 mm lateral in the same anteroposterior plane as the stimulating electrode. The depth of the recording electrode in the dentate gyrus is determined by stimulating through an electrode in the angular bundle or entorhinal cortex on the ipsilateral side (AP -8 mm, lateral 4.4 mm, depth 3 mm, Figure 4.7). Many types of recording electrodes can theoretically be used during these experiments (ion-sensitive, extracellular field, single unit, whole cell). The most common recording is of the extracellular field potentials with DC recording. The onset of maximal dentate activation is most distinct with DC recording (Figure 4.8). Extracellular recording electrodes can be made from glass or metal (AC recording). Most commonly capillary glass is used and pulled to a tip with an electrode puller (almost any model will do). The electrode is filled with NaCl (2 M) with 1% Fast Green to give an impedance of 0.5 to 10 तΩ. Generally, the lower the impedance the lower the signal-to-noise ratio.
Wheels of Motion: Oscillatory Potentials in the Motor Cortex
Published in Alexa Riehle, Eilon Vaadia, Motor Cortex in Voluntary Movements, 2004
Extracellular field potentials are generated by neuronal dipoles created within elongated dendritic fields, aligned in parallel arrays. Cortical pyramidal cells with their long apical dendrites are the classic example of dipole generators. The current sink is the site of net depolarization, and the source is the site of normal membrane polarity or of hyperpolarization. Oscillatory potentials are generated by a combination of mechanisms. Many cortical neurons have pacemaker-like membrane properties such that they can produce oscillatory potentials at a variety of frequencies; generally, the higher the depolarization, the faster the frequency.4 For the oscillations to be stabilized and sustained, however, a resonant circuit needs to be recruited. Inevitably such circuits involve inhibitory interneurons to reinforce the excitation-inhibition alternation.5,6 Furthermore, the circuits entrain components both within the cerebral cortex and the associated parts of the thalamus to create a thalamocortical network.5
A review on qualifications and cost effectiveness of induced pluripotent stem cells (IPSCs)-induced cardiomyocytes in drug screening tests
Published in Archives of Physiology and Biochemistry, 2023
Golrokh Malihi, Vahid Nikoui, Elliot L. Elson
Considering electrical conductance in cardiac functionality allowed researchers to characterise immaturity of iPSC-CMs, tissue health or disease state on cardiac model of iPSCs, and to distinguish between cell types in iPSC-CMs. Electrical conductance of iPSC-CMs is measured by extracellular field potential recordings, or sharp electrode recordings. Field potential recordings are easily measured by multi electrode array (MEA) plates. Field potential duration (FPD) correlates with the action potential duration (APD) in a single cardiomyocyte, and APD also correlates with the QT interval in EKG of the heart (Stett et al.2003). The technique, which has been used to test drug-induced arrhythmia (e.g. QT prolongation), is an important effect that can cause withdrawal of many drugs from the market. (Kehat et al.2002, Stett et al.2003, Yamazaki et al.2012).
Pharmacological characterization of the α2A-adrenergic receptor inhibiting rat hippocampal CA3 epileptiform activity: comparison of ligand efficacy and potency
Published in Journal of Receptors and Signal Transduction, 2022
Joseph P. Biggane, Ke Xu, Brianna L. Goldenstein, Kylie L. Davis, Elizabeth J. Luger, Bethany A. Davis, Chris W.D. Jurgens, Dianne M. Perez, James E. Porter, Van A. Doze
Microelectrodes were made from borosilicate glass using a PP-830 vertical two-stage puller (Narashige, Tokyo, Japan) and filled with 3 M NaCl. A slice was submerged in the recording chamber and perfused at a rate of ≥4 ml/min with ACSF at RT. Using a SZ-61 stereo microscope (Olympus, Melville, NY) to visualize the CA3 region of the hippocampus, the microelectrode was placed in the center of stratum pyramidale. Extracellular field potentials were detected using either an Axoclamp 2B (Molecular Devices, Sunnyvale, CA) or BVC-700A (Dagan, Minneapolis, MN), amplified by a Brownlee 440 (Brownlee Precision, San Jose, CA), digitized with a Digidata 1322 A (Molecular Devices), and recorded using Axoscope 9.0 software (Molecular Devices).
Fly seizure EEG: field potential activity in the Drosophila brain
Published in Journal of Neurogenetics, 2021
The LFP signal we observed was likely a product dominated by brain field potentials, with some other bioelectric phenomena (e.g. heart beats) and system noise picked up between the recording and reference electrode. To identify the origins of LFP signals, we sought to determine how activity patterns were altered by blocking action potential propagation or synaptic transmission. Using a dorsal vessel (DV) drug injection technique (Howlett & Tanouye, 2013; Lee et al., 2019), we systemically applied the NaV channel blocker tetrodotoxin (TTX), or the nicotinic acetylcholine (ACh) receptor blocker mecamylamine (MEC). Within seconds of injection of TTX, we observed behavioral paralysis coupled with elimination of grooming or flight activity, and the failure of giant-fiber pathway, i.e., brain-stimulation failed to evoke single DLM spikes or ECS discharges. Remarkably, MEC injection led to a comparable effect. Following TTX or MEC administration, the LFP signals were decreased in power to a similar extent (Figure 3(A)). Both treatments abolished LFP spiking events (Figure 3(A)), and across the frequency range examined, the signal power was attenuated by ∼20 dB (Figure 3(B), note that the pre-injection spectra are comparable to the rest-associated spectra in Figure 2(D)). The results demonstrate that TTX-sensitive NaV channel-driven brain activities generate the predominant component of the LFP signal recorded. Notably, MEC blockade of nAChR also achieved a similar level of LFP attenuation. As in other insects, it is known that ACh is the primary excitatory neurotransmitter in the Drosophila central nervous system (Salvaterra & Kitamoto, 2001). It is also known that synaptic potentials are more effectively picked-up by extracellular field potential recordings than Na+ action potentials (Lopes da Silva & Van Rotterdam, 2005). Our data provide an independent line of evidence for a major role of cholinergic system in maintaining the basal brain activity as monitored by our LFP protocol.