Extracellular Recording Of Electrical Activity Research Articles

Culture of Rat Primary Cortical Cells for Microelectrode Array (MEA) Recordings to Screen for Acute and Developmental Neurotoxicity.

Neurotoxicity testing of chemicals, drug candidates, and environmental pollutants still relies on extensive in vivo studies that are very costly, time-consuming, and ethically debated due to the large number of animals typically used. Currently, rat primary cortical cultures are widely used for in vitro neurotoxicity studies, as they closely resemble the in vitro brain with respect to the diversity of cell types, their physiological functions, and the pathological processes that they undergo. Common in vitro assays for neurotoxicity screening often focus on very target-specific endpoints such as morphological, biochemical, or electrophysiological changes, and such narrow focus can hamper translation and interpretation. Microelectrode array (MEA) recordings provide a non-invasive platform for extracellular recording of electrical activity of cultured neuronal cells, thereby enabling the evaluation of changes in neuronal (network) function as a sensitive and integrated endpoint for neurotoxicity screening. Here, we describe an in vitro approach for assessing changes in neuronal network function as a measure for neurotoxicity, using rat primary cortical cultures grown on MEAs. We provide a detailed protocol for the culture of rat primary cortical cells, and describe several experimental procedures to address acute, subchronic, and chronic exposure scenarios. We additionally describe the steps for processing and analyzing MEA and cell viability data. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Isolation and culture of rat primary cortical cells on 48-well MEA plates Support Protocol 1: Pretreatment and washing of 48-well MEA plates before first use or for re-use Support Protocol 2: Coating of 48-well MEA plates with 0.1% PEI solution Basic Protocol 2: MEA measurements during acute exposure Alternate Protocol 1: MEA measurements during subchronic exposure Alternate Protocol 2: MEA measurements during chronic exposure Support Protocol 3: Determination of cell viability after MEA experiments Basic Protocol 3: MEA data processing Basic Protocol 4: Analyzing MEA experiments after acute and subchronic exposure Alternate Protocol 3: Analyzing MEA experiments after chronic exposure.

Reimplantable Microdrive for Long-Term Chronic Extracellular Recordings in Freely Moving Rats.

Extracellular recordings of electrical activity in freely moving rats are fundamental to understand brain function in health and disease. Such recordings require a small-size, lightweight device that includes movable electrodes (microdrive) to record either a new set of neurons every day or the same set of neurons over time. Ideally, microdrives should be easy to implant, allowing precise and smooth displacement of electrodes. The main caveat of most commercially available microdrives is their relatively short half-life span, in average ranging from weeks to a month. For most experiments, recording days–weeks is sufficient, but when the experiment depends on training animals for several months, it is crucial to develop new approaches. Here, we present a low-cost, reusable, and reimplantable device design as a solution to extend chronic recordings to long-term. This device is composed of a baseplate that is permanently fixed to the rodent’s skull, as well as a reusable and replaceable microdrive that can be attached and detached from the baseplate, allowing its implantation and reimplantation. Reimplanting this microdrive is particularly convenient when no clear neuronal signal is present, or when the signal gradually decays across days. Our microdrive incorporates a mechanism for moving a 16 tungsten-wire bundle within a small (∼15 mm3) lightweight device (∼4 g). We present details of the design, manufacturing, and assembly processes. As a proof of concept, we show that recordings of the nucleus accumbens core (NAcc) in a freely behaving rat are stable over a month. Additionally, during a lever-press task, we found, as expected, that NAc single-unit activity was associated with rewarded lever presses. Furthermore, we also show that NAc shell (NAcSh) responses evoked by freely licking for sucrose, consistent with our previously published results, were conserved from a first implant to a second microdrive reimplant in the same rat, notably showing reimplantation is possible without overtly affecting the functional responses of the area of interest. In sum, here we present a novel microdrive design (low-cost, small size, and light weight) that can be used for long-term chronic recordings and reimplanted in freely behaving rats.

Correct techniques for extracellular recordings of electrical activity in gastrointestinal muscle.

Correct techniques for extracellular recordings of electrical activity in gastrointestinal muscle

Problems with extracellular recording of electrical activity in gastrointestinal muscle

Motility patterns of the gastrointestinal tract are important for efficient processing of nutrients and waste. Peristalsis and segmentation are based on rhythmic electrical slow waves that generate the phasic contractions fundamental to gastrointestinal motility. Slow waves are generated and propagated actively by interstitial cells of Cajal (ICC), and these events conduct to smooth muscle cells to elicit excitation-contraction coupling. Extracellular electrical recording has been utilized to characterize slow-wave generation and propagation and abnormalities that might be responsible for gastrointestinal motility disorders. Electrode array recording and digital processing are being used to generate data for models of electrical propagation in normal and pathophysiological conditions. Here, we discuss techniques of extracellular recording as applied to gastrointestinal organs and how mechanical artefacts might contaminate these recordings and confound their interpretation. Without rigorous controls for movement, current interpretations of extracellular recordings might ascribe inaccurate behaviours and electrical anomalies to ICC networks and gastrointestinal muscles, bringing into question the findings and validity of models of gastrointestinal electrophysiology developed from these recordings.

An Implantable 455-Active-Electrode 52-Channel CMOS Neural Probe

Neural probes have become the most important tool for enabling neuroscientists to place microelectrode sensors close to individual neurons and to monitor their activity in vivo. With such devices, it is possible to perform acute or chronic extracellular recordings of electrical activity from a single neuron or from groups of neurons. After the many developments in neural implants, it has become clear that large arrays of electrodes are desirable to further investigate the activity performed by complex neural networks. Therefore, in this paper, we propose a CMOS neural probe containing 455 active electrodes in the probe shank (100 μm wide, 10 mm long, and 50 μm thick) and 52 simultaneous readout channels in the probe body (2.9 × 3.3 mm2). In situ amplification under each electrode enables low-impedance interconnection lines, regardless of the electrode impedance, with a residual crosstalk of -44.8 dB. This design has been implemented in a 0.18-μm standard CMOS technology, with additional CMOS-compatible post-processing performed at wafer level to define the electrodes and the probe outline. In this architecture, the analog front-end achieves an input-referred noise of 3.2 μVrms and an NEF of 3.08. The power consumption of the core circuit is 949.8 μW, while the total power consumption is 1.45 mW. The high-density active-electrode array in this neural probe allows for the massive recording of neural activity. In vivo measurements demonstrate successful simultaneous recordings from many individual cells.

The role of slow potassium current in phenomena of voltage-dependent action of 4-aminopyridine in amphibian myelinated nerve fibres

The mechanism underlying the voltage-dependent action of 4-aminopyridine (4-AP) is investigated in experiments on amphibian myelinated nerve fibres (Rana ridibunda Pallas) by way of extracellular recording of electrical activity and using activators of potassium current (potassium-free solution and nitric oxide NO) and inhibitors of sodium current (tetrodotoxin). Measurement of action potential (AP) areas was used to evaluate the extent of general membrane depolarization during the activity of nerve fibres. Tetrodotoxin-induced decrease in general membrane depolarization (when the action potential amplitude was reduced by less than 20%) leads to an increase in the duration of depolarizing after-potential (DAP). This supports the dependence of time course of DAP in the presence of 4-AP on ratio of fast and slow potassium channels. In the absence of 4-AP, potassium-free solution and NO increase the potassium current through fast potassium channels (decreasing AP duration, reducing DAP and sometimes producing fast hyperpolarizing after-potential (HAP) after shortened AP), and in the presence of 4-AP these activators increase potassium current through unblocked slow potassium channels (making the development of slow HAP induced by 4-AP more rapid). The increase of slow HAP induced by 4-AP under the influence of potassium-free solution with NO supports the idea that slow HAP is due to activation of slow potassium channels and argues against the notion of removal of block of fast potassium channels. All analyzed phenomena of voltage-dependent action of 4-AP in amphibian myelinated nerve fibers can be accounted for by the activation of slow potassium current produced by membrane depolarization and a decrease of the amount of fast potassium channels involved in the membrane repolarization.

Estimation of Action Potential Changes from Field Potential Recordings in Multicellular Mouse Cardiac Myocyte Cultures

Background: Extracellular recordings of electrical activity with substrate-integrated microelectrode arrays (MEAs) enable non-invasive long-term monitoring of contracting multicellular cardiac preparations. However, to characterize not only the spread of excitation and the conduction velocity from field potential (FP) recordings, a more rigorous analysis of FPs is necessary. Therefore in this study we aim to characterize intrinsic action potential (AP) parameters by simultaneous recording of APs and FPs. Methods: A MEA consisting of 60 substrate-integrated electrodes is used to record the FP-waveform from multicellular preparations of isolated embryonic mouse cardiomyocytes. Simultaneous current clamp recordings in the vicinity of individual microelectrodes and pharmacological interventions allowed us to correlate FP and AP components and their time course. Results: The experiments revealed a linear relationship between AP rise time and FP rise time as well as a linear relationship between AP duration and FP duration. Furthermore a direct contribution of the voltage dependent Na⁺- and Ca²⁺-current to the FP could be identified. Conclusion: The characterization of the FP allows us for the first time to estimate AP changes and the contribution of individual current components to the AP by the help of non-invasive recording within a multicellular cardiac preparation during long-term culture.

Physiological and pharmacological characteristics of the baboon (Papio anubis) oviduct.

The pharmacological and electrophysiological characteristics of the oviduct of the preovulatory baboon (Papio anubis) have been investigated. The longitudinal and circular muscle of both isthmus and ampulla contract upon transmural stimulation, and this effect is completely blocked by phentolamine, guanethidine, and tetrodotoxin, suggesting that contractions are mediated by norepinephrine released from adrenergic nerves acting on α-receptors on the smooth muscle. In circular preparations of the isthmus and in ampulla, nonadrenergic, noncholinergic inhibitory nerves could be demonstrated in the presence of guanethidine. Pharmacologically, the oviductal smooth muscle is contracted by norepinephrine, histamine, acetylcholine, Substance P, 5-hydroxytryptamine, ATP, adenosine, PGF2α, U44069, and U46619 and is inhibited by PGE2 and isoproterenol. Extracellular recording of electrical activity of the ampulla determined that electrical impulses traveled at a velocity of 2–5 mm/sec, that there was a reduction in conduction velocity towards ovulation, and that following ovulation the duration of the electrical bursts increased.

Morphological and electrophysiological characteristics of a dorsal unpaired median neuron of the cricket, Acheta domesticus

1. 1. The dorsal unpaired median neuron (DUMDL) of the metathoracic dorsal longitudinal flight muscle was studied using cobalt and neutral red staining, various pharmacological agents and extracellular recording of electrical activity. 2. 2. The soma of DUMDL is posterior in the group of dorsal unpaired median neurons of the metathoracic ganglion; DUMDL does not degenerate following histolysis of its muscle. 3. 3. Slow, regular spontaneous activity of DUMDL is generated in the isolated metathoracic ganglion and is suppressed following stimulation of DUMDL and by discharges of the flight motor neurons. This spontaneous activity is increased by acetylcholine and eserine and blocked by anticholinesterase agents. 4. 4. The neurite of DUMDL appears to have several impulse initiation zones characterized by a low safety factor.

Patterns of canine gastric electrical activity.

Patterns of canine gastric electrical activity.

Configuration of intestinal slow waves obtained by monopolar recording techniques.

ARTICLESConfiguration of intestinal slow waves obtained by monopolar recording techniquesA BortoffA BortoffPublished Online:01 Jul 1967https://doi.org/10.1152/ajplegacy.1967.213.1.157MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByHigh‐resolution in vivo monophasic gastric slow waves to quantify activation and recovery profiles20 June 2022 | Neurogastroenterology & Motility, Vol. 146Methods for High-Resolution Electrical Mapping in the Gastrointestinal TractIEEE Reviews in Biomedical Engineering, Vol. 12High‐resolution optical mapping of gastric slow wave propagation20 August 2018 | Neurogastroenterology & Motility, Vol. 31, No. 1Opportunities and Challenges for Single-Unit Recordings from Enteric Neurons in Awake Animals25 August 2018 | Micromachines, Vol. 9, No. 9High-resolution mapping of gastric slow-wave recovery profiles: biophysical model, methodology, and demonstration of applicationsN. Paskaranandavadivel, L. K. Cheng, P. Du, J. M. Rogers, and G. O’Grady1 September 2017 | American Journal of Physiology-Gastrointestinal and Liver Physiology, Vol. 313, No. 3Problems with extracellular recording of electrical activity in gastrointestinal muscle19 October 2016 | Nature Reviews Gastroenterology & Hepatology, Vol. 13, No. 12Normal and abnormal electrical propagation in the small intestine18 September 2014 | Acta Physiologica, Vol. 213, No. 2The Principles and Practice of Gastrointestinal High-Resolution Electrical Mapping2 June 2013Quantitative Analysis of Electrical Activity in the Gastrointestinal Tract2 June 2013Rapid high-amplitude circumferential slow wave propagation during normal gastric pacemaking and dysrhythmias19 June 2012 | Neurogastroenterology & Motility, Vol. 24, No. 7The analysis of human gastric pacemaker activity1 March 2012 | The Journal of Physiology, Vol. 590, No. 5Gastrointestinal extracellular electrical recordings: fact or artifact?21 December 2011 | Neurogastroenterology & Motility, Vol. 24, No. 1Movement based artifacts may contaminate extracellular electrical recordings from GI muscles25 September 2011 | Neurogastroenterology & Motility, Vol. 23, No. 11Detection of Small Bowel Slow-Wave Frequencies From Noninvasive Biomagnetic MeasurementsIEEE Transactions on Biomedical Engineering, Vol. 56, No. 9Origin and propagation of the slow wave in the canine stomach: the outlines of a gastric conduction systemWim J. E. P. Lammers, Luc Ver Donck, Betty Stephen, Dirk Smets, and Jan A. J. Schuurkes1 June 2009 | American Journal of Physiology-Gastrointestinal and Liver Physiology, Vol. 296, No. 6Noninvasive detection of small bowel electrical activity from SQUID magnetometer measurements using SOBIElectrophysiology of the intestinal musculature1 January 2011ElectrogastrographyDigestive Diseases and Sciences, Vol. 33, No. 8Study of transcutaneous and intraluminal measurement of gastric electrical activity in humansMedical & Biological Engineering & Computing, Vol. 25, No. 4The Relationship between Extracellular and Intracellular Slow WavesRecording of Extracellular Electrical ActivityPropagation and electrical entrainment of intestinal slow wavesThe American Journal of Digestive Diseases, Vol. 17, No. 4Intestinal motility: I. Control mechanisms in the basic electric rhythm of the canine small intestineJournal of Surgical Research, Vol. 11, No. 9Intestinal motility: II. Electro-motor correlations in the canine small intestineJournal of Surgical Research, Vol. 11, No. 9Electrical activity of the stomach and upper intestineThe American Journal of Digestive Diseases, Vol. 16, No. 7Electrophysiology of vascular smooth muscleElectrical activity of small intestinal smooth muscleThe American Journal of Surgery, Vol. 117, No. 6Electromyography of the Colon In SituGastroenterology, Vol. 56, No. 2Activity of Pilomotor Muscles of Single Tactile Hairs in the Cat1 July 2014 | Acta Physiologica Scandinavica, Vol. 74, No. 3The electrical activity of the alimentary tractThe American Journal of Digestive Diseases, Vol. 13, No. 4 More from this issue > Volume 213Issue 1July 1967Pages 157-162 Copyright & PermissionsCopyright © 1967 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1967.213.1.157PubMed6027912History Published online 1 July 1967 Published in print 1 July 1967 Metrics