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Neurophysiology
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| PowerLab data acquisition systems and neurophysiological amplifiers provide complete solutions for researchers recording and analyzing neurophysiological signals either in vitro or in vivo. |
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Neuroscience is a field that concentrated on the scientific study of the nervous system. These studies include the structure, function, evolutionary history, development, genetics, biochemistry, physiology, pharmacology, informatics, computational neuroscience and pathology of the nervous system. Currently, the scope of neuroscience has broadened to include any systematic scientific experimental and theoretical investigation of the central and peripheral nervous system as the investigative methods have expanded from biochemical and genetic analysis of dynamics of individual nerve cells to imaging representations of perceptual and motor tasks in the brain.
Neurophysiology is a part of physiology that involves the study of nervous system function. It is related with other area of brain sciences such as neurobiology, psychology, neurology, clinical neurophysiology, electrophysiology, ethology, neuroanatomy and cognitive science.
Electrophysiology is the study of the electrical properties of biological cells and tissues. It involves measurements of voltage change or electrical current flow on a wide variety of scales from single ion channel proteins to whole tissues like the heart. In neuroscience, it includes measurements of the electrical activity of neurons, and particularly action potential activityIntracellular RecordingIntracellular recordings involve measuring voltage and/or current across the membrane of a cell. There are many intracellular recording techniques including: - Voltage Clamp – measures the ionic current across a cell's membrane when the membrane potential is held at a constant
- Current Clamp - measures the membrane potential changes when injecting a constant current into a cell through the recording electrode.
- Patch Clamp – measures voltage or current across ion channels using a blunt a micropipette
- Sharp Electrode Technique – measures the potential inside the cell membrane with a sharp electrode (glass micropipette with a smaller pore)
Extracellular RecordingExtracellular recordings involve measurements outside of a cell and they include recording from cells, nerve fibers and the brain. These extracellular recordings include: - Single Unit Recording – records the electrical activity of a single one neuron with a small tip electrode
- Multi-Unit Recording – records electrical activity generated by several neurons
- Field Potentials - records the field potential generated from undistinguishable activity generated by many cells
- Amperometry - records changes in the chemical composition of the oxidized components of a biological sample using a carbon electrode
PowerLab data acquisition systems and Dagan Corporation provide complete solutions that allow researchers to record and analyze neurophysiological signals either in vitro or in vivo. These systems can be used for measuring nerve conduction velocity, spontaneous nerve and muscle activity, action potentials, evoked potentials, population spikes as well as field potentials in brain slice as well as extracellular and intracellular recordings. Note: Equipment supplied by Dagan Corporation is NOT suitable for connection to human subjects. ADInstruments also provide the Neuro Amp EX, which is a specialized preamplifier and headstage that works together with a PowerLab data acquisition system. It is used with metal electrodes (metal electrodes are NOT supplied) for human and animal applications that include: - Extracellular recordings from single cells or groups of cells
- Single nerve fiber recordings (split-nerve preparation or human microneurography)
For more information on various applications please visit:
LabChart
LabChart software (for Windows and Macintosh) combines the familiar simplicity of a traditional strip chart recorder with the powerful analysis features of a digital acquisition system. LabChart software and a PowerLab data acquisition unit provide data integrity, easy selection of hardware settings, powerful online and offline analysis, procedure automation, seamless extraction of experimental data and flexible display options. Acquisition and analysis capabilities can be further increased with LabChart Extensions and LabChart Modules. LabChart Modules are available as part of LabChart Pro.
LabChart software is also suitable for evoked potential recordings that do NOT require waveform averaging or if more than two recording channels are required. The triggering option within LabChart is extremely useful to synchronize recordings with a stimulus, while the analog or digital outputs on the PowerLab may be used to control a third-party stimulator. The LabChart software can be used to identify the specific waveform components such as amplitude and latency. LabChart Extensions are free for download from the website for existing LabChart users and they include:
- Event Manager (Win Only): Allows the user to monitor user defined events online using different criteria, and to perform a variety of user defined actions.
- Export Axon (Win Only): Allows the user to save LabChart files in the ABF (Axon binary format) which can be read by pClamp.
- Evoked Response (Mac Only): This extension analyzes physiological responses to a stimulus (evoked response experiments). A number of response parameters can be measured and logged to the Data Pad. This process can be automated to analyze a series of stimuli/response cycles. Physiological responses of neurons to stimuli can be measured include value, latency, peak height, half-width, latency to peak, slope, population spike height and population spike area.
- Peak Parameters (Win or Mac): Allows the user to determine a number of parameters for an individual peak. Parameters calculated include peak height, width, slope and various time parameters. It is useful for determining parameters of action potentials such as cardiac potentials, EPSP and IPSP.
- Read Scope (Mac Only): Read Scope is a LabChart extension which allows LabChart for Mac to read Scope for Mac files directly.
- Export Matlab(Win only): Allows LabChart for Windows files to be saved and exported as MATLAB compatible files. MATLAB is a flexible data analysis program available from The Mathworks Inc. (www.mathworks.com).
- Translate Binary (Win only): Translate Binary is a LabChart extension which allows LabChart for Windows files to be saved and exported in a simple binary format. Translate Binary can import documents that have either been exported from LabChart, or generated by another application.
- Translate EDF (Win only): Allows LabChart to save data as an EDF file, and to read EDF files. Translate EDF does not support the EDF+ format.
- Telegraph (Win only): Makes use of the gain-telegraph output from an electrophysiological amplifier to continue to display data at the correct scale after a gain change. The Telegraph Extension uses the gain telegraph voltage from the amplifier to automate the display of electrophysiological data in LabChart, so that the correct units and scale are used.
Spike Histogram Module (Windows or Macintosh)
The MLS062/6 Spike Histogram Module for LabChart in combination with ADInstruments hardware provides the neuroscientist, in conjunction with our PowerLab systems, the ability to record and analyze extracellular spike data in real time and offline. Typical features include:
- Provides easy to use spike discrimination and data analysis
- Automatically indicates and examines changes in neural firing rate
- Automatically determines the distribution of all interspike intervals
- Performs autocorrelograms and crosscorrelograms analysis (Mac only)
 Autocorrelogram and crosscorrelogram analyses are also available with the Spike Histogram Module for Macintosh. The Spike Histogram for Windows Module has the added feature of saving data in a .nex format for easy transfer to NeuroExplorer software for further analyses.
Scope
Scope software, supplied with PowerLab systems, provides powerful display, recording and analysis features to transform your computer into a two-channel storage oscilloscope, XY plotter or Power Spectrum (FFT) analyser. Scope is used commonly to measure any high-frequency signal that is time-locked to a stimulus such as action potentials and evoked responses. For analyzing Evoked Potentials, the Scope Software is recommended because it provides signal averaging functions that are necessary to extract the evoked response from background noise.
This software:
- Provides the ability to record, display and analyze any high frequency signal that is time-locked to a stimulus
- Synchronizes sweeps with recorded or built-in stimulation patterns
- Provides a range of real-time and offline analysis features
- Generates stimuli of differing intensities and waveform structures (i.e. single-pulse, multiple pulse, simple ramps) and control an external stimulator using the analog output on the front of the PowerLab.
Therefore, Scope is an ideal software program for recording any type of evoked potential because each successive stimulus and evoked potential may be recorded in a single sweep and the results of multiple sweeps may be superimposed or averaged to minimize signal noise and isolate the evoked potential. Scope is useful in signal averaging techniques to improve the signal-to-noise ratio and minimize artifacts induced by related events such as the blink-response. Features in Scope such as filtering and spectral analysis, may be used to identify oscillating potentials. The analog output of the PowerLab data acquisition system may be used to control a stroboscopic flash unit (with suitable inputs) for presentation of the light stimuli.
GLP and 21 CFR Part 11
For those researchers working within a laboratory requiring GLP and 21 CFR Part 11 compliance the GLP Client and GLP Server are available for use with LabChart (Windows only) and PowerLab data acquisition systems. For more information, visit the Good Laboratory Practice application page or contact your nearest ADInstruments representative.
Data Recording and AnalysisPowerLab data acquisition systems and LabChart/Scope software are ideal for intracellular recordings due to their ability to record at high sampling rates. The high frequency of neuronal firing rates greatly exceeds the frequency of most other physiological signals. Sampling rates of 40 kHz to 200 kHz are recommended for most intracellular recordings. They include: Extracellular Recording SystemML870B70 Extracellular Recording System includes: Intracellular Recording SystemML870B71 Intracellular Recording System includes: Two Electrode Voltage Clamp SystemML870B72 Two Electrode Voltage Clamp System includes: Neuro AmplifierThe ML185 Neuro Amp EX is a low noise and high gain device which makes it suitable for all recording environments requiring a wide bandpass (100 Hz – 5 kHz) and a high signal to noise ratio. It provides a gain of 100x with a 10Hz High Pass filter. The cable shielding is directly connected to the casing, limiting the need for additional shielding at the input terminals. The device is certified safe for human connection with the supplied MLT185 Neuro Amp EX headstage. Only a single Neuro Amp EX may be connected to a single PowerLab. It is supplied: Preamplifiers and Accessories Stimulators
| Heat-evoked activation of the ion channel, TRPV4 |
| A D Guler; H Lee; T Iida; I Shimizu; M Tominaga and M Caterina, Journal of Neuroscience, 6408-4614, 2002 |
| Oocytes were defolliculated with collagenase (Worthington, Lakewood, NJ) and injected the next day with 1–50 ng of TRPV1 or TRPV4 cRNA in 50 nl of water. Oocytes were subjected to two-electrode voltage clamp (Eh =-40 mV) on days 2–7 after injection via a TEV-200A amplifier (Dagan, Minneapolis, MN), PowerLab A/D converter (AD Instruments, Mountain View, CA), and 3 M KCl-filled electrodes with a resistance of 0.4-2 M?. Normal (210 mOsm) bath solution composition (in mM) was 96 NaCl, 2 KCl, 1 MgCl2, 0.1 CaCl2, and 5 HEPES, adjusted to pH 7.4 with NaOH. Hyperosmotic (410 mOsm) bath solution was supplemented with 200 mM mannitol. Perfusion rate was 1 ml/min. |
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| Adenine nucleotide-induced activation of adenosine A2B receptors expressed in Xenopus laevis oocytes: Involvement of a rapid and localized adenosine formation by ectonucleotidases |
| I Matsuoka, S Ohkubo, J Kimura and Y Uezono, Molecular Pharmacology, 606-613, 2002 |
| Using Xenopus laevis oocytes electrophysiological recordings were performed at room temperature with the two-electrode voltage-clamp method using a TEV-200 Voltage Clamp System (Dagan, Minneapolis, MN). An oocyte was placed in a 100- l chamber containing ND96 solution composed of 96 mM NaCl, 2 mM KCl, 1.8 mM CaCl2, 1 mM MgCl2, and 5 mM HEPES, pH 7.6. Two microelectrodes with tip resistances of 0.2 to 1.0 M? filled with 3 M KCl were inserted. Membrane potential was then held at -60 mV. Oocytes were continuously superfused at a flow rate of 4 ml/min with ND96 solution. All test compounds were added to the ND96 superfusion solution. The duration of agonist application was 10 s. When the effects of inhibitors were examined, oocytes were perfused with the solution containing inhibitor for 1 min and then stimulated by agonists for 10 s in the presence of inhibitors. After stimulation by agonists, the inhibitor solution was applied for another 1 min. When the effects of ADA were examined, oocytes were continuously perfused with the solution containing ADA, and agonists were applied with a separate line for 10 s. The current-voltage relation was obtained by ramp pulses using a function generator (NF-121B; NF Corp, Yokohama, Japan). Currents were continuously recorded and analyzed using MacLab (ADInstruments Pty Ltd., Castle Hill, Australia). |
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The material on this page is provided in good faith and believed accurate at the time of writing. No responsibility will be taken, or liability accepted, for damages arising from the use of information herein. Readers are urged to check with respective manufacturers the accuracy of all product related information.
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