Neurophysiology Studies

Overview:

The nervous system is a complex network that allows an organism to communicate with its environment. The network includes afferent components, that relay information from the senses to the brain and detect changes in environmental stimuli, and efferent components, that relay motor and homeostatic control output to effector organs, such as smooth and skeletal muscles, which generate movement, contraction of cardiac and smooth muscle and glandular secretions. Integrative components of the nervous system receive, store, and process sensory information and then orchestrate the appropriate motor response.

The nervous system is organized into the central nervous system (CNS), consisting of the brain and spinal cord and the peripheral nervous system (PNS). The PNS consists of somatic and autonomic divisions: the somatic division is involved in conveying muscle and joint position information as well as touch, pressure, and pain to the CNS. The autonomic division consists of the enteric nervous system (ENS) which controls gut motor activity; the sympathetic nervous system which prepares the body for the fright-fight-flight response to stress; and the parasympathetic nervous system which promotes energy conservation and restoring homeostasis.

The study of Neuroscience includes the structure, function, evolutionary history, development, genetics, biochemistry, physiology, pharmacology, informatics, computational neuroscience and pathology of the nervous system.

Method:

Electrophysiology is the study of the electrical properties of biological cells and tissues. It involves measurement of the potential difference (voltage) or current flow in a wide range of applications; from the ion channels in cells to the electrical characteristics of a whole organ, such as the heart. In neuroscience, this includes measurements of the electrical activity of single neurons, e.g., action potentials, excitatory-postsynaptic potentials (EPSPs), inhibitory-postsynaptic potentials (IPSPs), local field potentials (LFPs) from multiple neurons in vivo or in vitro (e.g., brain slices and cultures).

Intracellular Recording

Intracellular recordings involve measuring voltage and/or current across the membrane of a cell. There are many intracellular recording techniques including:

  • Sharp Electrode Technique – measures the potential inside the cell membrane with a sharp electrode (glass micropipette with a smaller pore). This, by definition, is whole cell recording since the electrolyte solution in the electrode is in contact with the intracellular fluid. There are two types of Sharp Electrode Clamping:
    • Voltage Clamp – measures the ionic current across a cell's membrane when the membrane potential is held at a constant. Sharp Electrode Voltage Clamping can be further split into two groups:
      • Single Electrode Voltage Clamping (SEVC)
      • Two Electrode Voltage Clamping (TEVC)
      • Note: SEVC is generally only considered when the cells are too small for TEVC. TEVC is most commonly used on large cells such as oocytes and is also referred to as Oocyte clamping.
    • 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 tip micropipette

Extracellular Recording

Extracellular recordings involve recording potentials outside the cell, i.e. in the extracellular fluid. However, by definition, this is not limited to the extracellular fluid. 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
  • Whole Nerve Recordings - records the activity of peripheral nerves, which essentially are bundles of axons. Recording techniques include:
    • Wired – an electrode (usually silver wire) is placed in contact with the nerve of interest. ADInstruments NeuroAmp EX can be used for whole nerve recordings in animals and humans (certified safe for human connection).
    • Telemetry – the sympathetic nerve activity (SNA) series of transmitters and receiver by Telemetry Research (TR) enable recording of nerve activity in conscious freely moving animals.
  • Field Potentials - represent the integration of synaptic current within a local volume surrounding a single electrode tip. Field potentials are characterised by their slow frequency (< 200 Hz). Because the signals reflect a spatiotemporal sum of membrane currents, it is a useful technique for measuring the degree of synchronicity among neurons in small areas. With high-pass filtering it is possible to measure the much faster action potentials within the signal (e.g., > 300 Hz). Spike-sorting algorithms can also be used to determine individual neuronal contribution to the signal.
    • EEG- consists of set of field potential recordings for measuring the degree of cortical synchronicity over large areas.
  • Amperometry - records changes in the chemical composition of the oxidized components of a biological sample using a carbon electrode

For more information on various applications please visit:

Software:

The LabChart Advantage:

(may require additional Modules and Extensions)

  • Sample up to 200,000 Hz in a single channel (up to 400,000 Hz aggregate) with 35 series PowerLab units
  • Smoothing, Absolute Value, Integration and RMS Arithmetic calculations for quantification of neural activity
  • Spectrum feature for online or offline determination of the power and frequency components of ECG
  • Scope View for spike-triggered averaging and the overlay of evoked responses
  • Telegraph Extension for correct scale display of data after a gain change
  • Spike Histogram Module for discrimination analysis of extracellular data
  • Peak Analysis Module for analysis of peak heights, half-widths, latency periods, population spike heights, rise times and areas
  • Data can be easily transferred into popular spreadsheet and graphing programs for further analysis and reporting e.g. Excel, Matlab

LabChart

LabChart software (for Windows and Macintosh) together with a PowerLab data acquisition system offers up to 32 channels of real-time data acquisition, data integrity, easy selection of hardware settings, powerful online and offline analysis, procedure automation, seamless extraction of experimental data and flexible display options. Additional acquisition and analysis functionality is provided with the use of specialized LabChart Extensions and LabChart Modules. Modules are available as part of LabChart Pro while Extensions are free for download from the website for existing LabChart users.


Spike Histogram Module
The Spike Histogram Module (Windows or Macintosh) in conjunction with our PowerLab systems provides the capability to record and analyze extracellular spike data in real-time and offline.

  • Provides easy to use spike discrimination and sorting using easy to use amplitude and width discrimination, or semi-automated template matching
  • Real-time display of instantaneous firing rates on separate analysis channels for each sort neuron (32 Channel max)
  • Interspike intervals (ISI), amplitude, and rate histograms for neurons
  • Performs auto-correlograms and cross-correlograms analysis
  • Saves data in a .nex format for easy transfer to NeuroExplorer software for further analyses (Windows only)

Peak Analysis Module

The Peak Analysis Module (Windows) automatically detects and analyses multiple, non-overlapping peaks in recorded waveforms.

Features and benefits include:

  • View automatically detected peaks with highlighted parameter markers, values and peak areas in the Peak Analysis View.
  • Log calculated peak parameters to a table. Easily export parameters from the table into other programs.
  • Select from the default analysis settings available for general and specific signal types. For example, the Population Spike analysis detects and analyses extracellular evoked responses consisting of a spike population superimposed on an excitatory postsynaptic potential.
  • Customizable detection and calculation settings to suit your application or waveform.

Scope

Scope Software (Windows or Mac) provides powerful display, recording and analysis features to transform your computer into a two-channel storage oscilloscope, XY plotter or Power Spectrum (FFT) analyser.

Features and benefits include:

  • 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. 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.
  • 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.
  • Signal averaging techniques to improve the signal-to-noise ratio and minimize artifacts induced by related events such as the blink-response.
  • Filtering and spectral analysis may be used to identify oscillating potentials.

Scope View

Scope View (Windows) provides the features of a digital oscilloscope to facilitate recording and viewing consecutive sweeps of data. These sweeps, or pages, can be overlaid and averaged. The signal averaging functions are necessary to extract the evoked response from background noise.

There are several powerful features in Scope View that enhance analysis and display including:

  • Create pages or sweeps from Comments in Chart View in addition to block mode and Event Mode.
  • Events in Blood Pressure and ECG Module can be used to generate pages in Scope View.
  • 3D Depth and Saturation Overlay feature in the Scope Overlay Options to help distinguish overlaid traces.
  • Alter the active trace and overlay trace colors.
  • Change the display background to black for better contrast.

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.

Hardware:

PowerLab Data Acquisition Systems

The PowerLab is a high-performance data acquisition unit capable of recording at speeds of up to 400,000 samples per second continuously to disk (aggregate). PowerLab units are compatible with instruments, signal conditioners and transducers supplied by ADInstruments, as well as many other third-party companies. In addition to standard single-ended BNC inputs, 4 differential Pod ports are also available for direct connection of Pod signal conditioners and appropriate transducers. Research PowerLab units include:

Research Systems

PL3508B73 Extracellular Recording System

PL3508B74-V Intracellular Recording System

PL3508B75-V Two Electrode Voltage Clamp Recording System

PL3508B76-V Oocyte Clamp Workstation System

PL3508B77-V Single Channel Epithelial Voltage Clamp System

PL3508B78-V Dual Channel Epithelial Voltage Clamp System

PL3508B79/10-V Patch Clamp Recording System with 5101-10G Headstage

PL3508B79/8-V Patch Clamp Recording System with 5101-100M Headstage

PL3508B79/9-V Patch Clamp Recording System with 5101-01G Headstage

Signal Conditioners

The FE185 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 with the following:

Instruments

Note: For more products please contact your local ADInstruments representative.

 Stimulators

Transducers

Accessories

Social cues from conspecifics alter electrical activity of gonadotropin-releasing hormone neurons in the terminal nerve via visual signals
Ramakrishnan S, Wayne NL, American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, R135-R141, 2009

D1/D2-dopamine receptor agonist dihydrexidine stimulates inspiratory motor output and depresses medullary expiratory neurons
Lalley PM, American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, R1829-R1836, 2009

UTP regulation of ion transport in alveolar epithelial cells involves distinct mechanisms
Yang C, Su L, Wang Y, Liu L, American Journal of Physiology: Lung, Cellular and Molecular Physiology, L-439-L454, 2009

Citations Database


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.

Research Solutions
Education Solutions
Pharma Solutions
Citations Database
Top Solutions:
Site Feedback
X

Site Feedback

http://www.adinstruments.com/solutions/corporate/Neurophysiology-Studies/

* Denotes a required field
* Name
* E-Mail
* Operating System
* Web Browser

* Comments