Assessment of neuromodulation changes
The main neurophysiological techniques for assessment of cortical changes at this research unit are:
- Assessment of corticospinal excitability
Corticospinal excitability (CSE) is measured with single-pulse transcranial magnetic stimulation (TMS). Indeed, it is assessed via electromyography (EMG) electrodes placed over the skin’s surface. Surface EMG is an appropriate technique to measure TMS responses because it captures the summation of activated motor units from corticomotor stimulation, resulting in a motor evoked potential (MEP) trace that can be easily quantified by its amplitude.
- Assessment of cortico-cortical inhibition and facilitation using single-pulse and paired-pulse TMS induced motor evoked potentials:
This include assessment of:
- short interval intracortical inhibition (SICI)
- long interval intracortical inhibition (LICI)
- Intra Cortical Facilitation (ICF)
- Brain mapping using Q-EEG
Electroencephalography (EEG) is the measurement of electrical patterns at the surface of the scalp which reflect cortical activity, and are commonly referred to as “brainwaves”. Quantitative EEG (qEEG) is the analysis of the digitized EEG, and in lay terms this sometimes is also called “Brain Mapping”.
We use a 32 Channel EEG Amplifier with WinEEG Software (Mitsar, Russia) for qEEG
- Evoked related potentials (ERPs)
ERPs, formerly termed evoked potentials, are event-related voltage changes in the ongoing EEG activity that are time-locked to sensory, motor, and cognitive events. ERPs can be used to measure the electrical activity in certain areas of the brain and spinal cord. Electrical activity is produced by stimulation of specific sensory nerve pathways.
We use a 32 Channel EEG Amplifier with WinEEG Software (Mitsar, Russia) for evoked related potentials (ERPs)
- Near-infrared spectroscopy (NIRS)
NIRS is a non-invasive technique that continuously monitors regional brain tissue oxygenation. Functional NIRS is a noninvasive optical imaging technique that measures neuroactivation via hemodynamic changes in oxy- and deoxyhemoglobin safely using non-invasive near-infrared light.
We have the following systems in this research unit, for assessment of behavioural changes in response to application of neuromodulation techniques:
- Balance master system
The Balance Master system provides objective assessment and retraining of the sensory and voluntary motor control of human balance. With visual biofeedback on either a stable or unstable support surface and in a stable or dynamic visual environment, the clinician can assess patients performing tasks ranging from essential daily living activities through high-level athletic skills.
- Cedrus Stimulus Presentation/Response System
The system includes SuperLab software that creates a stimulus presentation program for psychological experiments that includes text information, images, sounds, movies, etc., and records and analyzes the reaction of the subject to them, a "test" that combines the created programs. In addition to this software, the system also includes different types of response pads, and StimTracker device which detects the onset of events in behavioural research, and does so autonomously to avoid operating system delays.
- Surface electromyography
Surface electromyography (sEMG) is a non-invasive procedure involving the detection, recording and interpretation of the electric activity of groups of muscles at rest (i.e., static) and during activity (i.e., dynamic). The procedure is performed using a pair or multiple pairs of electrodes placed on the skin covering the target muscles.
Other laboratory devices:
- Data acquisition hardware device:
PowerLab 8/35, ADInstruments, Australia)
Provides 16-bit resolution on all gain ranges for high resolution on even the smallest of signals. Each channel has individual filters and noise reduction circuitry for minimal channel crosstalk and signal noise. It has 2 analog outputs and a trigger input.
- Signal conditioner:
Dual Bioamplifier (ADInstruments, Australia)
The Dual Bio Amp consists of two galvanically isolated, high-performance differential amplifiers optimized for the measurement of a wide variety of biological signals such as ECG (EKG), EMG, EOG, and EEG recordings, with quality noise specifications and a range of filter settings.
- Nerve and muscle stimulator:
- Digitimer DS7A
This stimulator is suitable for general purpose human electrical nerve or muscle stimulation. It provides up to 100mA constant current high voltage pulses of brief duration for trans-cutaneous stimulation during investigation of the electrical activity of nerve and muscle tissue. It is also commonly used in psychology, cognitive neuroscience and pain research applications.
- DG2A Train Delay Generator
Is used for control of normal repetitive stimulation as well as for defining the Effective Refractory Period using a second, delayed pulse. The DG2A is especially useful as a frequency generator.
Sensors (ADInstruments, Australia):
- Skin temperature sensor
Skin Temperature Probes are specifically designed for continuous temperature monitoring using the skin as an indicator of body temperature.
- Tendon hammer sensor
Tendon Hammers available for connection via the BNC input channel of any PowerLab recording system, to provide triggering, timer or marker signals.
- Finger pulse sensor
Finger Pulse Transducers use a piezo-electric element to convert force applied to the active surface of the transducer into an electrical analog signal.
- Grip force sensor
A pre-calibrated ready-to-use strain gauge based isometric dynamometer with a linear response in the 0-800N range.
- Push Button Switch
Push Button Switches connect to any PowerLab, providing either a 1V or 6V output for triggering, timing or marker signals.
- Foot switch
The Foot Switch gives a momentary voltage output when pressed.
- Response meter
Provides the subject with the ability to quantify their response to a range of different stimuli in assessment of pain and psychology related experiments.
- Checktrode: Electrode impedance meter
The Checktrode provides rapid and easy evaluation of total electrode contact impedance and offset voltage between two applied electrodes.