Product Focus
DS4 Bi-phasic Stimulus Isolator – Stimulate with arbitrary waveforms using your DAQ
External Control – Voltage In, Current Out
If you want greater control over stimulus shape than our DS2A or DS3 stimulators permit or a bi-phasic output, why not take a look at the DS4? The DS4 accepts a bi-phasic analogue “command” voltage and uses this waveform to define the shape of a bi-phasic constant current output, allowing DS4 users to deliver stimuli of any shape with external control of the stimulus parameters. This means that any user with a computer and data acquisition system (featuring an analogue output) can control their stimulation parameters from their acquisition software. The DS4 is recommended over our clinical DS5 stimulator for non-human and in vitro applications, especially those involving threshold tracking and nerve excitability studies using QtracW software.
Versatile – Wide Input and Output Ranges
The DS4 accepts a variety of voltage input ranges (±1V, ±2.5V, ±5V and ±10V) and produces a constant current stimulus output in 4 overlapping ranges (±10µA, ±100µA, ±1mA and ±10mA) from a compliance voltage of ±48V. In addition, the DS4 has a GATE input which allows multiple DS4’s to be connected to a single analogue voltage source, with each DS4 being digitally enabled, separately.
Unique – Inactivity Sensor Reduces Leak Currents
One of the problems with stimulators that make use of an external voltage source to define a stimulus waveform is that small offsets or noisy baseline signals from the DAC’s used to drive them can result in unwanted battery drain, or perhaps worse, low amplitude stimulation. The DS4 uses a unique “inactivity sensor” to monitor the input voltage and disable the DS4 output if this voltage drops to 0±0.15% of the full scale value for a user selectable time period of 100ms, 200ms, 1s or 2s. Unlike other devices which only produce an output when the input voltage exceeds a threshold value, this “inactivity sensor” reduces battery usage and damaging “leak currents” during infrequent stimulation, while at the same time maintaining low levels of zero crossing distortion for repetitive waveforms.
The figure below illustrates how the DS4 inactivity sensor “wakes up” the DS4 output in tens of microseconds, when the input voltage exceeds 0±0.15% of the full scale value, thereby initiating stimulation. The DS4 output remains active unless the input voltage drops below this threshold for a period longer than that set by the user selectable internal jumper. The inactivity sensor clamps the output current (blue) to zero until the command voltage (red) reaches a level greater than 0.15% of the full scale value, whereupon it rapidly increases the current to reach the requested level.
Potential Applications for the DS4
The DS4 is ideally suited to applications that require low to medium amplitude constant current stimuli and where there may be a need for a biphasic, possibly arbitrary shaped waveform and/or external control of the stimulus parameters.
Example applications it has been employed in are:-
- Animal models of nerve excitability using threshold tracking techniques, under the control of QtracW software.
- Stimulation of isolated muscle and nerve preparations.
- In vivo peripheral nerve stimulation.
- Neuronal stimulation to study synaptic communication within whole animal or within brain slices.
- Stimulation of transmitter release in fast cyclic voltammetry.
- Simultaneous fMRI and deep brain stimulation.
- Galvanic vestibular stimulation in humans*
- Transcranial alternating current stimulation in studies of lucid dreaming** Note that the DS4 is not designed or approved for human use and we would only recommend our medically approved (EU MDD CE and US FDA 510(k)) DS5 stimulator for this.
- Temporal Interference Stimulation (TIS) – used in pairs, DS4’s can be used in place of our DS5 Isolated Bipolar Stimulators for non-human investigations of this new non-invasive stimulation modality.
Recent Publications
Hirano, M, Kimoto, Y, Shiotani, S, & Furuya, S (2024). A specialized inhibitory function sharpens somatosensory hand representation and enhances the production and perception of fast multifinger movements in pianists. bioRxiv, biorxiv.org, https://doi.org/10.1101/2024.01.23.576947.abstract
Lo, HH, Munkongcharoen, T, Muijen, RM, & … (2024). Application of near infra-red laser light increases current threshold in optic nerve consistent with increased Na+-dependent transport. … -European Journal of …, Springer, https://doi.org/10.1007/s00424-024-02932-1
Bachmann, H, Vandemoortele, B, Vermeirssen, V, & … (2024). Vagus nerve stimulation enhances remyelination and decreases innate neuroinflammation in lysolecithin-induced demyelination. Brain Stimulation, Elsevier, https://www.sciencedirect.com/science/article/pii/S1935861X24000706
Hamilton, AR, Vishwanath, A, & … (2024). Dopamine Release Dynamics in the Nucleus Accumbens Are Modulated by the Timing of Electrical Stimulation Pulses When Applied to the Medial Forebrain Bundle …. ACS Chemical …, ACS Publications, https://doi.org/10.1021/acschemneuro.4c00115
Chiorazzi, A, Canta, A, Carozzi, VA, & … (2024). Morphofunctional characterisation of axonal damage in different rat models of chemotherapy‐induced peripheral neurotoxicity: The role of nerve excitability testing. Journal of the …, Wiley Online Library, https://doi.org/10.1111/jns.12607
Rodríguez‐Meana, B, Valle, J Del, Viana, D, & … (2024). Engineered Graphene Material Improves the Performance of Intraneural Peripheral Nerve Electrodes. Advanced …, Wiley Online Library, https://doi.org/10.1002/advs.202308689
Riley, B, Gould, E, Lloyd, J, Hallum, LE, & … (2024). Dopamine transmission in the tail striatum: Regional variation and contribution of dopamine clearance mechanisms. Journal of …, Wiley Online Library, https://doi.org/10.1111/jnc.16052
Forderhase, AG, Ligons, LA, Norwood, E, & … (2024). Optimized Fabrication of Carbon-Fiber Microbiosensors for Codetection of Glucose and Dopamine in Brain Tissue. ACS …, ACS Publications, https://doi.org/10.1021/acssensors.4c00527
Viana, D, Walston, ST, Masvidal-Codina, E, Illa, X, & … (2024). Nanoporous graphene-based thin-film microelectrodes for in vivo high-resolution neural recording and stimulation. Nature …, nature.com, https://www.nature.com/articles/s41565-023-01570-5
Arnold, R., Moldovan, M., Rosberg, M. R., Krishnan, A. V., Morris, R., & Krarup, C. (2017). Nerve excitability in the rat forelimb: a technique to improve translational utility. Journal of Neuroscience Methods, 275, 19–24. https://doi.org/10.1016/j.jneumeth.2016.10.013