To Stories

NeuroIGNITOR, a selective bidirectional platform for advanced neuromodulation.

Imec has made significant progress on its NeuroIGNITOR platform, which will enable neuromodulation researchers and device developers to design and test stimulation paradigms directly in living tissue. It is a selective, bidirectional system that drastically reduces off-target effects and offers stimulation and read-out flexibility beyond conventional benchtop instruments.

From coarse stimulation to targeted neural control

Electrical neuromodulation has the potential to transform how we treat chronic diseases, from epilepsy to treatment-resistant depression. Its most prominent target is the vagus nerve, the main conduit that orchestrates communication between the brain and major organ systems.

By delivering electrical impulses along this neural pathway, therapies can tap into native autonomic reflexes to regulate cardiovascular dynamics, metabolic balance, systemic immune responses and, importantly, brain activity.

Yet clinical neuromodulation faces the fundamental constraint that applied electrical current spreads indiscriminately through tissue, activating unintended pathways along with the intended target.

In the vagus nerve, off-target activation produces side effects like painful muscle contractions and voice alterations, forcing clinicians to use stimulation levels well below therapeutic efficacy.

Advanced protocols, such as the high-frequency waveforms used in spinal cord therapies, can reduce side effects. Yet these complex waveforms demand sophisticated electronics to deliver currents precisely without damaging tissue or electrodes. They also multiply the number of adjustable parameters, making it significantly harder for clinicians to find and calibrate the optimal therapeutic settings.

To address these bottlenecks, imec has developed the NeuroIGNITOR platform. Built around the dedicated NeuroIGNITE ASIC, this bidirectional research system provides the hardware needed to execute complex, selective stimulation paradigms while recording real-time neural responses to stimulation.

More about imec’s exploration of selective peripheral nerve stimulation (PNS)

Achieving true selectivity by combining spatiotemporal steering and anodal blocking

True nerve selectivity requires precise control over both where a current travels and when individual axons fire. Imec addressed this by introducing a new method that uses interfering high-frequency burst stimuli.

Delivered through multi-contact electrodes, these stimuli interfere within the nerve to create a focus of activation that can be steered spatially, causing fibers caught within that focus to fire at a controlled delay relative to those outside of it.

Imec has previously shown that this approach – intermittent interferential current stimulation (i²CS) – enables localized recruitment of organ-specific fibers in the swine vagus nerve while steering the focus of interference to the off-target regions.

Delivering the waveforms in intermittent bursts rather than continuously sharpens spatiotemporal control and cuts power consumption substantially. Both are critical for chronic clinical implants, constrained by battery capacity and thermal limits.

However, while i²CS reduces side effects, it does not eliminate them. To further reduce off-target activation, the platform pairs the interferential stimulation with a precisely controlled anodal block. The system exploits the firing delay between fiber populations, triggering the block at the exact moment when off-target axons fire, effectively silencing them while leaving the target fibers unaffected.

The effects of combining i²CS and anodal block were recently published by imec in Nature Scientific Reports. This two-step method can achieve functionally selective fiber activation by first delivering targeted stimulation, then applying a timed anodal block to restrict signal propagation exclusively to the desired fibers.

The NeuroIGNITOR platform: enabling the next generation of neuromodulation research

The NeuroIGNITOR platform provides an open, integrated instrument for neuroscience research – one that is electrode-agnostic and ready to interface with off-the-shelf electrodes.

At the core of this hardware is the NeuroIGNITE ASIC, a custom silicon chip designed specifically to support i²CS and novel complex stimulation paradigms.

By recording neural activity immediately after stimulation, the platform allows theoretical models to be dynamically validated and calibrated in living biological systems. This bidirectional capability paves the way for the advanced closed-loop paradigms critical to the future of the field.

While currently serving as a foundational research tool, this technology is positioned to translate into real-world clinical applications. Capturing real-time sensory feedback will significantly enhance the programmability of future therapeutic solutions. The system will absorb the complexity of dynamic waveforms in the background, leaving clinicians with a simple, intuitive programming and/or monitoring process.

Ultimately, translating these tools from the laboratory to the clinic serves a clear mission: delivering a more valuable therapeutic tool that drastically reduces off-target side effects, increases clinical uptake, and improves overall patient outcomes and experiences.

Interested in deploying the NeuroIGNITOR platform for your neuromodulation research or testing novel stimulation paradigms? Contact us at health@imec.be to explore research collaborations.