This project investigates how different multi-electrode intracortical microstimulation (ICMS) strategies, specifically, multi-channel simultaneous stimulation and interleaved stimulation, affect perceptual adaptation in artificial touch. Perceptual adaptation, where evoked sensations fade within seconds, is a major challenge for providing stable sensory feedback in brain–computer interfaces (BCIs). Building on human psychophysics experiments [1] and the neuromorphic twin model of the somatosensory cortex [2], the goal is to predict and optimize stimulation patterns that prolong perception without increasing stimulation intensity.

The neuromorphic twin is a biologically grounded spiking neural network model implemented on mixed-signal neuromorphic hardware. It emulates layer IV microcircuits of the human primary somatosensory cortex, reproducing key adaptation dynamics observed under ICMS. This real-time emulation allows rapid testing of stimulation protocols in silico, guiding the design of strategies that can later be validated in human experiments.

 

Methodology

1. Map the multi-channel and interleaved stimulation protocols [similar to 1] into input patterns to the neuromorphic twin. Stimulation parameters will match experimental settings (electrode count, burst frequency, interleaving timing).

2. Use the neuromorphic hardware to run repeated trials for each stimulation scheme, measuring adaptation times and network activity decay.

3. Compare adaptation metrics between single-channel, multi-channel, and interleaved stimulation, correlating model outputs with human psychophysics data from [1].

4. Explore parameter variations (e.g., interleaving intervals, burst durations) to identify patterns that maximize perceptual persistence while minimizing charge delivery.

 

Available Material

• Neuromorphic hardware and somatosensory twin model.

• Experimental data and stimulation parameters, provided by Pittsburgh University.

 

Requirements

• Python programming

• Interest in neuroprosthetics and sensory neuroscience.

 

Contacts
Elisa Donati (elisa@ini.uzh.ch)

 

References
[1] Ramirez, Hector, et al. "A physical emulation of somatosensory cortex as aNeuromorphic Twin for neural prostheses." Research Square 4389036 (2024).

[2] Hughes, Christopher L., Sharlene N. Flesher, and Robert A. Gaunt. "Effects of stimulus pulse rate on somatosensory adaptation in the human cortex." Brain stimulation 15.4 (2022): 987-995..