Direct nerve stimulation can be used to provide sensory feedback to upper and lower-limb amputees both for prosthetic hand (bionic hand), or to improve their mobility/agility while walking (bionic leg). The intensity of the elicited sensations can be modulated using the frequency (Linear Frequency Modulation - LFM) of the injected stimuli.
One of the drawbacks of direct nerve stimulation is the adaptation which caused the patients to stop perceiving the restored sensations (even to low-frequency stimulation). In particular, when long-lasting trains of stimulation were delivered, the LFM stimulation (> 500 Hz) generated a fast adaptation (~ ms) and can last up to tens of few minutes. This effect presumably occurs in the somatosensory cortex. To understand it we expanded the search to include other sensory systems, such as the olfactory cortex, due to the assumption that adaptation to a constant stimulus would work similarly in other parts of the cortex. In a previous project (Evan Hoffman’s semester project) we identify the network that explain the adaptation and in the proposed project we want to implement it on Brian2 and on the neuromorphic chip Dynap-se to understand the mechanisms behind the neural adaptation and to emulate the neural process to prevent, in the real-time system.

Available:
• Data adaptation time collected in 2 implanted amputees (multiple stimulating channels) - Provided by D-HEST
• Spiking simulator with chip equation
• A mixed-signal neuromorphic chip, the DYNAPSEx

Project level:
The project can start immediately as a semester/master project, or (preferred) as a master thesis
References:
- Valle, Giacomo, F. M. Petrini, Ivo Strauss, Francesco Iberite, Edoardo D’Anna, Giuseppe Granata, Marco Controzzi et al. "Comparison of linear frequency and amplitude modulation for intraneural sensory feedback in bidirectional hand prostheses." Scientific reports 8, no. 1 (2018): 1-13.
- Eles, J. R., Stieger, K. C., & Kozai, T. D. Y. (2020). The temporal pattern of Intracortical Microstimulation pulses elicits distinct temporal and spatial recruitment of cortical neuropil and neurons. Journal of Neural Engineering.
- C. Linster, L. Henry, M. Kadohisa, and D. A.Wilson, “Synaptic adaptation and odor-background segmentation,” Neurobiology of Learning and Memory, vol. 87, no. 3, pp. 352–360, 2007, ISSN: 1074-7427