Cutrone, A. | bioRxiv Science

bioRxiv2020

Simultaneous decoding of cardiovascular and respiratory functional changes from pig intraneural vagus nerve signals

Bioelectronic medicine is opening new perspectives for the treatment of some major chronic diseases through the physical modulation of autonomic nervous system activity. Being the main peripheral route for electrical signals between central nervous system and visceral organs, the vagus nerve (VN) is one of the most promising targets. Closed-loop neuromodulation would be crucial to increase effectiveness and reduce side effects, but it depends on the possibility of extracting useful physiological information from VN electrical activity, which is currently very limited. Here, we present a new decoding algorithm properly detecting different functional changes from VN signals. They were recorded using intraneural electrodes in anaesthetized pigs during cardiovascular and respiratory challenges mimicking increases in arterial blood pressure, tidal volume and respiratory rate. A novel decoding algorithm was developed combining discrete wavelet transformation, principal component analysis, and ensemble learning made of classification trees. It robustly achieved high accuracy levels in identifying different functional changes and discriminating among them. We also introduced a new index for the characterization of recording and decoding performance of neural interfaces. Finally, by combining an anatomically validated hybrid neural model and discrimination analysis, we provided new evidence suggesting a functional topographical organization of VN fascicles. This study represents an important step towards the comprehension of VN signaling, paving the way to the development of effective closed-loop bioelectronic systems.

neuroscience↗

bioRxiv2018

Optic nerve intraneural stimulation allows selective visual cortex activation

Retinal prostheses have been developed to restore a functional form of vision in patients affected by outer retinal layer dystrophies. Other approaches, namely optic nerve, thalamic, and cortical prostheses are under investigation to expand this toolbox both as clinical devices and as tools for fundamental research. Optic nerve stimulation is attractive since it bypasses the entire retinal network and directly activates nerve fibers. At the same time, it still takes advantage of the high-level information processing occurring downstream in the visual cortex. Here we show that a new intraneural electrode array (OpticSELINE) is effective in inducing the activation of the visual cortex upon electrical stimulation of the optic nerve. We also demonstrate that intraneural optic nerve stimulation induces selective cortical activation patterns depending on the stimulating electrode, thus suggesting that the OpticSELINE possesses spatial selectivity in fiber stimulation. In conclusion, the OpticSELINE can be used both as visual prosthesis for blind patients and as tool to further investigate the effect of the electrical stimulation in the visual system.

bioengineering↗