(K-434) Stereotaxic Development for a Battery-less and Wireless Multichannel Neuronal Recording System

Introduction:: The reading of neuronal signals is essential to assess information to understand the brain’s functionalities and to diagnose neuronal diseases. The passive wireless neurosensing system (WiNS) [1] for multichannel neuropotential has been developed by our team with the purpose of substituting the battery in implantable devices that can cause heat radiation, damaging the surrounding tissue and affecting the reading of the neural frequencies. To address the fully implantation of our device, our team has decided to transition from rats to pigs due to the limitations regarding the antennas miniaturization when implementing neural signal RF backscattering. When the device is finally implanted, it will need a stereotaxic fixation helmet to be able to hold the RF interrogator in a steady position for the alignment and correct transmission of the neural frequencies.

Materials and Methods::
This study will be carried out in compliance with Animal Care and Use Committee Protocol at Florida International University (IACUC 23-023). Pigs surgeries will be performed under deep anesthesia (ketamine 20 mg/kg,xylazine 2.0 mg/kg and butorphanol 2.0 mg/kg intramuscular injection). Pig physiology will be continuously monitored using the PowerLab 8/35 data acquisition device and the LabChart software (AD Instruments). FDA approved electrodes (Fig.1C) will be inserted in the primary somatosensory cortex, as identified using [3]. A pair of needle electrodes will be inserted in the hind paw for current stimulation by a constant current range of twofold threshold of muscle responses to stimuli (200 μs, 4.7 Hz) delivered by an isolated pulse stimulator (A-M Systems Model 2100).

To create the adjustable 3D printed stereotaxic fixation helmet (Fig.1B), we took our measurements on the high-resolution magnetic resonance for adolescent domesticated pigs made by the university of Illinois [2] with the purpose of locating the pig’s somatosensory cortex (Fig.1C). Later, the measurements were taken to SolidWorks to create the model and make a hole that aligns the interrogator with the implant placed in the pocket. Then, it was 3D printed with TPU 95A which is suitable for the strength and flexibility needed to avoid the breakage or accidental removal from the usual pig activity.



Results, Conclusions, and Discussions:: We have created a stereotaxic adjustable helmet for the interrogator fixation to ensure proper transmission of RF neural signal (Fig.1B). which was created based on the existing pig’s brain atlas (Fig.1A) . (Fig.1C) shows the FDA approved electrodes that are going to be placed at the somatosensory cortex of the pig for hindlimb stimulation reading.

Acknowledgements (Optional): :

References (Optional): :
[1] C. Moncion, et. al. “Fully-Passive Wireless Implant for Neuropotential Acquisition: An In Vivo Validation,” in IEEE Journal of Electromagnetics, RF and Microwaves in Medicine and Biology, vol. 3, no. 3, pp. 199-205, Sept. 2019, doi: 10.1109/JERM.2019.2895657.



[2] Fil, Joanne E., et al. "High-resolution magnetic resonance imaging-based atlases for the young and adolescent domesticated pig (Sus scrofa)." Journal of Neuroscience Methods, vol. 354, 2021, article no. 109107, ISSN 0165-0270, https://doi.org/10.1016/j.jneumeth.2021.109107.



[3] Saikali S, Meurice P, Sauleau P, Eliat PA, Bellaud P, Randuineau G, Vérin M, Malbert CH. A three-dimensional digital segmented and deformable brain atlas of the domestic pig. J Neurosci Methods. 2010 Sep 30;192(1):102-9. doi: 10.1016/j.jneumeth.2010.07.041. Epub 2010 Aug 6. PMID: 20692291.