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21
OM&P
XXIII Congress of I.P. Pavlov Physiology Society
signal from the stimulus generator transmitted to the conductive pads by a contact board of the connector and then applied to the neuronal culture.
The connector consisted of a plastic box and a PCB board, which transmit stimuli for MEA. The box was designed in the Tinkercad software and printed on a 3D printer Ultimaker 2 plus (Ultimaker B.V., Netherlands) from PLA plastic with 2.65 mm diameter. The PCB board contained 4 gold pressure pins (Preci-Dip, Switeerland) which were connected by conductive paths with a connector to the stimulator.
Results and discussion
Developed connector consisted of the contact plate with pressure contacts and the plastic box for MEA installation. The MEA was installed in the cavity of the box base, the contact plate was fixed upon it, so the pressure electrodes touch the contact pads of the MEA. The special hole in the box base covered with a cover glass allowed to observe the neural network morphological development on an inverted microscope in sterile conditions inside the box. The gold pressure electrodes of the contact plate was connected by conductive paths with a connector and then with stimulus generator. A cylindrical protrusion was on the cover for a filter film, which transmits the CO2 that is necessary for the cells metabolism. The connector was placed in the incubator during chronic experiment where the neuronal culture was in optimal conditions for the development.
To test the survival of the neurons developed under conditions of chronic stimulation in the connector, we plated differentiated hippocampal neurons of mouse embryos (E18) on the microelectrode arrays. On the 2nd day after planting the MEA was installed into the connector for stimulation. The chronic stimulation consisted of loop of trains of 5 bipolar pulses with an amplitude of 600 ^V, 20 ms interpulse interval and an interval between trains of 120 ms. We found that such chronic stimulation did not affect of the culture negatively and the cells showed good viability. The developed connector can be used to study the neuronal cultures in vitro under conditions of chronic stimulation that simulates afferentation in brain. We suggest that such approach will induce activity similar to that observed in vivo conditions.
References
1. Ide A. N. Chronic network stimulation enhances evoked action potentials //Journal of neural engineering. - 2010. -T. 7. - №. 1. - 016008 c.
2. Leinekugel X. Correlated bursts of activity in the neonatal hippocampus in vivo //Science. - 2002. - T. 296. - №. 5575. - 2049-2052 c.
3. Leondopulos S. S. Chronic stimulation of cultured neuronal networks boosts low-frequency oscillatory activity at theta and gamma with spikes phase-locked to gamma frequencies //Journal of neural engineering. - 2012. - T. 9. - №. 2. - 026015 c.
4. Obien M. E. J. Revealing neuronal function through microelectrode array recordings //Frontiers in neuroscience. -2014. - T. 8.
Soft Multimodal Neuronal Interface to Restore Motor Function after Spinal Cord Injury
P. Musienko
Saint-Petersburg State University, Russia
The mechanical mismatch between soft neural tissues and stiff neural implants hinders the long-term performance of implantable neuroprostheses. We designed and fabricated soft neural implants with the shape and elasticity of dura mater, the protective membrane of the brain and spinal cord. The electronic dura mater, which we call e-dura, embeds interconnects, electrodes, and chemotrodes that sustain millions of mechanical stretch cycles, electrical stimulation pulses, and chemical injections. These integrated modalities enable multiple neuroprosthetic applications. The soft implants extracted cortical states in freely behaving animals for brain-machine interface and delivered electrochemical spinal neuromodulation that restored locomotion after paralyzing spinal cord injury.
14 Opera Med Physiol 2017 Vol. 3 (S1)
