APPLICABILITY OF CHRONICALLY IMPLANTABLE AND TRANSPARENT MICROECOG DEVICES FOR SIMULTANEOUS MEASUREMENT OF SPONTANEOUS CALCIUM AND ELECTROPHYSIOLOGICAL ACTIVITY IN AWAKE MICE
Madarász Miklós
János Szentágothai Neurosciences
Dr. Bereczki Dániel
SE Neurológiai és Pszichiátriai Klinika közös tanterme
2026-05-19 10:30:00
Functional neurosciences
Dr. Sperlágh Beáta
Dr. Rózsa Balázs
Dr. Borbély Sándor
Dr. Dávid Csaba
Dr. Kamondi Anita
Dr. Varga Viktor
Dr. Kis Petiková Katarína
Through extensive characterization and experiments in vitro and in vivo in awake mice, we sought to validate the usability of the Parylene HT/ ITO and Thiol-ene/acrylate / SIROF composed transparent, implantable ECoG devices in two-photon imaging experiments. We introduced novel material compositions and device designs and subjected those devices to many tests, covering particularly electrochemical properties, transparency and rigidity. In vitro tests on acute mouse brain slices served as a middle ground towards in vivo experiments, and we explored the optical characteristics, photothermal and photoelectric effects on the devices more in depth. As our main goal, we implanted these transparent devices in mice, both on the cortical and the hippocampal surface, for use in two-photon imaging and validated the in vivo, long term performance of ECoG and calcium imaging, the basis of concurrent measurements. Finally, we characterized the histological context of the implantations with DAPI, GFAP and NeuroTrace labelings at different time points post implantation.
The results of all of these tests point out conclusively the applicability of both Parylene HT/ ITO and Thiol-ene/acrylate / SIROF composed devices in concurrent ECoG and two-photon calcium imaging experiments in awake mice. The devices possess excellent optical transparency. Electrochemical properties reflected the material choices in the devices’ design and allowed good quality recordings months after implantation with minimal loss of recording sites. Two-photon calcium imaging of GCaMP6f labelled cortical neurons through the implanted devices provided satisfactory data on the activity of neuronal populations 51 days (Parylene HT / ITO) and 22 weeks (Thiol-ene/acrylate / SIROF) after implantation. Last but not least, the use of shape memory polymer materials supported the implantation of the devices and the tackling of the following immune response by conforming to the cortical surface better.
In light of these experiments we concluded that the implantable devices introduced here are suitable for combined electrocorticography and two - photon calcium imaging chronically, in awake mice and are good candidates for cellular level resolution mapping of neuronal ensembles with electrophysiology and simultaneous two-photon imaging.
