Human cortical organoids, three-dimensional neuronal cultures, are emerging as powerful tools to study brain development and dysfunction. However, whether organoids can functionally connect to a sensory network in vivo has yet to be demonstrated. Here, we combine transparent microelectrode arrays and two-photon imaging for longitudinal, multimodal monitoring of human cortical organoids transplanted into the retrosplenial cortex of adult mice. Two-photon imaging shows vascularization of the transplanted organoid. Visual stimuli evoke electrophysiological responses in the organoid, matching the responses from the surrounding cortex. Increases in multi-unit activity (MUA) and gamma power and phase locking of stimulus-evoked MUA with slow oscillations indicate functional integration between the organoid and the host brain. Immunostaining confirms the presence of human-mouse synapses. Implantation of transparent microelectrodes with organoids serves as a versatile in vivo platform for comprehensive evaluation of the development, maturation, and functional integration of human neuronal networks within the mouse brain.
Bibliographical noteFunding Information:
This project is funded through National Institutes of Health (NIH) BRAIN initiative (R21EY030727 to A.D. and D.K., R01MH111359 and R01DA050159 to A.D., and DP2 EB030992 to D.K.), Research Council of Norway (223273, 248828, and 283798 to O.A.A. and S.D.), K.G. Jebsen Stiftelsen (to O.A.A. and S.D.), South-Eastern Norway Regional Health Authority (#2022087 to S.D.), NIH (R21 EY029466 and R21 EB026180 to D.K. and R01MH108528, R01MH109885, and R01MH1000175 to A.R.M.), National Science Foundation (NSF) (ECCS-1752241, and ECCS-2024776 to D.K.), Office of Naval Research (ONR) (N000142012405 and N00014162531 to D.K.), the JPB Foundation (to F.H.G.) and the AHA-Allen Initiative award (19PABH134610000 to F.H.G.). The fabrication of the microelectrodes was performed at the San Diego Nanotechnology Infrastructure (SDNI) of UCSD, a member of the National Nanotechnology Coordinated Infrastructure, which is supported by the National Science Foundation (Grant ECCS-1542148). The acquisition of confocal images was conducted at the University of California at San Diego Neurosciences Microscopy Core, which is supported by the National Institute of Neurological Disorders and Stroke (Grant NINDS P30NS047101). We thank Mary Lynn Gage for her editorial assistance and Qun Cheng for contributions to surgical implantation of organoids and microelectrode arrays.
© 2022, The Author(s).