Colocalized, bidirectional optogenetic modulations in freely behaving mice with a wireless dual-color optoelectronic probe

Abstract

Optogenetic methods provide efficient cell-specific modulations, and the ability of simultaneous neural activation and inhibition in the same brain region of freely moving animals is highly desirable. Here we report bidirectional neuronal activity manipulation accomplished by a wireless, dual-color optogenetic probe in synergy with the co-expression of two spectrally distinct opsins (ChrimsonR and stGtACR2) in a rodent model. The flexible probe comprises vertically assembled, thin-film microscale light-emitting diodes with a lateral dimension of 125 × 180 µm2, showing colocalized red and blue emissions and enabling chronic in vivo operations with desirable biocompatibilities. Red or blue irradiations deterministically evoke or silence neurons co-expressing the two opsins. The probe interferes with dopaminergic neurons in the ventral tegmental area of mice, increasing or decreasing dopamine levels. Such bidirectional regulations further generate rewarding and aversive behaviors and interrogate social interactions among multiple mice. These technologies create numerous opportunities and implications for brain research.

Blueprints for measuring natural behavior

“…Although it is still a challenge, combining the ecologically relevant behavioral research with advanced methods of brain imaging, measuring neuronal activity, and manipulation of specific circuits has become more and more feasible over the last years. Even though such methodologies are not without their challenges, we are at the point when newly developing technologies allow wireless recording/manipulating many neurons at a time in group-housed animals ( Anpilov et al., 2020 ; Cai et al., 2022 ; Caras and Sanes, 2017 ; Inagaki et al., 2019 ; Li et al., 2022 ; Lu et al., 2018 ; Mayer et al., 2019 ; Montgomery et al., 2015 ; Murphy et al., 2016 ; Pinnell et al., 2015 ; Yang et al., 2021 ; Zong et al., 2022 ). Broader implementation of those methodologies increases our chances of developing experiments, whose results will stand over time and thus enable us to break the impasse in proposing new, effective therapeutic strategies.…”

3D Upconversion Barcodes for Combinatory Wireless Neuromodulation in Behaving Animals

“…[35,37] Even though implantable LED devices and associated powering circuits have become smaller, lighter, and more versatile to enable dual-color/dual-channel optogenetics, the requirement for electronic components still complicates the fabrication and implementation procedures. [38,39] Besides, such systems require a relatively large headstage/powering-board to power the LEDs, which could still be some burden to a small mouse. To eliminate the need for batteries or complicated electronics to power LEDs, various upconversion devices have been developed to enable photoactivation of neurons by utilizing the deep-tissue-penetrating NIR light.…”

Emerging Optoelectronic Devices Based on Microscale LEDs and Their Use as Implantable Biomedical Applications

“…Bio-optoelectronics are ground-breaking technologies that not only address the fundamental mismatch between the properties of biomedical systems (soft, curvilinear, and transient) [ 23 ] and those of modern semiconductor devices [ 24 ] (rigid, planar, and everlasting), but also demonstrate exceptional capabilities in energy conversion [ 25 , 26 ], function display [ 27 , 28 ], wireless sensing [ 4 , 29 , 30 ], stimulation [ 31 , 32 , 33 ], and other areas [ 34 , 35 ]. Thin-film semiconductor devices, such as microscale thin-film LEDs and photodiodes, are typically removed from growing substrates and transferred to other substrates employing epitaxial lift-off and heterogeneous integration processes [ 36 , 37 ].…”

“…Optogenetic stimulation of the same neurons expressing different light-sensitive proteins with correlated light enables the analysis of more complex and diverse neural activity responses, rather than optogenetic stimulation of neurons in different locations. As shown in Figure 2 d, the co-expression of two channelrhodopsins in the same set of neurons facilitated efficient light-induced cellular depletion by controlling cation and anion fluxes and hyperpolarization under red and blue light stimulation, respectively [ 31 ]. The implantable light source probe with red and blue light emission comprises vertically integrated microscale thin-film InGaP and GaN LEDs with stacked dimensions of 125 × 180 × 120 μm 3 and exhibits superior biocompatibility for long-term light stimulation in vivo.…”