In vivo voltage-sensitive dye imaging of mouse cortical activity with mesoscopic optical tomography

Abstract

Significance: Cellular layering is a hallmark of the mammalian neocortex with layer and cell type-specific connections within the cortical mantle and subcortical connections. A key challenge in studying circuit function within the neocortex is to understand the spatial and temporal patterns of information flow between different columns and layers. Aim: We aimed to investigate the three-dimensional (3D) layer-and area-specific interactions in mouse cortex in vivo. Approach: We applied a new promising neuroimaging method-fluorescence laminar optical tomography in combination with voltage-sensitive dye imaging (VSDi). VSDi is a powerful technique for interrogating membrane potential dynamics in assemblies of cortical neurons, but it is traditionally used for two-dimensional (2D) imaging. Our mesoscopic technique allows visualization of neuronal activity in a 3D manner with high temporal resolution. Results: We first demonstrated the depth-resolved capability of 3D mesoscopic imaging technology in Thy1-ChR2-YFP transgenic mice. Next, we recorded the long-range functional projections between sensory cortex (S1) and motor cortex (M1) in mice, in vivo, following single whisker deflection. Conclusions: The results show that mesoscopic imaging technique has the potential to investigate the layer-specific neural connectivity in the mouse cortex in vivo. Combination of mesoscopic imaging technique with optogenetic control strategy is a promising platform for determining depth-resolved interactions between cortical circuit elements.

Visualizing Oscillations in Brain Slices With Genetically Encoded Voltage Indicators

“…Advances in imaging technologies that brought us cameras of high spatial and temporal resolution have made imaging neural population activity with fluorescent probes accessible. Voltage sensitive dyes (VSDs) have been used in mice to image neural activity in the barrel cortex ( Davis et al, 2011 ; Tsytsarev et al, 2017 ; Margalit and Slovin, 2018 ), frontal cortex ( Nagasaka et al, 2017 ), insular cortex ( Fujita et al, 2017 ), sensory cortex ( Gollnick et al, 2016 ), sensorimotor cortex ( Luhmann, 2017 ; Sreenivasan et al, 2017 ; Kunori and Takashima, 2019 ; Tang et al, 2020 ), and the motor cortex ( Kunori et al, 2014 ; Kunori and Takashima, 2016 ) in vivo . In case of the motor cortex, the researchers imaged the neural activity of the M1 and M2 motor cortex 200–300 μm below the cortical surface using the VSD and were able to observe spread of neural activity from M2 to M1 following forelimb-related sensory-evoked M2 activity.…”

Presentation_1.pptx

“…Advances in imaging technologies that brought us cameras of high spatial and temporal resolution have made imaging neural population activity with fluorescent probes accessible. Voltage sensitive dyes (VSDs) have been used in mice to image neural activity in the barrel cortex (Davis et al, 2011;Tsytsarev et al, 2017;Margalit and Slovin, 2018), frontal cortex (Nagasaka et al, 2017), insular cortex (Fujita et al, 2017), sensory cortex (Gollnick et al, 2016), sensorimotor cortex (Luhmann, 2017;Sreenivasan et al, 2017;Kunori and Takashima, 2019;Tang et al, 2020), and the motor cortex (Kunori et al, 2014;FIGURE 6 | Investigating common neural substrates of oscillations. For each 10 s recording containing more than one oscillation, pairwise correlations of each unmasked pixel and the reference pixel were calculated.…”