Tissue clearing has been widely used for fluorescence imaging of fixed tissues, but its application to live tissues has been limited by toxicity. Here we develop minimally invasive optical clearing media for fluorescence imaging of live mammalian tissues. Light scattering is minimized by adding spherical polymers with low osmolarity to the extracellular medium. A clearing medium containing bovine serum albumin (SeeDB-Live) is compatible with live cells, enabling structural and functional imaging of live tissues, such as spheroids, organoids, acute brain slices and the mouse brains in vivo. SeeDB-Live minimally affects neuronal electrophysiological properties and sensory responses in vivo, and facilitates fluorescence imaging of deep cortical layers in live animals without detectable toxicity to neurons or behavior. We further demonstrate its utility to epifluorescence voltage imaging in acute brain slices and in vivo preparations. Thus, SeeDB-Live expands both the depth and modality range of fluorescence imaging in live mammalian tissues.

Local dendritic computations are thought to critically influence neuronal signaling and plasticity yet remain largely unexplored in vivo due to challenges in stably imaging small structures at ultrafast timescales. We developed a 3D real-time motion correction platform for movement-stabilized, ultrafast two-photon voltage imaging. By co-labeling CA1 pyramidal neurons with voltage and calcium indicators, we simultaneously measured somato-dendritic and electro-calcium coupling at multiple dendritic sites. We characterized isolated dendritic spikes and distance-dependent backpropagation of naturally occurring and photostimulation-evoked bursts and single spikes. We found that bursts backpropagated more reliably than single spikes, validated that somato-dendritic coupling decreases with distance from soma, and showed that electro-calcium coupling decreases with increasing branch order. These findings provide in vivo evidence for distance-dependent invasion of somatic signals into dendrites, highlight the prevalence of isolated dendritic events, and show that dendritic structure isolates voltage from calcium signaling, potentially enabling unique intracellular pathways in distal dendrites.

Understanding how behavior modulates neuronal integration is a fundamental goal in neuroscience. We combined voltage imaging with optogenetics to reveal how excitatory (E) and inhibitory (I) inputs modulate spiking output, subthreshold dynamics, and gain in genetically defined CA1 neurons. We imaged pyramidal cells (PCs), vasoactive intestinal peptide (VIP), somatostatin (SST), and parvalbumin (PV) interneurons (INs) and found that locomotion reduced firing in PCs and VIP INs while increasing activity in SST and PV INs. Prolonged optical depolarization revealed that inhibitory inputs substantially contribute to intracellular theta oscillations in PCs and VIP cells. Firing rate-laser intensity (F-I) curves revealed distinct gain modulation across cell types, with a divisive gain reduction in PC bursting during locomotion, while simple spikes are unaffected. A two-compartment model suggested that this effect results from a balanced increase in E/I input to the soma and dendrite. These findings reveal how behavior coordinates E/I signaling to modulate hippocampal computations.

Recent advances in the field of Voltage Imaging, with a special focus on new constructs and novel implementations.

Work related to place tuning, spatial navigation, orientation and direction. Mainly includes articles on connectivity in the hippocampus, retrosplenial cortex, and related areas.

Basal Ganglia Advances is a collection highlighting research on the structure, function, and disorders of the basal ganglia. It features studies spanning neuroscience, clinical insights, and computational models, serving as a hub for advances in movement, cognition, and behavior.

Advances in optical techniques and two-photon (2P) sensitive genetic voltage indicators (GEVIs) enabled in-depth voltage imaging at single-spike and single-cell resolution. These results were achieved using ASAP-type sensors, while rhodopsin-based GEVIs were mainly used with one-photon (1P) illumination. Here, we demonstrate compatibility of rhodopsin-based GEVIs with 2P illumination. We rationally engineer a fully genetically encoded, rhodopsin-based GEVI, just another voltage indicating sensor (Jarvis), and demonstrate its utility under 1P and 2P illumination. We further show 2P usability of the fluorescence resonance energy transfer (FRET)-opsin GEVIs pAce and Voltron2. Comparing 2P scanless with fast 2P scanning illumination revealed that responses are resolved with both approaches, but FRET-opsin GEVIs show improved signal-to-noise ratio (SNR) with low irradiance, inherent to scanless illumination. Utilizing Jarvis and pAce, we establish high-SNR action potential detection at kilohertz imaging rates in mouse hippocampal slices, zebrafish larvae, and the cortex of awake mice, demonstrating high-contrast action potential detection under 2P illumination with rhodopsin-based GEVIs in vitro and in vivo.

This study investigated the potential of integrating windcatchers into Egyptian social housing buildings to enhance natural ventilation and improve indoor thermal comfort, thereby reducing energy consumption used to enhance airflow inside residential spaces of residential communities, which is considered an important aspect of sustainable urban development that aims to counteract climate change. Computational Fluid Dynamics (CFD) simulations validated by site measurements were conducted on two distinctly oriented apartment models. The northwest-oriented apartment demonstrated a 7% improvement in natural ventilation rate with a single strategically placed windcatcher in the bedroom. The southwest-oriented apartment showed a remarkable 45.7% improvement when equipped with three windcatchers distributed across the living room and bedroom spaces. The results revealed that strategic windcatcher placement was more critical than quantity, with a dual-windcatcher configuration in the southwest-oriented apartment achieving a performance nearly comparable to that of a triple-windcatcher arrangement. Effectiveness relies on establishing appropriate pressure gradients through careful positioning to facilitate consistent airflow circulation. Configurations that enhance living room ventilation, the primary family gathering space, demonstrated the greatest potential for improving overall thermal comfort. Practical recommendations include orientation-specific design strategies, early integration of windcatchers into the architectural design process, and standardization of building codes for social housing projects. The implementation of passive cooling strategies offers multiple benefits, including reduced reliance on mechanical cooling, improved indoor air quality, connection to architectural heritage, and significant cumulative energy savings at scale. Future research directions encompass seasonal performance studies, combinations with other cooling strategies, and detailed analyses of windcatcher geometry.

The presence and abundance of malignant tumor cells (MTCs), particularly cell clusters (MTCCs) in clinical effusion samples serve as established correlative indicators for aggressive malignancy, elevated metastatic potential, and adverse clinical prognosis. While tumor cell-based liquid biopsy enables the detection of single MTCs, but clinical utility is limited by cellular damage and attrition of MTCCs. To overcome these limitations, we developed a cascaded inertial microfluidic device for high-throughput and multi-scale enrichment of both MTCs and intact MTCCs through two-stage inertial sorting. The parallelized serpentine microfluidics were employed as the first-stage sorter which depleted majority of background blood cell in an ultra-high throughput. The second-stage spiral microfluidics enabled further multi-scale enrichment of single MTCs and intact MTCCs from residual blood cells without cellular damage. After exploring the effects of particle size and flow rate on two-stage inertial sorting, cell enrichment performances using simulated samples were characterized. Quantitative results indicated a high recovery ratio of 81.7% and a high purity of 76.1% for enriched A549 cells, along with a high purity of 79.4% for A549 cell clusters. Using the cascaded microfluidic device, 50 mL pleural effusion samples were processed within 6.5 min, achieving a high purity of 68% for single MTCs and a high purity of 35% for intact MTCCs. Our cascaded inertial microfluidic device may provide a new tool for accelerating clinical cancer diagnosis and enhance malignancy assessment capability.