Although modern techniques such as two-photon microscopy can now provide cellular-level three-dimensional imaging of the intact living brain, the speed and fields of view of these techniques remain limited. Conversely, two-dimensional wide-field optical mapping (WFOM), a simpler technique that uses a camera to observe large areas of the exposed cortex under visible light, can detect changes in both neural activity and haemodynamics at very high speeds. Although WFOM may not provide single-neuron or capillary-level resolution, it is an attractive and accessible approach to imaging large areas of the brain in awake, behaving mammals at speeds fast enough to observe widespread neural firing events, as well as their dynamic coupling to haemodynamics. Although such wide-field optical imaging techniques have a long history, the advent of genetically encoded fluorophores that can report neural activity with high sensitivity, as well as modern technologies such as light emitting diodes and sensitive and high-speed digital cameras have driven renewed interest in WFOM. To facilitate the wider adoption and standardization of WFOM approaches for neuroscience and neurovascular coupling research, we provide here an overview of the basic principles of WFOM, considerations for implementation of wide-field fluorescence imaging of neural activity, spectroscopic analysis and interpretation of results.This article is part of the themed issue ‘Interpreting BOLD: a dialogue between cognitive and cellular neuroscience’.

The limited per-pixel bandwidth of most microscopy methods requires compromises between field of view, sampling density and imaging speed. This limitation constrains studies involving complex motion or fast cellular signaling, and presents a major bottleneck for high-throughput structural imaging. Here, we combine high-speed intensified camera technology with a versatile, reconfigurable and dramatically improved Swept, Confocally Aligned Planar Excitation (SCAPE) microscope design that can achieve high-resolution volumetric imaging at over 300 volumes-persecond and over 1.2 GHz pixel rates. We demonstrate near-isotropic sampling in freely moving C. Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:

Photodynamic therapy (PDT) is an emerging effective treatment for cancer. However, the great promise of PDT for bladder cancer therapy has not yet been realized because of tumor hypoxia. To address this challenge, we fabricated O2-generating HSA-MnO2-Ce6 NPs (HSA for human serum albumin, Ce6 for chlorin e6, and NPs for nanoparticles) to overcome tumor hypoxia and thus enhance the photodynamic effect for bladder cancer therapy.Methods: The HSA-MnO2-Ce6 NPs were prepared. We investigated the O2 generation of NPs in vitro and in vivo. The orthotopic bladder cancer model in C57BL/6 mice was established for in vivo study, and dual-modal imaging of NPs were demonstrated. Therapeutic efficacy of NPs for bladder cancer was evaluated.Results: HSA-MnO2-Ce6 NPs had an excellent performance in generating O2 in vitro upon reaction with H2O2 at endogenous levels. Moreover, 1O2 generation was increased two-fold by using HSA-MnO2-Ce6 NPs instead of HSA-Ce6 NPs in the presence of H2O2 under 660 nm laser irradiation. In vitro cell viability assays showed that HSA-MnO2-Ce6 NPs themselves were non-toxic but greatly enhanced PDT effects on bladder cancer cells under laser irradiation. In vivo near-infrared (NIR) fluorescence and magnetic resonance (MR) imaging suggested the excellent bladder tumor-targeting property of HSA-MnO2-Ce6 NPs. O2 content in orthotopic bladder cancer was increased 3.5-fold after injection of HSA-MnO2-Ce6 NPs as compared with pre-injection. Given the excellent tumor-targeting ability and negligible toxicity, HSA-MnO2-Ce6 NPs were then used to treat orthotopic bladder cancer by PDT. The PDT with HSA-MnO2-Ce6 NPs showed remarkably improved therapeutic efficacy and significantly prolonged lifetime of mice as compared with controls.Conclusion: This study not only demonstrated the great potential of HSA-MnO2-Ce6 NPs for bladder cancer photodynamic ablation but also provided a new therapeutic strategy to overcoming tumor hypoxia.

Patients with asthma experience circadian variations in their symptoms. However it remains unclear how specific aspects of this common airway disease relate to clock genes, which are critical to the generation of circadian rhythms in mammals. Here, we used a viral model of acute and chronic airway disease to examine how circadian clock disruption affects asthmatic lung phenotypes. Deletion of the core clock gene bmal1 or environmental disruption of circadian function by jet-lag exacerbated acute viral bronchiolitis caused by Sendai virus (SeV) and influenza A virus (IAV) in mice. Post-natal deletion of bmal1 was sufficient to trigger increased SeV susceptibility and correlated with impaired control of viral replication. Importantly, bmal1−/− mice developed much more extensive asthma-like airway changes post-infection, including mucus production and increased airway resistance. In human airway samples from two asthma cohorts, we observed altered expression patterns of multiple clock genes. Our results suggest a role for bmal1 in the development of asthmatic airway disease via the regulation of lung antiviral responses to common viral triggers of asthma.