Miniature microscopes for manipulating and recording in vivo brain activity (original) (raw)
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F1000 - Post-publication peer review of the biomedical literature, 2015
We describe an all-optical strategy for simultaneously manipulating and recording the activity of multiple neurons with cellular resolution in vivo. Concurrent two-photon optogenetic activation and calcium imaging is enabled by coexpression of a red-shifted opsin and a genetically encoded calcium indicator. A spatial light modulator allows tens of user-selected neurons to be targeted for spatiotemporally precise optogenetic activation, while simultaneous fast calcium imaging provides high-resolution network-wide readout of the manipulation with negligible optical crosstalk. Proofof-principle experiments in mouse barrel cortex demonstrate interrogation of the same neuronal population during different behavioral states, and targeting of neuronal ensembles based on their functional signature. This approach extends the optogenetic toolkit beyond the specificity obtained with genetic or viral approaches, enabling high-throughput, flexible and long-term optical 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:
Large-scale cellular-resolution imaging of neural activity in freely behaving mice
2021
Miniaturized microscopes for head-mounted fluorescence imaging are powerful tools for visualizing neural activity during naturalistic behaviors, but the restricted field of view of first-generation ‘miniscopes’ limits the size of neural populations accessible for imaging. Here we describe a novel miniaturized mesoscope offering cellular-resolution imaging over areas spanning several millimeters in freely moving mice. This system enables comprehensive visualization of activity across entire brain regions or interactions across areas.
bioRxiv (Cold Spring Harbor Laboratory), 2022
Electrophysiology is a vital tool in neuroscience research and translational treatment. It records or modulates neuronal activities with high temporal but low spatial resolutions. Optical technology such as two-photon microscopy (TPM), could complement electrophysiology with large-scale imaging at cellular resolution. Combining these two could provide a powerful platform that coordinates multimodal functions. However, prior attempts have been limited to the superficial brain from a top-down optical view. Here, we describe a novel combination of transparent microelectrode arrays (MEAs) with glass microprisms for electrophysiology and simultaneous optical imaging of all cortical layers in a vertical plane. We tested our device in Thy1-GCaMP6 mice for over 4 months and demonstrated its capability for multisite single unit recording, microstimulation, and TPM calcium imaging. Using this setup, we revealed the neuronal network activity across multiple cortical layers in response to microstimulation with varying depths and parameters. This work presents a multi-modal tool that extends integrated electrophysiology and optical imaging from the superficial brain to the whole cortical column, which will greatly advance neuroscience research and neurotechnology development.
Optogenetic investigation of neural circuits in vivo
Trends in Molecular Medicine, 2011
The recent development of light-activated optogenetic probes allows for the identification and manipulation of specific neural populations and their connections in awake animals with unprecedented spatial and temporal precision. This review describes the use of optogenetic tools to investigate neurons and neural circuits in vivo. We describe the current panel of optogenetic probes, methods of targeting these probes to specific cell types in the nervous system, and strategies of photostimulating cells in awake, behaving animals. Finally, we survey the application of optogenetic tools to studying functional neuroanatomy, behavior, and the etiology and treatment of various neurological disorders. Optogenetics The mammalian brain is composed of billions of neurons interconnected into circuits by trillions of synapses [1]. Some neural systems have been difficult to describe anatomically, such as the exquisitely complicated wiring of the cerebral cortex, while other neural systems are relatively well-characterized, such as the circuits that mediate vision, motor movements, breathing/respiration, and sleep/wake architecture. However, even these systems require functional dissection so that the relative contributions of individual cell types and their synaptic connections can be discerned. Perturbing one element in a neural circuit is especially difficult in vivo, where the complex environment of the brain in an awake, behaving animal imposes obstacles to the stimulation, inhibition, or manipulation of biochemical signaling events in specific cell types. Traditionally, cells and synapses have been manipulated using electrical, physical, pharmacological, and genetic methods (Figure 1) [2]. Although much progress has been made using these classical techniques, considerable drawbacks prevent their use in the study of neural circuits with fine spatial and temporal precision in vivo. Electrical and physical techniques are not spatially precise and can cause stimulation, inhibition, or inactivation of surrounding cells and processes. Pharmacological and genetic methods exhibit improved spatial selectivity but lack temporal resolution at the scale of single action potentials. To overcome these limitations, a new set of tools collectively referred to as "optogenetics" [3] has been developed to precisely stimulate [4-10], inhibit [11-16], or alter biochemical activity [17, 18] in specific cells or their processes with high temporal precision and rapid
Miniaturized Optical Neuroimaging in Unrestrained Animals
NeuroImage, 2015
The confluence of technological advances in optics, miniaturized electronic components and the availability of ever increasing and affordable computational power have ushered in a new era in functional neuroimaging. Namely, an era in which neuroimaging of cortical function in unrestrained and unanesthetized rodents has become a reality. Traditional optical neuroimaging required animals to be anesthetized and restrained. This greatly limited the kinds of experiments that could be performed in vivo. Now one can assess blood flow and oxygenation changes resulting from functional activity, image functional response in disease models such as stroke and seizure, and even conduct long-term imaging of tumor physiology, all without the confounding effects of anesthetics or animal restraints. These advances are shedding new light on mammalian brain organization and function, and helping to elucidate loss of this organization or 'dysfunction' in a wide array of central nervous system d...
Frontiers in Neural Circuits, 2020
The exquisite intricacies of neural circuits are fundamental to an animal's diverse and complex repertoire of sensory and motor functions. The ability to precisely map neural circuits and to selectively manipulate neural activity is critical to understanding brain function and has, therefore been a long-standing goal for neuroscientists. The recent development of optogenetic tools, combined with transgenic mouse lines, has endowed us with unprecedented spatiotemporal precision in circuit analysis. These advances greatly expand the scope of tractable experimental investigations. Here, in the first half of the review, we will present applications of optogenetics in identifying connectivity between different local neuronal cell types and of long-range projections with both in vitro and in vivo methods. We will then discuss how these tools can be used to reveal the functional roles of these cell-type specific connections in governing sensory information processing, and learning and memory in the visual cortex, somatosensory cortex, and motor cortex. Finally, we will discuss the prospect of new optogenetic tools and how their application can further advance modern neuroscience. In summary, this review serves as a primer to exemplify how optogenetics can be used in sophisticated modern circuit analyses at the levels of synapses, cells, network connectivity and behaviors.
A platform for brain-wide imaging and reconstruction of individual neurons
eLife, 2016
The structure of axonal arbors controls how signals from individual neurons are routed within the mammalian brain. However, the arbors of very few long-range projection neurons have been reconstructed in their entirety, as axons with diameters as small as 100 nm arborize in target regions dispersed over many millimeters of tissue. We introduce a platform for high-resolution, three-dimensional fluorescence imaging of complete tissue volumes that enables the visualization and reconstruction of long-range axonal arbors. This platform relies on a high-speed two-photon microscope integrated with a tissue vibratome and a suite of computational tools for large-scale image data. We demonstrate the power of this approach by reconstructing the axonal arbors of multiple neurons in the motor cortex across a single mouse brain.