1,721,151 research outputs found
Centripetal integration of past events in hippocampal astrocytes regulated by locus coeruleus
No full text<h2>Raw data of astrocytic calcium imaging</h2>
<p>Example raw data of calcium imaging of astrocytes in hippocampus of behaving mice. The example includes recording segments with spontaneous behavior and behavior-evoked astrocytic activity, as well as recording segments with optogenetic stimulation of the locus coeruleus with opto-evoked responses. The main goal of the dataset is to convey an impression of raw data quality.</p>
<h3>Raw calcium imaging data</h3>
<p>The raw calcium imaging data are in the folder 2023-05-11. Each subfolder contains data from three simultaneously acquired imaging planes as .tif files. Between recording segments, a short break was made due to limitations of the data acquisition software. Recordings have already been motion-corrected using non-rigid motion correction. Layer 1 was recorded typically around the pyramidal layer or more ventrally; Layer 2 was typically recorded at the pyramidal layer or more dorsally; Layer 3 (analyzed for the manuscript) was recorded in the <em>stratum oriens</em> of CA1. The extracted average activity across planes is saved as a .mat file in each subfolder for convenient inspection. </p>
<h3>Behavior videos</h3>
<p>Behavior videos are saved in the main folder as *.avi files. Their sequence corresponds to the calcium imaging subfolders. The behavioral videos are used to extract face/paw motion as well as pupil diameter as described in the associated manuscript.</p>
<h3>Recorded behavioral events</h3>
<p>Additional behavioral or experimental events are save in *.mat files (to be opened with MATLAB or Python's scipy.io module). These metadata include the locomotion of the animal (<em>time_running </em>and <em>running</em>), the times of sugar rewards (<em>reward_times</em>) and, when applicable, the timing and properties of optogenetic stimulation (<em>opto_times </em>and <em>opto_protocols</em>).</p>
<h3>Relative timing of behavioral and calcium data</h3>
<p>Calcium imaging data were recorded at a different framerate and with a small temporal offset compared to the behavioral videos and the behaviorally recorded events. This raw data example mainly serves to illustrate raw data quality and therefore does not include scripts to synchronize behavioral to calcium imaging data. If such a synchronization is necessary to judge the data, please get in touch with the corresponding authors (<span>[email protected]</span>).</p>
Neocortex in the Spotlight: Concepts, Questions, and Methods
No full textWhen mammals such as mice, cats, monkeys, or humans act in the world, they continually make behaviorally relevant decisions based on perceived sensory information and memorized experiences and they constantly adapt to outside challenges through learning. These cognitive capabilities largely arise from neural processing in the outermost thin sheet of the forebrain called the neocortex. Although the mammalian neocortex has been studied extensively, the astounding complexity of both its structure and dynamics has precluded a comprehensive understanding of its function so far. Higher cortical function emerges from the interplay of myriads of diverse neocortical cells, organized across multiple hierarchical levels from local neuronal networks (“microcircuits”) to communicating brain regions (“macrocircuits”). It remains elusive how these neural circuits operate—assisted by glial networks and fuelled by the vascular system—to generate intelligent behavior and ensure adequate learning. Advances in experimental methodology are essential to further unravel cortical function and in this book we highlight the rapid recent progress in optical methods for measuring and controlling neocortical dynamics, complementing classic electrophysiological approaches. In this chapter we provide a brief overview of the functional organization of the neocortex, its tissue constituents, and current concepts of neocortical dynamics. In preparation of subsequent chapters, we summarize the manifold ways photons can be used to study neocortical function, utilizing specially designed molecular tools and various imaging technologies. We conclude with a brief future outlook. Putting neocortex literally “into the spotlight” may help uncover its intriguing mysteries
Little strokes fill big oaks: a simple in vivo stain of brain cells
No full textHigh-resolution functional imaging of neural activity in vivo relies on appropriate labeling methods. In this issue of Neuron, Nagayama et al. introduce a simple procedure for staining subsets of neurons with organic calcium indicator dyes via local electroporation. Neuronal populations are sparsely labeled, preserving the ability to resolve calcium signals in dendrites and synaptic structures
Calcium indicator loading of neurons using single-cell electroporation
Full text linkStudies of subcellular Ca(2+) signaling rely on methods for labeling cells with fluorescent Ca(2+) indicator dyes. In this study, we demonstrate the use of single-cell electroporation for Ca(2+) indicator loading of individual neurons and small neuronal networks in rat neocortex in vitro and in vivo. Brief voltage pulses were delivered through glass pipettes positioned close to target cells. This approach resulted in reliable and rapid (within seconds) loading of somata and subsequent complete labeling of dendritic and axonal arborizations. By using simultaneous whole-cell recordings in brain slices, we directly addressed the effect of electroporation on neurons. Cell viability was high (about 85%) with recovery from the membrane permeabilization occurring within a minute. Electrical properties of recovered cells were indistinguishable before and after electroporation. In addition, Ca(2+) transients with normal appearance could be evoked in dendrites, spines, and axonal boutons of electroporated cells. Using negative-stains of somata, targeted single-cell electroporation was equally applicable in vivo. We conclude that electroporation is a simple approach that permits Ca(2+) indicator loading of multiple cells with low background staining within a short amount of time, which makes it especially well suited for functional imaging of subcellular Ca(2+) dynamics in small neuronal networks
Brain-wide microstrokes affect the stability of memory circuits in the hippocampus
No full textCognitive deficits affect over 70% of stroke survivors, yet the mechanisms by which multiple small ischemic events contribute to cognitive decline remain poorly understood. In this study, we employed chronic two-photon calcium imaging to longitudinally track the fate of individual neurons in the hippocampus of mice navigating a virtual reality environment, both before and after inducing brain-wide microstrokes. Our findings reveal that, under normal conditions, hippocampal neurons exhibit varying degrees of stability in their spatial memory coding. However, microstrokes disrupted this functional network architecture, leading to cognitive impairments. Notably, the preservation of stable coding place cells, along with the stability, precision, and persistence of the hippocampal network, was strongly predictive of cognitive outcomes. Mice with more synchronously active place cells near important locations demonstrated recovery from cognitive impairment. This study uncovers critical cellular responses and network alterations following brain injury, providing a foundation for novel therapeutic strategies preventing cognitive decline
Dendritic Branch-constrained N-Methyl-d-Aspartate Receptor-mediated Spikes Drive Synaptic Plasticity in Hippocampal CA3 Pyramidal Cells
Full text linkN-methyl-d-aspartate receptor-mediated ( spikes can be causally linked to the induction of synaptic long-term potentiation (LTP) in hippocampal and cortical pyramidal cells. However, it is unclear if they regulate plasticity at a local or global scale in the dendritic tree. Here, we used dendritic patch-clamp recordings and calcium imaging to investigate the integrative properties of single dendrites of hippocampal CA3 cells. We show that local hyperpolarization of a single dendritic segment prevents NMDA spikes, their associated calcium transients, as well as LTP in a branch-specific manner. This result provides direct, causal evidence that the single dendritic branch can operate as a functional unit in regulating CA3 pyramidal cell plasticity
3D laser-scanning techniques for two-photon calcium imaging of neural network dynamics in vivo
No full textSpatial organization of neural activity in a premotor area involved in song production in songbirds investigated using two-photon calcium imaging
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Characterization of auditory responses recorded in the caudal medial nidopallium in the freely behaving, awake juvenile zebra finch
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