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Tag Archives: Calcium Imaging
Large-scale calcium imaging & noise levels
Calcium imaging based on two-photon scanning microscopy is a standard method to record the activity of neurons in the living brain. Due to the point-scanning approach, sampling speed is limited and the dwell time on a single neuron reduces with … Continue reading
Posted in Calcium Imaging, Data analysis, Imaging, Microscopy, Neuronal activity
Tagged Calcium Imaging, Data analysis, Microscopy, photons, Scanning
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5 reasons why to use Cascade for spike inference
Our paper on A database and deep learning toolbox for noise-optimized, generalized spike inference from calcium imaging is out now in Nature Neuroscience. It consists of a large and diverse ground truth database with simultaneous calcium imaging and juxtacellular recordings … Continue reading
Fast scanning, triplet states and photon yield
In point-scanning microscopy like two-photon or confocal microscopy, a focused laser beam is scanned across the field of view and thereby sequentially recovers an image of the object. In this blog post, I will discuss the idea that scanning faster … Continue reading
Posted in Calcium Imaging, Imaging, Microscopy, Neuronal activity
Tagged Calcium Imaging, Microscopy, photons, Scanning, zebrafish
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Online spike rate inference with Cascade
To infer spike rates from calcium imaging data for a time point t, knowledge about the calcium signal both before and after time t is required. Our algorithm Cascade (Github) uses by default a window that is symmetric in time … Continue reading
Temporal dispersion of spike rates from deconvolved calcium imaging data
On Twitter, Richie Hakim asked whether the toolbox Cascade for spike inference (preprint, Github) induces temporal dispersion of the predicted spiking activity compared to ground truth. This kind of temporal dispersion had been observed in a study from last year … Continue reading
Simultaneous calcium imaging and extracellular recording from the same neuron
Calcium imaging is a powerful method to record from many neurons simultaneously. But what do the recorded signals really mean? This question can only be properly addressed by experiments which record both calcium signals and action potentials from the same … Continue reading
Discrepancies between calcium imaging and extracellular ephys recordings
To record the activity from a population of neurons, calcium imaging and extracellular recordings with small electrodes are the two most widely used methods that are still able to disentangle the contributions from single units. Here, I would like to … Continue reading
How well do CNNs for spike detection generalize to unseen datasets?
Some time ago, Stephan Gerhard and I have used a convolutional neural network (CNN) to detect neuronal spikes from calcium imaging data. (I have mentioned this before, here, here, and on Github.) This method is covered by the spikefinder paper … Continue reading
Preamplifier bandwidth & two ways of counting photons
For two-photon point scanning microscopy, the excitation laser is typically pulsing at a repetition rate of 80 MHz, that is one pulse each 12.5 ns. To avoid aliasing, it was suggested to synchronize the sampling clock to laser pulses. For this, it is important … Continue reading
Posted in Calcium Imaging, Imaging, Microscopy
Tagged Calcium Imaging, laser scanning microscopy, Microscopy, Scanning
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Whole-cell patch clamp, part 1: introductory reading
Ever since I my interested in neuroscience become more serious, I was fascinated by the patch clamp technique, especially applied for the whole cell. Calcium imaging or multi-channel electrophysiology (recent review) is the way to go in order to get an idea what … Continue reading
Posted in electrophysiology, Microscopy, zebrafish
Tagged Calcium Imaging, electrophysiology, patch clamp, zebrafish
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A blog about neurophysiology 