How does calcium imaging work?
Calcium imaging enables neuroscientists to visualize the activity of hundreds of individual neurons simultaneously using fluorescent activity sensors. Changes in fluorescence indicate fluctuations in intracellular calcium, which is an indirect indicator of neural activity (Grienberger & Konnerth, 2012).
What is in vivo fiber photometry?
In vivo fiber photometry is a powerful technique to analyze the dynamics of population neurons during functional study of neuroscience.
What is GCaMP6f?
GCaMP6f is the fastest genetically-encoded calcium indicator for cytoplasmic free calcium in neurons, with sensitivity comparable to OGB1-AM (Fig. 1d-g).
How does GCaMP report on calcium levels?
When bound to Ca2+, GCaMP fluoresces green with a peak excitation wavelength of 480 nm and a peak emission wavelength of 510 nm. It is used in biological research to measure intracellular Ca2+ levels both in vitro and in vivo using virally transfected or transgenic cell and animal lines.
Why is calcium imaging important?
Calcium ions generate versatile intracellular signals that control key functions in all types of neurons. Imaging calcium in neurons is particularly important because calcium signals exert their highly specific functions in well-defined cellular subcompartments.
What is 2 photon calcium imaging?
Two-photon calcium imaging is a powerful means for monitoring the activity of distinct neurons in brain tissue in vivo. In the mammalian brain, such imaging studies have been restricted largely to calcium recordings from neurons that were individually dye-loaded through microelectrodes.
Is fiber a photometry imaging?
Fiber photometry is an imaging method that enables scientists to image population-level neural activity in the brain of freely-behaving animals.
How does fiber photometry work?
Fiber photometry, a technique related to optogenetics, provides detailed insight into the activity and behavior of neuronal populations. This technique stimulates neurons with light and measures fluorescence signals that correspond to calcium dynamics.
What is iGluSnFR?
The iGluSnFR construct provides an improved means to map excitatory synaptic activity in the brain directly and will complement existing imaging methods for studies of neural activity and signaling events.
Is GCaMP ratiometric?
We report on GCaMP-Rs, a new family of genetically encoded ratiometric calcium indicators that extend the virtues of the GCaMP proteins to ratiometric measurements. We have engineered a tandem construct of calcium-dependent GCaMP and calcium-independent mCherry fluorescent proteins.
How does the calcium indicator dye work?
The binding of calcium to the dye alters its fluorescence properties, which provides a way to quantify the changes in calcium concentration, which is represented here by the difference in fluorescent intensity emitted by this neuron at two different excitation wavelengths.
How does in vivo calcium imaging work?
Calcium imaging measures changes in intracellular calcium concentrations, providing an indirect indicator of neural activity. Compared to changes in voltage, fluctuations in calcium levels are much slower and may reflect a summation of signals rather than individual spikes (Wei et al. 2019).