What does two-photon calcium imaging measure?

Abstract. 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.

What is in vivo calcium imaging?

In vivo calcium imaging provides the means to study specific populations of neurons within or across brain regions in freely-behaving animals. Thus, neuroscientists can investigate how neural activity may be linked to aspects of behaviour and cognition, connecting genetically-identified cells with function.

Is calcium imaging electrophysiology?

Calcium imaging using fluorescent protein sensors is a powerful method for recording activity in large neuronal populations[5,8]. In systems neuroscience, cellular calcium imaging fills a complementary role to extracellular electrophysiology.

Why is calcium imaging important?

As mentioned, a major advantage of calcium imaging is that it allows one to record activity from genetically identified neuronal subtypes. Thus, investigators can apply Cre-Lox approaches to record from (or optogenetically manipulate) different subtypes of striatal interneurons selectively using specific promoters.

How calcium imaging is done?

Images are analyzed by measuring fluorescence intensity changes for a single wavelength or two wavelengths expressed as a ratio (ratiometric indicators). If necessary, the derived fluorescence intensities and ratios may be plotted against calibrated values for known Ca2+ levels to measure absolute Ca2+ concentrations.

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 does Gcamp stand for?

Green fluorescent protein. Myosin light-chain kinase.

What is Inscopix?

Inscopix is empowering researchers in academia and industry with a pioneering neural circuit approach, to improve our understanding of the brain and accelerate therapeutic development for neurological and psychiatric disorders.

When was calcium imaging invented?

Scientists at the University of California Berkley developed the first fluorescein-based calcium indicator in the 1980s. This breakthrough meant intracellular calcium could be visualised and quantified.

What does fiber photometry measure?

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.

How does fiber photometry work?

Fiber photometry systems are designed to deliver precise excitation wavelengths of light that are specific to a calcium (i.e. GCaMP) or neurotransmitter indicator (i.e. dLight). This light travels down an optical fiber to a fiber optic that is implanted in the brain region or regions of interest.

Can GCaMP be used to study the brain?

Neuronal activity GCaMP has played a vital role in establishing large-scale neural recordings in animals to investigate how activity patterns in neuronal networks influence behavior. For example, Nguyen et al. (2016) used GCaMP in whole-brain imaging during free movement of C.

Is GCaMP pH sensitive?

GCaMP fluorescence was sensitive to pH, the intensity increasing with increasing pH both in the presence and absence of calcium, but mCherry fluorescence was not affected.

What is Miniscope?

The miniscope, a miniature fluorescence microscope originally pioneered in the lab of Mark Schnitzer at Stanford University [1], is small and portable, making it an ideal tool for studying brain activity in mice engaged in behavior.

What is optogenetics technology?

In 2005, a new technique was created, called optogenetics. This technique uses a combination of light and genetic engineering (changing the genetic information of a living thing by inserting or deleting information in the genetic code) to control the cells of the brain.

How do you measure calcium levels in cells?

Changes in intracellular calcium concentration can be measured using the calcium sensitive fluorescent ratiometric dye fura-2 AM. This method is a high throughput way to measure agonist mediated calcium responses.

Is calcium imaging used in humans?

Calcium imaging, also referred to as calcium mapping, is also used to perform research on myocardial tissue.

How do Geci work?

The genetically encoded calcium indicator (GECI), which binds to calcium ions and emits fluorescence visualizing intracellular calcium concentration, enables detection of in vivo neuronal firing activity. Various GECIs have been developed and can be chosen for diverse purposes.

What is meant by photometry?

Definition of photometry : a branch of science that deals with measurement of the intensity of light also : the practice of using a photometer.