What does calcium imaging tell you?
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).
Can calcium imaging be used in humans?
Calcium is a critical signaling molecule for most cells, and it is especially important in neurons. Imaging calcium in brain cells can reveal how neurons communicate with each other; however, current imaging techniques can only penetrate a few millimeters into the brain.
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.
What is neuronal calcium imaging?
Calcium imaging enables researchers to investigate the highly synchronous network activity of neurons. Here, neuroscientists used calcium imaging to assess the fluorescent signal of 40 neurons. With this information, network properties such as signal propagation and neural correlations can be determined.
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.
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.
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).
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.
How do thapsigargin and calcium ionophore A23187 mediate endoplasmic stress?
Thapsigargin and the calcium ionophore A23187 mediate ER-stress through depletion of calcium from the ER lumen and consecutive accumulation of unfolded or misfolded proteins in the ER. Thapsigargin specifically inhibits the ER Ca 2+ -ATPase, while the calcium ionophore A23187 mediates the efflux of Ca 2+ from the endoplasmic lumen.
How does thapsigargin inhibit ER Ca2+?
Thapsigargin inhibits ER Ca2+ -dependent ATPase, leading to a depletion of ER Ca 2+ storage, which, in turn, decreases the activity of Ca-dependent chaperones leading to an increase in unfolded proteins and the corresponding induction of UPR signaling ( Denmeade and Isaacs, 2005 ).
What is the mechanism of action of thapsigargin?
Thapsigargin is a specific inhibitor of the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA). Treatment with thapsigargin results in a decrease in ER calcium levels. When calcium levels are lowered in the ER, the calcium-dependent ER chaperones, such as calnexin, lose their chaperone activity, leading to the accumulation of unfolded proteins.
How is Ca2+ uptake into the endoplasmic reticulum mediated by thapsigargin?
1 Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA. Ca2+ uptake into the endoplasmic reticulum (ER) is mediated by Ca2+ ATPase isoforms, which are all selectively inhibited by nanomolar concentrations of thapsigargin.