What is a GCaMP?

What is a GCaMP?

GCaMP is a genetically encoded calcium indicator (GECI) initially developed in 2001 by Junichi Nakai. It is a synthetic fusion of green fluorescent protein (GFP), calmodulin (CaM), and M13, a peptide sequence from myosin light-chain kinase.

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 are genetically encoded calcium indicators?

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 iGluSnFR?

iGluSnFR was developed in 2013 by Loren Looger’s lab at HHMI Janelia Research Campus to give researchers the ability to monitor glutamate release from neurons and other brain cells in vivo. Glutamate plays a variety of roles in synaptic communication and can trigger other forms of neuronal signaling and regulation.

What are GECIs?

GECIs measure calcium, the key signal molecule underlying cell functions such as heart, vessel, and airway contraction, lung secretion, autonomic neurotransmission, and immunocyte function. GCaMP, originally developed by Junichi Nakai is an example of a GECI.

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 calcium sensors?

The Ca2+ sensors used to transduce changes in cellular Ca2+ into changes in fluorescence must bind Ca2+ to produce a signal. By binding Ca2+, these sensors can act as buffers, often reducing the magnitude of a Ca2+ change several fold and producing a proportional slowing of the rates of change.

How does Fura 2 am work?

Fura-2AM is a ratiometric dye. It can be excited by two wavelengths, 340 nm for calcium bound and 380 nm for unbound. Irrespective of the excitation wavelength, the dye will emit at 510 nm wavelength. The ratio of 340/380 is usually calculated for normalizing unequal loading of the dye into the cells.

What is a ratiometric dye?

Ratiometric dyes are a subcategory of fluorescent dyes that are widely used to quantitatively measure intracellular calcium concentrations. They are unique in that they are dual-wavelength dyes that exhibit two peak excitation wavelengths when either bound to or free of Ca2+.

What is in vivo electrophysiology?

In vivo electrophysiology measures neuronal activity in the brain as either local field potentials or single units. Brain regions are targeted precisely, and the effect of test compounds can be assessed following either systemic delivery or by direct application using iontophoresis.

What is Electrophysiology in neuroscience?

Electrophysiology is the branch of neuroscience that explores the electrical activity of living neurons and investigates the molecular and cellular processes that govern their signaling.

What does glutamate do for your brain?

Glutamate is the principal excitatory neurotransmitter in the CNS. It plays a central role in fundamental brain functions, including synaptic plasticity (important for learning and memory), formation of neural networks during development and repair of the CNS.