Question

The principle that underlies genetically encoded optical recording methods is that:

Select one:

a. Some ion channels can be ‘gated’ by light (e.g. Channelrhodopsin2), allowing investigators to stimulate neurons using specific wavelengths of light

b. The electrons emitted during action potential generation are visible to an electron microscope, and can therefore be imaged in real-time

c. Changes in intracellular calcium concentration during action potential generation subtly change the 3D structure of genetically engineered fluorescent proteins, changing the intensity of emitted light

d. Electrical fields generated by neuronal activity distort light, so ‘red shifting’ of incident light can be interpreted as evidence of neuronal activity

e. Active neurons draw more blood to them; discolouration of brain tissue by increased blood flow denotes activity of neurons in that region

Answer 1

Genetic encoding optical recording tells us about the order of the nucleotides that make up the genetic code and proteins recorded under the influence of a focused laser beam. In simple language a great tool for imaging the function of organ and specially brain. Genetic targetting enables the measuring of neuronal activities. Genetically encoded reporters are typically derivatives of ion channels or expressed proteins so during neural activity the major class of genetic encoded reporters sense calcium or voltage. So the answer will be (c)