Question

Bidirectional control of neurons with optogenetics:

Select one:

a. None of these choices

b. is not possible as light wavelengths are too similar to differentiate between photosensitive ion channels

c. is possible if the different (inhibitory vs excitatory) photosensitive ion channels are excited by different light wavelengths

d. is possible if one wavelength of light can stimulate and inhibit the same cell

e. is not possible as all photosensitive opsins only activate neuron

Answer 1

Bidirectional control of neurons with optogenetics:

Ans : Option c

is possible if the different (inhibitory vs excitatory) photosensitive ion channels are excited by different light wavelengths.  

Reason : One major advantage of optogenetics is its bidirectional control of the neural activities simultaneously. Optogenetics is a photostimulation technique allows the modulation of the neuronal activity by different wavelengths of light. Opsin proteins are light sensitive and being stimulated by light are expressed in the neurons which are genetically targeted. In addition, appropriate wavelengths of light are needed to expose these neurons. Most commonly used light-sensitive proteins is called channelrhodopsin-2. It is activated by blue light and increases(excites) the electrical activity of neurons. Another protein called halorhodopsin which responds to yellow light and inhibits the firing of neurons. Using light of particular colors onto neurons and other light-sensitive proteins, it is possible to manipulate the activity of large number of neurons. In this way bidirectional control of neurons is done using optogenetics.