Photostimulation

Additionally, photostimulation may be used for the mapping of neuronal connections between different areas of the brain by “uncaging” signaling biomolecules with light.

The other major photostimulation method is the use of light to activate a light-sensitive protein such as rhodopsin, which can then excite the cell expressing the opsin.

Well-known scientific advancements such as the use of electrical stimuli and electrodes have succeeded in neural activation but fail to achieve the aforementioned goal because of their imprecision and inability to distinguish between different cell types.

[3] For instance, the technique can be applied to channelrhodopsin cation channels to initiate neuronal depolarization and eventually activation upon illumination.

Natural and abundant in microbials, rhodopsins—including bacteriorhodopsin, halorhodopsin and channelrhodopsin—each have a different characteristic action spectrum which describes the set of colors and wavelengths that they respond to and are driven to function by.

[4] It has been shown that channelrhodopsin-2, a monolithic protein containing a light sensor and a cation channel, provides electrical stimulation of appropriate speed and magnitude to activate neuronal spike firing.

In most cases, photo-uncaging is the technique revealing the active region of a compound by the process of photolysis of the shielding molecule (‘cage’).

Two researchers, Walther Stoeckenius and Dieter Oesterhelt discovered an ion pump known as bacteriorhodopsin which functions in the presence of light in 1971.

[8] Photostimulation is notable for its temporal precision, which may be used to obtain an accurate starting time of activation of caged effectors.

Calcium ions play an important signaling role, and controlling their release with caged channels has been extensively studied.

Optogenetics has the potential to facilitate the manipulation and targeting of specific cell types or neural circuits, characteristics that are lacking in current brain stimulation techniques like DBS.

At this point, the use of optogenetics in treating neural diseases has only been practically implemented in the field of neurobiology to reveal more about the mechanisms of specific disorders.