Optogenetics is the combination of genetic and optical methods to achieve gain or loss of function of well-defined events in specific cells of living tissue. This method is based on the modulation of ion channel activity by light.
- The channelrhodopsins-2 (ChR2) is a light-gated ion channel. ChR2 has broad cation conductance, including for Na+, K+, and even Ca2+
- The halorhodopsins (NpHR) is a light-activated ion pump transporting chloride. NpHR control gradients across the cell membrane by transporting chloride ions from the extracellular medium into the cell.
With specific wave lengths (470nm and 589nm), we are able to control which ions pass the membrane. Inserted in neurons, the control of the ChR2 or NpHR allows to activate or inhibit specifically the transfected cell population.
Advantages of this method
- Specific localization, targeting
- Choice of neuronal sub-population
- Specific action
- Modulation : activation with ChRs or inhibition with HRs
With Optogenetics, we are able to study a specific neural network without affecting the operation of neighboring structures. Coupled with electrophysiological recordings, we perform in-vitro but also in-vivo studies, that enable to observe the causal relationship between the activity of targeted brain pathways and behaviors of freely moving animals.