1. 12-10-14Optogenetics1 Consolato Sergi, M.D., Ph.D. University of Alberta Hospital

2. 12-10-14Optogenetics2 Signals Single-electrode recordings - Limitations - Intracellular recordings: Only a few neurons and difficult in vivo - Extracellular recordings: No capture information about sub- threshold activity, bias against small cells, poorly defined cell identity 2-deoxyglucose (2DG) imaging (H 3 or C 14 ) - Limitations - Visualization of active brain areas or neurons (post-mortem) - Temporal resolution in min or hrs, not msec. - ‘One-shot’ or ‘two-shot’ ways.

3. PET/fMRI: poor spatio-temporal resolution, hemodynamic transformation, drug receptor activation patterns. Optical Intrinsic Signal Imaging (OISI): hemodynamic response in local capillaries related to local activity. Voltage Sensitive Dye Imaging (VSDI): membrane voltage, mostly sub-threshold activity in neurons and glia cells. 12-10-14Optogenetics3 Signals Cont’

4. 12-10-14Optogenetics4 Optogenetics - Applications Fast depolarization / hyperpolarization of specific cells in living animals Precise control and study of cell population dynamics The identification of causal positive and negative proof with cell specificity Superior targeting & biocompatibility vs. electrical stimulation Visual confirmation of target morphology using fluorescent labeling

5. 12-10-14Optogenetics5 Zhang F, Wang L-P, Boyden ES and Deisseroth K (2006) Channelrhodopsin-2 and optical control of excitable cells. Nature Methods 3(10): 785–792. Chlamydomonas reinhardtii- Wikipedia

6. 12-10-14Optogenetics6 Zhang et al (2007) Multimodal fast optical interrogation of neural circuitry. Nature 446: 633–641. Archaea – Wikipedia

7. 12-10-14Optogenetics7 Light-activated chloride pump Archaebacterium Natronomas pharaonis 22 mW/mm 2 @ 560 +/- 27 nm Inactivates after ~1 sec Halorhodopsin (NpHR)

8. 12-10-14Optogenetics8 Current Status of Applications Some published work in animals (e.g. mouse & zebrafish): Control and mapping of the function of motor cortex Expression restores light responses in retinal ganglion cells Dissection of Parkinson’s circuitry Dissection of role of DA neurons in behavioral conditioning Temporally precise in vivo control of intracellular signaling Potential control of epileptiform activity High-speed mapping of synaptic connectivity Dissection of a behavioral module in the spinal cord

9. 12-10-14Optogenetics9 Take Home Message Optogenetics is Nature Method of the Year 2010 and is going to have more biology applications in the future!!!...but how much is there to be discovered? More Information on Pub Med and on website of Dr. Chou Hung, Ph.D. vision.ym.edu.tw/courses/methods/Presenta tion2.ppt …is it up to us? Thank you