Optogenetics

Optogenetics

Reviewed by Faisal Zaidi

A method that makes chosen cells respond to light so that researchers can switch them on at will.

What it is

In the 2012 engram study, dentate gyrus neurons active during fear learning were tagged with a light-sensitive protein, and light on those cells in a different setting made the mice freeze more. Control groups with a marker protein instead, or without fear conditioning, did not freeze.

In effect

The article on what an engram is uses it to show how tagged memory cells were reactivated in mice.

What it does not say

It is a laboratory method used in mice, and the 2012 study shows that light on tagged cells led to freezing in a new setting. It does not show that memories can be switched on in people.

Sources

  1. Liu, X., Ramirez, S., Pang, P. T., Puryear, C. B., Govindarajan, A., Deisseroth, K., & Tonegawa, S. (2012). Optogenetic stimulation of a hippocampal engram activates fear memory recall. Nature, 484(7394), 381-385.
  2. Ramirez, S., Liu, X., Lin, P.-A., Suh, J., Pignatelli, M., Redondo, R. L., Ryan, T. J., & Tonegawa, S. (2013). Creating a false memory in the hippocampus. Science, 341(6144), 387-391.