In vivo calcium recordings and channelrhodopsin-2 activation through an optical fiber

Cold Spring Harb Protoc. 2014 Oct 1;2014(10):pdb.prot084145. doi: 10.1101/pdb.prot084145.


We describe here an approach for the fluorometric monitoring of population activity in neurons in live mice combined with the activation of optogenetic actuators in vivo. In this protocol, a thin multimode fiber, which is used for both delivering excitation light and collecting emitted fluorescence signals, is inserted into the skull of a mouse. When combined with multicell bolus loading of Ca(2+) indicators, this optical fiber and its associated fluorescence detection system can be used for the in vivo recording of brain Ca(2+) signals from a local cluster of coactive neurons. The fiber can also be used for the optogenetic stimulation of light-activated ion channels, such as channelrhodopsin-2, allowing the monitoring of local calcium signals evoked by optogenetic stimulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / metabolism*
  • Calcium / metabolism*
  • Channelrhodopsins
  • Fiber Optic Technology* / instrumentation
  • Fiber Optic Technology* / methods
  • Mice
  • Mice, Transgenic
  • Optogenetics


  • Channelrhodopsins
  • Calcium