Optogenetic patterning of whisker-barrel cortical system in transgenic rat expressing channelrhodopsin-2

PLoS One. 2014 Apr 2;9(4):e93706. doi: 10.1371/journal.pone.0093706. eCollection 2014.

Abstract

The rodent whisker-barrel system has been an ideal model for studying somatosensory representations in the cortex. However, it remains a challenge to experimentally stimulate whiskers with a given pattern under spatiotemporal precision. Recently the optogenetic manipulation of neuronal activity has made possible the analysis of the neuronal network with precise spatiotemporal resolution. Here we identified the selective expression of channelrhodopsin-2 (ChR2), an algal light-driven cation channel, in the large mechanoreceptive neurons in the trigeminal ganglion (TG) as well as their peripheral nerve endings innervating the whisker follicles of a transgenic rat. The spatiotemporal pattern of whisker irradiation thus produced a barrel-cortical response with a specific spatiotemporal pattern as evidenced by electrophysiological and functional MRI (fMRI) studies. Our methods of generating an optogenetic tactile pattern (OTP) can be expected to facilitate studies on how the spatiotemporal pattern of touch is represented in the somatosensory cortex, as Hubel and Wiesel did in the visual cortex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Channelrhodopsins
  • Magnetic Resonance Imaging
  • Optogenetics*
  • Rats
  • Rats, Transgenic

Substances

  • Channelrhodopsins

Grant support

This work was supported by a Grant-in-Aid for Scientific Research on Innovative Areas "Mesoscopic Neurocircuitry" (No. 23115501) of the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan, Grant-in Aid for Scientific Research (No. 25115701) and Grant-in-Aid for challenging Exploratory Research (No. 25670103) of Japan Society for the Promotion of Science (JSPS), the Program for Promotion of Fundamental Studies in Health Sciences of the National Institute of Biomedical Innovation (NIBIO) and Research Foundation for Opto-Science and Technology. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.