PLoS ONE (Jan 2020)

Auditory cortical activity elicited by infrared laser irradiation from the outer ear in Mongolian gerbils.

  • Yuta Tamai,
  • Yuki Ito,
  • Takafumi Furuyama,
  • Kensuke Horinouchi,
  • Nagomi Murashima,
  • Itsuki Michimoto,
  • Ryuichi Hishida,
  • Katsuei Shibuki,
  • Shizuko Hiryu,
  • Kohta I Kobayasi

DOI
https://doi.org/10.1371/journal.pone.0240227
Journal volume & issue
Vol. 15, no. 10
p. e0240227

Abstract

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Infrared neural stimulation has been studied for its potential to replace an electrical stimulation of a cochlear implant. No studies, however, revealed how the technic reliably evoke auditory cortical activities. This research investigated the effects of cochlear laser stimulation from the outer ear on auditory cortex using brain imaging of activity-dependent changes in mitochondrial flavoprotein fluorescence signal. An optic fiber was inserted into the gerbil's ear canal to stimulate the lateral side of the cochlea with an infrared laser. Laser stimulation was found to activate the identified primary auditory cortex. In addition, the temporal profile of the laser-evoked responses was comparable to that of the auditory responses. Our results indicate that infrared laser irradiation from the outer ear has the capacity to evoke, and possibly manipulate, the neural activities of the auditory cortex and may substitute for the present cochlear implants in future.