Fast varifocal two-photon microendoscope for imaging neuronal activity in the deep brain

Masaaki Sato, Yuki Motegi, Shogo Yagi, Keiko Gengyo-Ando, Masamichi Ohkura, Junichi Nakai

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


Fluorescence microendoscopy is becoming a promising approach for deep brain imaging, but the current technology for visualizing neurons on a single focal plane limits the experimental efficiency and the pursuit of three-dimensional functional neural circuit architectures. Here we present a novel fast varifocal two-photon microendoscope system equipped with a gradient refractive index (GRIN) lens and an electrically tunable lens (ETL). This microendoscope enables quasi-simultaneous imaging of the neuronal network activity of deep brain areas at multiple focal planes separated by 85-120 µm at a fast scan rate of 7.5-15 frames per second per plane, as demonstrated in calcium imaging of the mouse dorsal CA1 hippocampus and amygdala in vivo.

Original languageEnglish
Article number#297011
Pages (from-to)4049-4060
Number of pages12
JournalBiomedical Optics Express
Issue number9
Publication statusPublished - 2017 Sept 1
Externally publishedYes


  • Endoscopic imaging
  • Fluorescence microscopy
  • Gradient-index lenses
  • Nonlinear microscopy
  • Three-dimensional microscopy

ASJC Scopus subject areas

  • Biotechnology
  • Atomic and Molecular Physics, and Optics


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