Concave-shaped transparent electrode to simultaneously monitor electrical activity from multiple sites within the optical sampling area of the intact rat cerebral cortex

  • Noriyuki HamaEmail author
  • Minako Kawai
  • Shin-ichi Ito
  • Yuki Yoshida
  • Yasuhisa Fujita
  • Akihiko Hirota
Technical Note


We have developed a concave-shaped transparent electrode unit that enables the placement of several electrodes within the optical sampling area on the spherical surface of the rat brain. This concave-shaped transparent electrode unit consists of an insulator base (a plano-concave lens) and a gallium-doped zinc oxide film that is a transparent conductor coating the base. Most of the unit is wrapped in an insulator film made of silicon dioxide, and the few areas left unwrapped act as electrodes. In the study reported here this newly developed transparent electrode unit worked well within the optical detection area without affecting optical recording. We applied this unit to our multiple-site optical recording system for membrane potential in order to eliminate pulsation artifacts and succeeded in optically recording spontaneous neural activity, including small changes in membrane potential, in the cerebral cortex in a single-sweep recording.


Transparent electrode Spontaneous neural activity Single-sweep optical recording Epifluorescence optics Cerebral cortex Voltage-sensitive dye 



We are grateful to Dr. Kohtaro Kamino for critically reading the manuscript and providing constructive comments. This work was partly supported by KAKENHI (21650095) from the Japan Society for the Promotion of Science.


  1. 1.
    Cohen LB, Salzberg BM (1978) Optical measurement of membrane potential. Rev Physiol Biochem Pharmacol 85:33–88Google Scholar
  2. 2.
    Grinvald A, Lieke E, Frostig RD, Gilbert CD, Wiesel TN (1986) Functional architecture of cortex revealed by optical imaging of intrinsic signals. Nature 324:361–364CrossRefGoogle Scholar
  3. 3.
    Tsien RY (1989) Fluorescent probes of cell signaling. Annu Rev Neurosci 12:227–253CrossRefGoogle Scholar
  4. 4.
    Sato K, Momose-Sato Y (2017) Functiogenesis of the embryonic central nervous system revealed by optical recording with a voltage-sensitive dye. J Physiol Sci 67:107–119CrossRefGoogle Scholar
  5. 5.
    Kawai M, Hama N, Ito S, Hirota A (2014) Improvement of the optical imaging technique for intact rat brain using a plano-concave lens. J Physiol Sci 64:445–449CrossRefGoogle Scholar
  6. 6.
    Hirota A, Sato K, Momose-Sato Y, Sakai T, Kamino K (1995) A new simultaneous 1020-site optical recording system for monitoring neural activity using voltage-sensitive dyes. J Neurosci Methods 56:187–194CrossRefGoogle Scholar
  7. 7.
    Hirota A, Ito S (2006) A long-time, high spatiotemporal resolution optical recording system for membrane potential activity via real-time writing to the hard disk. J Physiol Sci 56:263–266CrossRefGoogle Scholar
  8. 8.
    Hama N, Ito S, Hirota A (2010) An improved multiple-site optical membrane potential-recording system to obtain high-quality single sweep signals in intact rat cerebral cortex. J Neurosci Methods 194:73–80CrossRefGoogle Scholar
  9. 9.
    Hama N, Kawai M, Ito S, Hirota A (2018) Optical study of interactions among propagation waves of neural excitation in the rat somatosensory cortex evoked by forelimb and hindlimb stimuli. J Neurophysiol 119:1934–1946CrossRefGoogle Scholar
  10. 10.
    Schwartz AB, Cui XT, Weber DJ, Moran DW (2006) Brain-controlled interfaces: movement restoration with neural prosthetics. Neuron 52:205–220CrossRefGoogle Scholar
  11. 11.
    Towe A (1973) Sampling single neuron activity. In: Thompson RF, Patterson MM (eds) Bioelectric recording technique Part A Cellular processes and brain potentials. Academic Press, New YorkGoogle Scholar
  12. 12.
    Paxinos G, Watson C, Carrive P, Kirkcaldie M, Ashwell K (2009) Chemoarchitectonic atlas of the rat brain, 2nd edn. Academic Press, AmsterdamGoogle Scholar
  13. 13.
    Yoshida Y, Tanaka S, Hiromitsu I, Fujita Y, Yoshino K (2008) Ga-doped ZnO film as a transparent electrode for phthalocyanine/perylene heterojunction solar cell. Jpn J Appl Phys 47:867–871CrossRefGoogle Scholar
  14. 14.
    Hama N, Ito S, Hirota A (2015) Optical imaging of the propagation patterns of neural responses in the rat sensory cortex: comparison under two different anesthetic conditions. Neuroscience 284:125–133CrossRefGoogle Scholar
  15. 15.
    Gao X, Xu W, Wang Z, Takagaki K, Li B, Wu J (2012) Interactions between two propagating waves in rat visual cortex. Neuroscience 216:57–69CrossRefPubMedCentralGoogle Scholar
  16. 16.
    Kuhn B, Denk W, Bruno RM (2008) In vivo two-photon voltage-sensitive dye imaging reveals top-down control of cortical layers 1 and 2 during wakefulness. Proc Natl Acad Sci USA 105:7588–7593CrossRefGoogle Scholar
  17. 17.
    Kunori N, Takashima I (2015) A transparent epidural electrode array for use in conjunction with optical imaging. J Neurosci Methods 251:130–137CrossRefGoogle Scholar
  18. 18.
    Ledochowitsch P, Olivero E, Blanche T, Maharbiz MM (2011) A transparent µECoG array for simultaneous recording and optogenetic stimulation. Conf Proc IEEE Eng Med Biol Soc 2011:2937–2940Google Scholar
  19. 19.
    Park DW, Schendel AA, Mikae S, Brodnick SK, Richner TJ, Ness JP, Hayat MR, Atry F, Frye ST, Pashaie R, Thongpang S, Ma Z, Williams JC (2014) Graphene-based carbon-layered electrode array technology for neural imaging and optogenetic applications. Nat Commun 5:5258CrossRefPubMedCentralGoogle Scholar
  20. 20.
    Rubehn B, Bosman C, Oostenveld R, Fries P, Stieglitz T (2009) A mems-based flexible multichannel ECoG-electrode array. J Neural Eng 6:036003CrossRefGoogle Scholar

Copyright information

© The Physiological Society of Japan 2019

Authors and Affiliations

  • Noriyuki Hama
    • 1
    Email author
  • Minako Kawai
    • 1
  • Shin-ichi Ito
    • 1
  • Yuki Yoshida
    • 2
  • Yasuhisa Fujita
    • 2
  • Akihiko Hirota
    • 1
  1. 1.Department of Neural and Muscular PhysiologyShimane University School of MedicineIzumoJapan
  2. 2.Interdisciplinary Graduate School of Science and EngineeringShimane UniversityMatsueJapan

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