Short infrared laser pulses block action potentials in neurons

Alex J. Walsh, Gleb P. Tolstykh, Stacey L. Martens, Bennett L. Ibey, Hope T. Beier

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Short infrared laser pulses have many physiological effects on cells including the ability to stimulate action potentials in neurons. Here we show that short infrared laser pulses can also reversibly block action potentials. Primary rat hippocampal neurons were transfected with the Optopatch2 plasmid, which contains both a blue-light activated channel rhodopsin (CheRiff) and a red-light fluorescent membrane voltage reporter (QuasAr2). This optogenetic platform allows robust stimulation and recording of action potential activity in neurons in a non-contact, low noise manner. For all experiments, QuasAr2 was imaged continuously on a wide-field fluorescent microscope using a Krypton laser (647 nm) as the excitation source and an EMCCD camera operating at 1000 Hz to collect emitted fluorescence. A co-aligned Argon laser (488 nm, 5 ms at 10Hz) provided activation light for CheRiff. A 200 mm fiber delivered infrared light locally to the target neuron. Reversible action potential block in neurons was observed following a short infrared laser pulse (0.26-0.96 J/cm2; 1.37-5.01 ms; 1869 nm), with the block persisting for more than 1 s with exposures greater than 0.69 J/cm2. Action potential block was sustained for 30 s with the short infrared laser pulsed at 1-7 Hz. Full recovery of neuronal activity was observed 5-30s post-infrared exposure. These results indicate that optogenetics provides a robust platform for the study of action potential block and that short infrared laser pulses can be used for non-contact, reversible action potential block.

Original languageEnglish (US)
Title of host publicationOptogenetics and Optical Manipulation
EditorsE. Duco Jansen, Nitish V. Thakor, Samarendra K. Mohanty, Nitish V. Thakor
ISBN (Electronic)9781510605459
StatePublished - 2017
EventOptogenetics and Optical Manipulation - San Francisco, United States
Duration: Jan 28 2017Jan 29 2017

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


ConferenceOptogenetics and Optical Manipulation
Country/TerritoryUnited States
CitySan Francisco


  • Infrared inhibition
  • Infrared stimulation
  • Neurons
  • Optogenetics

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology Nuclear Medicine and imaging


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