Laser speckle contrast reveals cerebral blood flow dynamics evoked by optogenetically controlled neuronal activity

Nan Li, Nitish V. Thakor, Galit Pelled

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

Abstract

As a critical basis of functional brain imaging, neurovascular coupling describes the link between neuronal and hemodynamic changes. The majority of in vivo neurovascular coupling studies was performed by inducing sensory stimulation via afferent inputs. Unfortunately such an approach results in recruiting of multiple types of cells, which confounds the explanation of neuronal roles in stimulus evoked hemodynamic changes. Recently optogenetics has emerged to provide immediate control of neurons by exciting or inhibiting genetically engineered neurons expressing light sensitive proteins. However, there is a need for optical methods capable of imaging the concurrent hemodynamic changes. We utilize laser speckle contrast imaging (LSCI) to obtain high resolution display of cerebral blood flow (CBF) in the vicinity of the targeted neural population. LSCI is a minimally invasive method for imaging CBF in microvessels through thinned skull, and produces images with high spatiotemporal resolution, wide field of view. In the integrated system light sources with different wavelengths and band-passing/blocking filters were used to allow simultaneous optical manipulation of neuronal activities and optical imaging of corresponding CBF. Experimental studies were carried out in a rodent model expressing channalrhodopsin (ChR2) in excitatory neurons in the somatosensory cortex (S1). The results demonstrated significant increases of CBF in response to ChR2 stimulation (exciting neuronal firing) comparable to the CBF response to contralateral forepaw stimulation. The approach promises to be an exciting minimally invasive method to study neurovascular coupling. The complete system provides a novel approach for broad neuroscience applications.

Original languageEnglish (US)
Title of host publicationOptogenetics
Subtitle of host publicationOptical Methods for Cellular Control
DOIs
StatePublished - 2013
Externally publishedYes
EventOptogenetics: Optical Methods for Cellular Control - San Francisco, CA, United States
Duration: Feb 2 2013Feb 3 2013

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume8586
ISSN (Print)1605-7422

Other

OtherOptogenetics: Optical Methods for Cellular Control
Country/TerritoryUnited States
CitySan Francisco, CA
Period2/2/132/3/13

Keywords

  • cerebral blood flow
  • functional brain imaging
  • hemodynamics
  • laser speckle contrast imaging
  • neuronal activity
  • neurovascular coupling
  • optogenetics
  • somatosensory cortex

ASJC Scopus subject areas

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

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