<  Back to the Polytechnique Montréal portal

Repetitive and Retinotopically Restricted Activation of the Dorsal Lateral Geniculate Nucleus with Optogenetics

Alexandre Castonguay, Sébastien Thomas, Frédéric Lesage and Christian Casanova

Article (2014)

[img]
Preview
Published Version
Terms of Use: Creative Commons Attribution.
Download (848kB)
Cite this document: Castonguay, A., Thomas, S., Lesage, F. & Casanova, C. (2014). Repetitive and Retinotopically Restricted Activation of the Dorsal Lateral Geniculate Nucleus with Optogenetics. PloS One, 9(4). doi:10.1371/journal.pone.0094633
Show abstract Hide abstract

Abstract

Optogenetics allows the control of cellular activity using focused delivery of light pulses. In neuroscience, optogenetic protocols have been shown to efficiently inhibit or stimulate neuronal activity with a high temporal resolution. Among the technical challenges associated with the use of optogenetics, one is the ability to target a spatially specific population of neurons in a given brain structure. To address this issue, we developed a side-illuminating optical fiber capable of delivering light to specific sites in a target nucleus with added flexibility through rotation and translation of the fiber and by varying the output light power. The designed optical fiber was tested in vivo in visual structures of ChR2-expressing transgenic mice. To assess the spatial extent of neuronal activity modulation, we took advantage of the hallmark of the visual system: its retinotopic organization. Indeed, the relative position of ganglion cells in the retina is transposed in the cellular topography of both the dorsal lateral geniculate nucleus (LGN) in the thalamus and the primary visual cortex (V1). The optical fiber was inserted in the LGN and by rotating it with a motor, it was possible to sequentially activate different neuronal populations within this structure. The activation of V1 neurons by LGN projections was recorded using intrinsic optical imaging. Increasing light intensity (from 1.4 to 8.9 mW/mm(2)) led to increasing activation surfaces in V1. Optogenetic stimulation of the LGN at different translational and rotational positions was associated with different activation maps in V1. The position and/or orientation of the fiber inevitably varied across experiments, thus limiting the capacity to pool data. With the optogenetic design presented here, we demonstrate for the first time a transitory and spatially-concise activation of a deep neuronal structure. The optogenetic design presented here thus opens a promising avenue for studying the function of deep brain structures.

Uncontrolled Keywords

Animals; Channelrhodopsins; Geniculate Bodies; Mice; Neurons; Optical Fibers; Optogenetics; Photic Stimulation; Visual Cortex; Channelrhodopsins

Open Access document in PolyPublie
Subjects: 1900 Génie biomédical > 1900 Génie biomédical
2500 Génie électrique et électronique > 2500 Génie électrique et électronique
Department: Département de génie électrique
Research Center: Non applicable
Funders: Fonds de Recherche du Québec-Nature et Technologies (FRQ-NT), CRSNG / NSERC, Fonds de Recherche en Santé du Québec (FRSQ), Faculté des Études Supérieures et Postdoctorales-Institut de Génie Biomedical (FESP-IGB)
Grant number: 165075, 194670, 239876
Date Deposited: 22 Nov 2018 15:39
Last Modified: 23 Nov 2018 01:20
PolyPublie URL: https://publications.polymtl.ca/3464/
Document issued by the official publisher
Journal Title: PloS One (vol. 9, no. 4)
Publisher: PloS
Official URL: https://doi.org/10.1371/journal.pone.0094633

Statistics

Total downloads

Downloads per month in the last year

Origin of downloads

Dimensions

Repository Staff Only