Protocol for minimizing off-target neuronal activation during optical stimulation in vivo

Simon Weiler; Mateo Vélez-Fort; Luke O'Hara; Stephen C Lenzi; Eleni Maria Amaniti; Troy W Margrie

doi:10.1016/j.xpro.2025.104342

Protocol for minimizing off-target neuronal activation during optical stimulation in vivo

STAR Protoc. 2026 Mar 20;7(1):104342. doi: 10.1016/j.xpro.2025.104342. Epub 2026 Jan 19.

Authors

Simon Weiler¹, Mateo Vélez-Fort², Luke O'Hara³, Stephen C Lenzi², Eleni Maria Amaniti³, Troy W Margrie²

Affiliations

¹ Sainsbury Wellcome Centre for Neuronal Circuits and Behavior, University College London, 25 Howland Street, W1T 4JG London, UK; Neurobiological Research Facility, Sainsbury Wellcome Centre, University College London, London, UK. Electronic address: s.weiler@ucl.ac.uk.
² Sainsbury Wellcome Centre for Neuronal Circuits and Behavior, University College London, 25 Howland Street, W1T 4JG London, UK.
³ Neurobiological Research Facility, Sainsbury Wellcome Centre, University College London, London, UK.

Abstract

In vivo optogenetic stimulation is a powerful approach for dissecting neuronal circuit function, yet it can inadvertently lead to activation of endogenous retinal opsins, producing off-target responses that propagate to the cortex and therefore confound experimental interpretation. Here, we present a protocol for optical device implantation in the mouse brain that minimizes light leakage from the implant and skull. We also describe in vivo electrophysiological techniques to assay off-target neuronal activity and ensure its amelioration. For complete details on the use and execution of this protocol, please refer to Weiler et al.¹.

Keywords: Behavior; Neuroscience; Systems biology.

MeSH terms

Animals
Brain / physiology
Mice
Neurons* / physiology
Optogenetics* / methods
Photic Stimulation* / methods