Shedding light on neurons: optical approaches for neuromodulation

Abstract

Today's optical neuromodulation techniques are rapidly evolving, benefiting from advances in photonics, genetics, and materials science. In this review, we provide an up-to-date overview of the latest optical approaches for neuromodulation. We begin with the physical principles and constraints underlying the interaction between light and neural tissue. We then present advances in optical neurotechnologies in seven modules: conventional optical fibers, multifunctional fibers, optical waveguides, light-emitting diodes, upconversion nanoparticles, optical neuromodulation based on secondary effects of light, and unconventional light sources facilitated by ultrasound and magnetic fields. We conclude our review with an outlook on new methods and mechanisms to afford optical neuromodulation with minimal invasiveness and footprints.

Programmable, Spatiotemporal Control of Colloidal Motion Waves via Structured Light

“…In addition, there is a pressing need for coordinating a group of autonomously moving micro-/nanorobots in a complex environment such as human bodies. , A key requirement in this application is fast information relay through a large group of microrobots, without distortion, and preferably along a winding, branched path. Recent studies have demonstrated how information can be relayed among microrobots through hydrodynamic interactions or chemical signals. , The colloidal wave studied here is another biomimetic strategy to achieve this goal, by illuminating in vivo a microrobot swarm with programmable structured light that adapts to a changing environment, possibly by flexible optical fibers. , Figure and Video S12 demonstrate a very preliminary example. Previously, we have discovered that the chemicals released by an oscillating silver particle can activate nonoscillatory bimetallic microrods into a pulse of directional motion .…”

“…25,80 The colloidal wave studied here is another biomimetic strategy to achieve this goal, 30 by illuminating in vivo a microrobot swarm with programmable structured light that adapts to a changing environment, possibly by flexible optical fibers. 81,82 Figure 10 and Video S12 demonstrate a very preliminary example. Previously, we have discovered that the chemicals released by an oscillating silver particle can activate nonoscillatory bimetallic microrods into a pulse of directional motion.…”

Protocol for wireless deep brain stimulation in freely behaving mice with infrared light

“…Neuromodulation techniques are powerful tools for dissecting complex neural circuitry and potentially treating neurological disorders ( Fenno et al., 2011 ; Jiang et al., 2022 ; Montgomery et al., 2015 ; Tsai et al., 2009 ). Current popular electrical and optical neuromodulation techniques, however, require invasive implantation of the stimulation electrode or optical fiber, which inevitably leads to acute brain damage, chronic gliosis, and physical tethering.…”

Opsin-free optical neuromodulation and electrophysiology enabled by a soft monolithic infrared multifunctional neural interface

“…Precise and reliable tools to modulate and monitor neuronal activities are essential elements within this frame [2,3]. With the discovery of optogenetics [4,5] and infrared neuromodulation (INM) [6,7], light-induced control of neurons with high spatiotemporal resolution became one of the most powerful tools in neuroscience [8]. Therefore, new milestones have been set within the biotechnology community for novel devices able to deliver light in localized brain regions across the full electromagnetic spectrum [9][10][11].…”

“…While optogenetics is arguably one of the most powerful methods for high-resolution modulation of neural populations, the necessity for genetic manipulation of the targeted cells adds further complexity to the process by requiring either the injection of a viral vector or the use of genetically modified animals [8, 15]. INM has thus attracted significant attention as a viable transgene-free alternative to optogenetics.…”