Spatially expandable fiber-based probes as a multifunctional deep brain interface

Abstract

Understanding the cytoarchitecture and wiring of the brain requires improved methods to record and stimulate large groups of neurons with cellular specificity. This requires miniaturized neural interfaces that integrate into brain tissue without altering its properties. Existing neural interface technologies have been shown to provide high-resolution electrophysiological recording with high signal-to-noise ratio. However, with single implantation, the physical properties of these devices limit their access to one, small brain region. To overcome this limitation, we developed a platform that provides three-dimensional coverage of brain tissue through multisite multifunctional fiber-based neural probes guided in a helical scaffold. Chronic recordings from the spatially expandable fiber probes demonstrate the ability of these fiber probes capturing brain activities with a single-unit resolution for long observation times. Furthermore, using Thy1-ChR2-YFP mice we demonstrate the application of our probes in simultaneous recording and optical/chemical modulation of brain activities across distant regions. Similarly, varying electrographic brain activities from different brain regions were detected by our customizable probes in a mouse model of epilepsy, suggesting the potential of using these probes for the investigation of brain disorders such as epilepsy. Ultimately, this technique enables three-dimensional manipulation and mapping of brain activities across distant regions in the deep brain with minimal tissue damage, which can bring new insights for deciphering complex brain functions and dynamics in the near future.

Customizing MRI‐Compatible Multifunctional Neural Interfaces through Fiber Drawing

“…The obtained values are comparable to those of previously reported multifunctional fibers, and indicate that these integrated polymer waveguides are suitable for optogenetic modulation mediated by blue‐light activated opsins in vivo. [ 2,4,26 ] Figure 3e shows typical illumination profiles from the waveguides for fibers produced via iterative and convergence drawing methods immersed in a solution of Fluorescein dye (0.01 m m ).…”

Multimodal neural probes for combined optogenetics and electrophysiology

“…(2015) ; Park et al. (2017) Polymer; Laser: 473 nm Polymer Diameter: ∼85 μm Sti: 1 High throughput TDP Flexibility Rec: 1 Long-term stability Jiang et al. (2020) Polymer; Laser: 473 nm Polymer Diameter: ∼250 μm Sti: 1 High throughput TDP Rec: 5, 7 Large spatial coverage Zou et al.…”

Lighting the Path: Light Delivery Strategies to Activate Photoresponsive Biomaterials In Vivo

“…Microfabrication techniques can nonetheless be used to expose micron‐resolution windows in the cladding material for precise side emission. [ 146 ] All aspects of multimaterial fiber production have been recently reviewed by Sorin and co‐workers. [ 147 ]…”

“…[ 171 ] For a similar purpose, laser‐cut windows (20 μm x 20 μm) were introduced into waveguide claddings to allow side emission at multiple points spanning the cortex, hippocampus, and thalamus of live mice. [ 146 ] Microfabrication approaches to introduce side‐emission domains can involve hours of manual work using expensive equipment, with the cost per fiber estimated at USD 1000. [ 171 ]…”