Imaging membrane potential changes from dendritic spines using computer-generated holography

Abstract

Electrical properties of neuronal processes are extraordinarily complex, dynamic, and, in the general case, impossible to predict in the absence of detailed measurements. To obtain such a measurement one would, ideally, like to be able to monitor electrical subthreshold events as they travel from synapses on distal dendrites and summate at particular locations to initiate action potentials. It is now possible to carry out these measurements at the scale of individual dendritic spines using voltage imaging. In these measurements, the voltage-sensitive probes can be thought of as transmembrane voltmeters with a linear scale, which directly monitor electrical signals. Grinvald et al. were important early contributors to the methodology of voltage imaging, and they pioneered some of its significant results. We combined voltage imaging and glutamate uncaging using computer-generated holography. The results demonstrated that patterned illumination, by reducing the surface area of illuminated membrane, reduces photodynamic damage. Additionally, region-specific illumination practically eliminated the contamination of optical signals from individual spines by the scattered light from the parent dendrite. Finally, patterned illumination allowed one-photon uncaging of glutamate on multiple spines to be carried out in parallel with voltage imaging from the parent dendrite and neighboring spines.

Recording Spikes Activity in Cultured Hippocampal Neurons Using Flexible or Transparent Graphene Transistors

“…For neuro-rehabilitation process, one needs to stimulate, detect, and track the activity of specific single neurons, as shown for restoring accurate motor motion (Hochberg et al, 2012 ; van den Brand et al, 2012 ) sensory feedbacks (Raspopovic et al, 2014 ) or vision (Hornig et al, 2005 ). To get a closer access to single cells and sub-cellular nanoscale events, optical techniques could be used for instance to manipulate ion channel activity (Szobota and Isacoff, 2010 ), to follow sub-threshold electrical signals along neuronal arborization (Zecevic, 1996 ; Tanese et al, 2017 ) or to track neurotransmitters release (Nicovich et al, 2017 ). Also, electronics devices can provide quantitative information and are still required for long lasting recordings or when interfacing unaltered (genetically or stained) cells.…”

High-Accuracy Detection of Neuronal Ensemble Activity in Two-Photon Functional Microscopy Using Smart Line Scanning

“…Optimization of the fluorescence excitation based on pixelwise SNR may increase the SNR and reduce photodamage in functional voltage and calcium imaging using holographically sculpted light schemes Castanares et al, 2016;Dal Maschio et al, 2010;Foust et al, 2015;Nikolenko et al, 2008;Szabo et al, 2014;Tanese et al, 2017;Yang et al, 2015). SLS is characterized by high SNR and high acquisition rates.…”

A novel multisite confocal system for rapid Ca2+ imaging from submicron structures in brain slices

“…Two‐photon imaging without scanning microscopy is achievable by patterning the light shape to match the imaged structures, that is, by performing 2‐photon holographic illumination . In voltage imaging, signals have been recorded at several kHz from small neuronal compartments using 1‐photon holographic illumination . In contrast, 2‐photon holographic illumination has been set for Ca 2+ imaging in brain slices and in vivo, but without achieving recordings from submicron structures in the kHz range .…”