High‐Throughput Analysis of Behavior Under the Control of Optogenetics in Caenorhabditis elegans

Abstract

In this unit, we describe an inexpensive and versatile method for optogenetic stimulation of a large population of genetically engineered Caenorhabditis elegans worms while quantitatively analyzing behavior. A custom light‐emitting diode light source is used to deliver blue‐light stimuli, causing direct depolarization of neurons expressing the light‐gated cation channel Channelrhodopsin‐2, which in turn evokes behavioral responses. The behavioral responses are recorded by a high‐throughput machine vision–based tracking system, the Multi‐Worm Tracker, for detailed analysis. This approach allows researchers to bypass technical obstacles to simultaneously deliver uniform stimuli to a large number of freely behaving animals and investigate the neural underpinnings of behavior. © 2018 by John Wiley & Sons, Inc.

Habituation Is More Than Learning to Ignore: Multiple Mechanisms Serve to Facilitate Shifts in Behavioral Strategy

“…Why do animals habituate to nociceptive stimuli that signify danger or potential harm? To answer this question, we recently established a high‐throughput paradigm to assess multiple components of habituation to repeated optogenetic activation of ASH nociceptor neurons in populations of freely behaving animals . Repeated stimulation of the ASH nociceptor neurons led to robust habituation of the duration and latency of a reflexive reversal response (Figure ; habituation is observed as a decrease in reversal duration and increase in reversal latency, respectively) .…”

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“…The optogenetics techniques aids in vivo regulation of neural activity through the use of those specific genetically encoded light-sensitive tools. For example, gated ion channels and calcium indicators are targeted to regulate neural cell excitation and activity respectively [76]. Therefore, the principal optogenetic tools consists of the actuators (opsins) and sensors.…”

Upconversion Nanoparticles–Based Multiplex Protein Activation to Neuron Ablation for Locomotion Regulation

“…To assess whether the UCNPs potentiate cell killing by simultaneously activating both miniSOG and Chrimson under NIR light, we choose C. elegans DVC neuron as an exemplary neuron to perform the experiments, in view that it is a single, unilateral excitatory glutamatergic interneuron that regulates the backward locomotion 8a,16. With representative tail localization of the DVC soma in dorsorectal ganglion, a long ventral neurite outgrows from soma to the nerve ring (NR) in the head ( Figure A).…”