Spectral color

Transmission photometry for simultaneous optogenetic stimulation and multicolor recording of neuronal activity

Figure 1 All-fiber transmission multi-color optogenetics and registration system. (a) An image of the four branch fiber bundle. (b) Schematic of the common branch of the v four-branch fiber bundle. (c) Block diagram of the multifunction fiber photometry system constructed with the four-branch fiber bundle. (d) Block diagram of the lock-in amplifier for the multi-function fiber photometry system. Credit: Compuscript Ltd.

A new publication from Advances in optoelectronics discusses all-fiber transmission photometry for simultaneous optogenetic stimulation and multicolor neuronal activity recording.

Understanding the structure and function of the brain is the most challenging scientific frontier of the 21st century, as more and more countries participate in the Brain Initiative. Neurons are the basic structural and functional units of the nervous system, and their state of activity is closely related to the physiological functions of the brain. These neurons are interconnected by synapses to perform a specific function, which form neural circuits and then form large-scale brain networks. In brain science research, real-time manipulation and monitoring of cell type-specific neuron activities efficiently with low damage and high spatio-temporal resolution during animal behavior is fundamental work to explore the functional connectivity, information transmission and physiological functions of neural circuits in vivo. , also the basis for the research and treatment of brain diseases.

In the current study of neural circuitry, it is necessary to manipulate and monitor the activity of neurons to explore causal investigations of neural circuitry and behavioral function. Electrophysiological recording and optical sensing are the primary methods for monitoring neuronal activities, while manipulation of neuronal activity is usually achieved through optogenetics. However, prior techniques or systems for optogenetically manipulating or monitoring neural activity in behaving animals are mostly separate and operate independently. In order to study neural activities and behavioral function in neural circuitry and optogenetic manipulation feedback responses, it is important to combine manipulation and monitoring technologies.

Photométrie de transmission pour une stimulation optogénétique simultanée et un enregistrement multicolore de l'activité neuronale

Figure 2 Multicolor recording and optogenetic manipulation of neuronal activities in NAc from a free-moving mouse. (a) Simultaneous recording of dopamine and neuronal Ca dynamics2+ signals in the NAcLat of a freely moving mouse. (b) Simultaneous multicolor recording and optogenetic manipulation of neuronal activities in the NAc of a free-moving mouse. Credit: Compuscript Ltd.

Fiber photometry has become increasingly popular among neuroscientists as a convenient tool for recording genetically defined neuronal populations in behaving animals. The brain includes various neurons, which can transmit information via synaptic junctions or neurotransmitters. The ability to optogenetically manipulate and multi-color monitor neural activity or neurotransmitter activity with cell-type specificity is indispensable for neuroscientists to study neural circuitry in behaving animals. However, it is quite difficult to combine multicolor registration with optogenetics. Since the excitation spectrum of commonly used opsin sensors is close to the emission spectrum of GFP-based and RFP-based GEFIs and considering that it is quite difficult to completely filter optogenetic stimulation light with milliwatt, Obvious optogenetic stimulation artifacts are unavoidable in a weak (pico watt) fluorescent signal during recording. Therefore, traditional optical methods only support monitoring one type of neural activity when applying optogenetic manipulation at present.

The authors of this paper report an all-fiber transmission photometry system for simultaneous optogenetic manipulation and multicolor recording of neuronal activities and neurotransmitter release in a freely moving animal. They first demonstrated successful two-color recording of neuronal Ca2+ dopamine signals and dynamics in the NAc upon delivery of an unexpected reward and simultaneous optogenetic input from the upstream ventral tegmental region, which exist significant differences in the time course of reward or response intensity for optogenetic input.

Using a custom-designed multi-branch fiber bundle, the system can easily deliver all the required light using fiber optics, making the system more robust for use in free-behaving experimental settings and two-color recording. This system has more excellent light transmission performance than the traditional epifluorescence system. Additionally, there was no substantial channel interference or stimulation artifacts for simultaneous multicolor recording of neuronal Ca2+ dynamics of signals and neurotransmitters and precise optogenetic manipulations in freely moving animals.

Better understand the communication between neurons in the brain

More information:
Zhongyang Qi et al, All-fiber transmission photometry for simultaneous optogenetic stimulation and multicolor neuronal activity recording, Advances in optoelectronics (2022). DOI: 10.29026/oea.2022.210081

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Quote: Transmission Photometry for Simultaneous Optogenetic Stimulation and Multicolor Neural Activity Recording (2022, Jun 22) Retrieved Jun 22, 2022 from https://phys.org/news/2022-06-transmission-photometry-simultaneous -optogenetic-multi-color .html

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