In a recent bioRxiv preprint, Scott Owen and Anatol Kreitzer share PhotometryBox, an open-source solution for electronic control of fiber-based fluorescence measurements.
Fluorescence measurements from deep-brain structures through optical fibers (fiber photometry) represent a versatile, powerful, and rapidly growing neuroscience technique. A typical fiber photometry system consists of three
parts: (1) an implant with an optical fiber that is cemented to the skull, (2) optical components for generation of fluorescence excitation light and detection of emission light, and (3) electronic components for controlling light sources and acquiring signals. Excellent technical solutions are available for implants and optical components; however, currently available electronic control systems are not optimized for these experiments. The most commonly used electronic components are either over-engineered or unnecessarily inflexible. To address these issues, Owen et al have developed an open-source, low-cost solution for the electronic components. This system is based on a programmable microcontroller (MBED LPC1768) and can be assembled in ~1 hour (less than a day for an inexperienced user with limited soldering experience). The total estimated cost is about $650, less than one tenth the price of the most commonly used commercially available systems.
The design, development and implementation of this project is described in a manuscript now available on bioRxiv, while details regarding parts, construction and use are available on Hackaday.
In a 2014 PLoS ONE article, Shaun R. Patel and colleagues share their design for PriED, an easy to assemble modular micro-drive system for acute primate neurophysiology.
Electrode micro-drives are a great tool that allow for independent positioning of multiple electrodes in primate neurophysiology, however, commercially available micro-drives are often expensive. Printed Electronic Device (PriED) is designed to advance existing micro-drive technology while staying inexpensive and requiring minimal skill and effort to assemble. The device combines 3D printed parts and affordable, commercially available steel and brass components which can then be controlled manually, or automatically with the addition of an optional motor. Using 3D printing technology researchers have the flexibility to be able to modify part designs and create custom solutions to specific recording needs. A public repository of drive designs has been made available where researchers can download PriED components to print for assembly. Additionally, researchers can upload modified designs with annotations for others to use. PriED is an innovative, inexpensive, and user friendly micro-drive solution for flexible multi-site cortical and subcortical recordings in non-human primates.
OpenBehavior has been covering open-source neuroscience projects for a few years, and we are always thrilled to see projects that are well documented and can be easily reproduced by others. To further this goal, we have formed a collaboration with Hackaday.io, who have provided a home for OpenBehavior on their site. This can be found at: https://hackaday.io/OpenBehavior, where we currently have 36 projects listed ranging from electrophysiology to robotics to behavior. We are excited about this collaboration because it provides a straightforward way for people to document their projects with instructions, videos, images, data, etc. Check it out, see what’s there, and if you want your project linked to the OpenBehavior page simply tag it as “OPENBEHAVIOR” or drop us a line at the Hackaday page.
Note: This collaboration between OpenBehavior and Hackaday.io is completely non-commercial, meaning that we don’t pay Hackaday.io for anything, nor do we receive any payments from them. It’s simply a way to further our goal of promoting open-source neuroscience tools and their goal of growing their science and engineering community.
In a special issue of Journal of Neural Engineering, Dominique Martinez and colleagues their share design for NeRD, an open source neural recording device for wireless transmission of local field potential (LFP) data in in freely-behaving animals.
Electrophysiological recording of local field potentials in freely-behaving animals is a prominent tool used by researchers for assessing the neural basis of behavior. When performing these recordings, cables are commonly used to transmit data to the recording equipment, which tethers the animals and can interfere with natural behavior. Wireless transmission of LFP data has the advantage of removing the cable between the animal and the recording equipment, but is hampered by the large number of data to be transmitted at a relatively high rate.
To reduce transmission bandwidth, Martinez et al. propose an encoder/decoder algorithm based on adaptive non-uniform quantization. As proof-of- concept, they developed a NeRD prototype that digitally transmits eight channels encoded at 10 kHz with 2 bits per sample. This lightweight device occupies a small volume and is powered with a small battery allowing for 2h 40min of autonomy. The power dissipation is 59.4 mW for a communication range of 8 m and transmission losses below 0.1%. The small weight and low power consumption offer the possibility of mounting the entire device on the head of a rodent without resorting to a separate head-stage and battery backpack. The use of adaptive quantization in the wireless transmitting neural implant allows for lower transmission bandwidths, preservation of high signal fidelity, and preservation of fundamental frequencies in LFPs from a compact and lightweight device.
In Current Protocols in Neuroscience, Alexander Jacob and colleagues share their open source compact head-mounted endoscope (CHEndoscope) for imaging in the awake behaving mouse.
This miniature microscope device is designed to provide an accessible set of calcium imaging tools to investigate the relationship between behavior and population neuronal activity for in vivo rodents. The CHEndoscope is open source, flexible, and consists of only 4 plastic components that can be 3D printed. It uses an implanted gradient index (GRIN) lens in conjunction with the genetically encoded calcium indicator GCaMP6 to image calcium transients from hundreds of neurons simultaneously in awake behaving mice. The aim of the open source model is to provide an accessible and flexible set of calcium imaging tools for the neuroscience research community. The linked article describes in depth the assembly, surgical implantation, data collection, and processing of calcium signals using the CHEndoscope.
In a recent preprint on BioRxiv, Alessio Buccino and colleagues from the University of Oslo provide a step-by-step guide for setting up an open source, low cost, and adaptable system for combined behavioral tracking, electrophysiology, and closed-loop stimulation. Their setup integrates Bonsai and Open Ephys with multiple modules they have developed for robust real-time tracking and behavior-based closed-loop stimulation. In the preprint, they describe using the system to record place cell activity in the hippocampus and medial entorhinal cortex, and present a case where they used the system for closed-loop optogenetic stimulation of grid cells in the entorhinal cortex as examples of what the system is capable of. Expanding the Open Ephys system to include animal tracking and behavior-based closed-loop stimulation extends the availability of high-quality, low-cost experimental setup within standardized data formats.
In a recent publication in the Frontiers in Systems Neuroscience, Solari and colleagues of the Hungarian Academy of Sciences and Semmelweis University have shared the following about a behavioral setup for temporally controlled rodent behavior. This arrangement allows for training of head-fixed animals with calibrated sound stimuli, precisely timed fluid and air puff presentations as reinforcers. It combines microcontroller-based behavior control with a sound delivery system for acoustic stimuli, fast solenoid valves for reinforcement delivery and a custom-built sound attenuated chamber, and is shown to be suitable for combined behavior, electrophysiology and optogenetics experiments. This system utilizes an optimal open source setup of both hardware and software through using Bonsai, Bpod and OpenEphys.
An interesting summary of recent methods for monitoring behavior in rodents was published this week in Nature.The article mentions Lex Kravitz and his lab’s efforts on the Feeding Experimentation Device (FED) and also OpenBehavior. Check it out: https://www.nature.com/articles/d41586-018-02403-5
William Liberti, from the Gardner Lab out of Boston University, has shared the following with Open Behavior regarding ‘FinchScope’. Although originally designed for finches, the 3D printed single-photon fluorescent imaging microscope has since been adapted for rodents and other avian species.
The FinchScope project aims to provide a modular in-vivo optophysiology rig for awake, freely behaving animals, with a transparent acquisition and analysis pipeline. The goal is to produce a customizable and scaleable single-photon fluorescent imaging microscope system that takes advantage of developing open-source analysis platforms. These tools are built from easily procured off-the-shelf components and 3D printed parts.
We provide designs for a 3D printed, lightweight, wireless-capable microscope and motorized commutator, designed for multi-month monitoring the neural activity (via genetically encoded calcium indicators) of zebra finches while they sing their courtship songs. It has since been adapted for rodents, and to other birds such as canaries.
Jakob Voigts, from the Massachusetts Institute of Technology, has shared the following regarding www.open-ephys.org. Open Ephys aims to distribute reliable open source software as well as tools for extracellular recording and stimulation.
“Open Ephys is a collaborative effort to develop, document, and distribute open-source tools for systems neuroscience. Since the spring of 2011, our main focus has been on creating a multichannel data acquisition system optimized for recordings in freely behaving rodents. However, most of our tools are general enough to be used in applications involving other model organisms and electrode types.
We believe that open-source tools can improve basic scientific research in a variety of ways. They are often less expensive than their closed-source counterparts, making it more affordable to scale up one’s experiments. They are readily modifiable, giving scientists a degree of flexibility that is not usually provided by commercial systems. They are more transparent, which leads to a better understanding of how one’s data is being generated. Finally, by encouraging researchers to document and share tools they would otherwise keep to themselves, the open-source community reduces redundant development efforts, thereby increasing overall scientific productivity.” – Jakob Voigts
Open Ephys features devices such as the flexDrive, a “chronic drive implant for extracellular electrophysiology”, as well as an arduino-based tetrode twister. The Pulse Pal generates precise voltage pulses. Also featured on Open Ephys is software such as Symphony, a MATLAB-based data acquisition system for electrophysiology.