The authors also wish to express thanks to Kris Burner, Stephen McKinney, Laura Tobin, Jenny Gilbreath, Ashley Olley, Megan Hoffer, and Megan Hyde for their work in fine-tuning this assay.

1. Preparation of Individual Flies for Locomotion Assay
<ol>
	<li>Transfer flies by gently tapping into individual empty vials and cap the vials with a cotton plug. Allow flies to sit undisturbed 20-30 min before observation. It is important to not anesthetize the flies within the hours prior to behavioral observation as previous studies have found anesthesia exposure can alter behavior as compared to unanesthetized flies14.</li>
	<li>Gently tap the fly out of the vial and place individual flies under a 5 cm diameter Petri dish cover (5 mm high) with small slits to allow air passage. Illuminate from below and observe the flies using a webcam mounted above the Petri dish.</li>
</ol>
2. Preparation of Individual Flies for Seizure Assay
<ol>
	<li>Feed two-day old seizure sensitive flies either standard yeast/cornmeal/agar media or standard media mixed directly with drug. For the data presented here, flies were fed either 1 g of standard media or 1 g of standard media mixed with 25 mg of metformin.</li>
	<li>After the flies have fed for two days on the media or media plus drug, transfer them by gentle tapping into individual empty vials and cap the vials with a cotton plug. Allow flies to sit undisturbed for 20 min before observation. It is important to not anesthetize the flies within the hours prior to behavioral observation as previous studies have found anesthesia exposure can alter behavior as compared to unanesthetized flies14.</li>
	<li>Vortex individual vials containing a single fly on a lab vortexer using the highest setting for 10 sec. Place the immobilized fly on a blank white sheet of paper directly below a webcam mounted above the paper.</li>
</ol>
3. Video Recording
<ol>
	<li>Record the movement or SLA using the HandyAvi software program <a href="http://www.azcendant.com/download.htm">http://www.azcendant.com/download.htm</a>. This program uses the webcam to capture images based upon the user settings.</li>
	<li>Select the Time-Lapse images option under the Capture tab, When the window opens, select the webcam as the capture device. For most experiments the video frame size of 640 x 480 is adequate.</li>
	<li>Select Intel IYUV codec for the compression and choose 0.1 sec/frame for the seizure assay or choose 0.1-0.5 sec/frame for the movement assay. Under the advanced tab, select create a .bmp image file for each capture and select a folder for the program to store the images that it takes (the image stack).</li>
	<li>Place a dead fly on the sheet of paper. Click on the Video settings box and adjust the settings under the Device settings tab so that there is a bright white background and a clear contrast with the darker fly.</li>
	<li>Click the start button to begin the recording. Once the recording period has finished, click the stop button. The image stack should now be in the folder selected. Note: Before recording, ensure that the folder selected for the image stack is empty.</li>
</ol>
4. Data Analysis Using ImageJ
<ol>
	<li>Open NIH&#39;s free image processing software ImageJ, which can be downloaded at <a href="http://rsbweb.nih.gov/ij/download.html">http://rsbweb.nih.gov/ij/download.html</a>. Note: In addition to downloading the program, the Multitracker plug-in must be downloaded and installed as indicated at <a href="http://rsbweb.nih.gov/ij/plugins/index.html">http://rsbweb.nih.gov/ij/plugins/index.html</a>.</li>
	<li>Import the image stack into ImageJ by clicking on the File tab and then selecting Import &#8594; Image sequence.
	<ol>
		<li>Select the folder that contains the image stack, highlight one of the images and select open. A Sequence Options dialogue box will open. Click the Sort names numerically and then select OK and the image stack will be loaded into ImageJ.</li>
	</ol>
	</li>
	<li>Threshold all the images so that each consists of a white background with the fly being converted to a black dot. To begin this process, convert the image to an 8-bit format by selecting Type &#8594; 8 bit under the Image tab.
	<ol>
		<li>Click on the Image tab again and select Adjust &#8594; Threshold. This will open the Threshold dialogue box in which the threshold cut off point can be adjusted.</li>
		<li>Scan through the images to see if there are extra black dots or if a slice lacks a black dot. If this is the case, adjust the threshold to alleviate the problem. Usually the threshold does not need to be adjusted as the program defaults to an adequate value. 
		Note: Every slide in the stack should have just one black dot representing the position of the fly.</li>
		<li>Select apply in the Threshold dialogue box and a Convert to Mask dialogue box will open. Do not click any of the options but simply click OK to threshold the image stack.</li>
	</ol>
	</li>
	<li>After thresholding the image stack, select the Multitracker plug-in under the Plugins tab in order to measure the movement of the fly in pixels. The Object Tracker dialogue box will appear.
	<ol>
		<li>Click all of the four options given in the dialogue box and then select OK. The Multitracker plug-in will then attach coordinates to the black dot in each slice and list these in the Results window as well as the total path length in pixels. The Paths window gives a graphical display of the path the fly took.</li>
		<li>Copy the x-&#160;and y-coordinate list from the Results window and paste the data into an Excel spreadsheet. If any slide in the stack does not have a black dot in it, the Multitracker program will halt at that slide. If this occurs, it is necessary to go back to step 4.2 and re-threshold the stack to ensure that the fly registers as a black dot in the slide in question.</li>
	</ol>
	</li>
	<li>In order to convert the path lengths from pixels to cm, take a separate image of two dots that are spaced one cm apart on a blank white piece of paper.
	<ol>
		<li>Follow the above steps (3.1-4.4.2), to determine the x, y&#160;pixel coordinates for the two dots and use this information to determine the number of pixels corresponding to a cm. This conversion factor is used in step five to generate movement data in cm. Note: Once this is done, it is important to keep the camera fixed for all future recordings. Every time the camera is moved or adjusted, one needs to repeat this step to convert the pixels to cm.</li>
		<li>The path length that is generated by the Multitracker plug-in overestimates movement because slight fluctuations in body position and light intensity/reflection will affect the size and center of the black dot that is generated when thresholding the images. This noise must be removed in order to get an accurate estimation of fly movement.</li>
	</ol>
	</li>
</ol>
5. Data Analysis Using Excel
<ol>
	<li>Remove the noise from the recorded data by importing the series of x, y&#160;coordinates generated by the Multitracker program into Fly Analysis, an Excel Visual Basic program created by the authors. (The program is available by contacting the authors.)</li>
	<li>Click the Click Me button and select a threshold value cut-off. Select a threshold value of 0.5 cm/sec for SLA analysis or select a value between 0.1- 0.3 cm/sec for movement analysis. Click OK and the program will calculate the velocity, time and distance of movement. Note: The program uses a sliding window analysis to evaluate the data in sequential 0.5-1.0 sec bins and calculates the velocity during that window. Anything above the user-defined cutoff is treated as fly movement.</li>
</ol>

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S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dietary+modulation+of+Drosophila+sleep-wake+behaviour.">Dietary modulation of Drosophila sleep-wake behaviour.</a> PLoS One. 5, (2010).</li><li>Donelson, N., Kim, E. Z., Slawson, J. B., Vecsey, C. G., Huber, R., Griffith, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-Resolution+positional+tracking+for+long-term+analysis+of+Drosophila+sleep+and+locomotion+using+the+''Tracker''+program.">High-Resolution positional tracking for long-term analysis of Drosophila sleep and locomotion using the ''Tracker'' program.</a> PLos ONE. 7, (2012).</li><li>Duboff, B., Fridovich-Keil, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mediators+of+a+long-term+movement+abnormality+in+a+Drosophila+melanogaster+model+of+classic+galactosemia.">Mediators of a long-term movement abnormality in a Drosophila melanogaster model of classic galactosemia.</a> Dis. Model Mech. 5, 796-803 (2012).</li><li>Seiger, M. B., Kink, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+anesthesia+on+the+photoresponses+of+four+sympatric+species+of+Drosophila.">The effect of anesthesia on the photoresponses of four sympatric species of Drosophila.</a> Behav. Genet. 23, 99-104 (1993).</li><li>Pavlidis, P., Ramaswami, M., Tanouye, M. 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The authors declare that they have no competing financial interests.

When examining locomotor or movement patterns in Drosophila, it is useful to be able to extract information regarding the distance traveled, the velocity of movement and the pattern of movement. In order to extract this information, expensive equipment has traditionally been employed that is often prohibitive for smaller labs or labs that wish to use such assays sparingly4,8,9.
The assay described here can be used to determine the distance traveled (Figures 2</stron...

Given its short lifespan and the robust genetic tools available, Drosophila melanogaster is an excellent model system for investigating the etiology of various diseases and the underlying physiology of various biological processes. In many cases, it is advantageous to measure the effects that behavioral, genetic or pharmacological manipulations have on locomotion in these model organisms1,2.
There are a variety of methods that are commonly used for measuring fly movement in two-dimensions3-7. These systems can support the tracking of multiple flies simultaneously and can measure velocity, record path lengths and record the percentage of time a fly has spent moving. They have been used to study movement in a variety of contexts including the effects of drugs on locomotion and the sexual dimorphic nature of fly movement6-9. The major drawback of these systems is cost of the tracking system or the corresponding software and camera. In some cases, this can run in the thousands of dollars. Cost is a particular concern for a lab that would only need limited use of such a system, for example, quantifying locomotive patterns of a newly isolated mutant.
A simpler but less robust method is to use systems which record movement based on how many times a fly crosses an infrared light beam path that is placed in the middle of a closed tube10,11. While such systems can give valuable information on movement and sleep-wake cycles, they can over or under estimate movement because they fail to capture the actual path of the fly. For example, flies that exhibit considerable movement at the ends of the tube will register as low movement flies although additional high-resolution methods have been used to try and circumvent these limitations12.
Simpler and cheaper still are climbing devices that measure geotaxis, the upward movement of flies, through a single tube or a series of tubes2,13. While such systems are cheap and can easily identify geotaxis defects, they fail to capture many other aspects of movement that would be of interest to investigators.
For many labs, a low-cost robust analysis system that is simple to set-up and operate would be an advantageous tool for characterizing behavioral differences in D. melanogaster strains. Here we describe an assay that can be set-up for less than two hundred dollars and is able to give information about the path, velocity and duration of the fly&#39;s movement. To demonstrate the efficacy of the assay, we present data showing that it can be used to identify; 1) a locomotor defect in a Bang-sensitive (BS) mutant that is susceptible to seizures and 2) the ability of the drug metformin, which is commonly used to treat type II diabetes, to reduce the intensity of seizure-like activity (SLA) in two BS mutants.

<table border="0" cellpadding="0" cellspacing="0" style="width:1117px;" width="1117">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="68">
			<td height="68" style="height:68px;width:251px;">Name of the Reagent/Equipment</td>
			<td style="width:152px;">Company</td>
			<td style="width:169px;">Catalog Number/Model</td>
			<td style="width:545px;">Comments</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">WebCam</td>
			<td>Logitech</td>
			<td>Pro900</td>
			<td>Any quality webcam will suffice.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">HandiAVI time-lapse software</td>
			<td>Azcendant software</td>
			<td></td>
			<td>Latest version can be found at http://www.azcendant.com/</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">ImageJ</td>
			<td>NIH</td>
			<td></td>
			<td>Latest version can be found at http://rsbweb.nih.gov/ij/download.html</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Multiracker Plug-In</td>
			<td>NIH</td>
			<td></td>
			<td>Latest version can be found at http://rsbweb.nih.gov/ij/plugins/index.html</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Vortexer</td>
			<td>VWR</td>
			<td>Vortex Genie 2</td>
			<td>Most standard size vortexers such as the Vortex Genie 2 will suffice.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">5cm petri dish cover</td>
			<td>LabM Limited</td>
			<td>D011</td>
			<td>Smaller or larger petri dish covers can be used for an arena in movement assay.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Light box</td>
			<td colspan="2">Built from scrap material.</td>
			<td>Illumination is used for the locomotion assay. Depending on the room lighting, it is possible to perform the assay without the light box.&#160;</td>
		</tr>
	</tbody>
</table>

a low-cost method for analyzing seizure-like activity and movement in drosophila

Video tracking systems have been used widely to analyze Drosophila melanogaster movement and detect various abnormalities in locomotive behavior. While these systems can provide a wealth of behavioral information, the cost and complexity of these systems can be prohibitive for many labs. We have developed a low-cost assay for measuring locomotive behavior and seizure movement in D. melanogaster. The system uses a web-cam to capture images that can be processed using a combination of inexpensive and free software to track the distance moved, the average velocity of movement and the duration of movement during a specified time-span. To demonstrate the utility of this system, we examined a group of D. melanogaster mutants, the Bang-sensitive (BS) paralytics, which are 3-10 times more susceptible to seizure-like activity (SLA) than wild type flies. Using this novel system, we were able to detect that the BS mutant bang senseless (bss) exhibits lower levels of exploratory locomotion in a novel environment than wild type flies. In addition, the system was used to identify that the drug metformin, which is commonly used to treat type II diabetes, reduces the intensity of SLA in the BS mutants.

The technique described here has been used previously to analyze differences in SLA in the Drosophila BS mutants1. The results presented here involve the BS strains easily shocked (eas), bang senseless (bss), and technical knockout (tko). The eas locus encodes an ethanolamine kinase involved in phosphatidyl ethanolamine synthesis15 and the tko locus encodes a mitochondrial riboprotein16. The bss muta...

Watch this Scientific Journal Video about A Low-cost Method for Analyzing Seizure-like Activity and Movement in Drosophila at JoVE.com

A Low-cost Method for Analyzing Seizure-like Activity and Movement in Drosophila

Using a webcam and a combination of free and inexpensive software programs, locomotive patterns in Drosophila melanogaster can be analyzed to detect differences in the speed, distance, and time of various motor activities.

A Low-cost Method for Analyzing Seizure-like Activity and Movement in Drosophila

Video tracking systems have been used widely to analyze Drosophila melanogaster movement and detect various abnormalities in locomotive behavior. While ...

a-low-cost-method-for-analyzing-seizure-like-activity-movement

Research

JoVE Journal

Neuroscience

13.5K Views.  Franciscan University of Steubenville. Using a webcam and a combination of free and inexpensive software programs, locomotive patterns in Drosophila melanogaster can be analyzed to detect differences in the speed, distance, and time of various motor activities.

Video: A Low-cost Method for Analyzing Seizure-like Activity and Movement in Drosophila

A Low Cost Setup for Behavioral Audiometry in Rodents

In auditory animal research it is crucial to have precise information about basic hearing parameters of the animal subjects that are involved in the experiments. Such parameters may be physiological response characteristics of the auditory pathway, e.g. via brainstem audiometry (BERA). But these methods allow only indirect and uncertain extrapolations about the auditory percept that corresponds to these physiological parameters. To assess the perceptual level of hearing, behavioral methods have to be used. A potential problem with the use of behavioral methods for the description of perception in animal models is the fact that most of these methods involve some kind of learning paradigm before the subjects can be behaviorally tested, e.g. animals may have to learn to press a lever in response to a sound. As these learning paradigms change perception itself 1,2 they consequently will influence any result about perception obtained with these methods and therefore have to be interpreted with caution. Exceptions are paradigms that make use of reflex responses, because here no learning paradigms have to be carried out prior to perceptual testing. One such reflex response is the acoustic startle response (ASR) that can highly reproducibly be elicited with unexpected loud sounds in na&iuml;ve animals. This ASR in turn can be influenced by preceding sounds depending on the perceptibility of this preceding stimulus: Sounds well above hearing threshold will completely inhibit the amplitude of the ASR; sounds close to threshold will only slightly inhibit the ASR. This phenomenon is called pre-pulse inhibition (PPI) 3,4, and the amount of PPI on the ASR gradually depends on the perceptibility of the pre-pulse. PPI of the ASR is therefore well suited to determine behavioral audiograms in na&iuml;ve, non-trained animals, to determine hearing impairments or even to detect possible subjective tinnitus percepts in these animals. In this paper we demonstrate the use of this method in a rodent model (cf. also ref. 5), the Mongolian gerbil (Meriones unguiculatus), which is a well know model species for startle response research within the normal human hearing range (e.g. 6).

A fast and inexpensive method for the behavioral determination of hearing parameters like hearing thresholds, hearing impairments or phantom perceptions (subjective tinnitus) is described. It uses pre-pulse inhibition of the acoustic startle response and can be easily implemented in a personal computer using a programmable AD/DA-converter and a piezo sensor.

In auditory animal research it is crucial to have precise information about basic hearing parameters of the animal subjects that are involved in the ...

A Human-machine-interface Integrating Low-cost Sensors with a Neuromuscular Electrical Stimulation System for Post-stroke Balance Rehabilitation

A stroke is caused when an artery carrying blood from heart to an area in the brain bursts or a clot obstructs the blood flow to brain thereby preventing delivery of oxygen and nutrients. About half of the stroke survivors are left with some degree of disability. Innovative methodologies for restorative neurorehabilitation are urgently required to reduce long-term disability. The ability of the nervous system to reorganize its structure, function and connections as a response to intrinsic or extrinsic stimuli is called neuroplasticity. Neuroplasticity is involved in post-stroke functional disturbances, but also in rehabilitation. Beneficial neuroplastic changes may be facilitated with non-invasive electrotherapy, such as neuromuscular electrical stimulation (NMES) and sensory electrical stimulation (SES). NMES involves coordinated electrical stimulation of motor nerves and muscles to activate them with continuous short pulses of electrical current while SES involves stimulation of sensory nerves with electrical current resulting in sensations that vary from barely perceivable to highly unpleasant. Here, active cortical participation in rehabilitation procedures may be facilitated by driving the non-invasive electrotherapy with biosignals (electromyogram (EMG), electroencephalogram (EEG), electrooculogram (EOG)) that represent simultaneous active perception and volitional effort. To achieve this in a resource-poor setting, e.g., in low- and middle-income countries, we present a low-cost human-machine-interface (HMI) by leveraging recent advances in off-the-shelf video game sensor technology. In this paper, we discuss the open-source software interface that integrates low-cost off-the-shelf sensors for visual-auditory biofeedback with non-invasive electrotherapy to assist postural control during balance rehabilitation. We demonstrate the proof-of-concept on healthy volunteers.

A novel low-cost human-machine interface for interactive post-stroke balance rehabilitation system is presented in this article. The system integrates off-the-shelf low-cost sensors towards volitionally driven electrotherapy paradigm. The proof-of-concept software interface is demonstrated on healthy volunteers.

A stroke is caused when an artery carrying blood from heart to an area in the brain bursts or a clot obstructs the blood flow to brain thereby preventing ...

A Method to Inflict Closed Head Traumatic Brain Injury in Drosophila

Traumatic brain injury (TBI) affects millions of people each year, causing impairment of physical, cognitive, and behavioral functions and death. Studies using Drosophila have contributed important breakthroughs in understanding neurological processes. Thus, with the goal of understanding the cellular and molecular basis of TBI pathologies in humans, we developed the High Impact Trauma (HIT) device to inflict closed head TBI in flies. Flies subjected to the HIT device display phenotypes consistent with human TBI such as temporary incapacitation and progressive neurodegeneration. The HIT device uses a spring-based mechanism to propel flies against the wall of a vial, causing mechanical damage to the fly brain. The device is inexpensive and easy to construct, its operation is simple and rapid, and it produces reproducible results. Consequently, the HIT device can be combined with existing experimental tools and techniques for flies to address fundamental questions about TBI that can lead to the development of diagnostics and treatments for TBI. In particular, the HIT device can be used to perform large-scale genetic screens to understand the genetic basis of TBI pathologies.

A Method to Inflict Closed Head Traumatic Brain Injury in Drosophila

Here we describe a method to inflict closed head traumatic brain injury (TBI) in Drosophila. This method provides a gateway to investigate the cellular and molecular mechanisms that underlie TBI pathologies using the vast array of experimental tools and techniques available for flies.

Traumatic brain injury (TBI) affects millions of people each year, causing impairment of physical, cognitive, and behavioral functions and death. Studies ...

Direct-current Stimulation and Multi-electrode Array Recording of Seizure-like Activity in Mice Brain Slice Preparation

Cathodal transcranial direct-current stimulation (tDCS) induces suppressive effects on drug-resistant seizures. To perform effective actions, the stimulation parameters (e.g., orientation, field strength, and stimulation duration) need to be examined in mice brain slice preparations. Testing and arranging the orientation of the electrode relative to the position of the mice brain slice are feasible. The present method preserves the thalamocingulate pathway to evaluate the effect of DCS on anterior cingulate cortex seizure-like activities. The results of the multichannel array recordings indicated that cathodal DCS significantly decreased the amplitude of the stimulation-evoked responses and duration of 4-aminopyridine and bicuculline-induced seizure-like activity. This study also found that cathodal DCS applications at 15 min caused long-term depression in the thalamocingulate pathway. The present study investigates the effects of DCS on thalamocingulate synaptic plasticity and acute seizure-like activities. The current procedure can test the optimal stimulation parameters including orientation, field strength, and stimulation duration in an in vitro mouse model. Also, the method can evaluate the effects of DCS on cortical seizure-like activities at both the cellular and network levels.

Studies have shown that cathodal transcranial direct-current stimulation can produce suppressive effects on drug-resistant seizures. In this study, an in vitro experimental setup was devised in which the direct-current stimulation and multielectrode array recording of seizure-like activity were evaluated in mice brain slice preparation. The direct-current stimulation parameters were evaluated.

Cathodal transcranial direct-current stimulation (tDCS) induces suppressive effects on drug-resistant seizures. To perform effective actions, the ...

High-density Electroencephalographic Acquisition in a Rodent Model Using Low-cost and Open-source Resources

Advanced electroencephalographic analysis techniques requiring high spatial resolution, including electrical source imaging and measures of network connectivity, are applicable to an expanding variety of questions in neuroscience. Performing these kinds of analyses in a rodent model requires higher electrode density than traditional screw electrodes can accomplish. While higher-density electroencephalographic montages for rodents exist, they are of limited availability to most researchers, are not robust enough for repeated experiments over an extended period of time, or are limited to use in anesthetized rodents.1-3 A proposed low-cost method for constructing a durable, high-count, transcranial electrode array, consisting of bilaterally implantable headpieces is investigated as a means to perform advanced electroencephalogram analyses in mice or rats.

Procedures for headpiece fabrication and surgical implantation necessary to produce high signal to noise, low-impedance electroencephalographic and electromyographic signals are presented. While the methodology is useful in both rats and mice, this manuscript focuses on the more challenging implementation for the smaller mouse skull. Freely moving mice are only tethered to cables via a common adapter during recording. One version of this electrode system that includes 26 electroencephalographic channels and 4 electromyographic channels is described below.

Instructions for the low-cost construction and surgical implantation of a chronic transcranial high-density electroencephalographic montage into mice are provided. Signal recording, extraction, and processing techniques are also described.

Advanced electroencephalographic analysis techniques requiring high spatial resolution, including electrical source imaging and measures of network ...

Acute In Vivo Electrophysiological Recordings of Local Field Potentials and Multi-unit Activity from the Hyperdirect Pathway in Anesthetized Rats

Converging evidence shows that many neuropsychiatric diseases should be understood as disorders of large-scale neuronal networks. To better understand the pathophysiological basis of these diseases, it is necessary to precisely characterize in which way the processing of information is disturbed between the different neuronal parts of the circuit. Using extracellular in vivo electrophysiological recordings, it is possible to accurately delineate neuronal activity within a neuronal network. The application of this method has several advantages over alternative techniques, e.g., functional magnetic resonance imaging and calcium imaging, as it allows a unique temporal and spatial resolution and does not rely on genetically engineered organisms. However, the use of extracellular in vivo recordings is limited since it is an invasive technique that cannot be universally applied. In this article, a simple and easy to use method is presented with which it is possible to simultaneously record extracellular potentials such as local field potentials and multiunit activity at multiple sites of a network. It is detailed how a precise targeting of subcortical nuclei can be achieved using a combination of stereotactic surgery and online analysis of multi-unit recordings. Thus, it is demonstrated, how a complete network such as the hyperdirect cortico-basal ganglia loop can be studied in anesthetized animals in vivo.

Acute In Vivo Electrophysiological Recordings of Local Field Potentials and Multi-unit Activity from the Hyperdirect Pathway in Anesthetized Rats

In this study, the methodology is presented on how to perform multi-site in vivo electrophysiological recordings from the hyperdirect pathway under urethane anesthesia.

Converging evidence shows that many neuropsychiatric diseases should be understood as disorders of large-scale neuronal networks. To better understand the ...

In vivo Calcium Imaging in Mouse Inferior Olive

Inferior olive (IO), a nucleus in the ventral medulla, is the only source of climbing fibers that form one of the two input pathways entering the cerebellum. IO has long been proposed to be crucial for motor control and its activity is currently considered to be at the center of many hypotheses of both motor and cognitive functions of the cerebellum. While its physiology and function have been relatively well studied on single-cell level in vitro, presently there are no reports on the organization of the IO network activity in living animals. This is largely due to the extremely challenging anatomical location of the IO, making it difficult to subject to conventional fluorescent imaging methods, where an optic path must be created through the entire brain located dorsally to the region of interest.
Here we describe an alternative method for obtaining state-of-the-art -level calcium imaging data from the IO network. The method takes advantage of the extreme ventral location of the IO and involves a surgical procedure for inserting a gradient-refractive index (GRIN) lens through the neck viscera to come into contact with the ventral surface of the calcium sensor GCaMP6s-expressing IO in anesthetized mice. A representative calcium imaging recording is shown to demonstrate the feasibility to record IO neuron activity after the surgery. While this is a non-survival surgery and the recordings must be conducted under anesthesia, it avoids damage to life-critical brainstem nuclei and allows conducting large variety of experiments investigating spatiotemporal activity patterns and input integration in the IO. This procedure with modifications could be used for recordings in other, adjacent regions of the ventral brainstem.

In vivo Calcium Imaging in Mouse Inferior Olive

We present a protocol to expose the brainstem of adult mouse from the ventral side. By using a gradient-refractive index lens with a miniature microscope, calcium imaging can be used to examine the activity of inferior olive neural somata in vivo.

Inferior olive (IO), a nucleus in the ventral medulla, is the only source of climbing fibers that form one of the two input pathways entering the ...

Stimulating and Analyzing Adult Neurogenesis in the Drosophila Central Brain

The molecular and cellular mechanisms underlying neurogenesis in response to disease or injury are not well understood. However, understanding these mechanisms is crucial for developing neural regenerative therapies. Drosophila melanogaster is a leading model for studies of neural development but historically has not been exploited to investigate adult brain regeneration. This is primarily because the adult brain exhibits very low mitotic activity. Nonetheless, penetrating traumatic brain injury (PTBI) to the adult Drosophila central brain triggers the generation of new neurons and new glia. The powerful genetic tools available in Drosophila combined with the simple but rigorous injury protocol described here now make adult Drosophila brain a robust model for neural regeneration research. Provided here are detailed instructions for (1) penetrating injuries to the adult central brain and (2) dissection, immunohistochemistry, and imaging post-injury. These protocols yield highly reproducible results and will facilitate additional studies to dissect mechanisms underlying neural regeneration.

Stimulating and Analyzing Adult Neurogenesis in the Drosophila Central Brain

This article provides detailed protocols for inflicting Penetrating Traumatic Brain Injury (PTBI) to adult Drosophila and examining the resulting neurogenesis.

The molecular and cellular mechanisms underlying neurogenesis in response to disease or injury are not well understood. However, understanding these ...

Stimulating Mouse Brain with a Low-Cost EEG and Millimeter-Sized Coil

Low-Cost Electroencephalographic Recording System Combined with a Millimeter-Sized Coil to Transcranially Stimulate the Mouse Brain In Vivo

A low-cost electroencephalographic (EEG) recording system is proposed here to drive transcranial magnetic stimulation (TMS) of the mouse brain in vivo, utilizing a millimeter-sized coil. Using conventional screw electrodes combined with a custom-made, flexible, multielectrode array substrate, multi-site recording can be carried out from the mouse brain. In addition, we explain how a millimeter-sized coil is produced using low-cost equipment usually found in laboratories. Practical procedures for fabricating the flexible multielectrode array substrate and the surgical implantation technique for screw electrodes are also presented, which are necessary to produce low-noise EEG signals. Although the methodology is useful for recording from the brain of any small animal, the present report focuses on electrode implementation in an anesthetized mouse skull. Furthermore, this method can be easily extended to an awake small animal that is connected with tethered cables via a common adapter and fixed with a TMS device to the head during recording.The present version of the EEG-TMS system, which can include a maximum of 32 EEG channels (a device with 16 channels is presented as an example with fewer channels) and one TMS channel device, is described. Additionally, typical results obtained by the application of the EEG-TMS system to anesthetized mice are briefly reported.

Author Spotlight: Low-Cost Electroencephalographic Recording System Combined with a Millimeter-Sized Coil to Transcranially Stimulate the Mouse Brain In Vivo  

A low-cost electroencephalographic recording system combined with a millimeter-sized coil is proposed to drive transcranial magnetic stimulation of the mouse brain in vivo. Using conventional screw electrodes with a custom-made, flexible, multielectrode array substrate, multi-site recording can be carried out from the mouse brain in response to transcranial magnetic stimulation.

A low-cost electroencephalographic (EEG) recording system is proposed here to drive transcranial magnetic stimulation (TMS) of the mouse brain in vivo, ...

Monitoring Epileptiform Events in &lt;em&gt;Drosophila&lt;/em&gt; via Calcium Imaging

Ex Vivo Calcium Imaging for Drosophila Model of Epilepsy

Epilepsy is a neurological disorder characterized by recurrent seizures, partially correlated with genetic origin, affecting over 70 million individuals worldwide. Despite the clinical importance of epilepsy, the functional analysis of neural activity in the central nervous system is still to be developed. Recent advancements in imaging technology, in combination with stable expression of genetically encoded calcium indicators, such as GCaMP6, have revolutionized the study of epilepsy at both brain-wide and single-cell resolution levels. Drosophila melanogaster has emerged as a tool for investigating the molecular and cellular mechanisms underlying epilepsy due to its sophisticated molecular genetics and behavioral assays. In this study, we present a novel and efficient protocol for ex vivo calcium imaging in GCaMP6-expressing adult Drosophila to monitor epileptiform activities. The whole brain is prepared from cac, a well-known epilepsy gene, knockdown flies for calcium imaging with a confocal microscope to identify the neural activity as a follow-up to the bang-sensitive seizure-like behavior assay. The cac knockdown flies showed a higher rate of seizure-like behavior and abnormal calcium activities, including more large spikes and fewer small spikes than wild-type flies. The calcium activities were correlated to seizure-like behavior. This methodology serves as an efficient methodology in screening the pathogenic genes for epilepsy and exploring the potential mechanism of epilepsy at the cellular level.

Author Spotlight: Insights into the Techniques and Findings of Recent Advancements in Epilepsy Research 

Here, we present a protocol for ex vivo calcium imaging in GCaMP6-expressing adult Drosophila to monitor epileptiform activities. The protocol provides a valuable tool for investigating ictal events in adult Drosophila through ex vivo calcium imaging, allowing for exploration of the potential mechanisms of epilepsy at the cellular levels.

Epilepsy is a neurological disorder characterized by recurrent seizures, partially correlated with genetic origin, affecting over 70 million individuals ...