Name: a novel method to model chronic traumatic encephalopathy in drosophila
Uploaded: 2017-07-04T13:00:00
Description: Watch this Scientific Journal Video about A Novel Method to Model Chronic Traumatic Encephalopathy in Drosophila at JoVE.com

The authors have nothing to disclose.

1. Assembly of the Strike Device (Figure 1)
<ol>
	<li>Remove the plunger from a 1&#160;mL tuberculin syringe. Cut the barrel at the 1&#160;mL mark.</li>
	<li>Remove an aerosol barrier (3 mm height x 4 mm diameter) from a 200&#160;&#181;L pipette tip and use it as an impactor. Place the impactor inside the syringe barrel. Gently tap the barrel to move the impactor to the tip end, with the flat side covering the nozzle opening.</li>
	<li>Attach the barrel tip end to plastic tubing that is co...

<ol>
	<li>McKee, A. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+first+NINDS/NIBIB+consensus+meeting+to+define+neuropathological+criteria+for+the+diagnosis+of+chronic+traumatic+encephalopathy.">The first NINDS/NIBIB consensus meeting to define neuropathological criteria for the diagnosis of chronic traumatic encephalopathy.</a> Acta Neuropathol. 131, 75-86 (2016).</li><li>Martland, H. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Punch+drunk.">Punch drunk.</a> JAMA. 91 (15), 1103-1107 (1928).</li><li>Millspaugh, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dementia+pugilistica.">Dementia pugilistica.</a> US Naval Med Bull. 35, 297-303 (1937).</li><li>Omalu, B. I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chronic+traumatic+encephalopathy+in+a+national+football+league+player:+part+II.">Chronic traumatic encephalopathy in a national football league player: part II.</a> Neurosurgery. 59 (5), 1086-1092 (2006).</li><li>Goldstein, L. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chronic+traumatic+encephalopathy+in+blast-exposed+military+veterans+and+a+blast+neurotrauma+mouse+model.">Chronic traumatic encephalopathy in blast-exposed military veterans and a blast neurotrauma mouse model.</a> Sci Transl Med. 4 (134), (2012).</li><li>Mez, J., Stern, R. A., McKee, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chronic+traumatic+encephalopathy:+where+are+we+and+where+are+we+going?.">Chronic traumatic encephalopathy: where are we and where are we going?.</a> Curr Neurol Neurosci Rep. 13 (12), 407 (2013).</li><li>McKee, A. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+spectrum+of+disease+in+chronic+traumatic+encephalopathy.">The spectrum of disease in chronic traumatic encephalopathy.</a> Brain. 136 (Pt 1), 43-64 (2013).</li><li>Petraglia, A. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+spectrum+of+neurobehavioral+sequelae+after+repetitive+mild+traumatic+brain+injury:+a+novel+mouse+model+of+chronic+traumatic+encephalopathy.">The spectrum of neurobehavioral sequelae after repetitive mild traumatic brain injury: a novel mouse model of chronic traumatic encephalopathy.</a> J Neurotrauma. 31 (13), 1211-1224 (2014).</li><li>Hirth, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+melanogaster+in+the+study+of+human+neurodegeneration.">Drosophila melanogaster in the study of human neurodegeneration.</a> CNS Neurol Disord Drug Targets. 9 (4), 504-523 (2010).</li><li>Littleton, J. T., Ganetzky, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ion+channels+and+synaptic+organization:+analysis+of+the+Drosophila+genome.">Ion channels and synaptic organization: analysis of the Drosophila genome.</a> Neuron. 26 (1), 35-43 (2000).</li><li>Appel, L. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Drosophila+Stubble-stubbloid+gene+encodes+an+apparent+transmembrane+serine+protease+required+for+epithelial+morphogenesis.">The Drosophila Stubble-stubbloid gene encodes an apparent transmembrane serine protease required for epithelial morphogenesis.</a> Proc Natl Acad Sci USA. 90 (11), 4937-4941 (1993).</li><li>Piyankarage, S. C., Featherstone, D. E., Shippy, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoliter+hemolymph+sampling+and+analysis+of+individual+adult+Drosophila+melanogaster.">Nanoliter hemolymph sampling and analysis of individual adult Drosophila melanogaster.</a> Anal Chem. 84 (10), 4460-4466 (2012).</li><li>Katzenberger, R. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Drosophila+model+of+closed+head+traumatic+brain+injury.">A Drosophila model of closed head traumatic brain injury.</a> Proc Natl Acad Sci USA. 110 (44), E4152-E4159 (2013).</li><li>Barekat, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+Drosophila+as+an+integrated+model+to+study+mild+repetitive+traumatic+brain+injury.">Using Drosophila as an integrated model to study mild repetitive traumatic brain injury.</a> Sci Rep. 6, 25252 (2016).</li><li>Katzenberger, R. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Method+to+Inflict+Closed+Head+Traumatic+Brain+Injury+in+Drosophila.">A Method to Inflict Closed Head Traumatic Brain Injury in Drosophila.</a> J Vis Exp. (e52905), (2015).</li><li>Branson, K., Robie, A. A., Bender, J., Perona, P., Dickinson, M. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-throughput+ethomics+in+large+groups+of+Drosophila.">High-throughput ethomics in large groups of Drosophila.</a> Nat Methods. 6 (6), 451-457 (2009).</li><li>Straw, A. D., Dickinson, M. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Motmot,+an+open-source+toolkit+for+realtime+video+acquisition+and+analysis.">Motmot, an open-source toolkit for realtime video acquisition and analysis.</a> Source Code Biol Med. 4 (5), 1-10 (2009).</li><li>Talavage, T. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functionally-detected+cognitive+impairment+in+high+school+football+players+without+clinically-diagnosed+concussion.">Functionally-detected cognitive impairment in high school football players without clinically-diagnosed concussion.</a> J Neurotrauma. 31 (4), 327-338 (2014).</li><li>Theadom, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Frequency+and+impact+of+recurrent+traumatic+brain+injury+in+a+population-based+sample.">Frequency and impact of recurrent traumatic brain injury in a population-based sample.</a> J Neurotrauma. 32 (10), 674-681 (2015).</li><li>Drobysheva, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+optimized+method+for+histological+detection+of+dopaminergic+neurons+in+Drosophila+melanogaster.">An optimized method for histological detection of dopaminergic neurons in Drosophila melanogaster.</a> J Histochem Cytochem. 56 (12), 1049-1063 (2008).</li></ol>

Animal models that faithfully model CTE features, including neurophysiological alterations, neuropathological hallmarks, and neurobehavioral deficits, are essential for uncovering disease mechanisms and for developing diagnostic and therapeutic targets. It is understandable that no animal model of a human disease is perfect at mimicking all clinically relevant endpoints. However, we believe that a robust CTE model should satisfy the following three requirements: (1) the impact must be directly applied to a head that has ...

Chronic Traumatic Encephalopathy (CTE) has recently been recognized as a distinct neurodegenerative disorder, separate from other tauopathies such as Alzheimer&#39;s disease1. Unlike Alzheimer&#39;s disease and other common tauopathies-whose most important risk factors are advancing age and a family history of dementia,&#160;CTE, as indicated by its name, implies a close association with a history of brain trauma, most likely seen in contact sports athletes, such as boxers and football players, as well as in military veterans2,3,4,5. It is thought to be initiated by repeated concussive and subconcussive blows to the head. Patients may present symptoms and signs such as cognitive deficits, mood and behavior changes, and movement dysfunction, which overlap significantly with Alzheimer&#39;s disease, frontotemporal dementia, Lewy body dementia, and Parkinson&#39;s disease6. In contrast, post-mortem examinations of brain tissue reveal a distinct pattern of hyperphosphorylated tau accumulation surrounding small blood vessels at the depths of the cortical sulci, a pathognomonic feature not observed in the other degenerative conditions7. However, so far, very little is known about the pathogenesis leading to disease manifestation. This is in large part due to the lack of a faithful animal model - only recently have rodent models been generated5,8. These model organisms have the disadvantages of cost-intensive care and a relatively long life span, which are not well-suited for neurodegenerative disease studies.
Compared to mammalian counterparts, invertebrate animals such as Drosophila&#160;are an excellent alternative, with their cost-effective maintenance, extensive tools for dissecting genetic determinants, and relatively short lifespan9. Remarkably, fly and human brains share evolutionarily conserved molecular and cellular pathways, as well as anatomical similarities10,11,12. Two ingenious Drosophila models to study traumatic brain injury have been reported previously13,14. The first &#34;High Impact Trauma&#34; (HIT) device designed by Katzenberger and colleagues contained free-moving flies in a plastic vial that was tied to the free end of a metal spring13,15. When the plastic vial was tilted upright and released, it hit a polyurethane pad and imparted trauma to the flies as they bounced to the vial wall and rebounded. In contrast, Barekat and colleagues designed a different delivery method using the Omni Bead Ruptor-24 homogenizer platform14. Flies were incapacitated with CO2 and placed in a 2&#160;mL screwcap tube that was secured to the homogenizer and subjected to preprogrammed shaking conditions. One benefit of using the tissue homogenizer system is that the experimenter could modulate the intensity of injury, duration of injury, and number of injury bouts. However, both regimes suffer the same drawback: primary injuries to the head are randomly inflicted in terms of impact location and strength. In addition, both methods resulted in considerable mortality, caused by inevitable collateral damage to other parts of the body and internal organs. Here, we describe a novel method to induce mTBI in fruit flies. Our apparatus consists of a gas-propelled ballistic impactor. Compared to the existing Drosophila models14,15, our method has the unique advantage of delivering measurable impact, directed only at the free-moving fly head, thus allowing for the accurate control of various factors, such as impact severity, the time interval between impacts, and the total number of impacts sustained.

<table border="0" cellpadding="0" cellspacing="0" width="692">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">Aerosol Barrier</td>
			<td style="width:151px;">USA Scientific</td>
			<td style="width:119px;">1120-8810</td>
			<td style="width:207px;">Used as an impactor</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">200 ul Pipette Tip</td>
			<td style="width:151px;">USA Scientific</td>
			<td style="width:119px;">1111-0706</td>
			<td>Used as a fly head holder</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">1000 ul Pipette Tip</td>
			<td style="width:151px;">USA Scientific</td>
			<td style="width:119px;">1122-1830</td>
			<td>Used as a connector</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">1 ml Tuberculin Syringe</td>
			<td style="width:151px;">Becton Dickinson</td>
			<td style="width:119px;">309625</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">60 mm Petri Dishes</td>
			<td style="width:151px;">Fisher Scientific</td>
			<td>FB0875713A</td>
			<td>Used as a tracking arenas</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">Flow Regulator</td>
			<td>Genesee Scientific</td>
			<td style="width:119px;">59-122WC</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">Standard Clamp Holder/stand</td>
			<td style="width:151px;">EISCO Scientific</td>
			<td style="width:119px;">CH0688</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">Fine Brush</td>
			<td style="width:151px;">Genesee Scientific</td>
			<td style="width:119px;">59-204</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">Flypad</td>
			<td style="width:151px;">Genesee Scientific</td>
			<td style="width:119px;">59-114</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">Sylgard Silicone Elastomer</td>
			<td style="width:151px;">Dow Corning</td>
			<td>4019862</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">CCD Camera</td>
			<td style="width:151px;">Microsoft&#160;</td>
			<td style="width:119px;">HD-5000</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Ctrax Walking Fly Tracker</td>
			<td style="width:151px;">Caltech</td>
			<td style="width:119px;">Ctrax 0.2.11</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">MATLAB Image Processing Toolbox</td>
			<td style="width:151px;">MATLAB</td>
			<td style="width:119px;">R2015b</td>
			<td></td>
		</tr>
	</tbody>
</table>

a novel method to model chronic traumatic encephalopathy in drosophila

Chronic Traumatic Encephalopathy (CTE) is an established neurodegenerative disease that is closely associated with exposure to repetitive mild Traumatic Brain Injury (mTBI). The mechanisms responsible for its complex pathological changes remain largely elusive, despite a recent consensus to define the neuropathological criteria. Here, we describe a novel method to develop a model of CTE in Drosophila melanogaster&#160;(Drosophila&#160;)&#160;in an attempt to identify the key genes and pathways that lead to the characteristic hyperphosphorylated tau accumulation and neuronal death in the brain. Adjustable-strength impacts to inflict mild closed injury are delivered directly to the fly head, subjecting the head to rapid acceleration and deceleration. Our method eliminates the potential problems inherent with other Drosophila mTBI models (e.g.,animal death might be induced by damage to other parts of the body or to internal organs). The less labor- and cost-intensive animal care, short life span, and extensive genetic tools make the fruit fly ideal to study CTE pathogenesis and make it possible to perform large-scale, genome-wide forward genetic and pharmacological screens. We anticipate that the ongoing characterization of the model will generate important mechanistic insights on disease prevention and therapeutic approaches.

To establish a CTE model using adult Drosophila, we determined the effectiveness of our device at inflicting a single closed-head injury. To eliminate the variations relating to genotype, sex, or age, we used 2-day-old Canton-S WT female flies in the experiment. We could easily control the strength of the impactor by regulating the flow rate of CO2 at a constant gas pressure of 100 kPa. Flies exposed to a single strike at the highest flow rate (15 L/min) exhibited mini...

Watch this Scientific Journal Video about A Novel Method to Model Chronic Traumatic Encephalopathy in Drosophila at JoVE.com

A Novel Method to Model Chronic Traumatic Encephalopathy in Drosophila

Here, we describe a new approach to inflict closed-head traumatic brain injury in Drosophila melanogaster. Our method has the advantage of directly delivering repetitive impacts with adjustable strength to the head alone. Further exploration of the invertebrate system will help to illuminate the pathogenesis of chronic traumatic encephalopathy.

A Novel Method to Model Chronic Traumatic Encephalopathy in Drosophila

Chronic Traumatic Encephalopathy (CTE) is an established neurodegenerative disease that is closely associated with exposure to repetitive mild Traumatic ...

The overall goal of this novel procedure is to inflict closed traumatic brain injuries in the fruit fly, Drosophila, to establish a new chronic traumatic encephalopathy model. This method can help answer key questions in the chronic traumatic encephalopathy field, such as how the repetitive trauma induces neuron degeneration. The main advantage of this technique is that it delivers the repetitive impacts of adjustable strengths to the fly head directly without causing damage to other parts of the animal body.Real world demonstration of this method is critical as assembly of the device and fly loading steps are difficult to learn, because the Drosophila head is so small and it is important to apply the impact only to the head. To make the apparatus used to concuss or strike the fruit flies, first, make the impactor portion of the apparatus. Remove the plunger from a one milliliter polycarbonate tuberculin syringe and then cut the barrel at the one milliliter mark.For an impactor, use the aerosol barrier found on a 200 microliter pipette tip. This impactor should be three millimeters long and four millimeters in diameter. Then, pack the impactor into the syringe barrel with the flat side towards the nozzle.To provide force, attach the syringe barrel to a carbon dioxide flow regulator. The regulator must have an On Off toggle switch and good control of the gas flow rate. Then, clamp the barrel vertically to an iron stand, such that the impactor will fall to the bottom of the barrel.Next, make the fly holder. Start with a 200 microliter pipette tip. Cut the pipette's tip five millimeters from the small end to make a 8 millimeter diameter opening.A fly head will fit through this hole, but the thorax will not. Lastly, make a for the fly holder and impactor device. First, cut a one milliliter pipette tip 44 millimeters from the small opening.Second, cut a six millimeter length from the needle cover for a one milliliter syringe. Then, push the two together. Anesthetize a single, two-day old adult female fly using carbon dioxide.From the carbon dioxide pad, use a fine brush to gently transfer the fly into the holder. Then, gently tap the holder until the head protrudes from the tip. Of the proboscis is exposed, use a blunted, one milliliter syringe needle to gently tuck it back inside the tip.It is critical to keep the fly body, especially the mouth part, inside the holder. Otherwise, the fly may die from damage to the internal organs or from not being able to ingest food. Next, set the gas pressure to 100 kilopascals and adjust the flow as needed.Once the fly is loaded, tighten the holder to the syringe barrel using the connector, such that the fly head faces downward. Then, using the toggle switch, send a burst of gas that moves the impactor to strike the fly once and only once. Now, detach the fly holder and dump the fly back onto the carbon dioxide pad.Brush the fly into an empty vial until it recovers. Keep one fly per vial. The recovery takes only a few minutes.Repeat the process to test four flies per experimental group. Processing two groups, a test and a sham, should only take 20 to 30 minutes. Treat shams just like test animals, except do not include an aerosol barrier in the impactor tube.To track fly movements in a Petri dish, first, fill a six centimeter dish with transparent silicon elastomer to make the tracking arena. Leave a three millimeter gap between the silicon and the lid so that flies can walk freely in the gap, but not take flight. Beneath the tracking arena, have a white background.Next, anesthetize four flies from the same treatment group and place them in the arena. Let the flies acclimate for an hour to the arena, which should be fully lit and at about 22 degrees Celsius. Not hotter than room temperature.After an hour, use a charge-coupled device camera positioned above the arena to record the fly's activity for five minutes. After the five minute recording, anesthetize the flies in the arena and return them to a new home vial. Then, dispose of the arena.Later, analyze the recordings using the freely available Ctrax software. This software generates tracking data, which can be exported in a programmable language compatible format, such as the MATLAB format. From the data, calculate the distance traveled per frame, the mean walking distance for each fly, and the average distance traveled per fly.For statistical significance, expect to test about 100 flies per treatment group. To establish a chronic traumatic encephalopathy model, the effectiveness of a single, closed-head injury made by the impacting apparatus at different speeds was analyzed using two-day old Canton-S females. The gas pressure was held at 100 kilopascals.Flies exposed to a single strike at the highest tested flow rate, exhibited minimal external defects. Despite no clear evidence for external damage, injuries at a flow rate of 15 liters per minute were acutely lethal, resulting in less than a 10%survival within 24 hours. Survival increased with lower flow rates.One hundred percent survival was achieved at five liter per minute or less, so five liters per minute was selected as the standard for the model. Just after being struck, flies gradually recovered their mobility within four minutes. Recovery for the shams was about a minute quicker.Post-impact, video-assisted movement tracking was used to measure locomotive function. During the two days after the impact, locomotion slowly returned to normal. This evidence for gradual recovery is in line with CTE recovery in humans.To evaluate long term effects, a repetitive traumatic brain injury protocol of five strikes over five days was applied. Twenty days post-treatment, the locomotion of surviving members in each group was compared and the treated group clearly walked less. The lifespan of the treated group was also substantially reduced, with a median at 26 days compared to 37 days for controls.After its development, this technique paves the way for researchers in the field of mild repetitive traumatic brain injury to explore pathogenic mechanisms in the classic animal model Drosophila melanogaster. While attempting this procedure, it is important to remember to shield the proboscis, thorax and abdomen from direct impact by the aerosol barrier.

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Research

JoVE Journal

Neuroscience

Novel Apparatus and Method for Drug Reinforcement

Animal models of reinforcement have proven to be useful for understanding the neurobiological mechanisms underlying drug addiction. Operant drug self-administration and conditioned place preference (CPP) procedures are expansively used in animal research to model various components of drug reinforcement, consumption, and addiction in humans. For this study, we used a novel approach to studying drug reinforcement in rats by combining traditional CPP and self-administration methodologies. We assembled an apparatus using two Med Associate operant chambers, sensory stimuli, and a Plexiglas-constructed neutral zone. These modifications allowed our experiments to encompass motivational aspects of drug intake through self-administration and drug-free assessment of drug/cue conditioning strength with the CPP test. In our experiments, rats self-administered cocaine (0.75 mg/kg/inj, i.v.) during either four (e.g., the "short-term") or eight (e.g., the "long-term") alternating-day sessions in an operant environment containing distinctive sensory cues (e.g., olfactory and visual). On the alternate days, in the other (differently-cued) operant environment, saline was available for self-infusion (0.1 ml, i.v.). Twenty-four hours after the last self-administration/cue-pairing session, a CPP test was conducted. Consistent with typical CPP findings, there was a significant preference for the chamber associated with cocaine self-administration. In addition, in animals undergoing the long-term experiment, a significant positive correlation between CPP magnitude and the number of cocaine-reinforced lever responses. In conclusion, this apparatus and approach is time and cost effective, can be used to examine a wide array of topics pertaining to drug abuse, and provides more flexibility in experimental design than CPP or self-administration methods alone.

Operant drug self-administration and conditioned place preference (CPP) procedures are expansively used in research to model various components of drug reinforcement, consumption, and addiction in humans. In this report, we combined traditional CPP and self-administration methods as a novel approach to studying drug reinforcement and addiction in rats.

Animal models of reinforcement have proven to be useful for understanding the neurobiological mechanisms underlying drug addiction.  Operant drug ...

Lateral Fluid Percussion: Model of Traumatic Brain Injury in Mice

Traumatic brain injury (TBI) research has attained renewed momentum due to the increasing awareness of head injuries, which result in morbidity and mortality. Based on the nature of primary injury following TBI, complex and heterogeneous secondary consequences result, which are followed by regenerative processes 1,2. Primary injury can be induced by a direct contusion to the brain from skull fracture or from shearing and stretching of tissue causing displacement of brain due to movement 3,4. The resulting hematomas and lacerations cause a vascular response 3,5, and the morphological and functional damage of the white matter leads to diffuse axonal injury 6-8. Additional secondary changes commonly seen in the brain are edema and increased intracranial pressure 9. Following TBI there are microscopic alterations in biochemical and physiological pathways involving the release of excitotoxic neurotransmitters, immune mediators and oxygen radicals 10-12, which ultimately result in long-term neurological disabilities 13,14. Thus choosing appropriate animal models of TBI that present similar cellular and molecular events in human and rodent TBI is critical for studying the mechanisms underlying injury and repair.
Various experimental models of TBI have been developed to reproduce aspects of TBI observed in humans, among them three specific models are widely adapted for rodents: fluid percussion, cortical impact and weight drop/impact acceleration 1. The fluid percussion device produces an injury through a craniectomy by applying a brief fluid pressure pulse on to the intact dura. The pulse is created by a pendulum striking the piston of a reservoir of fluid. The percussion produces brief displacement and deformation of neural tissue 1,15. Conversely, cortical impact injury delivers mechanical energy to the intact dura via a rigid impactor under pneumatic pressure 16,17. The weight drop/impact model is characterized by the fall of a rod with a specific mass on the closed skull 18. Among the TBI models, LFP is the most established and commonly used model to evaluate mixed focal and diffuse brain injury 19. It is reproducible and is standardized to allow for the manipulation of injury parameters. LFP recapitulates injuries observed in humans, thus rendering it clinically relevant, and allows for exploration of novel therapeutics for clinical translation 20.
We describe the detailed protocol to perform LFP procedure in mice. The injury inflicted is mild to moderate, with brain regions such as cortex, hippocampus and corpus callosum being most vulnerable. Hippocampal and motor learning tasks are explored following LFP.

Lateral fluid percussion (LFP), an established model of traumatic brain injury in mice, is demonstrated. LFP fulfills three major criteria for animal models: validity, reliability and clinical relevance. The procedure, consisting of surgical craniotomy, fixation of hub followed by induction of injury, resulting in focal and diffuse injuries, is described.

Traumatic brain injury (TBI) research has attained renewed momentum due to the increasing awareness of head injuries, which result in morbidity and ...

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.

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.

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

A Novel Method of Drug Administration to Multiple Zebrafish (Danio rerio) and the Quantification of Withdrawal

Anxiety testing in zebrafish is often studied in combination with the application of pharmacological substances. In these studies, fish are routinely netted and transported between home aquaria and dosing tanks. In order to enhance the ease of compound administration, a novel method for transferring fish between tanks for drug administration was developed. Inserts that are designed for spawning were used to transfer groups of fish into the drug solution, allowing accurate dosing of all fish in the group. This increases the precision and efficiency of dosing, which becomes very important in long schedules of repeated drug administration. We implemented this procedure for use in a study examining the behavior of zebrafish in the light/dark test after administering ethanol with differing 21 day schedules. In fish exposed to daily-moderate amounts of alcohol there was a significant difference in location preference after 2 days of withdrawal when compared to the control group. However, a significant difference in location preference in a group exposed to weekly-binge administration was not observed. 
This protocol can be generalized for use with all types of compounds that are water-soluble and may be used in any situation when the behavior of fish during or after long schedules of drug administration is being examined. The light/dark test is also a valuable method of assessing withdrawal-induced changes in anxiety.

A Novel Method of Drug Administration to Multiple Zebrafish Danio rerio and the Quantification of Withdrawal

A novel method for reducing variability when exposing fish to drugs is explained. Fish exposed to various patterns of ethanol exposure were found to have altered anxiety levels during withdrawal in a light/dark scototaxic assay.

Anxiety testing in zebrafish is often studied in combination with the application of pharmacological substances. In these studies, fish are routinely ...

Quantitative Analysis of Climbing Defects in a Drosophila Model of Neurodegenerative Disorders

Locomotive defects resulting from neurodegenerative disorders can be a late onset symptom of disease, following years of subclinical degeneration, and thus current therapeutic treatment strategies are not curative. Through the use of whole exome sequencing, an increasing number of genes have been identified to play a role in human locomotion. Despite identifying these genes, it is not known how these genes are crucial to normal locomotive functioning. Therefore, a reliable assay, which utilizes model organisms to elucidate the role of these genes in order to identify novel targets of therapeutic interest, is needed more than ever. We have designed a sensitized version of the negative geotaxis assay that allows for the detection of milder defects earlier and has the ability to evaluate these defects over time. The assay is performed in a glass graduated cylinder, which is sealed with a wax barrier film. By increasing the threshold distance to be climbed to 17.5 cm and increasing the experiment duration to 2 min&#160;we have observed a greater sensitivity in detecting mild mobility dysfunctions. The assay is cost effective and does not require extensive training to obtain highly reproducible results. This makes it an excellent technique for screening candidate drugs in Drosophila mutants with locomotion defects.

We present an optimized inexpensive and reliable negative geotaxis assay in Drosophila melanogaster as a model for neurodegenerative disorders. Being more sensitive to mild locomotor defects, this assay will help screen for potential genetic interactions and drug targets.

Locomotive defects resulting from neurodegenerative disorders can be a late onset symptom of disease, following years of subclinical degeneration, and ...

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 ...

Recording EEG in Freely Moving Neonatal Rats Using a Novel Method

EEG is a useful method to detect electrical activity in the brain. Moreover, it is a widely used diagnostic tool for various neurological conditions, such as epilepsy and neurodegenerative disorders. However, it is technically difficult to obtain EEG recordings in neonates as it requires specialized handling and great care. Here, we present a novel method to record EEG in neonatal rat pups (P8-P15). We designed a simple and reliable electrode using computer pin loci; it can be easily implanted into the skull of a rat pup to record high-quality EEG signals in the normal and epileptic brain. Pups were given an intraperitoneal (i.p.) injection of the neurotoxin kainic acid (KA) to induce epileptic seizures. The surgical implantation performed in this procedure is less expensive than other EEG procedures for neonates. This method allows one to record high-quality and stable EEG signals for more than 1 week. Furthermore, this procedure can also be applied to adult rats and mice to study epilepsy or other neurological disorders.

Here, we introduce a novel technique designed to record electroencephalography (EEG) in freely moving neonatal epileptic pups and describe its procedures, features, and applications. This method allows one to record EEG for more than 1 week.

EEG is a useful method to detect electrical activity in the brain. Moreover, it is a widely used diagnostic tool for various neurological conditions, such ...

Novel Assay for Cold Nociception in Drosophila Larvae

How organisms sense and respond to noxious temperatures is still poorly understood. Further, the mechanisms underlying sensitization of the sensory machinery, such as in patients experiencing peripheral neuropathy or injury-induced sensitization, are not well characterized. The genetically tractable Drosophila model has been used to study the cells and genes required for noxious heat detection, which has yielded multiple conserved genes of interest. Little is known however about the cells and receptors important for noxious cold sensing. Although, Drosophila does not survive prolonged exposure to cold temperatures (&#8804;10 &#186;C), and will avoid cool, preferring warmer temperatures in behavioral preference assays, how they sense and possibly avoid noxious cold stimuli has only recently been investigated.
Here we describe and characterize the first noxious cold (&#8804;10 &#186;C) behavioral assay in Drosophila. Using this tool and assay, we show an investigator how to qualitatively and quantitatively assess cold nociceptive behaviors. This can be done under normal/healthy culture conditions, or presumably in the context of disease, injury or sensitization. Further, this assay can be applied to larvae selected for desired genotypes, which might impact thermosensation, pain, or nociceptive sensitization. Given that pain is a highly conserved process, using this assay to further study&#160;thermal nociception will likely glean important understanding of pain processes in other species, including vertebrates.

Novel Assay for Cold Nociception in Drosophila Larvae

Here we demonstrate a novel assay to study cold nociception in Drosophila larvae. This assay utilizes a custom-built Peltier probe capable of applying a focal noxious cold stimulus and results in quantifiable cold-specific behaviors. This technique will allow further cellular and molecular dissection of cold nociception.

How organisms sense and respond to noxious temperatures is still poorly understood. Further, the mechanisms underlying sensitization of the sensory ...

A Novel In Vitro Model of Blast Traumatic Brain Injury

Traumatic brain injury is a leading cause of death and disability in military and civilian populations. Blast traumatic brain injury results from the detonation of explosive devices, however, the mechanisms that underlie the brain damage resulting from blast overpressure exposure are not entirely understood and are believed to be unique to this type of brain injury. Preclinical models are crucial tools that contribute to better understand blast-induced brain injury. A novel in vitro blast TBI model was developed using an open-ended shock tube to simulate real-life open-field blast waves modelled by the Friedlander waveform. C57BL/6N mouse organotypic hippocampal slice cultures were exposed to single shock waves and the development of injury was characterized up to 72 h using propidium iodide, a well-established fluorescent marker of cell damage that only penetrates cells with compromised cellular membranes. Propidium iodide fluorescence was significantly higher in the slices exposed to a blast wave when compared with sham slices throughout the duration of the protocol. The brain tissue injury is very reproducible and proportional to the peak overpressure of the shock wave applied.

A Novel In Vitro Model of Blast Traumatic Brain Injury

This paper describes a novel model of primary blast traumatic brain injury. A compressed-air driven shock tube is used to expose in vitro mouse hippocampal slice cultures to a single shock wave. This is a simple and rapid protocol generating a reproducible brain tissue injury with a high throughput.

Traumatic brain injury is a leading cause of death and disability in military and civilian populations. Blast traumatic brain injury results from the ...

Construction and Implementation of Carbon Fiber Microelectrode Arrays for Chronic and Acute In Vivo Recordings

Multichannel electrode arrays offer insight into the working brain and serve to elucidate neural processes at the single-cell and circuit levels. Development of these tools is crucial for understanding complex behaviors and cognition and for advancing clinical applications. However, it remains a challenge to densely record from cell populations stably and continuously over long time periods. Many popular electrodes, such as tetrodes and silicon arrays, feature large cross-diameters that produce damage upon insertion and elicit chronic reactive tissue responses associated with neuronal death, hindering the recording of stable, continuous neural activity. In addition, most wire bundles exhibit broad spacing between channels, precluding simultaneous recording from a large number of cells clustered in a small area. The carbon fiber microelectrode arrays described in this protocol offer an accessible solution to these concerns. The study provides a detailed method for fabricating carbon fiber microelectrode arrays that can be used for both acute and chronic recordings in vivo. The physical properties of these electrodes make them ideal for stable and continuous long-term recordings at high cell densities, enabling the researcher to make robust, unambiguous recordings from single units across months.

Construction and Implementation of Carbon Fiber Microelectrode Arrays for Chronic and Acute In Vivo Recordings

This protocol describes a procedure for constructing carbon fiber microelectrode arrays for chronic and acute in vivo electrophysiological recordings in mouse (Mus musculus) and ferret (Mustela putorius furo) from multiple brain regions. Each step, following the purchase of raw carbon fibers to microelectrode array implantation, is described in detail, with emphasis on microelectrode array construction.